Can anyone help me fix this transformer??? (pics)

Started by dirkfunk, March 10, 2005, 01:05:41 AM

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dirkfunk

If anyone can post a link or a "how to" on repairing this vintage electro harmonix hot tubes transformer. As in the pics you can see that all i need to do is re wire the positive and negitve to the transformer from the power cord. The transformer is a 20v ct 2x10 50ma....10ma. Thank you..








ninoman123

Id buy a new transformer, must likely ur vintage transformer isnt adding much to the sound (if thats what ur going for). Plus transformers are scary  :shock: I think (and someone check me on this) That you would have to rewind the primary side to attach the power cord. If so, screwing up the primary of a transformer can cause some problems if you dont do it right. GEO has a webpage for a power supply called the Spyder. They have an step by step for rewinding the secondary.

toneman

i agree w/nino..
an xfmr is an xfmr.
ALA it' has the right V out.
while U R at it, why not add a linear reg(?)
on the EH HotTubes, it's not *real* tubes, is it?
don't have my fuzz list nearby.
if box runs on 9VDC, fersure add that reg.
also,  adding a reg will allow a more diverse selection
of xfmrs ALA the rectified V doesn't exceed max reg inputV.
*if* it's tubes, & a hiV supple, a reg will B a little harder.
but *not* impossible.......
stayregged
tone
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TONE to the BONE says:  If youTHINK you got a GOOD deal:  you DID!

dirkfunk

if i were to run 2 9 volts? how would i wire up the 3 wires going to the board? Or will that even be enough power ?

ninoman123


dirkfunk

im trying to power this pedal, without it blowing up,or changing the sound of it. What are you trying to do?

R.G.

Dirk, don't mess with it.

You're trying to rewire the 120ac onto the transformer, right? Don't do that. If you had the necessary skill to do that safely, you wouldn't have needed to ask.

Your life isn't worth what you'd save.

If the objective is to keep it "vintage" so it doesn't look like it's been repaired, get someone to rewind the transformer that's there.

For a premium replacement, whip in a Digikey TE62002-ND Amveco toroidal ($13.68); 12+12 at 67ma, probably smaller than what you have and definitely quieter. AS an economy alternative, the Xicon power transformers from Mouser will do the job. The 41FJ300 is rated at 20.6Vac CT at no load, and sags to 18.0Vct at full load - or 300ma! Powering the EH it will always be loafing. It's $4.55. The datasheet and physical measurements are at Mouser's site.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

dirkfunk

i hooked up one 9 volt to the circuit and it worked. I am wondering if there is any sound differennce if i were to run a 12v transformer?

Rob Strand

QuoteYour life isn't worth what you'd save.

or someone elses....
Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

flatten

HUm...I got a similar problem...I found this vintage EH hot tubes and played with during a couple of hour, then the box stopped to play anymore...

I tested the transformer :

voltage mode = 0V accross each secondary (unit plugged)
resistance mode = 39.4 / 39.5 ohms for each secondary and I found infiny for the primary

Well, I can say my transfo is out...Right ??? this transfo is yet a replacement one...may be with bad values...don't know...
I found in this forum :

2 x 10V 50mA / 100mA
2 x 12V 67mA
and more...
but I live in France and I need a primary at 220/240V...Someone can give me accurate values for this transfo...

thanks