Vox Berkeley ll Low output

[52 Bill]

very faint at neg end of C5 Bill

and faint sig at the emitter of Q2

Check all of the tone pots and related wiring, etc.

Inject the signal at the wiper of the treble control and then at the top of the treble control at C8. Inject the signal at the top of the bass control. Be sure to sweep the controls through their full ranges while doing these tests.

Did you test Q1 and Q2?

[Garydean]

thanks Bill,

The signal is very soft on the signal side of J1's 68k resistor. The output side of that resistor I get a louder signal. On J2 it's the same scenario but the signal is stronger but not as strong as the wiper of the volume pot. I get a good signal around the controls and is fully adjustable.

I am getting an OK signal when I inject at the emitter of Q2. Before really cleaning the pots I did not . When I inject at the emitter of Q1 it faint and scratchy.

[52 Bill]

The signal is very soft on the signal side of J1's 68k resistor. The output side of that resistor I get a louder signal. On J2 it's the same scenario but the signal is stronger but not as strong as the wiper of the volume pot. I get a good signal around the controls and is fully adjustable.

The three input jacks are wired like a Fender, so that when you use a single jack (J1) all three input isolation resistors are paralleled across each other through the N.C. switches on the jacks. Make sure that you clean all of the contacts on the three input jacks.

I am getting an OK signal when I inject at the emitter of Q2. Before really cleaning the pots I did not. When I inject at the emitter of Q1 it faint and scratchy.

Test Q2? Inject a signal at base of Q1.

[Garydean]

the signal is coming through but not as strong as the base of Q3. As I work toward the jacks I loose strength.

[Garydean]

Here's something that's interesting. I replaced Q1 and Q2 with 2n4401 transistors. Not sure why but.... Q1 Used to have 15v on the collector, now has 4v. Q2 dropped in voltage as well. I flipped the board to see if something had gone wrong and everything is visually dandy. I'm supposed to be getting 17v to the board which feeds Q1. I have 4v. I checked the specs of 2n4401 and it seems like it should work.

This is getting old.

Gary

[Enzo]

Are the legs in the same order as the old parts? ANy chance the transistor needs to turn the other way? Vollow the trances to other components and verify teh base, collector and emitter are connected to the right spots.

[Mike C]

I found your site while looking for some trouble shooting info for this same amp with just about the same symptoms. The volume control has no real effect on the output level and when turned just about all the way up with the reverb turned on it will start to go into oscillation. I do not have a schematic or even a board layout to go by. Just wondering how yours turned out.

Thanks
Mike C.

[Enzo]

Hi Mike, welcome to the forum.

May I suggest you start a new thread for your amp. You will get better response than by tacking on the end of an old 2008 thread.

At the top of this section is a schematic request sub-section. You can post a schematic request there, and someone may have it.

We also have a search function right here in the forum, you could search for Vox Berkley and see if other threads already have schematics and other useful stuff already posted.