700/1 “Tim” WOPL driver board

[AngrySailor]

Better?

 

[laatsch55]

Did you have to readjust bias?

 

[AngrySailor]

Did you have to readjust bias?

No, 350mV both sides.
Here’s a pic of light board. The screw driver points to the meter input leads from the speaker outputs. By removing both 10 resistors, the circuit will be open.

 

[Gepetto]

Better?

That is the easy button Andrew

 

[Gepetto]

No, 350mV both sides.
Here’s a pic of light board. The screw driver points to the meter input leads from the speaker outputs. By removing both 10 resistors, the circuit will be open. View attachment 57034

The meter leads are supposed to come in on the same edge of the board as the 2 white ground wires are.

 

[AngrySailor]

The pads are labeled “hot” (meter?), ground and filament (lights). That is how it’s wired.

 

[AngrySailor]

Here’s the backside of the light board. As you can see removing the parallel 10 ohm resistors breaks the circuit. Those pads go nowhere but through those two resistors and on to the meter through then 23k and a diode, then through the meter to ground.

Fug forgot pic.

 

[laatsch55]

Remove the resistors, then jump the holes on top that are not connected.

 

[laatsch55]

Hold it, was looking at the wrong trace..let me look again..

 

[AngrySailor]

Remove the resistors, then jump the holes on top that are not connected.

They would have to be jumped in place of one resistor each side so top to bottom to complete the circuit. Will this overload the meters as you’re removing 5 ohm of resistance.

 

[AngrySailor]

Where the blue line is would need to be jumped.

 

[Gepetto]

Here’s the backside of the light board. As you can see removing the parallel 10 ohm resistors breaks the circuit. Those pads go nowhere but through those two resistors and on to the meter through then 23k and a diode, then through the meter to ground.

Fug forgot pic. View attachment 57035

It is just one of many PL design errors. The board is wrong.

 

[Gepetto]

 

[AngrySailor]

View attachment 57037

Ok so that’s the same as a jumper wire. What about removing that 5 ohm resistance? Meters be ok? They were sluggish before, hardly moved...

 

[laatsch55]

When compared to the 13k and diode the 5 ohms ain't shit.

 

[laatsch55]

Two tens in parallel mean 5 ohms..

 

[Gepetto]

The minute you removed the caps, the 10 ohm resistors are out of the circuit IF you move the meter wires to where they are supposed to be.

 

[Gepetto]

The reason that the meters are sluggish is that PL did not introduce the -20dB switch until the 700B, they then recognized that most users don't run their amps at full tilt (certain exceptions here)

 

[Gepetto]

The other error that PL made on the PL700 was putting the zoebel on the meter board instead of in the speaker signal path where it is supposed to be.

I suppose that is why the 700B came into existence, among other things.

 

[AngrySailor]

What are ya getting at Joe

ok resistors removed and jumpers in place. I think Tim’s ready to rock, got to repair my crossover now then it’s “go time”...