TG-16 strange vertical hold/rolling image issue

[wiggyx]

So, I did a quick composite mode to this TG-16 that a friend gave to me (the RF modulator is toast, so I don't know if it had this issue prior to the composite mod). You guys ever seen this sort of problem?


Click the image to see the video.

I have the mod hardwired to the board, not the ghetto D-sub connector method. I've quintuple checked the pinout, and I know that isn't the issue at this point. I'm using pin A22 for vid signal and I've used no less than 4 ground points including the board itself. This rolling image is what I get every time. I've also tried 4 TVs. A Sony Trinitron CRT, Samsung LCD, Samsung LCD monitor, Sony DLP. Same thing on all of them.

[jb143]

Using multiple points as ground can cause ground loop issues in video, though I think that this is more likely to cause scrolling interference patterns rather than a scrolling picture. It seems odd that you would get a vertical hold issue. Still, it might be worth a try to only connect the composite ground to pin A21.

Have you tried it through a Turbobooster to make sure it's not some issue with the composite signal? Also, is it just a straight pinout to composite wiring or do you have any filters or amplifiers in there as well?

[wiggyx]

Using multiple points as ground can cause ground loop issues in video, though I think that this is more likely to cause scrolling interference patterns rather than a scrolling picture. It seems odd that you would get a vertical hold issue. Still, it might be worth a try to only connect the composite ground to pin A21.

Have you tried it through a Turbobooster to make sure it's not some issue with the composite signal? Also, is it just a straight pinout to composite wiring or do you have any filters or amplifiers in there as well?

I've tried using both multiple and single grounds. I've used A21 as a ground, as well as C2, C8, C17, C20, and the board itself (in a few different locations). None make a difference of any sort. Right now the video is grounded to the board on its own. Before that, to A21 on its own (and I've had all three grounded there as well).

I don't have a turbo booster unfortunately, and I have zero desire to buy one considering how much they cost versus how much it costs to just pull composite right from the board. Straight to composite. No ups, no extras.

The only other things that I've done are remove the RF modulator (which I actually reinstalled just to rule it out), and obviously the RF shielded is no longer soldered to the board. None of the ground traces were severed as a result of removing the shields. If they had been severed, then I would have repaired them.

I'm beyond baffled.

[theclaw]

Have you tried its RGB lines? Could be the composite encoder is going bad.

[wiggyx]

I don't have any means by which to employ RGB output :/

[alec006]

I don't have any means by which to employ RGB output :/

Ew, well you could try getting a converter so your TV can either accept low res component or HDMI. Testing the RGB lines to see if they give a stable signal is the best way to see if it's either the video processor or the composite encoder.

From there you could either replace the encoder if it's the problem or convince the person your modifying the console for that hey RGB is better and just buy one of these convertors.

SCART to HDMI would be the better option since it's the easiest and will work on modern TV's.

It may also be capacitors on the board going dry possibly.

[wiggyx]

I'm modding it for myself

I'm gonna try an S-vid mod (since that's as far as I ever wanted to take it in the 1st place) and if that doesn't work, then fuck it. It's not worth the headache of replacing encoders and whatnot to me.

Like I was saying before, I don't have any desire to buy a converter or anything like that. For that sort of money I can just grab another TG-16. I'm not impressed by RGB output on the TG, making that sort of investment even less desirable for me.

[theclaw]

Yeah TG16 isn't worth putting money into. Wait until you have a Japanese model to get serious.