phase linear 400

[gene french]

Done. No change... I even swapped out the bottom row with tested and matched 410's. I'm at a loss.

another christine!!!

 

[George S.]

One further consideration. The previous owner wired in a couple of input potentiometers ala Series 2. I didn't mention them as I assumed the Amp was working prior to losing some transistors. Here are some pictures, I somewhat wonder if the input/output wiring is incorrect? I would remove them, however there are two holes in the faceplate for them. I did go ahead and put them back in the faceplate just to see if there was some sort of grounding needed, but the issue of the dbt still exists.

Original 400 S2 pot and wiring.
The middle lug (red wire) is known as the "wiper", and ALWAYS carries signal to the control board.
The black wire carries signal from the RCA to the pot.
The sliver wire is the ground or shield wire. Goes from the RCA copper plate to that pot lug, then from the pot lug to the control board.
You can use a twisted pair, mini coax such as Belden RG316, or the original Belden cable that PL used as shown in the photo.
Many of us building or having built WOPLs bypass the signal attenuators (front pots) or leave them out all together.
My three S2 WOPLs have LEDs in place of the attenuators.

 

[gene french]

Original 400 S2 pot and wiring.
The middle lug (red wire) is known as the "wiper", and ALWAYS carries signal to the control board.
The black wire carries signal from the RCA to the pot.
The sliver wire is the ground or shield wire. Goes from the RCA copper plate to that pot lug, then from the pot lug to the control board.
You can use a twisted pair, mini coax such as Belden RG316, or the original Belden cable that PL used as shown in the photo.
Many of us building or having built WOPLs bypass the signal attenuators (front pots) or leave them out all together.
My three S2 WOPLs have LEDs in place of the attenuators.

great idea...i heard some put dcp led on front panel too....one for 110 and other no dc un outout!!!

 

[Sunnbobb]

Original 400 S2 pot and wiring.

Thanks George!

 

[gene french]

dont understand why both channels...with either speaker connected...
try cutting input and output wires off their respective jacks/posts ... you need to change inputs since old ones are almost always problems...i got mine from watts when i ordered a dcp board...gold plated...and you need to change posts to install new posts with dcp board...

 

[Sunnbobb]

utting input and output wires off their respective jacks/posts

I tried that when I removed the pots... I also checked the jacks, and they test fine as for grounding and connectivity.. sigh, I've hunted the schematic, and don't find any clue. Another cup of coffee, another pondering session.

 

[gene french]

none should be grounded to chassis...did you connect speakers with jumpers bypassing posts??
interesting...

 

[gene french]

none of the wires soldered to the bottom of control board are broken???...very common...

 

[gene french]

been here almost 20 years...
first rain i ever experienced in march....

 

[J!m]

End of days

 

[gene french]

End of days

lol

 

[Sunnbobb]

dont understand why both channels...with either speaker connected...
try cutting input and output wires off their respective jacks/posts ... you need to change inputs since old ones are almost always problems...i got mine from watts when i ordered a dcp board...gold plated...and you need to change posts to install new posts with dcp board...

Has me befuddled too.

 

[George S.]

Perhaps it's going into protection mode. Info is in the manual.

 

[gene french]

that would be q5 or q8...i think

 

[gene french]

gonna have to scour the board for bad/shorted diodes or transidtors

 

[Sunnbobb]

Perhaps it's going into protection mode. Info is in the manual.

Good thought, that would explain the problem being on both channels. I'll give it a shot, Thanks for the idea!

 

[Sunnbobb]

I lifted the legs on d9 and d10. No change

 

[Sunnbobb]

Narrowed in on the issue. Removed both rail fuses and the dbt does not light with speakers attached. Replaced right fuse (as viewed from back of amp), and dbt does not light up with speakers attached. Removed left fuse, and BDT lights up with speakers attached. With left fuse still installed, removed each speaker one at a time, and DBT still lit up. So at least I now have a rail to trace.

 

[gene french]

interesting day...electrical storm yesterday struck both solar panels powering the internet microwave setup...had one extra panel....it is a 24v system...it should keep up unless we get several days of heavy clouds...gonna replace the two fried ones and keep the other as a spare..after holy week...everything shuts down...very catholic country...

 

[gene french]

piddled with the pl200 ....got left channel working...will test the right channel board...
will probably give it away...but, it was fun...
been recapped years ago...hated to junk it...