Quick Teardown, Pairing: J.Burrows Wireless 2.4Ghz USB Keyboard & Mouse Combo

Earlier today, my Dad requested some assistance with his J.Burrows Wireless Keyboard and Mouse Combo that was purchased from Officeworks. It was a rather low-cost set, not one I would have chosen myself, but after the batteries in the keyboard were replaced, it seems the keyboard stopped functioning and he was wondering whether it could be fixed.

Troubleshooting 101

With battery-operated consumer electronics, the first question was whether the batteries were any good. After swapping them for another set that was checked on a multimeter to be fresh, the keyboard remained non functioning. It was noticed that the red light on the keyboard “blinked” once when the batteries were put in – a good sign it was still alive.

Was it actually alive though? I got out my IC-R20 radio, tuned to 2470MHz in AM and when pressing a key … the radio confirmed hearing a signal. I was certain the keyboard was still alive.

Instead, the issue would be a loss of pairing code. Perhaps when the keyboard was operated with low battery, the pairing code was erased (or lost during battery replacement). Regardless, the keyboard seemed to be sending codes, but the receiver was not decoding them. At least the mouse continued to operate correctly. I went in search of a “connect” button, but there wasn’t any …

The Quest to Re-Pair

Unfortunately, whatever documentation and packaging that the unit came with was long disposed of and there are no hints at all on the Officeworks site. In the end, we were on our own with their own “house-brand” product that had not even a model number.

My thought was that a teardown was necessary to try and determine the manufacturer, in the hopes of finding a firm model number and similar models from which pairing information could be gleaned.

After taking out an immense number of screws, I was surprised at just how cheaply the keyboard is made and how few components it involved. Each key has a rubber dome which pushes on a membrane “sandwich” which is backed by the rear cover – nothing unusual there. But the logic involved in controlling all of that resides in a PCB that is rather small – around the size of three full-size keyboard keys.

The rear side of the PCB has the carbonised traces which are used with a silicone pad to make contact with the silver printed membrane traces. In all, it seems there are 8 rows and 18 columns, for a theoretical matrix maximum of 144 keys. The board has a few test pads as well.

The front of the board shows that the PCB is dated week 19 of 2016. The board seems to have omitted a few components which may have controlled unintentional radiation from the battery wires. The markings of interest are HK9330 JBM K2100_VC SZDKWXJP2.4G_V4.0 dated 16th February 2014.

Unfortunately, searching for any of the above fragments did not net any insight into who makes the keyboard (a Shenzhen company it seems) or how to pair it.

Plan B was just to look aimlessly for wireless keyboard pairing instructions and try them out. After a few trial and error results, I only managed to stumble upon a set of instructions which worked because I ended up looking at other local retailer “house brand” sets and their quick start guides.

Pairing Completed

The instructions which worked were for the K-Mart OfficeOne Wireless Desktop Mouse and Keyboard set. The procedure for the mouse is to press and hold the scroll wheel and right click button simultaneously for a few seconds. For the keyboard, it is to hold the ESC and K key for a few seconds. It worked with the red LED on the keyboard turning solid.

Conclusion

It seems quite likely that for many people buying such simple low-cost equipment, their expectation would be that the product is “plug and play” and there would be no need to refer to the documentation. As a result, it is likely that the packaging and the seemingly useless one-page leaflet (that was probably never read) was long recycled.

However, upon encountering trouble, such house brand products rarely have any support and users are left “out in the cold” with no online access to relevant documentation or any solid model numbers to go on. There is every chance that a consumer may just chalk it down to the unit failing and just “buy another” – great for their bottom line but terrible for the environment.

I’m not particularly pleased that I had to jump through a few hoops to get it working again – is it too hard just to print these instructions on the approval labels that already go onto the rear of the unit? There was so much blank space I ended up writing the instructions on the label with Sharpie. At least this one was saved from the scrap heap … after some careful reassembly. Those silicone domes don’t like staying in place …

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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