Traynor YCV-40 No Reverb

[ca7922303]

Reverb tank tested bad, replaced tank with known good tank, still no reverb. Replaced op amp associated with reverb circuit, no change. RCA cables have continuity. Changed preamp tubes to known good tubes?

[Jazz P Bass]

Are you getting a signal out of U2 pin 7: That is the Send.
Are you getting a signal out of U1 pin 7: that is the Return

[ca7922303]

Are you getting a signal out of U2 pin 7: That is the Send.
Are you getting a signal out of U1 pin 7: that is the Return

Yes, getting signal out of u1 & u2 pin#7. Tested again a known good reverb tank and still no signal, previously replaced u1.

[Enzo]

Just thinking, when you say known good pan, are we making sure it is the correct type? A 4EBxxx would be expected here, a 4ABxxxx would be the type Fender uses with the little transformer drive. They are not interchangeable.

Make sure cables are not reversed.

What exactly is wrong here? All reverbs have two sides: the drive side and the return side. One side can be good but the other side bad, and no reverb results. Assuming the reverb cables are good - we did test them didn't we? - plug the cables into the amp, and touch the tip of each with a finger. One should make a loud hum. THAT one plugs into the OUTPUT jack on the pan. If neither one hums, then your return side is bad. If one does hum, great, that means the drive side is bad.

[ca7922303]

Just thinking, when you say known good pan, are we making sure it is the correct type? A 4EBxxx would be expected here, a 4ABxxxx would be the type Fender uses with the little transformer drive. They are not interchangeable.

Make sure cables are not reversed.

What exactly is wrong here? All reverbs have two sides: the drive side and the return side. One side can be good but the other side bad, and no reverb results. Assuming the reverb cables are good - we did test them didn't we? - plug the cables into the amp, and touch the tip of each with a finger. One should make a loud hum. THAT one plugs into the OUTPUT jack on the pan. If neither one hums, then your return side is bad. If one does hum, great, that means the drive side is bad.

Yes, a 4eb was in it and it tests bad, bought a new 4eb which works in the twin reverb in another post, but not in this traynor. RCA cables both show continuity. I will do the hum test again tomorrow to make sure.

[ca7922303]

Just thinking, when you say known good pan, are we making sure it is the correct type? A 4EBxxx would be expected here, a 4ABxxxx would be the type Fender uses with the little transformer drive. They are not interchangeable.

Make sure cables are not reversed.

What exactly is wrong here? All reverbs have two sides: the drive side and the return side. One side can be good but the other side bad, and no reverb results. Assuming the reverb cables are good - we did test them didn't we? - plug the cables into the amp, and touch the tip of each with a finger. One should make a loud hum. THAT one plugs into the OUTPUT jack on the pan. If neither one hums, then your return side is bad. If one does hum, great, that means the drive side is bad.

I've got the white RCA cable(input) humming, red RCA cable(output), no hum.

[Enzo]

I've got the white RCA cable(input) humming, red RCA cable(output), no hum.

Humming cable plugs into the jack on the reverb pan marked OUTPUT

[ca7922303]

Humming cable plugs into the jack on the reverb pan marked OUTPUT

I'm pretty sure I already tried swapping cables, but I'll check again this evening when off work. Thanks for the help.

[ca7922303]

I'm pretty sure I already tried swapping cables, but I'll check again this evening when off work. Thanks for the help.

Swapped cables, no reverb. Could u2 be an issue?

[ca7922303]

Humming cable plugs into the jack on the reverb pan marked OUTPUT

Could reverb pot be an issue?

[Enzo]

I wasn't concerned over swapping cables, I just wanted to verify the humming cable plugs into the pan OUTPUT.

Once that is secure, if you bounce the pan, with the reverb control up, do you hear the loud spring crash? If so, the return circuit is working and the drive is the issue.

Repair is about isolating the problem, not guessing if this part or that part is at fault. What if the problem is not a bad part at all? We could have a cracked copper trace or something.

[ca7922303]

I wasn't concerned over swapping cables, I just wanted to verify the humming cable plugs into the pan OUTPUT.

Once that is secure, if you bounce the pan, with the reverb control up, do you hear the loud spring crash? If so, the return circuit is working and the drive is the issue.

Repair is about isolating the problem, not guessing if this part or that part is at fault. What if the problem is not a bad part at all? We could have a cracked copper trace or something.

Ok, humming white RCA cable into output of 4eb pan producing no sound when bouncing pan. Reverb pot does function. I get only static when turning volume up on either channel with reverb on 10. Tried 3 other reverb tanks I have around, and no luck.

[Enzo]

Measure resistance from th outer contact of th white plug up to chassis. The cable may be OK< but is the whole gound circuit?

[ca7922303]

Measure resistance from th outer contact of th white plug up to chassis. The cable may be OK< but is the whole gound circuit?

Getting resistance white plug outer contact to chassis.

[ca7922303]

Measure resistance from th outer contact of th white plug up to chassis. The cable may be OK< but is the whole gound circuit?

Getting 000 white plug outer contact to chassis on continuity range. 098 red plug outer contact to chassis continuity range.