Powerboard question

[Oddvar R]

Super.

[Oddvar R]

So now I have 12v and a 12v relay, but the audio is still very low from the input, but very loud when I touch the volume output and the V1B grid connection. I wonder if it could have anything to do with some wrong way of connecting the relay itself? There is no reaction on the drive pot, but the middle pot acts as a volume, when on zero, no sound.

[martin manning]

Did you verify that your relay PCB has the same connections (traces) as I'm showing?

[pompeiisneaks]

You could do some simple continuity tests. As far as I understand relays, though, it's pretty much they are ON or OFF, no in between, think about it. They have a magnet that pulls the paddle back or forward, so either the connection is 100% or not at all. The coil needs to get 12V to make it engage the paddle that flips between NC and NO sides. Does the panel switch for the OD change anything now? I.e. does the weak output disappear or get louder with using the OD switch? Low input volume usually means the first triode has something either poorly connected, or a ground reference is somehow much higher than it should be causing the current to be heavily limited (i.e. a cathode resistor of say 1.5 or 2.2k isn't making a good connection causing 30k or something similar in apparent resistance.

I'd focus on one thing at a time. first make sure you know the relay is working. That is easy with a multimeter on continuity mode. Connect one side to the entrance of the relay, and the other to the other side of the switch, and see which pole is 'connected' then flip the switch and see if they change.

one thing of note that bit me on my first relay testing, is if you're used to switches where the common point is the center and top or bottom are the other switched sides, relays don't work that way, the common pole is the closest to the relay coil and the other two farther away from the coil are the NC and NO connections.

Once that's confirmed as working, I'd try to input some kind of signal and use a DMM on AC volts and measure after each coupling cap to see if you see where the signal is dropping out.

~Phil

[Oddvar R]

Did you verify that your relay PCB has the same connections (traces) as I'm showing?

I did that many times. Same result, seems to be accurate. The problem may be some kind of grounding issue, caiuse when I touch the chassis the noise lowers itself. Also when I hold my hand over the preamp section, the it also increase.

When I touch the output of the volume control it gets really loud, so it seems like the tube section works. I have also changed the tubes many times. The only control that isn't working is the overdrive pot, no reaction, not even by touching the poles. Which all the others have.

[Oddvar R]

Does the panel switch for the OD change anything now? I.e. does the weak output disappear or get louder with using the OD switch?

No, but the voltage change to 12v either side.


Once that's confirmed as working, I'd try to input some kind of signal and use a DMM on AC volts and measure after each coupling cap to see if you see where the signal is dropping out.

I will check that.

~Phil

[pompeiisneaks]

Did you verify that your relay PCB has the same connections (traces) as I'm showing?

I did that many times. Same result, seems to be accurate. The problem may be some kind of grounding issue, caiuse when I touch the chassis the noise lowers itself. Also when I hold my hand over the preamp section, the it also increase.

When I touch the output of the volume control it gets really loud, so it seems like the tube section works. I have also changed the tubes many times. The only control that isn't working is the overdrive pot, no reaction, not even by touching the poles. Which all the others have.

Touching the output of the volume means that the first triode is likely where you're losing the signal. If it's loud at the volume output, then the input guitars signal isn't being amplified by the first stage, just passed through. This is what I was referring to. If you get very loud pops or noise from touching any part of the signal path, that area is having good signal. If the volume is at max, then basically you should have a dead short between the input and output of the volume pot. This should also mean touching the input should give you the same pop no? If so, then it's something between the input jack, and the first triode. Anode, grid,cathode etc.

That seems to limit it to a pretty specific area.

~Phil

[martin manning]

I’m asking if the PCB itself has the same copper traces as I’m showing.

[Oddvar R]

They are like this: This is a leftover board I had from my Dumble ODS 100w, which works great by the way, and the boards where made after your drawings if my memory serves me well-

[erwin_ve]

They are like this: This is a leftover board I had from my Dumble ODS 100w, which works great by the way, and the boards where made after your drawings if my memory serves me well-

Is thiss one of my relay boards and if so, the layout is different. On the other side the connection point have markings nc, no?

[Oddvar R]

There are no markings on the other side...

The diode point is going to the middle of the Manual switch, either pedal or manual?
Com1: level and preamp?
Com2: Goes to board
NC1: Connected to NO2, to the board
NC2: Ground
NO1: to board,

The level pot works

[erwin_ve]

There are no markings on the other side...

Ok not my board, probably with layout of Martin

[Oddvar R]

There are no markings on the other side...

Ok not my board, probably with layout of Martin

Yes, the layout I have says Manning. I bought a set off Taylor Cox.

[martin manning]

Yes Taylor’s boards were made from my drawing. The wiring should follow that shown in the modified 2nd Gen layout snip, where the Calrad relay is replaced with the DIP relay. I’d verify that the relay operation is correct, and then look for a loss of signal.

[Oddvar R]

So I finally solved one out of two problems, I didn't see the wire I have marked on the drawings. Now the amp functions on the level and volume side of things. I have also changed the relay board, but still no reaction on the OD channel. Might be something wrong in the relay itself. Waiting for the new ones.