RGB Encoder issue

Helpdesk
1

I have build another Cadet system.

When testing the modules, it became clear that the sync cable was manufactured wrong.
All pins are shorted together.

I tested the RGB Encoder with another cable first, it worked correctly.

Then I used the sync cable to test some other modules. This did not work because the cable was shorted.

Now, the Encoder is behaving weird:

If I plug a VCO in the R/G/B channel, I see black & white bars with interference over them.
When I adjust the VCO frequency (sweep it up and down), the color comes in. It seems like the sync signal needs a nudge to work.
The PAL / NTSC switch has the effect that when switch to NTSC and back to PAL, the B&W effect appears again. This can also be resolved when adjusting the frequency of the VCO.

My question is: can a shorted out cable damage the RGB encoder?

And: how do I fix this problem? (I’ve also contacted LZX & Thonk about this issue)

I have another RGB Encoder that I build years ago that works perfectly.
So I cross-checked all the parts and solderpoints. no visible issues there so far.

2

I actually have this issue with the green channel on one I built earlier this year. Haven’t exactly been able to solve it either. Didn’t do anything different than on previous builds, so the questions do linger…

3

@reverselandfill & @cinema.av, I know it’s been a while but did ye ever get to the bottom of this problem?

4

no. I try to live with it. Maybe I’ll replace the SMT part one day, to see if that caused it.
I’ll build the new sync gen when it will come out, hopefully it can replace this one.

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