First PL-400 Restoration

[silver_face]

If my memory serves me correct the caps you had in the photo were made by Temple(?)
If so, I hope you replaced them. They had a very high failure rate.

Yes, it was a complete redo, everything new...….

 

[silver_face]

I mean a complete WOPL 400...

 

[silver_face]

anyway, enough of my crap,

where are at on your amp dtafil?

 

[marcok]

Perry ,
In Europe we have 230 V ( nominal ) and labels on PL 400 and 700B are different .
4A and 5A AGC are the right value for export models .
The same for PL 4000 , PL 700 and if my memory
serves me PL 700 has 5X 20 fuses .
Ciao
Marco

 

[WOPL Sniffer]

We are discussing an amp that is here.

 

[dtafil]

where are at on your amp dtafil?

Waiting for Digikey to show up with a bunch 'o fuses. Looks to be Thursday, then a dim bulb test. Also want to remove those rear transistor covers and see if they're all still there, and if they're the originals. I'll add a pic(s) later tonight of them.

Also, after thinking about this over the past couple of days, one of you guys earlier had a good point... instead of messing around with the old board, I'll probably just go to a new White Oak board, as well as new filter caps and the speaker protection board. Just waiting to see what the dim bulb test shows and then grab any DC readings from the output terminals. If it's low (I'm guessing less than 50 mV (?) I can try some junk speakers to see what happens (sound for example, lol). Then, time to start ordering boards and parts. After I get my head around this one, there's a 700b waiting in the wings

 

[dtafil]

Rear transistors

 

[laatsch55]

XPL 910's were a Darlington configuration....kinda rare nowadays to see those..

 

[WOPL Sniffer]

Pray to the PL gods that your 40 year old transistors (rare or not) don't take your amp to see Marvin any time soon. I got a 5 gallon bucket of that stuff you can have for the cost of shipping.

 

[WOPL Sniffer]

No goop to clean up too!!!!! Bonus

 

[mlucitt]

XPL 910's were a Darlington configuration....kinda rare nowadays to see those..

They had lots of them XPL 910s in 1976, apparently... Also, someone has left their tracks there with XPLs on the left channel and 2SDs on the right channel (and the aforementioned sil-pads, which were not widely available in 1976).

 

[laatsch55]

Yeppers...

 

[wattsabundant]

If an XPL910 failed after they became obsolete the only choice was to replace them all in order to meet the requirement that all outputs in a channel be of the same type. The service manual states that P/L would exchange obsolete devices for current devices as long as the devices were not defective. I never took advantage of this policy as I usually found a home for obsolete ones. If they passed the load share test they were good. I matched dates codes when at all possible.

The NEC 2SD555 and 2SB600's were great devices. I saw very few failures of those. It was a major disappointment when they were discontinued.

The picture of the channel with the 555's is a concern because it appears the silpads were reused. I've never seen a silpad fail, but I wouldn't reuse them either. I ran into a lifetimee supply of Berquist silpads years ago at a surplus shop. Im down to about 5000 of them now.

 

[dtafil]

Got the fuses in today and replaced all. 2x AGX-8 and the single AGC-8 amp. Failed the dim bulb test w/ a 150 watt bulb. Light stayed on, right meter swung for a few seconds and settled down. I don't recall the left meter moving at all.

So, thinking I'll just order up a new control board and build one, as well as a set of new drivers/outputs,sil-pads, filter caps, plus the DC protection board. Besides a 6-pack, anything else needed? Would like to stay away from the backplane for this build, planning on going all-in for the 700b in the near future instead. Besides the Watts board, looks like everything can be sourced from the WhiteOak website; am I missing anything? Any other things to check before jumping in?

Thanks guys... Dave

 

[silver_face]

wattsabundant: DC Relay Protection Board

White Oak:
PL400 Capacitor Assembly:
2 x 15,000 uF/100V for amps with die cast cradle

PL400 L14_20 RevE5 Control Board Kit:
Unassembled Kit PL14_20-KIT: build to quasi-comp

Optional: PL400 LED Light Board, 4 Color options

Driver Outputs, sil-pads

Staying with quasi-comp, so no Backplane Board Kit.

 

[dtafil]

Parts ordered from Joe and note sent to wattsabundant. Off to finish a Sansui 5000a restoration & clean off the bench this weekend.

 

[WOPL Sniffer]

Parts ordered from Joe and note sent to wattsabundant. Off to finish a Sansui 5000a restoration & clean off the bench this weekend.

Did you buy a pair of 5000 amp boards from me??. I've sold a shitload of them.

 

[dtafil]

Did you buy a pair of 5000 amp boards from me??. I've sold a shitload of them.

Not me; got lucky this time. Even the updated driver boards were in there.

 

[WOPL Sniffer]

Even those were pretty crappy as far as workmanship and have a ton of obsolete parts on them. I just sold 2 more pairs today... Gotta build some more.

 

[dtafil]

OK... White Oak control board (to be assembled), filter caps, outputs and Watts Abundant parts are all in... going to clean off the bench this weekend and get going on this. Pictures and (probably) some questions to come. Nice detailed instructions all printed out for reference.