Ibanez Thermion

[drewl]

Holy @#$% what a piece of @#$%.

Looks like whoever built these did the B52 amps.

Fried power trans, don't suppose anyone replaced one or know of a source before I begin my journey to try and find one, eh?

What a month of weird crap I've been subjected to.
Ho, ho, ho, merry busy Christmas for me.

[Jazz P Bass]

"High efficiency toroidal core transformer with automatically resetting thermal fuse."

It appears that it is no longer 'automatic'.

I'd ditch the toroid & go with something Fendery.
(unless there are goofy taps, like on the Egnater's).

[J M Fahey]

Any generic 100W tube amp transformer should work, anything which can supply around +450V and enough Amperes at 6.3VAC .
As JPB says, however, Orientals have a fascination about adding lots of extra dedicated taps, such as, say, 18+18VAC for the Op Amps (I bet you have a couple even in a supposedly all tube amp) , maybe 7 to 9VAC for some (horror of horrors) Digital stuff, etc.

But before despairing, check and post transformer wiring and where it goes, for an educated guess about voltages.

I guess that worst case you can put a regular transformer as mentioned (EI of course ) ,maybe even a "pull" which is gathering dust (I would, definitely) plus a small one for the low voltage stuff.

And yes, it's probably just another product of a mighty slave factory which makes stuff for everybody.

[drewl]

Thanks, it seems to have a shorted primary

Yeah it does have some odd taps, I have a Dual Rec. around here that might work or use two trans.

Thanks again.


Edit: After finding the schem. it might be worth checking to see if the thermal fuse somehow caused the short, can't hurt.

[J M Fahey]

What makes you think it's a shorted primary?

A fuse, thermal or otherwise, if anything would make for an open primary.

What resistance do you measure across primary leads?

[drewl]

Less than one ohm on the primary with it disconnected from everything.

I have planned to try powering it up with secondaries disconnected as soon as I dig out a replacement for the missing slide in mini fuse holder.

[drewl]

Oh dang the thermal fuse blowing did short the primary and I was able to fix the short after replacing thermal fuse.
Is there nothing I can't conquer?

Then the gods of electronics mocked me as I spent fifteen minutes troubleshooting the front panel lights before seeing the mini switch that turns them off or on.

Humbled once again.

[J M Fahey]

Oh dang the thermal fuse blowing did short the primary and I was able to fix the short after replacing thermal fuse.

Congratulations on having a working amp, whatever you did, but still quite unclear.

Fuses do not short when they fail, they do the exact opposite.

A good fuse is a short ... in series with the winding, not in parallel, and if it blows , it blows open .

a) if you measured 1 ohm DCR across primary winding, no fuse can cause that.
b) what DCR do you measure now?
c) what did you do to repair it?
what did you replace?
how/where was it connected?

Sorry for the questions, but you state something that goes against common knowledge and plain old Physics.

Thanks.

[drewl]

The fuse didn't short, it opened.

What happened is the connection to the thermal fuse shorted to the other side of the primary, as it burned through the insulation.

[Jazz P Bass]

#1: how did you reattach the new thermal fuse?
(Usually they are crimped)

#2: What took out the original fuse?
(overcurrent draw on the secondary?)

[g1]

Yes, if that thermal got hot enough to melt the insulation, there must have been some major current.

[drewl]

Massive current judging by the burn marks from shorted filament which arced on tube socket.

My guess is owner kept putting fuses in and trying it over and over , possibly why fuse holder was missing.