Salvage, Teardown: DingTong DT-98 8W 403-470Mhz Handheld Transceiver

Imagine my surprise when stopping to catch the bus one day, I see a hand-held radio in the grass not far from the bus stop. I was in a hurry and had to leave, so I hopped on the bus and forgot about it.

The next day, I was catching the bus again, and the unit was still there. Figuring it was probably lost and unwanted, I examined the unit but was unable to determine to whom it belonged. It was dead, with no identifying markers on it. It was also fairly dinged up, as if it had case damage from being thrown out of a speeding car, and then possibly run over, flinging it up from the road into the grass.

No matter the case, it was a Chinese import radio, of the sort that ACMA looks scornfully on. So I suppose maybe it was a good thing the owner threw it out the window, otherwise they might be liable for a fine. But this does give me a chance to examine one, so I took it home and took it apart.

The Unit

The unit is a DingTong branded unit, of a most basic design similar to the BaoFeng BF-888S, possessing no LCD display whatsoever. The unit has a short whip antenna, with front speaker, mic and LED indicator. There is a belt clip on the rear with cradle charging contacts, and both sides show damage from skidding across the road.

The discarded unit had no volume control knob, presumably lost in the impact. Like many Chinese import radios, the polarity of the SMA connector is reversed – male on the unit and female on the antenna. The whip is marked for 400-470Mhz operation, gain is unknown but not presumed to be high.

The left side has the PTT, and two other buttons, presumably monitor and (possibly) power level/light/something else.

 

The right side has a pair of jacks used for a remote headset/earpiece.

Removing the belt-clip and battery shows that it is a DingTong DT-98, claiming 8W of power output and a frequency range of 403-470Mhz. The URL listed does not lead to the manufacturers’ site (instead, to some advertising).

On Trial

The unit was practically dead on arrival. This is not unexpected, as it was left powered up on Channel 16 since its abandonment. As a result, to see what it could do, I had to give the battery a little charge first. A quick trip to my benchtop supply and that was enough to get it started.

As part of being a low-cost no-frills radio, it has no LCD at all. As a result, it relies on a rotary selector dial with markings. But as this can get hard to read with 16 positions in all, the unit also has voice synthesis which announces the channel numbers in mandarin (which sounds like this). The unit pops loudly at every frequency change, so it’s probably not very good with an earpiece.

I was interested to know who might have used the unit and how they were using it, so I hooked the antenna output through some adapters to a dummy load to give it a quick test on all 16 programmed channels. A small amount of leakage from the dummy load would ensure that nobody would be adversely interfered with, along with being short 2-second burst transmissions. The leakage was sufficient for my old radio scanner in frequency counter mode to register the frequencies.

These were (in Mhz):

1. 430.025
2. 431.025
3. 432.025
4. 433.025
5. 434.025
6. 435.025
7. 436.025
8. 437.025
9. 438.025
10. 439.025
11. 439.125
12. 439.225
13. 439.325
14. 439.425
15. 439.525
16. 439.625

A quick check of the frequencies seems to show a pattern which may be used for factory alignment, so it seems this radio was never programmed. This seems to be a radio sold by people who may not know much about radios as “walkie talkies” on the premise of “select-a-channel and it works”. But unfortunately, the frequencies that they come programmed with can cause trouble – they could overlap with licensed users and cause interference.

For one, the frequencies chosen do not seem to align with any known “CB style” service. It’s not:

  • Australian UHF CB (476-477Mhz)
  • “Public radio service” in China (409Mhz)
  • SLPR (420-422Mhz) as used in Japan
  • UHF-FM (448-449Mhz) as used in South Korea
  • FRS/GMRS (462/467Mhz) as used in the USA
  • PMR446 (446Mhz) as used in Europe.

Instead, they are in the 70cm Amateur Radio band (430Mhz – 450Mhz) with some overlap with the 433-434Mhz LIPD devices. Based on an ACMA Radcomms database search, and a look in the WIA bandplans, the channels are used by the following in the Sydney/NSW area:

