"russ lavergne" wrote in message
news:OiSBf.38334$Me5.2515@trnddc05...
That is what I did with the Huntron but every chip shows problems. I know
every chip is not bad. I think the one bad chip influences the circuit
and makes all chips look bad. Or maybe I am doing something wrong.?
"DaveM" wrote in message
. ..
"russ lavergne" wrote in message
news:KfEBf.2092$AV.429@trnddc07...
I am working on a little board that is part of a big coin op redemption
piece. It has 5 IC's 12 TIP22 transistors a bunch of caps on the IC's.
another transistor and two other electrolytic. There are five of these
boards. All exact duplicates. So I thought that this would be a good
time for a Huntron. But no matter what I do I can't seem to isolate the
problem. It seems where ever the fault is it influences the whole board.
Is there a technique or tool I can use to figure out where the problem
is? I can't apply power because it needs the whole setup to run and it is
far away in a crowed busy place. Any helpful ideas out there for me.
Thanks
Russ


In this scenario, your best approach might be to get a known good board
and record (sketch) the Huntron waveforms on each of the ICs and
transistors. Then you can compare the waveforms on the bad boards to the
good one and come up with a likely bad component.

Another approach could be to try to reverse engineer the circuit and draw
a schematic. That would certainly help you to analyze the problems. The
circuit schematic would also allow you to design and build a test setup
that would simulate normal inputs and allow you to analyze the outputs.

What kind of ICs are on the boards? Download datasheets from the
internet to help you determine what's working and what isn't.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters
in the address)

Never take a laxative and a sleeping pill at the same time!!



A way that I've used in the past to reverse engineer a board and determine a
schematic for it, is to photocopy the print side, then draw on the actual
parts, but in schematic form rather than physical form. You can then derive
the schematic trace by trace, scribbling them out on the photocopy as you
go, using a coloured felt tip pen. From the number of components on the
board, and the simple logic function ICs, should be practical in your case.
I suppose these days, you could probably do the same thing with a scanner
rather than photocopier.

Arfa