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Sega Rally video issue

misile42

misile42

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Hello dears I've a problem with my sega rally twin. From one of the two video board the sync signal is missing .I'm looking for a schematic of this board in order to try to fix it but I can't find anything. Can anyone help me ?
Thank you!!
I've also tried to bring the signal from a board to the other with to wires and this is the result

https://www.dropbox.com/scl/fi/u5xv...ey=l4qs9jlqmj8ad4c6curjyywmo&st=iwnrrcox&dl=0
 
Hi , nobody has an idea where to start in order to try to fix this problem? Thank you
 
Mrhide said:
That doesn't seem like a sync issue to me (but what do I know!).

First, does the issue follow the board or the screen if you switch the video from one side to the other?
Click to expand...
Hi thank you for your answer
Yes the problem follows the booard the video show the result after I send the sync signal from the working board to the other simply using 2 wires. Here below you can see the starting situation

https://www.dropbox.com/scl/fi/urja...ey=ru0k6fdl88hy8ulm6hec82hu6&st=koi4d0p0&dl=0

I tried with the potentiometer on the chassis of the screen but no results so I checked with the oscilloscope and I discovered thar the sync signal from the video board was missing
 
I can give you prints but I can tell you any sync issues on Model 2 or 2A are a combination of bad diodes on sync output and custom IC 315-5648. 95% of the time its a shorted diode and bad output of custom.
 
irepairsega said:
I can give you prints but I can tell you any sync issues on Model 2 or 2A are a combination of bad diodes on sync output and custom IC 315-5648. 95% of the time its a shorted diode and bad output of custom.
Click to expand...
Dear
irepairsega said:
I can give you prints but I can tell you any sync issues on Model 2 or 2A are a combination of bad diodes on sync output and custom IC 315-5648. 95% of the time its a shorted diode and bad output of custom.
Click to expand...
I would be very glad to you if you could give me these schematics, in the meantime I'll check the the components mentioned above!Thank you!
 
misile42 said:
Dear

I would be very glad to you if you could give me these schematics, in the meantime I'll check the the components mentioned above!Thank you!
Click to expand...
irepairsega said:
I can give you prints but I can tell you any sync issues on Model 2 or 2A are a combination of bad diodes on sync output and custom IC 315-5648. 95% of the time its a shorted diode and bad output of custom.
Click to expand...

irepairsega said:
I can give you prints but I can tell you any sync issues on Model 2 or 2A are a combination of bad diodes on sync output and custom IC 315-5648. 95% of the time its a shorted diode and bad output of custom.
Click to expand...
Dear Irepairsega could you send the schematic? I tried to check what you suggest but the board is still not working!thank you very mutch !
 
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