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Original post by: Floyd Brooks ,


After some time of trouble shooting i found that the shut down issue was related to a crow bar circuit in a voltage control circuit,  this circuit is used to set the output voltage of the 5.3v supply.  With the out put at pins 3 and 4 using the red ground wire a pin one.  There is a sensitive gate SCR Q971 PN. MCR101L  ( near the top left corner of the pcb)  that was turning on when heat was applied to it, some place around 150 deg. F.  There is also another SCR Q972 that is used for the 24 / 11.9 supply that may cause the same issue,  Q972 is near the lower center of the pcb, near a heat sink.  i found a similar part at digi-key  PN BT169-L, there is an issue and the -parts leads are not in the correct order, with some care one can rearrange them to work.

As also ways i will not take any responsibility for the repair, or any damage to you or the equipment,  (KMA)

I have am having success with my fix , happy fixing


Hope this helps,