Atari SC1224 monitor - need help with troubleshooting

[chad5200]

I have an Atari SC1224 monitor that is just showing a black screen regardless of contrast/brightness level.

 

This is a Gold Star model (manufactured March 1988) with a power supply with part number 111-694A.  This is the kind of SC1224 with the three adjustment knobs (power/volume, contrast, brightness) on the right side.

 

I saw that the big 330ohm 250volt capacitor was bulging so I replaced all the capacitors on the power supply listed here:

https://caps.wiki/wiki/Atari_SC1224

 

 

Still no luck after recapping the power supply.

 

But I would like to verify the voltages that I should expect to come out of the power supply.

 

Power supply connector P904 is measuring 137.9 vdc.

Power supply connector P905 is measuring 2.5 vdc.

Power supply connector P906 is measuring 18.1 vdc.

 

Unfortunately, the service manuals I see online do not match up with this particular Gold Star model.

 

Can anyone help confirm what those voltages should read at those connectors?  I have labeled this picture below with the three connector names.  If they are wrong voltages, any ideas what else should be replaced on the power supply besides the capacitors?

 

 

 

Edited February 16 by chad5200

[chad5200]

Important correction:

 

Power supply connector P904 is measuring 137.9 vdc.

Power supply connector P905 is measuring 15.8 vdc.

Power supply connector P906 is measuring 18.1 vdc.

[chad5200]

I recapped the power supply as noted above.

 

I have now also recapped and the neck board as described here:

 

 

Still no luck.    Screen remains black.

 

Does anyone have any ideas what to try next?

 

Any suggestions would be helpful.