Super Reverb pr469 2000 era no reverb

[nosaj]

I have a 2000 super reverb driving me nuts. no reverb I get signal to reverb send but nothing on the out.
Ok so I look at tp19 15 or 16 vac disconnect reverb transformer connections us hp sig gen input 15vac sine transformer looks ok so i do the same with reverb tank it also passes signal.
I put a jumper between send/receive reverb connections signal passes though the rca jacks.

Any pointers would be great.

nosaj

[The Dude]

Maybe you have signal, but not enough? Bad tube or plate resistor? What are your plate and cathode voltages on V3 and V4?

[Chuck H]

You're probably already ahead of this, but how about continuity for the RCA cable and reverb pot? I don't know what test points you used when you found signal passes with a jumper. And I assume you used the reverb cable from the amp as a jumper, but test both leads.

[g1]

You disconnected reverb drive transformer and put 15VAC into it's primary? Did you check the output of it while driving the tank? Should have been around 285mV there (TP20) with tank connected.
Still could be an issue with the drive transformer when high voltage put to it.
Try Enzo's trick of connecting reverb send to 8 ohm speaker instead of reverb tank. Should be able to hear a clear signal.

[Helmholtz]

Enzo whack test?

If negative, check for tank in/out reversal and inspect the tank itself for broken connections or even spring suspensions.

[nosaj]

Maybe you have signal, but not enough? Bad tube or plate resistor? What are your plate and cathode voltages on V3 and V4?

No signal applied All voltage Vdc
nosaj
V3
Pin1 437
Pin2 .01
Pin3 7.76
Pin4 437
Pin5/6 .001
Pin7 .04
Pin8 7.76
Pin9 .001

V4
Pin1 258
Pin2 .004
Pin3 2.16
Pin4 258
Pin5/6
Pin7 -.011
Pin8 2.15
Pin9 -.001

[nosaj]

You're probably already ahead of this, but how about continuity for the RCA cable and reverb pot? I don't know what test points you used when you found signal passes with a jumper. And I assume you used the reverb cable from the amp as a jumper, but test both leads.

Signal is not reaching the reverb pot. Yep continuity on red and white cable(tried known good cable just cause)
Also tried another reverb pan. i can hit the springs and hear that in speaker showing reverb recovery is working.
nosaj

[nosaj]

You disconnected reverb drive transformer and put 15VAC into it's primary? Did you check the output of it while driving the tank? Should have been around 285mV there (TP20) with tank connected.
Still could be an issue with the drive transformer when high voltage put to it.
Try Enzo's trick of connecting reverb send to 8 ohm speaker instead of reverb tank. Should be able to hear a clear signal.

I did not check the voltage though i should have I was just using a scope probe to see it.
i forgot to hookup ch1 output of scope to my test amp so i can hear when I probe. Will follow up tomorrow after another grueling day of work. Only a few more weeks and it should cool off here.
nosaj

[nosaj]

Enzo whack test?

If negative, check for tank in/out reversal and inspect the tank itself for broken connections or even spring suspensions.

Nothing broken signal just stops at the input transformer. Same thing with known good reverb tank.
nosaj

[Helmholtz]

So unplug the reverb drive cable at the amp and measure resístance at the plug (pin to "crown").
Should be around 1R.

If that's good, you must have a contact/connection issue at the reverb drive RCA jack.

[Chuck H]

No signal applied All voltage Vdc
nosaj
V3
Pin1 437
Pin2 .01
Pin3 7.76
Pin4 437
Pin5/6 .001
Pin7 .04
Pin8 7.76
Pin9 .001

V4
Pin1 258
Pin2 .004
Pin3 2.16
Pin4 258
Pin5/6
Pin7 -.011
Pin8 2.15
Pin9 -.001

I think these pin numbers must still be off.?. 4/5 should be the filament and 6 should be a plate.

[Chuck H]

Signal is not reaching the reverb pot. Yep continuity on red and white cable(tried known good cable just cause)
Also tried another reverb pan. i can hit the springs and hear that in speaker showing reverb recovery is working.
nosaj

I'm having trouble with this. If signal isn't reaching the reverb pot then how can spring vibration resound in the speaker?

[g1]

I think he means the 'audio' signal is not getting as far as the reverb pot. But non-signal crashing of the tank shows recovery side is good.
Still doubt the tank input is getting sufficient drive.

[Helmholtz]

The resistance test I suggested above will show if:

- both cable conductors are good
- there's no short between cable conductors
- the drive transducer is well connected and
- is not open or shorted and
- has correct DCR.

Also, how about the speaker (or headphone) test suggested in post #4?

[nosaj]

So unplug the reverb drive cable at the amp and measure resístance at the plug (pin to "crown").
Should be around 1R.

If that's good, you must have a contact/connection issue at the reverb drive RCA jack.

Getting 2.3 ohms
nosaj