Tempest - reversed video

gmontag

Member
Joined
Jul 13, 2009
Messages
477
Reaction score
26
Location
Seattle, Washington
My beloved Tempest machine developed a couple of problems lately. First, I powered it on and the screen was completely reversed left to right, like a mirror image. Then a few days later, I powered it on and the bottom half was gone.

I traced the latter problem to a bad power transistor (Q706). I replaced it and the bottom half returned. However the reversed video persists. It otherwise plays ok. The image is bright and stable. All self tests pass.

Does anyone know the fix? Is this a common failure mode with a (hopefully) easy fix?

-EricJ
 
There are X & Y invert leads on the edge connector, pins 15 & S, the picture should invert (hor for one and vert for the other ), if you change one of them from high (+5V) to low (Gnd), you may have a ground on one that should be high, if changing from high to low won't invert the display you may have lost one of the LF13201 analog switches or the inverter at J11.
Dick
 
There are X & Y invert leads on the edge connector, pins 15 & S, the picture should invert (hor for one and vert for the other ), if you change one of them from high (+5V) to low (Gnd), you may have a ground on one that should be high, if changing from high to low won't invert the display you may have lost one of the LF13201 analog switches or the inverter at J11.
Dick

Yes! Thank you so much.

Pin 15 was dislodged from the edge connector.
 
I just had this problem.
I re-did my edge connector and had a reversed image. The wire from pin 15 to H did not have continuity. I re-did that connection and now I have the correct image.
 
That is why the search function is so great. It will give gratification that has been solved years past.
 
Yes, The search function is a great tool, except when you find your exact problem, read all the posts, and the OP never says what fixed the problem. Then it sucks.
 
Back
Top Bottom