Tek 7613 Vertical Slot Failure - help!

tmall@...
 

Greetings,

The middle module slot (right vertical) in my 7613 has failed. Upon power up there was smoke and the smell of a hot component after which neither vertical module will work when plugged into the middle (right vertical) position. Both modules work fine when plugged into the left vertical slot. If plugged into the middle slot it acts as if there is no vertical module plugged in, just a single trace across the zero crossing X graticule line.

I have taken the covers off and have not been able to see anything visibly scorched although there is a mica capacitor in the proximity of the back of the edge connector that looks a little dark. I have measured the +/- 15V and +/- 50V supply voltages at test points on a side PCB and found they are good there. I do not have a card extender to check the voltages on the middle edge connector but as they are common with the other two edge connectors (which are working normally) I imagine they must be OK.

Looking at the schematic I notice separate vertical slot connections to the vertical interface PCB and wonder if I should try to do some diagnostic measurements on it.

I wonder if anyone in this group has any suggestions or experience that might get me on the right track?

Thanks in advance for any help!

Best Regards,
TMA

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