smalltownguy2 Posted March 15, 2018 Author Share Posted March 15, 2018 Success! I was able to inject my own 5v from an arcade power supply and the system booted. Interesting note: I believe the fault in the OEM power supply was a broken wire at the plug. When I was testing wires for continuity, the 9v lines were great and the brown (5v) line was good to the plug. The blue line however, showed intermittent connection at the plug. Wiggling the plug made the multimeter beep. Aha... broken connection inside the plug. I went ahead and soldered some wires to the 5v and gnd rails on the underside of the pcb and she fired right up. Sweet! Looks like I need to buy a new power plug connector. 2 Quote Link to comment Share on other sites More sharing options...
carlsson Posted March 15, 2018 Share Posted March 15, 2018 (edited) Hm, so the 7805 reads 5V output even if there is no reliable 5V input? Does it generate 5V from the 9VAC after rectifying? I assumed the PSU and the power connector would be fairly OK if you got those voltages internally, but perhaps you should've measured the PSU on its own before starting the repairs. Of course the LED not being lit might have been a hint about that. Edited March 15, 2018 by carlsson Quote Link to comment Share on other sites More sharing options...
smalltownguy2 Posted March 15, 2018 Author Share Posted March 15, 2018 I DID measure the power supply, or at least I believe I did. I got 5v using my meter. But it must have been making a good enough connection for the meter, or maybe I read it wrong. Yes, the power for the VIC chip is rectified from the 9v line. Learned that over on the Lemon forums. Once I figured that out, it was easy to see that I was missing 5v from the power supply. 1 Quote Link to comment Share on other sites More sharing options...
smalltownguy2 Posted March 15, 2018 Author Share Posted March 15, 2018 My power LED is not working. Where can I get a replacement? Quote Link to comment Share on other sites More sharing options...
carlsson Posted March 15, 2018 Share Posted March 15, 2018 Pretty much anywhere they sell electronics, I would think. Standard 5V (?) LED, round 5 mm as yours is a breadbin. Quote Link to comment Share on other sites More sharing options...
smalltownguy2 Posted April 9, 2018 Author Share Posted April 9, 2018 Working on buttoning up this project this week. What's the best way to clean the keyboard to restore key functionality? Some of the keys you really need to punch on to get them to register. Quote Link to comment Share on other sites More sharing options...
carlsson Posted April 9, 2018 Share Posted April 9, 2018 I would take it apart completely. Clean the keycaps in some dishwater, clean the PCB with isopropanol. The plungers supposedly can be revitalized with graphite spray or a pencil, though I've never had a lot of luck with that. Bad function sounds like a problem with the plunger, unless the PCB really is in need of the cleaning. Quote Link to comment Share on other sites More sharing options...
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