PL 400 - Nearly complete! Let's talk meters...

dtafil

Journeyman
Joined
Jan 23, 2020
Messages
101
#1
Hi Guys - So, hot off the FedEx truck, got my driver transistors installed. All the others pieces were already in place... WA speaker protection, all new outputs, control board, new filter caps (had to relocate 'em to clear the meters). Biased to 0.35 vDC, singing away. Impressive as all hell!

This amp came to me with sticking meters... confirmed again this afternoon. They kinda work, (you can zero them out), but they each stick (each appears to have it's own particular preference). I did try a zerostat gun I own; no dice.

As I'm reluctant to get too deep into these meters myself (this amp was purchased from an Estate sale, so not sure if someone's been in there before or it's just buildup), looking to see if anyone on the forum repairs these, or would have a matched set to sell. These do not measure OC, so I assume there's crud build up inside the meter assembly. They are Dixson's. Should be viewable in the pics, but can grab more. Also need to tie down those wires for the LED board :)

Pics attached to this point:




Any suggestions welcome... happy to post up a "Wanted" ad in the Buy/Sell section if proper.
 

mlucitt

Veteran and General Yakker
Joined
Jun 24, 2011
Messages
3,339
Location
Jacksonville, FL
#3
There is also a technician here that has had some luck cleaning the meter movement. It is like a fine watch, but add electric components; and it becomes a real challenge to do it correctly without destroying the movement.
The fact that your meters move means they are electrically not dead (open windings usually), but instead just suffering from a mechanical disability.
 

dtafil

Journeyman
Joined
Jan 23, 2020
Messages
101
#5
Question for Joe / @Gepetto or someone on the LED light board.

The original PL 400 light board had the wires attached as such in order:

Pad1 - Red
Pad2 - White
Pad3 - Black
Pad4 - Yellow
Pad5- Yellow

On the White Oak instructions for the LED board, the picture in here ( https://www.whiteoakaudio.com/documents/PL400 LED Board Instructions.pdf ) shows the silkscreen pad numbers in this order, with wires attached as such:

Pad1 (white)
Pad3 (red)
Pad2 (black)
Pad8 (grey/AC)
Pad9 (grey/AC)

On the actual LED board I have, the pad silkscreens are in order like this:

Pad1
Pad2
Pad3
Pad4 (My yellow AC wire)
Pad5 (My yellow AC wire)

Can anyone confirm Pad 1, 2, and 3 wiring for me? (white / red / black is correct in that order?)

TY
 

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
13,473
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#6
Question for Joe / @Gepetto or someone on the LED light board.

The original PL 400 light board had the wires attached as such in order:

Pad1 - Red
Pad2 - White
Pad3 - Black
Pad4 - Yellow
Pad5- Yellow

On the White Oak instructions for the LED board, the picture in here ( https://www.whiteoakaudio.com/documents/PL400 LED Board Instructions.pdf ) shows the silkscreen pad numbers in this order, with wires attached as such:

Pad1 (white)
Pad3 (red)
Pad2 (black)
Pad8 (grey/AC)
Pad9 (grey/AC)

On the actual LED board I have, the pad silkscreens are in order like this:

Pad1
Pad2
Pad3
Pad4 (My yellow AC wire)
Pad5 (My yellow AC wire)

Can anyone confirm Pad 1, 2, and 3 wiring for me? (white / red / black is correct in that order?)

TY
 

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dtafil

Journeyman
Joined
Jan 23, 2020
Messages
101
#8
Thanks Joe - Just to confirm then, for the LED board, this is correct:

Pad1: Red (right channel)
Pad2: White (left channel)
Pad3: Black (ground)
Pad4: Yellow (AC)
Pad5: Yellow (AC)

If so, yep, had it wired right. Analysis paralysis, lol. End result is wonky meters (for now).
 

Gepetto

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Staff member
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Messages
13,473
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#9
Thanks Joe - Just to confirm then, for the LED board, this is correct:

Pad1: Red (right channel)
Pad2: White (left channel)
Pad3: Black (ground)
Pad4: Yellow (AC)
Pad5: Yellow (AC)

If so, yep, had it wired right. Analysis paralysis, lol. End result is wonky meters (for now).
Yup, unfortunately your meters are misbehaving...
 

MarkWComer

Veteran and General Yakker
Joined
Nov 1, 2014
Messages
3,198
Location
Gaston, SC
Tagline
Victim of the record bug since age five
#12
PLay this through the amplifier and see if that fixes the meters:

It's a jewel from 1943.
BEAU-TI-FUL! Love it!
I’m becoming more interested in this period/genre, my latest purchase was Cab Calloway “Tyron Swing” / “Jumpin’ Jive” from 1939. HOT shellac!
 
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