Stop in for a cup of coffee

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Miller C-3829. Found a couple of beat up ones on ebay.
book also lists 1-360 but don't know if its Miller or not. Not showing up in my searches.

I think they are calibrated for so its easier to tell if one of the three diodes in the rectifier is open or shorted.
 
Define diode tester. I have a test bench deal fell through on it. you can use a multi meter to test just the diodes.
 
halifaxhops said:
Define diode tester. I have a test bench deal fell through on it. you can use a multi meter to test just the diodes.
Click to expand...
It has an ammeter on it.
Attach one lead on the common, and touch the probe to each lead.
Identify bad ones without snipping the stator connections..
a. Approx 1.75 amps across each is good
b. low on two and 0 amps on one is diode shorted.
c. normal on two, 1 amp on one is diode open.
 
Mattax said:
It has an ammeter on it.
Attach one lead on the common, and touch the probe to each lead.
Identify bad ones without snipping the stator connections..
a. Approx 1.75 amps across each is good
b. low on two and 0 amps on one is diode shorted.
c. normal on two, 1 amp on one is diode open.
Click to expand...
Without a load a ohm meter will still show open or shorted if you put it on either side, we used to do that all the time on aircraft. Now I never had to load test them. They were used a lot with the black box system so the instruments did not get any unwanted signals.
 
I have a cheap cap tester works great. Think it was 30 or so, use it on the distribs, takes to long for the one on the 504 to warm up usually. I be impatient doing them when I run a lot of them at the same time. Have to have the pump running also a lot of wear on it since no parts are available for them (Leather cups)
 
halifaxhops said:
Personally looks like over kill. why you need one?
Click to expand...
The caps? Just to check the ones in the stack of alternators here. In theory, also could use it to check the ones in an older radio here when I get around to it...
 
s-l1600.jpg
 
Mattax said:
The caps? Just to check the ones in the stack of alternators here. In theory, also could use it to check the ones in an older radio here when I get around to it...
Click to expand...
Just use a ohm meter unless you are rebuilding them. Still have to test the output off the alt.
 
halifaxhops said:
Without a load a ohm meter will still show open or shorted if you put it on either side,
Click to expand...
That's what I was doing when checking alternators in the past. I only had an analog multimeter. The GM SI aren't replaced individually anyway so it really doesn't matter if one is bad or all are bad. Same with the squarebacks.

With the roundbacks, the diodes need to be snipped and pressed out individually. When I was reading the book, I was curious how that tester could tell if just one of the 3 were bad.
 
By the total in paraell I would think. If one was open then the value would change and if one is shorted they would all come up shorted.
 
halifaxhops said:
Just use a ohm meter unless you are rebuilding them. Still have to test the output off the alt.
Click to expand...
I've got three to fix. Two are almost certainly blown diodes. Probably replace the cap at the same time. All the replacement is WAI WEI Transpo china made so prob a crap shoot if they last a long time or die in first use. One has a bearing that seized up on me. Got it free with Kroil beleive it or not, but it needs replacing.
The third runs well but a little loose, so it too needs at least one bearing. Someone may want this one for a correct isolated field roundback '70 to '71 only
 
I have some bushings, a few brushes have to check on diodes, get them in the ignition lots quite a bit.
 
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