jonschultz's latest activity
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.There are several sort of silly things that could be wrong at this point, each having a low probability of being the root cause...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.No big deal, I found the problem really quickly and I have plenty of random replacement parts. It was a good lesson anyway, to be really...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.Just a word of warning though: I just killed my QP7 MOSFET (the one with the small heatsink, just north of IP7) while probing around at...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.For IP7 pin 6 on my system, with hard-power on but soft-power off, I measure -55V relative to chassis ground and 0V relative to the...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.I think that whole section is floating relative to ground because it’s effectively on the AC side. The AC side and the secondary sides...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.Definitely seems like something is wrong with the supply section for the logic board power, right near IP7, though it's not necessarily...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.That's a good sign because it means the AC section and the CRT supply section are working. The logic board supply side could still have...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.Are you now getting no voltage on RV26 and RF19?
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.When a CC seems to be this dead, I recommend checking some of the low-voltage supplies. Many of them will normally be running even...
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JOver the years, there have been lots of discussions surrounding the infamous DL21 and DL22 18V Zener diodes on the Color Classic analog...
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Jjonschultz replied to the thread Mystic Color Classic Screen Distortion.Well CP35 appears to be in the power supply section. I'm less familiar with this territory of the analog board, but I think CP35 might...
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Jjonschultz replied to the thread Mystic Color Classic Screen Distortion.Yeah, the bulging is bad and a fairly typical problem on Color Classic analog boards, precisely because of the heat generated by those...
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.Yeah I agree, the DF2 voltage is suspiciously high. Do you have the correct value for RF11, which biases DF2? I think it should be 370 Ohms.
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Jjonschultz replied to the thread Colour Classic Display Issues After 84v Mod + Recap.Excellent suggestions regarding the voltages to check. I was also going to mention that checking a flyback-generated voltage would be a...
