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IIc strange image

WillJac

Well-known member
Ok I will get my new chips Tuesday so I will remove it and put in a socket for now and wait for the new. I also get the new memory so will do the ls32 first and if need the memory after
 

WillJac

Well-known member
Well here's to hoping!
Thanks for all your input and guidance. This how i learn and will be able to pass it along to others. Will keep you posted. If you think anything else let me know. I am retired so I am always around.
 

WillJac

Well-known member
You think good be something with the TMG chip as I have no video7M output from the chip only place I see something missing.
 

WillJac

Well-known member
Sorry vid7m from pin 13 goes to the video chip after on pin 6. I have no signal at all on 13 or 6 but on other machine as soon as I turn on, I have signal wave.
 

WillJac

Well-known member
Can’t trace more. The signal originates from tmg chip goes to IPS then the video signal. It’s a timing clock signal so if that not there I do t think the video will come up good.
 

Lycus

Well-known member
Can’t trace more. The signal originates from tmg chip goes to IPS then the video signal. It’s a timing clock signal so if that not there I do t think the video will come up good.
Let's see first if the 74LS fixes it, as broken RAM circuitry can cause cascading problems.
 

WillJac

Well-known member
I replaced the LS32 and 2 of the ram I found to be bad and now I get this. Any ideas?
 

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WillJac

Well-known member
Ok let me get the readings and send them. So far what I am finding is EN80 is not enabled coming from MMU and also going to that LS32.
 

WillJac

Well-known member
I am going to park this for a few days work on some other stuff. My mind is fried about this logic board. I have a plus, Mac II and SE to work on.
 
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