Vox Gremlins (90's AC15 TB).

[Sea Chief]

Chuck H I totally agree, but I will check in case I put a connector wire under X not over it. I definitely did not hear this prior to my dicking with it though.. it was one of the things I ticked off (clever tremolo joke) my list with it mind to sell soon.

Anyway will have to sell as is if I cant rid it- it's not too bad really. thanks again SC

[Sea Chief]

Could someone help me out again. I had success redoing the reverb tank spring.. but now the reverb is not working. Not even intermittantly. Zilch.

I've checked the tank springs/ intact. I've unplugged the ftsw plug from amp, but reverb still not working (not sure if will do only via ftsw).

Its a tremolo/ reverb 2x button, typical jobby. I put my DMM between the (stereo) plug tip, & ring middle section: I get an Ohm reading/ then infinity when I switch off. Same between the tip & the sleeve with this tremolo switch.

But doing the same DMM test clicking the reverb button on/ off.. it remains infinity. Does that define there's a problem with this switch-?

Many thanks- SC

[pdf64]

So with the footswitch unplugged and reverb and master vol controls turned up, is there a big clang through the speaker if the tank is knocked (like you'd knock on the front door of someone who is a little hard of hearing )?

[Sea Chief]

So with the footswitch unplugged and reverb and master vol controls turned up, is there a big clang through the speaker if the tank is knocked (like you'd knock on the front door of someone who is a little hard of hearing )?

I think I know what you mean that reverb 'clang', Pixies did this on a few recordings- I'll give it a go.

Lift amp & drop one of its corners a little you mean by 'knock' or literally a firm knock on the tank? thx pdf.. SC

[Sea Chief]

pdf64 yup get the echoey 'clang' alright. thx SC

[pdf64]

Ok so the issue is in the drive side of things.
I suggest to check for continuity on the tank’s drive transducer.
While you’ve got the RCA cable unplugged, may as well check the plug for continuity back through the drive transformer secondary.
Has V3 been warming up / is it properly seated / good?
How about CON2, try reseating it?

[Sea Chief]

Ok so the issue is in the drive side of things.
I suggest to check for continuity on the tank’s drive transducer.
While you’ve got the RCA cable unplugged, may as well check the plug for continuity back through the drive transformer secondary.
Has V3 been warming up / is it properly seated / good?
How about CON2, try reseating it?

Hi pdf.. so you mean take tank out, check continuity between two points within it? Or from one of the unplugged rca into the tank, discounting the tank, then measuring between here and a point within the amp.

Sorry as usual Im lost. Thanks SC

[Sea Chief]

pdf64 got the thing working again.. I think perhaps some tube3 pins bent, or a connection somewhere, anyway great!

I wonder if you had any ideas on the ticking trem? Last thing now.. & its in good health.

Tick only prominent from depth dial 3/4 mark to max. Last 1/4 rotation.

SC.

[pdf64]

As it manifested after you refitted the pcb, it seems likely that it’s due to something not being quite as it was before, eg a wire dislodged or just moved a bit, an 0V connection not properly remade or broken.
All you can do really is carefully review every little thing that might have changed.

[Sea Chief]

As it manifested after you refitted the pcb, it seems likely that it’s due to something not being quite as it was before, eg a wire dislodged or just moved a bit, an 0V connection not properly remade or broken.
All you can do really is carefully review every little thing that might have changed.

Understood pdf.. the only thing I can add to symptoms (& I've tried reseating all tubes, swapping all the 12ax7's, cleaned up el84 pins) is say the lower the speed rate, the earlier on the depth knob the ticking starts.

If I get a bit more 0v buzz when I let go of my gtr strings (might have been like this before I took out pcb tho) maybe some 0v numnums then.

great help- thanks SC

[Sea Chief]

Gordon Bennet. I get the reverb sorted, so put amp back in cab.. & it doesnt bloomin work.

pdf64 sorry I'm back a full step here pdf. Ok if I don't now hear the "clang" if I bump the amp with both its vols up high, erm what does that point to-?

(apart from abject idiocy that is)

thx SC

[pdf64]

That will be an issue with the return side of things, eg the pick up transducer / connection to it / bad valve in V2.
https://el34world.com/charts/Schemat...x_ac1596pr.pdf

[Sea Chief]

That will be an issue with the return side of things, eg the pick up transducer / connection to it / bad valve in V2.
https://el34world.com/charts/Schemat...x_ac1596pr.pdf

Ok thanks- will obviously do a thouragh rejigging of connections 1st up & go from there. I did try v2 by swapping in a new 12ax7, so think I crossed that off list. Transducer.. I dont like the sound of, out of Dr.Who or something.

Should the sleeve of the white 'input' have continuity to the tank case, as red output's seems to?

[pdf64]

Dunno for sure, the tank model code contains that spec. But usually not.

[Sea Chief]

Dunno for sure, the tank model code contains that spec. But usually not.

Hi pdf.. got the blighter working again- well, it's either an rca connection, or something inside the tank- but there's nothing suggesting amiss in here.

Anyway thanks pdf. Its back together & in good health again..