  1. Hornsby and District Amateur Radio Club Repeater Input (VK2RHT)
  2. Amateur Repeater Input (although none in NSW at this time)
  3. Earth-Moon-Earth Frequency Band
  4. Hunter Radio Group Repeater Input (VK2RNC)
  5. Goulburn & Southern Highlands Amateur Radio Society Repeater Input (VK2RHR)
  6. Amateur Satellite Band
  7. Amateur Satellite Band
  8. Amateur Satellite Band
  9. Goulburn & Southern Highlands Amateur Radio Society Repeater Output (VK2RHR)
  10. Amateur Simplex
  11. Hornsby Packet Radio Repeater (VK2RPH)
  12. Amateur Simplex
  13. Hellenic Amateur Radio Association of Australia Repeater Output (VK2RSV)
  14. Chifley Amateur Radio Club Repeater Input (VK2RCZ)
  15. WICEN Repeater Output (VK2RAV)
  16. WICEN Repeater Output (VK2RFI)

Looking at the channels, a good number of them are over repeater inputs which could cause them to key-up and rebroadcast the signal further than expected. Without the offset programmed into the radio, the user would not be aware that they’re perhaps being rebroadcasted over a wide range, and the people trying to “tell them off” would not be heard by the user. Of course, this is quite a notable issue with amateur radio repeaters, so many have CTCSS tone squelching on their inputs. While this stops them from being rebroadcast, their transmissions will still cause blocking and interference of legitimate transmissions and potentially an annoying heterodyne squeal.

Some of the channels are over repeater outputs. This is probably not as bad comparatively speaking, but will mean that they may hear some signals they’re not expecting to hear, and their transmissions may jam some legitimate users from hearing the output of the repeater (depending on the relative strength of the signal). With 8W to play with, this radio probably will put out a stronger signal than the average hand-held, but I suppose the antenna’s probably not too great either.

The remaining channels are a little more complex. Channel 3 in the Earth-Moon-Earth frequency band and Channels 6-8 in the Amateur Satellite Band are specially reserved regions of the bandplan as these services to space can require working very weak signals, and thus having the minimum of noise and interference is necessary. Sending out a strong terrestrial signal, when we’re trying to receive a space-borne signal which is very weak, is surely going to ruin the day. There is a potential that it could jam a satellite’s uplink frequency as well, denying service to a wide-footprint simultaneously (as the satellite has a large field of view which could span across states/countries).

Of all the channels, Channel 10 and 12 are probably the most innocuous of the bunch, as they are intended for simplex working. However, one must remember that to use the amateur radio bands, they must be appropriately licensed, pay the fees and identify by callsign at the required intervals.

At least the unit did not broadcast on the government band (roughly 410 to 430Mhz, using APCO25) or it could endanger lives by jamming first-line responder’s digital radios in an inconsistent and intermittent way (as analog signals jamming a digital transmission would not be decoded by the intended radio, and APCO25 trunking may cycle the frequencies from transmission to transmission, so only some transmissions are garbled). This probably explains the strong stance ACMA has against “Chinese import” radios, while understandable to some degree, is also confusing for some radio amateurs who are fully aware of the rules, have the tools to program radios appropriately and use them responsibly, and see that the radios are otherwise not causing significant issues in terms of spurious emissions.

I did take a look around for some programming software, but I couldn’t find any. The manufacturer’s website just leads to some advertising, a search online showed absolutely nothing. As a guess, it could be based upon the Baofeng or Woxun models, so I grabbed a standard Baofeng style programming lead and cycled through every radio supported by CHIP, but to no avail. The radio would not be read-out when it was powered on, or powered off.

As a result, given the frequencies it was already on and the damage it had suffered, I decided to take it apart and dispose of it.

Teardown

To take it apart, two Torx screws at the bottom need to be undone, and then the collars which hold the pots and SMA socket in place need to be undone and removed. Then, the whole rear assembly pops out, bottom first, similar to some Motorola radios.

We can see that all costs have been optimised, and the speaker (of a 16 ohm 1W rating) is glued into the case and soldered to the board. To take it apart more gracefully, I got out my soldering iron and desoldered the wires. The electret microphone is covered with a rubber boot which insulates against feedback, and this is “pressed into” by a channel in the front case – this has eaten into the rubber and damaged it. Apparently this radio was inspected by “QC04”.

The silkscreening is marked GLW-1, with a PCB date of Week 13 of 2017, making this a very recent unit. Components on this side include the electret microphone for use hand-held (although crushed somewhat by the case), a JRC NJM2904 dual-opamp and an RDA5802N FM stereo radio tuner. There is also a trimmer, which is probably used to align the frequency, conveniently placed on this side.

To remove the PCB to examine the other side, a large number of screws have to be undone, but also, the centre pin of the SMA jack needs to be desoldered to let the board come free of the metal casing.

