Video degradation

[motote]

Hello, I'm trying to fix a Issue 4B Board and I'm getting an strage video degradation that I never seen as an common failure.
I've already change the capacitors and the LM1889 and no luck. The ULA works perfect in a different board.
Any idea?

IMG_1755.mp4

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Thanks

[1024MAK]

Is this via RF/UHF or via a composite video modification? If the later, which version/type?

Mark

[motote]

Composite with a capacitor

[1024MAK]

If you did the modification, did it have the same problem beforehand when using the RF/UHF output?

Have you tried on another TV?

Does this TV you are using work okay with other computers that have been composite video modified?

I ask, because occasionally you may find a TV that isn’t happy with the video output of a composite video modified Speccy.

Mark

[motote]

I've finally been able to resurrect the spectrum!!
It got several problem, the video degradation got fixed once I replaced TR1 and TR2. It didn't boot because the ROM was also broken, once replaced with an EPROM (with the proper mod) it boots.
And finally, the yellow bars appears because some pins of the ULA didn't make proper contact with the socket.

Thanks!!

[1024MAK]

Good to hear that you have sorted many problems.

TR1 and TR2 don't often fail.

Sounds like you have been unlucky with that board.

Mark