Wanted Phase Linear DRS400 (for parts or working)

Tech19642020

New Around These Parts
Joined
Sep 12, 2020
Messages
13
#21
Hello,

Thank you very much for your reply. Yes I suspect shorted primary windings in one primary as well and the earlier tests performed seem to bear that out. Since it's a dual primary series-parallel I think the windings should be of equal inductance and one measures approximately 80% lower than the other. (while, the checker I have isn't reliable, relative measurements differ dramatically). I used to be able to smell failures like this but I've been a laryngectomee since 2011 and my sense of smell is greatly diminished. However, it's also discolored which may be a further sign of thermal damage to the windings. While the design of this amp certainly has it's limitations and your points are well taken the unit has a certain sentimental value to me that I hope to make it work again. Thanks again for your recommendations and feedback. Take care.
 

WOPL Sniffer

Veteran and General Yakker
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Aug 10, 2015
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5,975
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Arizona
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Screw it
#22
Do like Jim wanted to do. Stuff a transistor radio into the chassis and make it LOOK like it really works.

I'm not really a sentimental guy.
If it's junk.......... Strip it and let 10 other amps live because of the good parts. Then you can be sentimental with TEN working amps.
 
Joined
Apr 26, 2011
Messages
389
Location
Central Ohio
#24
it's safe to assume that one primary was would and then the second one on top of it. Therefore the second primary has longer wire and will measure higher resistance. I would expect the resistance though to be a few ohms.
 

nakdoc

Journeyman
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May 11, 2011
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473
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Nashville, TN Music City
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highly biased
#26
It is possible to have shorted windings caused by insulation failure. If you feed 20 volts AC into the good primary and get 20 volts on the "bad' primary, something else is wrong. You can't operate a transformer with any sort of winding short because it changes the mutual inductance.
 

J!m

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Dec 24, 2019
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Connecticut
#27
If we know the primary and secondary, wouldn’t it be possible to get an off the shelf torroid to replace the original? Maybe some output voltage tweaking with regulators?

How “unique” is this transformer?
 
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