The casing itself seems to be cast with channels and areas acting as both heatsink and shielding. Some of the work to do with the casting appears manually done – note the “B” marked into the mould. The rear battery clip mechanism is attached to the plastic at the top by two screws.

This is merely a plastic hook that is free to slide, with a spring providing the force to “return” it to the home position. It pushes against the channel cut into the metal casing.

The bulk of the components are on the other side, but surprisingly, the number of components is less than I expected, because of the use of mixed-signal IC technology. One of the transistors had thermal paste and a thermal pad to allow for heat conduction to the metal rear.

The bottom left corner appears to be the frequency reference crystal and modulator/demodulator section. This makes sense as the crystal oscillator is situated there, along with the tuning adjustment pot on the rear. The main chip is marked AT1846S and is an integrated single-chip transceiver based on DSP techniques in a CMOS technology chip. It has an analog IQ baseband interface, and supports a number of frequency bands and features such as AFC, AGC, emphasis/de-emphasis, RSSI, VOX, SQ, CTCSS/DCS encode/decode, DTMF, volume control and sleep modes. It has 8 GPIOs and an I2C control interface.

As a result, it seems that the control is taken care of by the left-top portion of the image, with a HM AP88F389 (unknown) microcontroller, with some ATMEL 24C08AN EEPROM for configuration data. The chip marked VOICE-D is probably the voice synthesis chip. I did try desoldering the EEPROM to read-out on my programmer, but I must have damaged it somehow as it was a dead short. There is also a MC34119L audio amplifier IC to drive the speaker.

The lower half of the board, towards the right, appears to be the RF front end filters and amplifier, hence the transistor with the thermal paste. This makes sense as it’s next to the transceiver chip, which only has an output of 8dBm (or about 6.3mW) and the radio claims an 8W output.

Testing the Battery

As I have taken the whole unit apart, I decided to take the battery apart too. Its rating is a very curious 7.4V 3000mAh, which seems too unrealistic for the size.

I was interested to see whether they used Li-Ion or Li-Poly cells as well. After all the physical trauma they’ve been through, I don’t think I want to keep it around for too long, just in case they suffer some “delayed” spontaneous combustion.

The cell is glued together at the seams, and it was a destructive process to pry it apart. Unexpectedly, it seems that the protection board is at the bottom of the battery, so there are long tabs that connect the terminals at the rear of the battery to this board. Because of their close proximity to each other, one wrong move and you have a short circuit. The construction also needs a soldering iron to deconstruct neatly.

A closer look at the bottom shows that the rear “T” thermistor contact on the outside is an absolute lie. There is no pack thermal monitoring, and thus the charger cradle itself might not even have circuitry that expects to use it. They probably included it just to “look safe”.

The end PCB is quite simple with two intermediate series contacts marked I-I on the left, and the battery pack + and – marked B+ and B- on the right. The charger input comes in through the Z+ and Z- terminals, and the power to the radio is supplied through the P+ and P- terminals.

The underside of the board is noticeably bare. It’s marked ChaoNian 885EF, and has just a single 8205A transistor package and a 6-pin IC. I wonder if this is a protection IC only, or a balancing IC only, or both. Regardless, it is lacking any form of secondary safeties, making it quite a questionable design.

Each cell is a prismatic Li-Ion cell with a thin metal shell. Terminals are spot-welded to the same end with cardboard insulation and blue shrink-wrap around the cells. Green insulating paper is wrapped around the assembly.

Each cell is marked KY483760 201703YX. I presume this means the cells were made in March 2017 by a company with the initials YX or KY, although more information could not be found.

For testing, I topped off each cell individually on my Keysight E36103A bench-top supply to 4.2V (CV) at 300mA (CC) until the current fell to 50mA. Then the discharge was run at 300mA (CC) until 2.8V on the B&K Precision Model 8600 DC Electronic Load.

As we can see, it seems that each of the cells tested at about 1300mAh. As a result, each of the cells being about 1500mAh is a possibility, as often the cells “settle” to between 80-90% of the rated capacity for the majority of their life. However, the claim that it is 7.4V 3000mAh is just patently wrong – when the cells are used in series, the voltages add but the capacity does not. As a result, it’s truly a 7.4V 1305mAh battery as tested.

Conclusion

The DingTong DT-98 seems to be quite an “anonymous” Chinese import radio. This unit seems to be a rather recent unit judging from the date codes, and didn’t live a long life before it was “discarded” by the roadside. Despite this, information about the unit appears to be sparse and the manufacturer’s website is non-existent. I could not find any compatible programming software for it either.

