Mojo 771 output transformer ???

[Jerome]

I was putting together a 5F2A and it has a Mojo 771 output transformer. It has the standard bule and red. but then it has a 4 ohm and 8 ohm plus negative. I tried many different ways to hook this up so I finally went to a SPST switch but I think I may have shorted out the transformer. Frustrated! Who can I be for sure the transformer is crap? How exactly are the double jacks to be hooked up for 4 and 8 ohms with out a switch?

[shooter]

here's what I found on Mojo's site.  Blue "should" be plate, Red B+, the 2ndary side looks like 1 lead is connected to tranny case, find that one = ground, the yellow says 4ohms, tape off the rest.  But If it was me and I paid, I'd call and get Mojo's input.

[HotBluePlates]

I was putting together a 5F2A and it has a Mojo 771 output transformer. It has the standard bule and red. but then it has a 4 ohm and 8 ohm plus negative. ... How exactly are the double jacks to be hooked up for 4 and 8 ohms with out a switch?

Negative goes to the Ring (ground) of both jacks.

4Ω tap goes to the Tip (positive) of your 4Ω jack.

8Ω tap goes to the Tip (positive) of your 8Ω jack.

If you're using switching jacks (there's a 3rd lug), you probably don't want to use that lug on either jack.  That's because if you ever plug into the other jack your output signal will be mostly shorted to ground and you'll get barely-there fizzy output.

... I tried many different ways to hook this up ... but I think I may have shorted out the transformer. Frustrated! Who can I be for sure the transformer is crap? ...

You probably can't hurt the output transformer by shorting the secondary.  So the transformer is probably fine and you're just having issues with wiring to a speaker jack.

[Jerome]

Were do I tie in the feedback wire? To the negative or positive?

[Jerome]

I was testing the yellow, green and black leads with the sound tester and no matter what combination I touch it beeps. does this mean its shot? I know my + and - shouldnt be tied in together.

[sluckey]

The beep means it's good. I thought you had all the info to hook that transformer up from our pm conversations?

[Willabe]

I know my + and - shouldnt be tied in together.

Yes they should.

Each set of primary and secondary wires on an OT or PT is a coil of wire wound around a magnetic core, steel lamination's.   

1 lead is the start of the coil wind and the other is the finish of the coil wind. It's all 1 wire. When you have more than 1 secondary speaker ohm option then the 3rd wire lead is a tap from somewhere along the wind.

Some have a center tap (CT) like a PT high voltage B+ wind or on a PT heater secondary.   

[Jerome]

Its not the OT after all. Every thing is firing up and looks good just not getting any sound just a soft signal when i touch the end of my instrument cable. I checked all my connections and every thing seems right. I hooked up the double input jacks and every thing looks good there. Confusion setting in. :)