Review, Teardown: Crest USB 2.0 All in 1 Mini Card Reader (CZUSBCR)

This particular review and teardown is a little different. In fact, this card reader was not one that I had purchased, since I normally swear by my Transcend RDF8‘s as being a decent performing, reliable and compatible reader at a good price. Instead, this one was purchased by a family member on sale at a local supermarket for about $10.


This unit comes in a “customer frustration guaranteed” heat-sealed plastic bubble package. It is branded “Crest”, an Australian AV accessories brand that mostly imports, rebadges and resells products of varying quality. This unit claims to support 40+ formats (although they will probably count every variation of every card format as a different one). Really, in modern times, the only formats that count are (micro/regular) SD(SC/HC/XC) and CF.

Having had problems with random-brand card readers in the past, I normally don’t just accept any reader for use without first doing some extensive testing. As it turns out, I was at my aunt’s place when we were trying to get a few cards read/written and the reader was being uncooperative, dropping out every few megabytes. I pinched the USB connectors and pulled them out and plugged them in again but couldn’t get it to work reliably with the Sandisk “standard” Class 4 microSDHC 32Gb card in use. As a result, I ended up taking the reader home for some more thorough diagnosis and testing.

A Closer Look

2016092817048665 2016092817048667

The unit is finished in a soft-touch plastic which likes to attract fingerprints. The unit features slots on the long sides, with one side having a full-size SD, xD, microSD, M2 and memory stick. The other side is occupied by CF alone. It seems no compatibility for the old SmartMedia (SM) cards is allowed for.


On another side, a USB miniB connection is used to the host upstream. The connector is a little on the stiff side, requiring a good push to get it to seat properly. The plastic moulding has very visible seam lines around the connector. There is a window on the top panel for the activity LED.


The cable supplied is awfully thin, and uses 28AWG for data and power connections. This could result in excessive voltage drop if the USB port is a little marginal, and depending on whether the cable has shielding, it could be a problem in harsh RF environments.


The reader shells are secured together by moulded push-pins and tabs, separating into three pieces. We can see the PCB is relatively compact, and the slots are mostly plastic-body slots with the exception of microSD.


Flipping the unit over, it seems there may have been a provision for a different type of slot with SmartMedia support with the footprint just behind where the SD slot is. The chipset is not visible, as the unit is constructed using chip-on-board “gob top” construction as a cost saving measure. The external components used are very few – an LED, a pair of resistors, three small capacitors and a crystal. The crystal layout is also somewhat odd, being at the extreme far side of the board compared to the location of the chip. This is because its through-hole nature requires an area of unobstructed board on the other side – the CF slot is in the way. They could have opted to put it near the USB connector, but then the traces would have to wrap around existing traces in an inelegant way.

fnk-device-installfnk-pidvidThe device installs as an FNK TECH USB CARD READER.

The VID is 3207 and PID is 0300.








Compatibility Testing

I decided to test it amongst my test platforms to see whether there were any USB compatibility issues. The results seem to suggest otherwise:

  • Intel Z97 Platform USB 3.0 ports – OK
  • Intel H61 Platform USB 2.0 ports – OK
  • Lenovo E431 (Intel i7-3630QM) USB 2.0 ports – OK
  • AMD 890FX chipset USB 2.0 ports – OK
  • AMD RS880MD chipset USB 2.0 ports – OK
  • AMD RS785E chipset USB 2.0 ports – OK
  • NEC/Renesas USB 3.0 ports – OK

As a result, it seems the reader is compatible with all of the ports under my roof, and the problem with dropouts on my aunt’s machine may be instead related to card-to-reader compatibility. I tested this with a number of cards under a read benchmark, but it too seems to have been successful (SD/microSD cards only, RDF8 results here).


Sandisk Ultra 1Gb microSD – performance shown is basically the performance limitation of the card itself.


Unbranded OEM 2Gb microSD – performance is limited by the card itself, reader had no compatibility issues.


Sandisk Extreme 32Gb microSDHC – this card is capable of 45MB/s on USB 3.0 card readers, thus showing that the USB 2.0 interface reader isn’t really making full effective use of the bus which should be capable of near 30MB/s. Instead, it offers just 16.6MB/s on average.


Toshiba 32Gb SDHC – a full size card to test the reader, and thus one is averaging 15.2MB/s, which is a little less. The card is known to be able to do 38MB/s.


Toshiba 64Gb Exceria Type II SDXC – this one averaged slightly better at 16.8MB/s, although this card is known to be capable of 83MB/s.


Sandisk Ultra 128Gb microSDXC – this one averaged 15.6MB/s, and is known to do 43.8MB/s.

In all, with the selection of SD/microSD cards tested (not all I have available, but most of them), no compatibility issues were encountered at all through SDSC/HC and XC capacities from 1Gb to 128Gb. The reason the reader failed to perform reliably at my Aunt’s place may have to do with her card, or her computer’s USB port specifically.


Rather annoyingly, when I tested it with my equipment, the unit was “no fault found”. The failure to operate properly with my aunt’s machine may be a problem with the USB port itself or card compatibility – perhaps strong RF fields affecting the USB cable or the card directly. The unit is cheap, and the performance, USB 2.0 connectivity and construction reflect this. But it does work, albeit slowly, with the cards tested and uses a chipset I hadn’t encountered previously. It doesn’t take full advantage of the USB 2.0 bus which can reach close to 30MB/s in most cases, but I suppose most consumers at this price point would be happy if they had something that allowed them to access the card, even if it was at a pedestrian 15-17MB/s.

About lui_gough

I'm a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!
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