I purchased a used Ubiqiti M2 2.4Ghz Bullet to support an outdoor WiFi project. The plastic of the unit was discolored from the sun and I was curious to check out PCB inside so I decided to do a combo teardown/plastic whitening experiment.
Misc - Ubiquiti Bullet M2 2.4Ghz - Plastic whitening and teardown
To whiten the plastic I tried submerging the enclosure in the mixture proposed by the "Retr0bright" project. I mixed about 1/4 teaspoon of Oxiclean (for Tetraacetylethylenediamine) into a container filled with very dated 3% hydrogen peroxide. Ideally I would have used a higher concentration of hydrogen peroxide (6-12%) but it was late and the stores were closed. Similarly I ended up having to use a halogen desk lamp instead of the sun as a UV light source to speed up the reaction:
After an 8 hour soak a noticeable improvement was observable. I would have left it in for longer but had concerns the adhesive on the clear plastic strip would break down with a longer soak duration:
(Left) Ubiquiti Bullet M2 before soak, (Right) Ubiquiti Bullet M2 after soak
In all I was pleased with the results given the effort involved. I look forward to trying this again with higher hydrogen peroxide concentrations and a better light source!
The Bullet M2 is designed in a manner which allows it to be taken apart and put back together very easily. The PCB is held in place via a single slotted nut which also serves as a weatherproofing seal. A c-span wrench can be used to remove the nut and allow the entire PCB to slide out the bottom of the unit.
Based on the silkscreen the FR4 board appears to be designed by Ubiquiti and fabricated by PLOTech Co., LTD. In the pictures below the RF shield has been removed as well as the heatsink which normally resides atop chip labeled "C" vi an adhesive pad. I was happy to find that a UART was present on the board but was curious why they bothered to populate the header. Perhaps Ubiquiti is open to tinkerers?
The lettered components in this image are described below:
- A - U30 - RFMD RF5602 - Linear Power Amplifier
- B - U95 - Atheros AR9283 - MAC/Baseband/Radio
- C - U1 - Atheros AR7240 - Wireless Network Processor
- D - M-TEK H16125MCG -10/100 Base-T Transformer Module
- E - Alpha & Omega Z1212AI - 3A Simple Buck Regulator
- H - DRAM(?) - Did not remove stickers
- I - ST Microelectronics 25P64V6G - Serial Flash 64Mb
If you found this project interesting or helpful and have the means feel free to donate!
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