Cinematronics monitor problem

Vectorman

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Guys (and especially MarkH),

What is wrong with this monitor? I'm guessing it's pretty simple, but I'm ignorant on these things.....

Appreciate any and all guidance....thanks!
John
 

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Try swapping the two DACs on the monitor board around and see if the corrupted part of the screen changes. If the screen doesn't change the analog switch is a good possibility of being the cause of the problem. The analog switch is difficult to find and expensive when you do find them, so you probably want to try everything else first. Occasionally a problem in the brightness circuit or the 7406 (I maybe wrong about it being a 7406 but it's The only 7400 series chip on the monitor board) can cause this sort of image issue.
 
Hey John, Mark will know. Not sure he reads the monitor forum regularly. I owe him a call tomorrow on something else. I'll point him over here.

You're getting X anf Y so the DACs seem to work. My guess is the analog switch. I have a bagful here somewhere, LMK if you need one. Wiggle or swap the ribbon cable just for kicks.
 
Yeah, looks like your signal is going south on you. I would start and make sure the signal is good coming from the pcb (make sure the pcb is good) next check the signal getting to the monitor (the ribbon cables are notorious for going bad) check the DAC's - swap them and see if the signal changes from Vert to horz issues (bad DAC) or swap with two known good DACS - the DAC sockets may be questionable also. and finally if the signal is good at that point Check the LF13331N (NTE861) analog switch and the TL081 op amps. Also check the solders on the adjustment pots, they can send a funky signal too.
check
pcb
ribbon cable
DAC and or sockets
analog switch

hope that helps, if you anything pm me.



Mark
 
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