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TheSolderMonger

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About TheSolderMonger

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  1. I'd like to be put on the list too if there is still room. Many thanks
  2. Could you check the 1000 uf capacitor and see if it's outputting 23 volts? It could be that the cap is bad. Also, I checked 2 caps on the logic board close to the regulators and they are getting 12 and 5 volts, but I check the other end and my probe gets nothing. Could that be a sign of a faulty capacitor?
  3. On my machine, the eject button pops off (like a lego brick) , not held in by screws/glue and the RF shielding pops off easily, just leaf spring metal pressure. I still recommend caution on your machine since mine was slightly disassembled when I bought it.
  4. Drat, well that rules out the PSU. I'm looking at doing a recap of the main logic board or a MUCH closer look at the soldering to rule out cold/broken joints and another 12 regulator replacement. Could it be possible for you to measure the 12 volt regulator INPUT voltage? If so I could reverse the path of the traces to a possible malfunctioning component.
  5. I did measure 10 volts from all 3 pins from the PSU brick to the daughter board. Can you measure your PSU output voltage from the brick?
  6. When I setup my channel F on my CRT instead of the flatscreen, I saw that the signal persists, but this is what the problem causes the picture to do. Could this have something to do with the RF circuitry? Or would this have to do with power and/or thermals?
  7. Yet another update, there was some residual electrolytic fluid on the daughter board, and there was a capacitor on the main logic board that had 1 leg unsoldered, and with that the problem still persists, though I may disassemble the switches themselves as a couple of them don't make clicking noises, perhaps stuck buttons cause glitching with conflicting instructions?
  8. Update: Applying thermal compound and a small heatsink did nothing to improve the picture. I still smell electrolytic fluid coming from the daughter board, even after cleaning a good portion of the leakage. Now I need to soak the daughter board in alcohol and see if it changes color, if it does, then there was electrolytic fluid possible conducting power where it should not be going.
  9. I measured the Input/output voltages and with that, the UA7812C regulator is regulating 23.3 volts down to 12.19 while the UA7805C is regulating 11.63 volts down to 5.03 volts. What I may do is to use a small heatsink over the regulator, and if the heat dissipation keeps the system on and working then the problem lies in the regulator or at least narrows down the power path to the regulator.
  10. Sure thing, attached below is the daughter board and the regulator arrangement. The regulator on the left is a UA7812 and the one on the right is a UA7805.
  11. Update: The issue at hand seems to be caused by a thermal problem, however the 1976 service manual screenshot 104 seems to match with my earlier uploaded picture of the white line, which points to a faulty PSU. I'm inclined to believe that the PSU is normal, and that the regulators may be in the wrong spot, as the UA7812 regulator is hot to the touch after the TV loses signal. Prior to the signal cutoff, with the regulator cold, the system works just fine until the regulator heats up, and likely causes a drop in the 12 Volt line? (Again, I'm not sure if the regulators are even in the right spot.) I would greatly appreciate if masschamber could upload a pic of the regulator setup, because if the person who last serviced the machine put the capacitors backward, then I am likely to assume the regulators were also put in incorrectly.
  12. Replaced the voltage regulators and the problem still persists. Can you provide a picture of the regulators at the back to make sure that these regs weren't put in the wrong way.
  13. Can you upload a picture of where the regulators are? I replaced that capacitor later after the picture was taken, it was no good.
  14. I thank you so much, however this problem (see attachment) still seems to persist after re-aligning the capacitors and powering the system on for a few seconds with or without a cart installed. When I power the system on the game shows up with a bit of garbage but then the picture goes to this line and then the TV loses signal.
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