retrocomp.org

Such a nuisance: I have a 600XL that worked fine. Mounted extension to 64k and U1MB, but it doesn't really matter. The modulator is also removed.

I have read that removing the C109 capacitor improves the image quality. So I took it out and it turned out that the image broke - dark screen and sometimes breaks synchro. I saw that when removing the C109 I broke my leg from the Q6 transistor. I changed the tenze.

At the moment, the painting is indeed edgy, but has no color. I changed GTIA and 4050 - no change. When I turn the potentiometer, sometimes a color appears, but the phase is shifted and the artifacts are very clearly visible.

I suppose I made some short circuit because all passive elements in the area are mounted vertically and easily tilted. I have looked through everything and I think I have removed any possible short circuits, but there is no change.

I was talking to Mr. Lothark and he suggests it is a passive component (capacitor or transistor). Well, before I start listing everything in turn around the video output, I wanted to ask the wiser than me if they have any suggestions, which could be the most likely cause of the problem?

And you put the transistor in the original or a replacement?

I also bet on this transistor (if it is probably one of the two in the video path).

And by any chance Q6 is not from luminance, and from chrominance are not Q7, Q8, Q9?
If, after replacing the transistor, the image from the dark turned into a "razor" then Q6 probably works.
At the beginning, I would try to return to the initial state, i.e. restore the C109, see what the image looks like and possibly just look further, starting from R66 and CR4.

Both the CD4050 and the Q6 are of brightness (B / W image). The CD4050 makes for a primitive DAC and synchro. I am a bit "worried" how you managed to break off the transistor "while" taking out the capacitor. The laminate of these boards is quite sensitive to overheating and it cannot be soldered "with just anything". I have an 800XL CD where it was necessary to restore 80% of the tracks within the OS-ROM after someone tried to replace it.

Photo "as a warning", how it ends when the "freshman", who just bought his first soldering iron in Lidl, starts "repairing" such a disc:

I have inserted the same transistor: 3409 and I believe that it works because
The problem is that, unfortunately, this conduit has disintegrated and I have no replacement. This is 18pf?


I saw the diagram and I know that it is marked in red because of the color - Lotharek explained it to me. As for the "by the way" of the break, I just tried to cut (just with the side claws) C109 and cut my leg from Q6, hence it by the way. It's really cramped there. I also have good stations, not a transformer from Lidl.

And one more thing: I had for a while! 6 inserted the other way round, means 180 degrees, because I am a lama. Anything that could get you hot?

At most, the transistor itself.

That's why I put another piece correctly.

What, then, to change next?

Are you sure the potentiometer is working? Did he measure it?

If you didn't break something, I would check the voltage on n. 17 GTIA or on the potentiometer slider, possibly also on Q1 (collector, this leg at R41).