Changed Output Transformer in a Blues Jr -Need Help!

[Nathan]

Hey all,


I decided to swap OT on my Fender Two Tone (really a green board Blues JR).


Here's what I did:


1) Replaced the power resistors to the correct value (all 2W metal oxide)


2) Removed the small PCB with the speaker jack and the FAT footswitch jack by desoldering all 4 wires from the main board


3) Added a Hammond 1760H with 2 mono switchcraft jacks wired for 4 and 8 ohms.


I got everything back together and now nothing works. No sound, no hiss, controls do nothing but tubes are glowing normal.


Here's a pic.


FWIW this amp has had the reverb mod and cathode follower done previously as well as trim pot for bias, but all was working fine before yesterday!


Thanks if you can help

[uki]

If you have the schematic, check all connections that have been changed, then check voltages.

[sluckey]

Recheck your work. Take it all apart if necessary.

[shooter]

Here's a pic.

did you take before pics? compare and contrast.
those spade lugs on the PS are pretty easy to get swapped if you just remembered

if you have to open it up again, look for broke solder connections, "loose teeth I call 'em"

[PRR]

> now nothing works. No sound, no hiss

How many Volts inside?

[tubeswell]

You possibly damaged one or more solder pad/traces removing those resistors or broke one or more jumper/ribbon cables by twisting everything around to get the main board out. Or didn’t put Humpty together again properly.

[dude]

I’d go with “Humpty/Dumpty Together Again” 

[mresistor]

Well glowing tubes means your filaments are working..
Do you have voltage on the plates of the power tubes?



https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-Blues-Junior-Schematic.pdf

[Nathan]

Following up, I got it all sorted out.
It's the Hammond polarity which is reversed from the stock OT.
I also had to figure out the NFB and FAT bypass since they were on that small PCB I removed (easy fix). Sounding great too! Thanks for taking the time to respond guys.