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Help with Secondary Wire Colors on Fender Output Tranny #018343

7/11/2000 1:34 PM
Tim P
Help with Secondary Wire Colors on Fender Output Tranny #018343
I have a question regarding a Fender amp output transformer I have. It is Fender 50 Watt output transformer for dual 6L6GC output tubes (Fender part #018343).  
My question is what are the correct wire colors for the 3 different output taps (i.e. green=4 ohms, etc.) for this tranny?  
I have seen conflicting information from several Fender authorized part dealers on the web regarding this transformer (specifically which wire is the 8 ohm tap and which wire is the 4 ohm tap).  
Tim P.
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7/12/2000 1:51 AM
Dave K

Black-common,white-2 ohm,green/yellow-4 ohm,green-8 ohm.Fender used these in the 60 series,schematic is in Pittmans book.  
Dave K
7/12/2000 3:19 PM
Tim P
Hoffman site says green/yellow-8ohm and green-4ohm
Hoffman's web site has the secondary wires for this transformer listed differently.  
I have an early 80's Rivera era Fender Concert with this output transformer.  
7/12/2000 9:28 PM
Dave K

Tim,I used the official Fender schematic printed in Pittman's book for the 60 series,plus the Angela web site has the color codes for this OT.If you have a DMM with a low ohms setting,just measure the resistance from the common to the various taps,then you'll be sure.  
Dave K
7/13/2000 3:17 AM
Carl Z1

Dave's colors seem more consistent with what comes out of the Schumacher facility. It's tricky to say for sure with the trannies that Hoffman and others use because these are non stock units from different manufacturers so all bets are off.  
A few notes on dave's measurement suggestion. First I have never seen a tranny that doesn't use black for ground so you're safe there. Now, you're going to get resistance measurements on the secondary that are really small. if you're over an ohm on any tap I'd be suprised and would suspect a blown tranny. You'll also want to lift the ground lead because the chassis resistance could screw up tehe values. For accuracy's sake short the leads and determine the resistance of the probe to help reduce erroneous readings. This will usually be around 0.8 ohms.  
Carl Z
7/15/2000 2:47 PM
Randy Jamz

One of the reason I shelled out a couple of hundred bucks for a fancy shmancy DMM was that it had an inductance measuring capability. I would measure the two inductances and the higher one would be 8 ohms while the lower reading would belong to the 4 ohm tap. Too easy, but before I bought this meter I had to 'borrow' an even more expensive impedance meter.  

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