While I didn’t test it for its spectral output or audio quality, I did see that the unit appeared to be unprogrammed and using a set of frequencies which resided in the 70cm amateur band. While this is not the worst outcome possible, it still poses a decent potential for interfering with amateur radio users. The general public and unknowing sellers who just buy and sell the units thinking they are walkie-talkies will be operating unlicensed and liable to a fine as well.

The radio uses the “latest” integrated DSP-based circuitry, and as a result, is much less complex than I expected. There is not much to tweak or align, or even repair. The performance might well leave something to be desired – judging from the rabid arguments that have gone on in regards to other Chinese import radios that have been posted online.

The battery is, in true Chinese fashion, overstated for capacity and relatively “lightweight” on safety features. While I don’t have the charger, I would suspect the safety of the charger may well be questionable as well. The longevity of either is not something I can accurately judge, but at a guess, I’d have to say it’s probably somewhat limited.

As a result, I’d have to say if you don’t know what you’re doing, stay away from these Chinese import radios. You don’t want to be responsible for jamming other paid license users who are conducting business, doing research, or possibly even saving lives (e.g. fire brigade, ambulance). Doing so can come with severe penalties if caught, and is downright irresponsible.

If you must play with the radios, educate yourself about the frequencies you’re allowed to use and then program the units accordingly. Don’t just use them out of the box.

While ACMA is very strict about what units comply with CB, of which none of these Chinese imports generally do, they’re a little less restrictive about amateur radio as the point of it is to research and experiment. That being said, owing to the open-ness of these radios for band-extension and almost any-frequency operation, I can understand their objection to these radios including some blanket statements which make it seem like it’s illegal to even possess them.

That being said, I don’t agree they should be illegal. As long as they’re being used responsibly (on frequency with no significant spurious emissions, transmitting at or below the legal power, following operation protocol), I don’t see what harm they would cause. That being said, it seems unlikely that ACMA will let anyone other than Standard/Advanced radio amateurs will be permitted to use them (even if they are allowed, which is slightly unclear at this stage). A Foundation call person like myself is limited to commercially produced amateur radio transceivers … so unfortunately, the people who might need low-cost handhelds the most are not allowed to use them.

I suppose that’s probably a good reason to take the test and upgrade my license … but at least, for now, the scourge of this DingTong DT-98 has come to an end.

Posted in Electronics, Radio | Tagged , , , , | 5 Comments

Opinion: Transport for NSW 26 Nov 2017 Timetable Changes

It’s been just over two full weeks since Transport for New South Wales (TfNSW) introduced a new timetable. The changes are claimed to increase capacity, adding extra services across the network across all modes. These changes were signalled by bright pink signage at most stations, as the change is considered a major one. The key benefits for the system as advertised make for quite positive reading, although as a regular public-transport user, I’d have to say that nothing comes for free. After travelling around various places over the past two weeks, this is what I think about the new timetables.

Trains

From my perspective, the biggest overhaul is in the train network. Aside from getting a new timetable, the route map and (logical) lines have changed, even though the physical tracks remain much the same as they were just prior to the new timetable.

Before the reconfiguration, the map looked like this. After the reconfiguration, the map now looks like this. Key changes to the network include:

  • Allocation of names to each of the ends of the lines – e.g. instead of being solely T1, it is now T1 Western, T1 Richmond, T1 Epping, T1 Northern and T1 North Shore, which should help commuters find their direction on the “multi-headed” lines.
  • Change of the T5 Cumberland line at both ends – now starts from Richmond and ends at Leppington. Users in-between Riverstone to Richmond and Leppington to Edmonson Park gain services on T5, whereas users from Macquarie Fields to Campbelltown lose service on T5.
  • Loss of former T2 line towards the City via Granville services for Macquarie Fields to Macarthur. Now solely served by T8 Airport & South Line.
  • T2 Inner West now has a “spur” to Parramatta, and eliminates Granville as an interchange point between south and western lines. This promotes Parramatta as the major interchange, at the cost of Granville.
  • T2 Inner West services take on the role once afforded by slower “shuttle” services between Ashfield and the city, and city to Homebush which were all-stops. As a result, T2 service appears to be slower than previously.
  • Clyde now becomes an interchange point for Leppington and Inner West T2 services, allowing for smoother transfers from the (rather anaemic) T6 Carlingford line.
  • The new Sydney Metro City and Southwest stations of Chatswood, Crows Nest, Victoria Cross, Barangaroo, Pitt St., Waterloo are now depicted.

