1963 Fender reverb box

[Valvehead]

Anyone worked on one of these ? Cool project came along --one of those 6G15 stand alone Fender reverb heads .

Got it up and running , needed new diodes , 3 prong ac cable , and a 12ax7. The unit passes signal fine and isnt noisy , but , No reverb !

All the voltages listed on the scem check out good , ive swapped all tubes , swapped rca type cables , and tanks .

This thing is all original inside and i dont see any leaking electrolytics .

Should i see any voltage at the rca jacks ? i have 0 vdc

any ideas ?

i can hear the Tone control working , but not the other 2 controls

Fender-Reverb-6G15-Schematic.pdf

[Helmholtz]

All the voltages listed on the scem check out good ..

Does this include tube cathode and plate voltages?

Should i see any voltage at the rca jacks ?

No DCV on rca jacks.

Can you hear the springs when you shake the tank?

Connect a speaker to the rev. send output to hear if the driver stage is working.

[Mick Bailey]

There's no voltage on the on the RCA plugs. If you unplug the tank output and touch the plug pin you should get a loud hum. If not, something is wrong with the recovery side, but make sure the pedal connection isn't shorted! If that's working, maybe tank isn't getting a signal. I use a pair of headphones connected to an RCA socket for listening the the input signal (just one side connected in mono connected to the unplugged tank input lead). The drive circuit is essentially a low-output power amp (about 1W). An 8 Ohm speaker also works. If there's nothing there then check the transformer is OK. You say the voltages are fine, so the transformer primary should be good, but the secondary could be open. Check you have a signal on the grid of the 6K6GT (scope or even a DMM set to AC works)

[Valvehead]

Does this include tube cathode and plate voltages?




No DCV on rca jacks.

Can you hear the springs when you shake the tank?

Connect a speaker to the rev. send output to hear if the driver stage is working.

no noise from tank--tried 2 , tried swapping the in/out just to make sure

will try the speaker check.

Yes , all voltages you see on that scem are good

[Helmholtz]

no noise from tank--tried 2 , tried swapping the in/out just to make sure

will try the speaker check.

Yes , all voltages you see on that scem are good

When you can't hear the springs, you have a problem on the recovery side.
With unit turned off, make sure the 7025 grid is not shorted to ground (by the pedal).
Also try the finger test with the return cable as Mick Bailey recommended.

BTW, tank input DCR should be around 1.2R and tank output DCR should be around 200R.

[Valvehead]

Continuity from amp jacks to and from tank

tank tests 33 ohm / 200 ohm at its jacks unplugged

8 ohm speaker wired to rev out jack on amp i DO hear guitar out of it

shorting jack and wire to 12ax7 is all good

when playing ACV jumps from 0 to 3v at pin 5 on 6k6

when uplugging / touching either rev cable there is zero buzz or noise .

i can try and completely bypass that shorting jack

[Helmholtz]

shorting jack and wire to 12ax7 is all good

Measure resistance from 7025 (upper triode) grid to ground.
Should be around 200R with tank connected.

[Valvehead]

Measure resistance from 7025 (upper triode) grid to ground.
Should be around 200R with tank connected.

yes , 198

[Valvehead]

For the heck of it, i un-wired the short jack , no verb.

tried another known good tank - no verb

[Helmholtz]

Ok, time for signal generator and scope.

Is the Tone pot good?

[Valvehead]

You arent going to believe this..........

the tone and mix pots are in the wrong holes in the chassis....and are wired wrong...........someone has been in here before i guess.....

[Valvehead]

Moved and re wired the pots proper.........unit works perfect---sounds pretty cool. Thanks for the help boys