Tiny chips and other 'stuff'

I mentioned Si5351 chips in the last post, this QCX arrived in a bit of a state, there'd been an issue with the 5V rail which had fried a few chips, the owner had removed the 74ACT00 already (and there was some minor track damage as a result) but wasn't confident he could deal with the Si5351 chip so he was about to scrap the radio.

Which seems a bit of a shame for a chip that costs less than £1 but I understand, the chip is tiny and fiddly to rework, it's not a part I'd recommend working with if you've little or no SMD rework experience.

I contacted him off list and offered to help, the radio arrived in due course and this is an intermediate progress pic, the Si5351 chip, IC1, removed, prior to flux cleanup.

I had to take out C2, R4 and R4 as well as the crystal to be able to get to the tiny MSOP-10 chip, the SOIC-16 FST3253 chip is huge in comparison.


After replacement (and removal of the FST3253, it's cheap enough that it's silly not to replace it):
I've also repaired the track damage around the regulator and replaced the damaged capacitor next to the two diodes.

Once the P-DIP 74ACT00 chips arrive I'm hopeful I'll have a working radio but I need to test the BS170 FETs and clean up the board as well as a few dodgy looking solder joints before I apply power.

A fun repair and while there's a lot of parts been replaced, the parts total is less than a fiver so far, I'm confident the QCX will be back with its owner and on air soon.

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