The changes to the network are predominantly logical changes, as the physical rails which they run on have not really changed all that much since the completion of the last project which saw turn-backs installed at Granville, a new platform at Lidcombe and Homebush, etc. Instead, these changes actually make better use of the network by reducing cross-overs between lines (although they cannot be eliminated entirely).

To illustrate this point, at Parramatta, platform 2 and 4 were for westbound services where 2 was predominantly the faster Blue Mountains Line trains and Emu Plains trains, and 4 was for the Richmond Line and remainder of the slower services. Platforms 1 and 3 were formerly for citybound services, again with 1 hosting the faster trains and 3 hosting the slower trains.

Because of this arrangement, the wye between Granville, Harris Park and Merrylands worked quite hard to get the trains where they needed to go. Platform 1 and 2 were relatively straightforward “through” to the city/west line services that needed few switches. However, Platform 3 and 4 were switched frequently as trains citybound on Platform 3 crossed over the Platform 2 tracks, and Cumberland Line services crossed over and intermingled with the slower Western and Richmond line services which also needed to cross the Platform 3 tracks on occasion.

Now, the platform reallocations have occurred, Platform 1 hosts all city-bound services, mostly of the express variety. Platform 2 hosts the faster west-bound services, with Platform 3 hosting the slower west-bound services. Platform 4 hosts the Cumberland line services (as it’s on that side of the wye) and the slow all-stops T2 Inner West services. This rearrangement makes commuting simpler, as westbound services are on two sides of the same platform and also reduces the amount of crossing-over that happens.

The up-side to all of this is that it seems that a firm direction is set – Parramatta has now won the war and is now the “Central of the west”. It has a strong bus interchange with routes to many areas, and services three lines along with ferry services as well. The downside is that Granville has lost, and as a result, what once was a bustling interchange that saw traffic from both western and south lines is much less important. This was a long while in the making – the renovation of the bus stands and incorporation of a new carpark in the old bus stand area was a sign that routes were no longer using Granville as an interchange. The removal of the high-speed western services from Granville at the last timetable made things a little worse. Now, the nail in the coffin is that Granville sees even fewer fast western line services, instead mostly being served by slower Leppington and Inner West T2 line services, half of which are all-stops during off-peak periods, increasing travel times immensely.

This also affects Auburn and Lidcombe as well – Auburn sees a reduction in trains as well, with the most recent newsletter from our local MP claiming a 50% increase in travel times. Lidcombe is much the same. It seems that the “central-west” area is losing out.

But this seems to be in order to balance the system and improve commute times for those living in the outer west areas. Faster express trains from Parramatta claim to be every 3 minutes in peak periods, with some very enticing stopping patterns such as Strathfield, Redfern, Central. This would be very much welcome for those living further out.

However, as I’ve recently had to commute from Granville in off-peak, sitting on a train that stops Clyde, Auburn, Lidcombe, Flemington, Homebush, Strathfield, Burwood, Croydon, Ashfield, Summer Hill, Lewisham, Petersham, Stanmore, Newtown, Macdonaldtown, Redfern, Central just to get to the bus to get to university is rather annoying. The train trip would have taken about 25 minutes with a fast western line service, but instead takes 41 minutes with an all-stop service. The faster T2 Leppington line service does the same distance in 33 minutes, however, as service intervals vary from 6 – 15 minutes, waiting for the faster service will save you no time at all. At least, the all-stops tends to have seats as it starts from Parramatta … but you might be sitting in a “classic”.

No offence, I actually really like the old S-set Comeng trains. However, I’d have to say that some of the other commuters won’t – on a slow service on a hot summers day.

Buses

There are more buses and more services across the network, along with a new B-Line service as stated on the Bus mode page. However, under the key benefits, there is a puzzling second point – “brand frequent” – what’s that supposed to mean? I’m not quite sure.

Regardless, while that is surely welcomed by the areas seeing extra buses, I was not one to benefit. In fact, the two routes that pass in front of my doorstep saw absolutely no timetable changes that I could discern. As a result, the primary service remains just as poor as it was before – hourly to half-hourly intervals, restricted operating times (not after 6:30pm), no buses on Sunday. The other route remains as bad as it was too – hourly service through restricted times, and no buses on Saturday or Sunday. The route that is a 10-minute walk away from the house also saw no changes I could discern, remaining fairly well serviced in comparison as a Metrobus service. However, that route used to pass in front of my doorstep prior to the Metrobus re-routing, so it’s unfortunate.

