Teisco checkmate 20 no reverb

[the19thbear]

image below:

https://imgur.com/ib73oui



Hi. I have a teisco checkmate 20(I think, the case itself has been destroyed and someone else built it into a new box). Looking at pictures of the unit, it seems to be a checkmate 20. (Maybe checkmate 18)
No sound is coming from the reverb.
I swapped out the 2 12ax7 (why is it showing 6 tubes in schematic, it only has 2? Not checkmate 20, or is it because a single tube has several functions?), also changed the 6av6 and still no sound from the reverb.
I don't really want to fiddle around with inside wiring, because of the possibility of high electrical shock (tube unit). I have repaired a lot of transistor based stuff (Still a beginner at electronics though, but i'm afraid of tube voltages

Also the tremolo dies out after abut 4 min of power on. What tube is responsible for tremolo?

It has a reverb pedal output/input on the back, the same for tremolo. Not shown in schematic though


Any suggestions?
thanks

[Jon Snell]

This reverb uses a crystal driven spring reverb unit and requires a high impedance driver stage.
If you tap the reverb unit, does it make a noise, if it does, the receiver part is working. If not, check the crystal output of the reverb tank.
If you monitor the driver side, there should be signal going to the transmitter side of the tank. If not, find out why not.
The 6AV6 has nothing to do with the reverb, it runs the tremolo.
Check the anode load resistors, especially the 100k resistors.

[the19thbear]

Sorry, but I'm stupid. Where are the anode resistors located?
And already changed the 6av6, so it can't be the tube that's dead.

[Jazz P Bass]

This may or may not help.

[Jon Snell]

Sorry, but I'm stupid. Where are the anode resistors located?
And already changed the 6av6, so it can't be the tube that's dead.

There are a few that may be suspect, circled. As I said the 6AV6 has nothing to do with the reverb.
The 20 is similar.

[the19thbear]

There are a few that may be suspect, circled. As I said the 6AV6 has nothing to do with the reverb.
The 20 is similar.

Thanks. Was talking about the tremolo though

And Jazz P Bass: thanks for the schematic

[Jon Snell]

From your first post; "also changed the 6av6 and still no sound from the reverb."
I would check the three 0.02uF oscillator capacitors, the 0.1uF coupling capacitor and of course the 100k Anode load resistor.

[g1]

It will be very helpful to figure out which schematic is correct. How many tubes of each type are in your amplifier?

[Jon Snell]

It will be very helpful to figure out which schematic is correct. How many tubes of each type are in your amplifier?

The schematics should not matter, as the relevent parts are similar.

[g1]

The schematics should not matter, as the relevent parts are similar.

It will be very difficult for a novice to find them. No offence intended to the OP, but he was unaware that a 12AX7 contained 2 triodes.
Best to have at least the proper reference to begin with.

[gui_tarzan]

Do you have it open? Can you post clear pics of the inside including the reverb pan?