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Nanao MS9 no screen

chinitosoccer

chinitosoccer

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plays blind, I can hear high current noise (a chirp first then an stable low pitched hum ) after powering it on but no neck glow, meassured B+ at TP2 at 76volts DC.

The neckboard has had its socket replaced at some point with another one taken from a MS8-29, but after further inspection on the solder side of the PCB I have found that some pins are not making contact because there are no solder pads:

4 and 12 pads are tottally gone, while the others look bad, checked ok for continuity, I tried to follow where these pins with missing solder pads go but found nothing??...where do these go?

YHAKnBp.jpg
 
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Are these single layer PCBs? is 4 & 12 just connected to the ground plane? if so just scrape off some of the mask and expose some copper to solder to.
 
They're not supposed to be connected to anything. They're unused.
 
No it is not, I went ahead and swapped the neckboard for a known working one and it did nothing;

I still can hear current, but heater/tube does not power on, maybe a bad flyback?
 
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If you crank up the flyback screen control does the screen go white? or can you see anything at all? If you hear the high voltage or feel static on the front of the screen then the flyback is working.

have you tested with different PCBs just to make sure it's not the source?

If there is still no picture, but you have high voltage, I would look at the RGBS input and the neck board connection wiring.
 
Tried tweaking the screen pot on the flyback and it does nothing, no static on the screen, brightness set at max, screen set at max, abl and evrything brightness related, black screen, nada.

I have tried 2 neckboards and 2 crts and it does the same.
 
chinitosoccer said:
Tried tweaking the screen pot on the flyback and it does nothing, no static on the screen, brightness set at max, screen set at max, abl and evrything brightness related, black screen, nada.

I have tried 2 neckboards and 2 crts and it does the same.
Click to expand...
ok, it sounds like you do have a flyback problem then, or the chassis is going into shutdown.
 
Ok, back on track again, I have connected a light bulb to the lifted pin2 of the flyback, b+ tested 76 vots at C515 Cathode so I already had my suspicions that the flyback was not the culprit, anyways... I tried swapping the FBT with a known working one, no change, damn.
 
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