Trem not working on Ampeg Gemini I

[beedoola]

Well then, nevermind. Have you read the voltages on the tube?

Ok with the footswitch ON, I'm getting 90-130v at Pin 6. with it OFF, I'm getting around 188v

At Pin 8, I'm getting a flux of 0-.8v with the switch ON. with the switch off, I get about 3v and it just climbs

Pin 1 - 77v with the with both ON and OFF
Pin 2 - no voltage
Pin 3 - around .6v with switch ON and OFF
Pin 4 & 5 - 13.3v both On and OFF
Pin 6 - as mentioned above
Pin 7 - No voltage
Pin 8 - as mentioned above
Pin 9 - 13.5v On and OFF

I used this schematic to get the voltages for Pins 6 and 8. And below are some pics of the guts of this gemini:

http://imageshack.us/f/199/ampeggemini1schematic.png/

[52 Bill]

Read the voltage on the purple wire going to optoisolator.

[audiopete]

Also disconnect the opto from the pot and read the resistance across the LDR with the trem oscillating. It should sweep up and down. If it reads open or zero ohms you found your problem. It should be zero or close with trem off. Also the neon bulb could be bad and not firing but you still could get the ticking as it tries to ignite the neon.

[beedoola]

Read the voltage on the purple wire going to optoisolator.

I get around 60v, it varies to down around 56v

Am I supposed to get voltage off the other write - the brown? Cause I get none. Its also tied to ground, is that right?

Also disconnect the opto from the pot and read the resistance across the LDR with the trem oscillating. It should sweep up and down. If it reads open or zero ohms you found your problem. It should be zero or close with trem off. Also the neon bulb could be bad and not firing but you still could get the ticking as it tries to ignite the neon.

I removed the side that does to the depth pot, I get a variable resistance when the trem switch is activated.

[52 Bill]

I get around 60v, it varies to down around 56v

Am I supposed to get voltage off the other write - the brown? Cause I get none. Its also tied to ground, is that right?




I removed the side that does to the depth pot, I get a variable resistance when the trem switch is activated.

The brown wire is grounded so there will be no voltage there.

What sort of resistance readings were you getting on the LDR side? How about the depth pot, does it go from 4 meg to zero ohms?

[beedoola]

with the switch OFF - getting around 28k. With it ON, getting around 33-46k on the LDR. - This is with the LDR leads disconnected from the Depth pot.

Also, should I get ANY voltage on the side of the 1uf coming off Pin 1 of V5? (schematic below). This goes to the depth pot. I around 180v on the side to pin 1,the schematic linked says 170v is what it should be, but on the other side of the cap I get zero-.2v - is that normal?

for the Depth pot - 50R when counterclockwise, 5.8M when Clockwise.

I'm also no longer getting any LFO tick when the Trem is On.

http://imageshack.us/f/199/ampeggemini1schematic.png/

[52 Bill]

with the switch OFF - getting around 28k. With it ON, getting around 33-46k on the LDR. - This is with the LDR leads disconnected from the Depth pot.

Also, should I get ANY voltage on the side of the 1uf coming off Pin 1 of V5? (schematic below). This goes to the depth pot. I around 180v on the side to pin 1,the schematic linked says 170v is what it should be, but on the other side of the cap I get zero-.2v - is that normal?

for the Depth pot - 50R when counterclockwise, 5.8M when Clockwise.

I'm also no longer getting any LFO tick when the Trem is On.

Imageshack - ampeggemini1schematic.png

There should be no voltage on the pot side of the cap that you are asking about. In fact if there was, it would need to be replaced.

When you take the reading on the LDR, the trem must be on and you should set the speed control as slow as it will go. The reading should fluctuate in time with the speed control. The faster the setting the faster the variation in the resistance reading. But the important thing is that it fluctuates in time with the speed control. I would hope for a fairly wide range of values.

[beedoola]

There should be no voltage on the pot side of the cap that you are asking about. In fact if there was, it would need to be replaced.

When you take the reading on the LDR, the trem must be on and you should set the speed control as slow as it will go. The reading should fluctuate in time with the speed control. The faster the setting the faster the variation in the resistance reading. But the important thing is that it fluctuates in time with the speed control. I would hope for a fairly wide range of values.

you mean with the LDR NOT attached to the depth pot? Just reading the leads?

There is .247v on the depth pot side of the 1uf 400v. I stopped by a store and got a 1uf 250v - will that work?

EDit*** So I had bought a new trem module and said screw it and installed it. The trem now works - its not very intense, I've read elsewhere that its not supposed to be.

I replaced the 3 - .047 caps in the term circuit with .053 - should that variance have a significant impact on the trem's performance?