My New Early Model PL400 w/ 4 Fin Heat Sink

[laatsch55]

Yep, no problem there, that's how I initially power up mine.. make sure the wire ends are taped, two of them are straight off the outputs...

 

[punchback]

Already taped up.

 

[punchback]

How does the DBT react to the AC Creeping up to 60VAC on the variac? I've only ever experienced whacking on full line voltage and seeing the bright then dim.

On the way to and once at 60VAC the bulb was glowing, which made me nervous so I shut down. No hot electronics smell though

 

[punchback]

Right now I'm monitoring both speaker outputs and the AC coming out of the variac. 1 Amp fuses in the B+/-. Only the pre-drivers installed. No speaker protect relay click as of yet. I can understand nothing on the speaker output meters since there's been no click. I measured the B voltages and they're a 8 volts. I'm guessing 60VAC isn't enough power to start things??

 

[punchback]

I'm going to wait for some input and watch a little 3rd round action at the Masters.

 

[Gepetto]

No issue as long as any loose wires are contained.

 

[laatsch55]

Right now I'm monitoring both speaker outputs and the AC coming out of the variac. 1 Amp fuses in the B+/-. Only the pre-drivers installed. No speaker protect relay click as of yet. I can understand nothing on the speaker output meters since there's been no click. I measured the B voltages and they're a 8 volts. I'm guessing 60VAC isn't enough power to start things??

Correct, keep goin..

 

[laatsch55]

Monitor speaker outs for DC volts....

 

[laatsch55]

Bulb should get bright then start to dim after a few seconds...

 

[laatsch55]

1 amp fuses are pretty light, check them each time you power down to make sure they are still good..

 

[punchback]

I went all the way to 120 and bulb never dimmed. While I was going to 120 I was monitoring the B+ and it never went above 8 volts. Something is a miss. Nothing seemed hot on the WOA board.

The WOA power up instructions say to install the 1 Amp fuse.

 

[punchback]

I'm confident the wires are connected to the WOA board correctly. That would leave a possible assembly error on the board. I checked and all of the electrolytes are correctly oriented. The TO220 transistors are in the right place. No diodes in backwards.

 

[punchback]

Can you disconnect the B+/- from the WOA board to see if it comes back? I checked and the 1 Amp fuses are OK

 

[laatsch55]

Check the +/- 15 volt voltages...

Any DC on the outputs?

 

[punchback]

+/-15 is about 6 volts. No DC on the outputs as measured on the left channel input of the DCP board.

 

[laatsch55]

No DC on right channel either?

 

[punchback]

None. When I turn on the DBT I get a brief voltage but with in a second goes to 0. After switching off the DBT voltage is shown quickly dissapating to 0.

 

[punchback]

Keep in mind that after installing the DCP and new bulk caps it was working albeit with a high offset on the left (edit) .

 

[laatsch55]

Fuses ok?

 

[punchback]

Both B+/- fuses OK