Recent content by Marconelly

I've made very sure that grounding loops on both the AB and main board have good contact with the shielding. I was thinking about the cracked trace, but the thing is, once the hissing starts, even the light push onto flyback modulates it. I guess it could still be a trace on the board somewhere...

I pulled all those black rectangular components around the power plug from LC575 board, and transplanted them onto the CC board that I'm troubleshooting - it changed nothing :( I did however notice that pushing and slightly twisting the analog board does change or eliminate the electrical hiss...

Right - that component was my prime suspect for a while, since I also noticed how hot it gets, and it sounded like the hiss was coming from around that area. I even found out what the component is, and there is a replacement sold for it (I think it's a PTH451C thermistor). But the thing is...

Recently my Color Classic has started misbehaving again :( Same thing as before - works for some time, then I can hear a high pitched electrical hiss and a few seconds later it shuts down. Lately this has started happening only a few minutes after powering it on, and I've noticed that the...

Yes, I see that one 1000uF cap on your board faces the other way. Just put the new one the same way the original one was facing, and you'll have the markings on the board to confirm this 100%. When in doubt, always follow the markings on the board. The photo of my board is before I did any...

No, I don't have the camera, but I do have an IR thermometer with the laser pointer. I haven't really measured the temperatures, just felt around the board with my finger right after powering the computer off. That's how I found that some components get pretty hot when the computer is shut down...

I have not replaced any of the diodes or resistors. They all look fine visually and no burn marks around any of them. Only component (other than the capacitors) I replaced was one CNY75GB which had some corrosion on its legs. After that computer worked markedly better. But as soon as I replaced...

Another interesting find I just had. Now that I've got this board stable (mostly - it still seems to sometimes power off after hours of working fine) I decided to revisit my replacement of the second optoisolator. So originally, after replacing the first optoisolator IC (the one close to the low...

Not sure if I'm using the right term, but what I mean by sub-brightness is the brightness of a pure black color. Ideally, that should be zero on a CRT, no light should be emitted for black pixels - but when I started using this board, the black color was very visibly bright and green tinted. So...

I needed to recap my LC 575 analog board, and couldn't find a guide for it, so I decided to make one, similar looking to what Branchus Creations has created for the Color Classic analog board. LC 575 AB is very similar in layout and uses very similar capacitors as the Color Classic AB. The...

Looks like the last piece of the puzzle to get this board fully operational was to increase the picture adjustment R/G/B pots at the back of the board. I used to keep them pretty low to avoid sub-brightness being too high (I originally didn't know the VG2 pot can be used to correct this...

Before you do anything else, I'd say just clean all the IC pins with alcohol, using a soft toothbrush. You can do that fairly quickly and at no cost.

That's where it is, yes. I have found that it leads to J23 jumper lead on the upper side, and measured between there and the metal cage, while the computer was running:

If the capacitors or the battery on the logic board have leaked, make sure to check if any traces need repairing. Make sure to also thoroughly clean all IC pins from any capacitor residue using 100% isopropyl alcohol as it can mess up with their operation. You should also most likely just...

I've ordered these, so I'll see how it goes. They were just $5, so I don't mind even if they end up not working: https://www.aliexpress.us/item/1005006899813268.html I felt a bit bad because speakers on my G3 sounded OK until some game that doesn't obey the system volume setting blasted music...