However, the biggest irk I have with the buses is that they don’t seem to match the whole train transport scheme. I can understand not leaving existing bus users in the lurch, especially the large elderly population in the area, however, the buses remain routed in the same ways they were. As a result, the buses in my area connect to Auburn and Granville, meaning they make poorer connections to the trains owing to the new paradigm which shifts the primary interchange out to Parramatta. Trips take much longer, as the trains are both less frequent and make more stops.

Instead, my best bet is now to make a 10-minute walk to the Metrobus, and catch it an extra 10-minutes further out to Parramatta so that I can benefit from the express services at Parramatta (which although faster, also has to cover slightly more distance, so it’s no big win on train-commute time). Each way is an extra time investment of about 20 minutes or more depending on how well-timed the connections are. This is a little better than copping the slow-service to a smaller station (Auburn) and attempting to make a connection there, as the bus intervals are already long and it could become a lose-lose situation where the connection times are poor.

As a result, I can see a few problems arising – routes which presently exist and are relied upon may not see the level of patronage that they previously had because their “ongoing” connection prospects have become poor. This may cause those routes to further deteriorate in the future in regards to service intervals (or whether they even exist). Other routes to more favourable interchange points are instead becoming oversaturated and crowded, as commuters shift their habits to more time-efficient routes.

The biggest news, I suppose, is the introduction of B-Line services to the Northern Beaches. This does help the public-transport deficient area, however, I suspect the vast majority have long preferred to drive (being an affluent area) and the congestion on the roads that already exists is unlikely to be alleviated by the B-Line buses sufficiently. After all, it seems that it will be a big spend just to cut travel times by six minutes – if that.

Ferry

I don’t really use the ferries, so I can’t comment on the situation. However, that being said, I did venture around the new Barangaroo Wharf which looks pretty nice compared to the Kings Street Wharf nearby. From the mode page, there are a few lost services to some wharves.

Light Rail

The light rail has seen some additional services added back in August, however, not much has changed. This is not surprising, as the network hasn’t exactly changed yet and the system operates “in isolation”.

The next major change may well be when the new Light Rail line to Randwick opens in 2019, although as both systems are incompatible and run “in isolation”, there is likely to be little impact with the exception of the choice of who operates both systems (as a new private operator will be chosen to operate both systems once it becomes operational).

Other Bits and Nostalgia

Of course, where there’s change, there’s a little bit of me that pines for the old days. I miss not seeing and hearing the old paper ticket machines (“ka-cheek … clunk, clunk, clunk” goes the dot-matrix print head and change-hopper), or seeing an attendant at the ticket window since Opal has come about. Opal has been fairly good to me nowadays – it seems that things going wrong are much less frequent than they were at the beginning, although the system is still limited in capabilities and clunky-slow at times.

Speaking of which, I came across this envelope and enclosed card from STA.

This was from my undergraduate days, when my TravelPass Yellow Concession was invalidated by a green AES Prodata “dipper” machine. I was trying to put my ticket in, but felt an obstruction. I reported it to the attendant as someone may have lost a ticket in the machine, but instead, the attendant just forced my fresh ticket in … and the machine faulted the ticket. As a result, I lost out that day and couldn’t use my fresh TravelPass, and instead had to fill in a form and pay postage to mail my faulted ticket back. A few days later, they mailed a fresh ticket back to replace it – but I was not happy.

The network map that most resonates with me is this map from 2003 and maybe even the version before it, prior to the introduction of “curves” on the map and the Airport and Cumberland lines, but I can’t find it anywhere online. It’s fascinating to think how far we have moved from this in the (almost) 15 years since:

  • Parramatta was supposed to “save” the Carlingford line, join up to Epping, and the rail link was to run to St Leonards. That never happened, and the Carlingford line remains as anaemic as it was back then.
  • Olympic Park was depicted as a loop, capable of being fed from either side, so catching a train to it can be achieved from Strathfield or Lidcombe. Now it tends to operate shuttle-only with some exception for major events.
  • The Sefton, Regents Park and Birrong wye was used to its full extent. Services from Sefton went both via Regents Park and Bankstown into the city, offering twice as much choice and easier connections to the west/south. Now, the City via Regents Park services are long gone and the stretch from Liverpool through to Sefton is routed through Birrong and only there can the Regents Park leg be reached, terminating at the new Platform 5 at Lidcombe.
  • Glenfield through Campbelltown had choices to run on Cumberland, Airport/East Hills or via Granville.
  • The Northern Line was a “thing”, so getting to Cheltenham to Normanhurst is much easier than the current network makes it, especially when coming from the west and not intending to travel through the city to the North Shore. (As that would entail changing at Strathfield, then at Epping).

