Service Manual/Full Schematic for Biddle BM10 Megger
 

Hey all,

I'm looking for something to help me repair a Biddle BM10 megger.
Capacitor C-16 has mechanical damage and requires replacement, I think
several of the 1N5400 diodes are bad I need a better capacitance meter
to troubleshoot further - I'm working on that. I have other questions a
schematic would help with.

TIA,

Boz

Service Manual/Full Schematic for Biddle BM10 Megger
 

I removed the 1N5400s, they tested fine when isolated. Probably a
Huntron would have helped in that regard.

Perhaps someone has suggestions on testing TO-92-cased transistors in
circuit? I've Googled it but find ambiguous, sometimes confusing
instructions. One method even said it of itself, it was potentially
destructive...yikes.

The Boz

Service Manual/Full Schematic for Biddle BM10 Megger
 

"The Boz" bravely wrote to "All" (26 Nov 05 22:12:07)
--- on the heady topic of " Service Manual/Full Schematic for Biddle BM10 Megger"

TB From: The Boz
TB Xref: core-easynews sci.electronics.repair:349653

TB I removed the 1N5400s, they tested fine when isolated. Probably a
TB Huntron would have helped in that regard.

TB Perhaps someone has suggestions on testing TO-92-cased transistors in
TB circuit? I've Googled it but find ambiguous, sometimes confusing
TB instructions. One method even said it of itself, it was potentially
TB destructive...yikes.


To test the TO-92 transistors in-circuit just use a dmm on diode
function to test the junctions. If you want to be thorough, then
isolate 2 of the 3 transistor terminals to run a hfe gain test. I
haven't met a TO-92 transistor I couldn't desolder using a solder pump
or a solder wick.

A*s*i*m*o*v

.... Letterman of Borg - "Ok, Top 10 reasons why resistance is futile:"

Service Manual/Full Schematic for Biddle BM10 Megger
 

The Boz wrote:

I removed the 1N5400s, they tested fine when isolated. Probably a
Huntron would have helped in that regard.

Perhaps someone has suggestions on testing TO-92-cased transistors in
circuit? I've Googled it but find ambiguous, sometimes confusing
instructions. One method even said it of itself, it was potentially
destructive...yikes.

The Boz
One instrument that I use on occasion is a "Supercricket".
It will test transistor gain incircuit.The other method is the back to
back diode check with a multimeter.Not quite as reliable and not always
useful on FET's.

Andrew