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CMB PET 3032 ( 2001N BOARD )

Right, so can you now check the following pins of G5 (with your oscilloscope):

3, 2, 6, 7, 12 and 13.

Dave
 
That doesn't mean the PET will work once you have replaced G5 of course.

This is the second device that is dead. There may be more!

Dave
 
G5 may well be defective. Still, with all its outputs low and definitely receiving the clock, I would just double check with the scope (not logic probe), before removing it, that pin 11 (the /INIT line) is definitely logic high, because if that line gets deployed low, it loads all zeros and G5's out[puts would be zero. Also worth double checking its power supply pin 16.
 
Dave, just to understand more, on G5 I should have found pulsating signals on pins 3 and 7, correct?
 

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Yes.

Pin 3 at 8 MHz and pin 7 at 1 MHz.

Pin 2 should also have been 4 MHz and pin 6 should also have been 2 MHz.

Can you just check pin 11 (using your oscilloscope) as Hugo has asked to see what the actual DC voltage level is please.

Dave
 
I am away on a business trip for a couple of days, so I might be busy until Wednesday.

I will check-in from time to time on my phone...

Dave
 
Hi Dave, i changed the ls191 but i have same black screen...now i have clock on cpu pin 7 and waveform signal on G5 pin 3 and 7 :(
 
A clock on CPU pin 7 is what we were looking for with this device replaced!

Just having my evening meal, so I will look at the schematics shortly...

Dave
 
Ok, so can you check the HDRIVE, VDRIVE and VIDEO signals on J7.

See if all of them are missing or not.

Dave
 
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