Testing BU406D's

How have you all gone about testing the BU406D?

When I remove this component and put it in my transistor tester, the
tester shows a diode drop in all combinations.

When yours have failed, do they open up, or short, or ???

I have three more Amplifone HV units that I'm trying to repair. I
suspect the HV transformer in all cases, but I'd like to know how to
tell if the BU406D is at fault or not.

One last thing .. I have 4 HV boards in total, all with red Hv
transformers. One of the HV units actually works. (I know, a rare
breed) Similar to what Clay mapped out with a DMM for the Wells Gardner
HV transformer, I performed similar type measurements on the Amplifone
HV transformer units. Every last one of them (including the working
one) had the same measurements. Yet, only one of them actually works.
The ohm test seemed pretty logical to me, and it sounded like it would
be a surefire way to detect an open or shorted winding ... but
apparently, that's not the whole story. If the windings appear to be
good, what else is wrong with these transformers? The BU406D's that I
can't test? :-) :-) :-)

I have not removed the HV transformers and swapped them into the known
good HV board, but I have checked every component except for the BU406D
and MC1, whatever that is?? Aside from that, these units have basically
been rebuilt! Any ideas?

Joel-
Received on Tue Oct 21 11:07:02 1997