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Not super sure if this is the right board to post this, but here goes.

So I have this old Magnatone Estey T-32 that has never worked the entire time that I've owned it. Every time I turn it on, the fuse blows almost immediately. My guess is that the output transformer is dead (cause it looks pretty sad). I'd like to replace it, but the only information I can gather from the transformer itself are the numbers 20-0120 and 7896-2 The almighty google has failed to aid me on this one.

I found the schematic online and all that shows is a step rating of "11,000:3.2". Is this a normal rating? And are there any other parameters I need to know?

I know nothing about transformers So if anyone can provide any knowledge/advice or knows of any tests I can do with a multimeter, I'd really appreciate it!


Schematic Link: http://www.prowessamplifiers.com/schema ... o_amp.html

Nice (but not nice that the amp's not working).

I was gonna suggest this link, but it doesn't look like they've got any info on transformers.

http://www.magnatoneamps.com/esteyamps.html

I, unfortunately, don't really know much about transformers either.

Maybe they can help you at Mercury Magnetics (or some other transformer manufacturer):

http://www.mercurymagnetics.com/pages/mainframe.htm

Yeah transformers are quite a mystery. Much more than meets the eye

But thanks for the help! I'll definitely look into them and maybe shoot them an email.

You're welcome. Yeah, you should definitely email 'em.

if its blowing a fuse its in the power section at the start of the circuit
if its the mains fuse theres a problem in the power section to make it go over and blow non stop

potentially a problem with the power transformer or something related around that section thats making it kick back all that current


11k:3.2 is the turns ratio for the output transformer

Ahhh ok. I originally figured the power section was the problem.

I had checked out some "amp diagnostics" website and they had a section for reasons why a fuse would blow. While they mostly suggested problems relating to the power section, they did mention that a bad output transformer could be a potential problem (albeit less likely). And my output transformer generally looked like shit, which is why I jumped to that first.

Are there any quick n' dirty tests I can do to maybe diagnose what's wrong with the power section? Or determine if a transformer still works?

off the top of my head you can check if the primary and secondary have gone short across but if that happened on your output transformer it would dump a huge amount of voltage on the speakers and if im thinking properly burn them to a crisp

not sure if you can check the transformer while in circuit

maybe do some googling on checking that with ya meter

its been a long time since i took my transformer classes

fuzzywolf wrote:Yeah transformers are quite a mystery. Much more than meets the eye

But thanks for the help! I'll definitely look into them and maybe shoot them an email.

Thank you for beating me to the punch.

tuffteef wrote:off the top of my head you can check if the primary and secondary have gone short across but if that happened on your output transformer it would dump a huge amount of voltage on the speakers and if im thinking properly burn them to a crisp

not sure if you can check the transformer while in circuit

maybe do some googling on checking that with ya meter

its been a long time since i took my transformer classes

Alrighty! I'll search around and see what I come up with. I appreciate all the help guys.

Mercury magnetics said they can clone my transformer if I send it to them. That'd be awesome, but I wanna be 100% sure that it's bad before I go shipping it out.

I would take it to a tech for a diagnosis and from there decide if I can fix it myself or not.