The physical lines have had some work done to implement the rail clearways program, but for the most part, the changes have happened on the “logical” side of the network – i.e. the runs the trains make over the rails, the stopping patterns, the timetables, the maps depicting the services.

Of course, nowadays, we do see a lot fewer S-sets, K-sets and C-sets which I feel is a little sad. As much as they are “hated”, especially the non-air-conditioned S-sets, they do come from an era where Australia’s engineering and industry were celebrated as being innovative and class-leading. The names Comeng and A Goninan & Co. come to mind. The new Waratahs that replace them are more comfortable, but they do come mostly from China and are starting to show some strange faults (e.g. blue LED panels, suggesting significant overdrive and failure in current regulators).

While looking them up, I came across several promotional videos on YouTube which I felt were very nostalgic and worth sharing:

It’s quite amazing to look back 35 years – the commercials really make public transport seem “advanced” for its time.

Conclusion

I suppose with every change, there’s going to be some things lost and some things gained. Unfortunately, it doesn’t quite work out that well for me meaning that it takes longer to get to the city and back, but in return, it should help improve the reliability of the service and benefit those living further out. I suppose we can’t have it all, but at least, the buses and trains are still here and I’m thankful for that.

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Teardown: Philips BDP2180/79 3D Blu-ray Player with Stuck Tray

Around three or four years ago, coincident with my purchase of a 3D TV, I decided to buy a Blu-ray player. I decided to opt for a 3D capable unit, so as to have something to watch on the new TV. At the time, there were a few units, but the Philips BDP2180/79 was the cheapest at AU$89, which was pretty much the same price as most regular Blu-ray players.

Since the initial first few weeks, the unit’s not seen much action as watching things on a TV (centrally located) has fallen out of favour to watching video on a personal device (be it a phone, tablet or computer) and optical discs have also fallen out of favour compared to streaming.

I decided to try and watch something just yesterday, and to my annoyance, the tray would not eject. It would try to eject, making a half-clunk before stalling, timing out, and clunking again. This is a fairly common issue with almost all tray-loading optical drives, so I decided to use the opportunity to show the insides of the player as well as the components that make up the tray-load mechanism.

The Player

The player is a very compact unit, rather unassuming, light and flimsy but with a decent remote control that has “clicky” buttons. The unit has a USB port for playing files from as well as the optical drive.

As part of the cost reduction, it features only HDMI output, with coaxial for audio and LAN for data (including network media play, firmware upgrade).

The model number sticker with region coding is adhered to the underside, which is a little different.

Under the Hood

The unit is extremely cost-minimised and as a result, it only has two black screws to hold the outer lid on.

Under this lid, we see that the optical drive assembly takes up most of the space, and it’s a “bare bones” plastic unit with some of the drive electronics integrated into the smaller green PCB that contains the rest of the brains (i.e. SoC, RAM, Flash, etc). The brown board in front is the power supply board.

Removing the drive in this state requires removing the three ribbons that connect the drive to the green PCB, and undoing the two silver screws near the rear. As the drive’s front fascia plate is still attached and the tray would not open, the front of the unit has to be removed too.

To do this, one silver screw has to be removed from near the power supply board.

Then, three clips on the fascia have to be unclipped. Then the fascia will slide slightly forward.

Remove the two cables from the power supply board, and the whole unit should now break free of the main body.

It’s rather unwieldy to work with this assembly like this, so we must eject the tray and remove the front fascia plate.

This can be done by sliding the drive’s plastic mechanism responsible for the position of the spindle and laser sled towards the right with a thin screwdriver.

The tray will pop out slightly, then you can slide the tray out and clip off the fascia by pushing it upward relative to the tray.

Closer Look at the Drive

I decided to do my best to take it all apart and put it back together again so I can show what goes on in the drive. To do that, I removed two silver screws and the cross-arm that sits over the spindle area. Then, I slid the tray out completely by pressing the two side retention tabs to let the tray move all the way out.

