We’re well into summertime here in Sydney, Australia. Time to throw another shrimp on the barbie, as they say. Not much relevance to this video, especially considering how long this repair has been waiting to be finished!

The capacitors have now been replaced, and it’s time to finish the soldering before giving the TeraDrive another test. Two of the particularly suspicious components were rated at 3300 uF and 6800 uF, both at 10 V. Those were among the capacitors showing signs of trouble.

Unfortunately, the surrounding corrosion had left some of the solder connections in rather poor condition. One of the pads was especially troublesome, so I spent some time ensuring the component was properly connected before reassembling the power supply. There was quite a bit of cleaning to do around the damaged area too.

The troublesome joint took some additional soldering before I was happy enough to continue. I also checked continuity around the nearby connections, just in case something had been damaged during the capacitor removal. With that done, it was finally time to put the power supply back into the TeraDrive.

And then came the moment of truth. Power on, listen carefully, and see whether the TeraDrive will start. Unfortunately, although there were no immediate signs of anything burning, the machine still wasn’t producing a useful display. The speaker was making some rather familiar noises too, which didn’t exactly inspire confidence.

Out came the multimeter again. The 12 V rail was now measuring approximately 12.1 V under load, which was considerably more encouraging than the earlier results. The 5 V rail, however, was another matter entirely.

At one point I measured around 4.83 V, with the voltage occasionally falling towards 4.73 V. The readings weren’t particularly stable, and the original failure to start remained. So the capacitor replacement appears to have improved part of the power supply’s behaviour without fixing the whole problem.

I tried reducing the machine to a simpler hardware configuration and checking the voltages again, but there was still no useful display. The 12 V rail was behaving itself rather better than before, while the 5 V readings kept giving me something to worry about. Perhaps the power supply still had another problem hiding somewhere.

I tried a known-working power supply for comparison, and the TeraDrive produced video again. That was an encouraging result for the rest of the machine, but rather less encouraging for my original power supply!

After all this experimenting, I decided it might be wiser to replace the troublesome supply with a suitable modern enclosed unit rather than keep chasing faults around the original circuitry. I started looking at Mean Well RD-65A supplies for that purpose, with the appropriate 5 V and 12 V outputs.

The replacement supply wasn’t installed in this recording, so the original repair remained unsuccessful. At least comparing the two supplies gave me a much better idea of where the problem was, and there was no point continuing to dismantle the rest of the TeraDrive when a known-good supply could get it producing video.

So there we have it. A considerable amount of soldering, some genuine capacitor damage discovered, and a partial improvement in the voltage readings. Unfortunately, no successful repair of the original power supply.

Sometimes you just have to know when to stop. Although apparently I haven’t quite learnt that lesson yet!

Related Posts