Recent content by jonschultz

I see, but a bright, horizontal line means that vertical deflection has failed. Horizontal deflection is still working just fine in that case. Failure of horizontal deflection almost always results in absolutely nothing on the CRT functioning because a lot of the circuitry depends on the flyback...

I'm not too familiar with the TDA1170N, but it looks like it's a vertical deflection IC, similar to other ones that I've seen. I don't think any of the horizontal deflection functions are handled by this IC, so it wouldn't have any effect on the width of the raster (though, a caveat would be...

Another place to check is on pin 7 of the TDA8172. You should get around 5V here. What you’re seeing could be related if it’s way off. In any case, modulation of the DC component of the vertical deflection (ie the vertical centering) is affected by components in that area.

I have a partial schematic here, but others have more complete ones. @ArjenCNX recreated the whole board and has the schematic posted in one of the recent CC threads.

Actually, CF10 might be just outside of the RF cage (I don’t have my board in front of me at the moment to check), so it might be easier to access than I initially thought.

The fact that it’s shifting around vertically makes me think it’s related to the TDA8172 (vertical deflection IC) or components around it. You could check electrolytic cap CF10. This stuff is inside the RF cage at the center rear of the analog board, so it’s unfortunately not that convenient to...

I’ve never really heard much of a noise from a CC’s degaussing coil, so I think it’s just the case that they’re designed for pretty low current and are pretty weak. You might just try multiple power cycles and see if that helps to improve the spot. The main power button is what initially powers...

I have a partial schematic of the AB around the video section here: https://github.com/jonschultz/colorclassic_video_processor/blob/main/CC_analog_video_section_20260513A.pdf I'm pretty confident in the component values (the ones that I have), though I don't have the tolerances. If you have any...

I checked out your KiCad project. Very impressive! At some point I hope to pull the trigger on getting one of these fabbed for myself. Any new observations or suggestion for the component (re-)assembly process?

Thanks! I will definitely look into this once I have some time for a new project.

Which diodes are you having problems with? FWIW, I replaced the infamous DL21 and DL22 Zeners with Onsemi's 1N5931BRLG years ago, and they've been running well since.

Good point, I was kind of assuming that @ArjenCNX wanted to do it in VGA mode only, but it would be great if it could be universal.

Are you looking for an easy way to switch the line sensing and B+ back and forth with switches, or simply a way that doesn't require cutting and bodging to do VGA mode (like with zero-ohm resistors that can be populated in the appropriate positions)?

Seems very doable with a VGA-to-HDMI converter, which you can probably find in IC form. The main challenge would be dealing with the CC’s composite sync, as it doesn’t natively produce independent VSYNC and HSYNC signals, like standard VGA. I use the LM1881 on my board to pull out VSYNC, and...

Sounds great. If you might consider socketing your XC1186B on this particular board, then you could swap in mine for initial testing. I’d be happy to send one to you, but it might take a little time (I only have one v3 board with a lot of rework). I’m trying to finish up v4 changes, and I’m...