As a result, you are now looking at the base of the drive – the two lasers each with their own lenses on the sled and the spindle in the middle, with the loading mechanism on the right of that. A white piece of plastic slides up and down (in the image) which controls the tilt of the sled and spindle – at one end it pushes it upward so that it “clamps” onto the disc with the cross-arm that was on the top. The cross-arm contains a metal piece inside some plastic, whereas the spindle contains a magnet, thus by magnetic attraction, the disc is secured to the spindle.

The slits in the white plastic allow for corresponding pegs in the black tilting platform to push it up into the “clamped” position, or down in the “retracted” position for eject/load. This piece is timed by two mechanisms – towards the end, the teeth on the right are engaged with the white cog to provide the final lock/unlock movement.

While the tray is loading or unloading, a channel inside the tray grabs onto the peg on the left of the piece, to stop it from engaging with the white cog until the tray is just about closed. When reassembling the drive, ensure the peg is aligned to the channel, else the tray cannot close.

You will need to use some finger pressure to do this.

The whole opening and closing procedure is powered by an electric motor. This drives a rubber belt, which drives the black cog, which then drives the white cog.

The logic which drives this whole mechanism requires on this white position sensor, which sits in the channel and gets deflected left or right to indicate fully-clamped or fully-released. Ensure the peg is within the limits when reassembling, or else the mechanism will not work.

Once everything in the loading mechanism is taken out, there aren’t that many parts to worry about. The main reason for problems in the mechanism are old dried out lubrication which results in stickiness or lack of lubrication and a stretched or worn belt along with slippery rollers. A stretched belt will slip earlier, thus not transferring enough torque to the mechanism to overcome the friction to “break apart” the spindle-and-metal-plate connection when it comes to ejecting. This is why such drives often have a symptom where they can always eject when a disc is in the drive, but become almost impossible to open when empty. The disc increases the separation between the spindle magnet and the plastic-and-metal-plate clamp, thus reducing the force required to lower the spindle-and-sled assembly. Almost all tray load mechanisms share the same principles, although PC drives are a little more tricky to disassemble as they must be extracted from their shell first by opening up the bottom PCB side first.

Some other drives avoid this failure mode by ensuring the motor is geared directly to the loading mechanism without a belt, however, these tend to be noisier. When these get stuck, it’s almost inevitably due to poor lubrication.

As I had no spare belt, and had nothing to measure it with to hand, I decided just to clean off all the lubrication and reapply some bike chain oil to all gears and running areas (although silicone grease is probably the best option). Do not get any lubricant on the rubber belt or you will regret it dearly – it will make it almost impossible to get working.

Reassembly and Test

When reassembling, a shortcut can be taken and the drive can be mounted into the frame without the fascia panel.

Once the whole unit is reassembled, eject the tray and then clip on the fascia panel.

Ultimately, my attempted fix without replacing the belt was only partially satisfactory. It’s increased the eject rate from virtually never to about 75% of the time. But it’s symptomatic of a loosening/slipping/stretched belt, and it looks like it will need to be replaced to restore full function. There are a few “generic” replacement belts on eBay, but it’s hard to know if it’s going to really be any better.

An Obvious Shortcut that I Missed

If you look closely at the bottom of the unit, there is a slot which matches up with a slot on the frame of the drive. This allows the white plastic bar to be moved from the outside, and is a form of emergency eject. As I am more used to the pinhole eject type, I totally missed that, and it would have made things a lot easier if I had noticed it. Unfortunately, not even the manual seems to say anything about it – but stick a thin screwdriver into the hole, and slide to the side and the tray will unlock and eject slightly.

If I were to disassemble the drive again, I would use this to prop out the tray, unclip the fascia panel from the tray, thus allowing me to remove the drive from inside the unit without needing to remove the whole front face of the player.

But even barring that, in case of desperation, you can just hit the eject button, wait until it gets “stuck” and give it an additional help through this slot. This can allow the tray to eject, although the “time-out” mechanism may try to retract the tray immediately, so you have to hit the eject button again in quick order to hold it open (or just force the tray to remain open).

Conclusion

It seems to be an unfortunate ailment for many motorized tray-loading drives that their trays get stuck. The reason boils down to poor lubrication and worn/stretched belts. It’s because of this that I had the chance to show the insides of the Philips BDP2180/79 3D Blu-ray player and take apart the loading mechanism of the drive to demonstrate its parts. I missed the emergency ejection slot mechanism when taking it apart – it would have been simpler if I had known, but this wasn’t even documented in the manual! While the “simple” lubrication didn’t quite fix the issue, it didn’t do any harm, and in time I might find myself back in there to replace the belt and fix it for good.

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