Post by themanfromsaturn on Feb 27, 2019 20:58:18 GMT
I have a model 1 UK Saturn fitted with a Type B (GND, GND, 3.3V, 5V, 9V) power supply.
After the Saturn has been running, say for an hour, then power cycled, it no longer boots. The system goes straight to the CD player and reports that the drive is empty. At the same time there are wavy lines on the screen and a whining sound coming through the speakers and unit itself.
Initially I thought this was the TOP202YAI issue, so I replaced this with a new one, but the problem persists. I swapped out the PSU with another I had spare and it works perfectly after a long run and power cycling, so it is definitely the PSU, but what component could be the culprit?
Having eyeballed the capacitors they all look OK, so I am a bit stumped.
Does anyone have any ideas as to what the faulty component(s) could be?
Only the electrolytic caps need replacement. The TOP chip is probably overheating. The TOP202YAI has been EOL'd for over a decade, so you probably replaced a dodgy old component with a dodgy old component. It's why the newer one is recommended.
Try installing an extra cap on the PSU, as marked with green on this image:
I do both this and replacing the TOP202YAI with a TOP224YN when I'm fixing power supplies.
Post by themanfromsaturn on Feb 28, 2019 15:32:46 GMT
Thanks for the image, that's really useful, but I think I've now wrecked the power supply anyway while I was tinkering with it. I was swapping components and now it will not power up at all .
I'm going to attempt to build my own replacement power supply using off-the-shelf power boards. I've had some success with that approach on a Japanese system, but it was a bit easier as it was only 5V and GND needed.
Anyway, that's a separate project and I'll probably create a separate thread for that if anyone is interested.