Bulk Capacitor Replacement Procedure for the PL 700B

Gepetto said:
If you follow the grounding schematic literally and explicitly then You should not face hum issues.
The normal/direct switch body should have NO wire connecting it to the floating copper input plate. The switch body will become chassis ground by virtue of the screws that mount it. All those little bus wire jumpers that PL added should be removed. The only bus wire jumper should be between the 2 negative speaker binding posts (this is shown on the schematic)
The end result should be that the ONLY connection between the star point ground and chassis ground occurs at the center lug of each of the 3 terminal solder lug strips mounted to the backplane

Hope this is clear
Click to expand...

Joe, there IS no connection to the floating RCA bar. I cut it. There is no wire from the normal switch to the spaker posts. I cut that also. I had hum. Now its true I still need to add a new and seperate wire to the speaker negative binding posts, and run it over to star ground, Lee has already dircted me to do so. But also take note, that you say the normal/direct coupled switch should be chasis ground by virtue of the screwes that hold it on to the amp. However, my amp has a wire that comes off there and ties into one of the triple bars on the back panel, then over to star ground. So wouldnnt that be redundant and need to be removed? Also, chasis ground for the WOAPL board, ties to the negative speaker binding posts, which lead to star ground directly through a dedicated wire. So it looks as though my wire i need to add is already there?? This leads me to believe that the wire going from the back panel to the normal/direct coupled switch, just needs to be removed. Does this sound like the correct solution to isolate my ground problem and solve my hum issue?

I just read in an unrelated post, that posting large pictures to inline text, can only be done using a photo sharring site. And i took my recent pics in full resolution. Perhaps too large for this and why i cannot upload images lately. I will downsize my photos now and see if that solves my picture posting problems. Maybe then I can provide pics of the issue. Well.......one ten hour day down; five more to go before I can get back to the PL. Have a good evening fellas.
 
There is no chassis ground on the WOPL board. The RCA's are grounded to the board and the rca's are isolated from the chassis. 5L should go to the star ground.
 
As Lee indicates as does the schematic, the 5L connection should be separate and go directly to the star point ground. There should be NO connection to the speaker negative terminals by either 5L or 5R.

The speaker negative binding posts should have a bus wire connection between them and then 2 separate wire connections to the star point ground. There should be no other connections to the speaker binding posts except these.

The schematic is pictorial in nature and represents how the ground runs should look when complete
 
Gepetto said:
As Lee indicates as does the schematic, the 5L connection should be separate and go directly to the star point ground. There should be NO connection to the speaker negative terminals by either 5L or 5R.

The speaker negative binding posts should have a bus wire connection between them and then 2 separate wire connections to the star point ground. There should be no other connections to the speaker binding posts except these.

The schematic is pictorial in nature and represents how the ground runs should look when complete
Click to expand...

Gentlemen, I am in understanding of the ground scheme. I think what we have hear is a simple miscommunication of terms. Since you can't SEE the amp, it's difficult to illustrate. Lee, my wording of "WOAPL board" and "Chassis" ground" COMES from the WOAPL color code schematic itself. All I am saying is that THAT is what the white wire says it is on the chart. In reality; I am to remove this white wire from the negative speaker binding posts and move it to star ground. (Its currently on 5R per the WOA color code chart). I get that. That's fine. I'll move that to the star point.


There are ALREADY two thicker grey wires running from the speaker binding posts, over to the star ground. And the binding posts are already connected with a bus wire. So cool. No need to run a new wire for that.

Ignore that question of the green/white/black wire running from the direct coupled/normal switch, over to the nearest tipple terminal block on the back wall. From looking at it, I see now it does NOT go to star ground. Rather, wired in a fashion as to do what it is supposed to do when used in direct coupled mode. Sorry.

Sooooooo really, it's just as easy as moving my white wire on the WOAPL board over to the bulk cap buss bar star point? yeah. I hope that's all it is? Again, Sunday I will get to this.

IMG_0055.jpgIMG_0050.jpgIMG_0053.jpg
 
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Hi Dave
Thanks for the photos to clear up your questions for me.

The original Excel wiring chart that you show a picture of presumes a direct drop in without the benefit of installing the ground optimization scheme. In other words, that wiring does reflect the way that the PL14_20 board would be installed if one chose not to rewire to the star point configuration. The original wiring to the original PL_20 board did indeed have that white wire going to the right side of the board, not the left side.


In the optimized ground wiring, 5L is used to go to the star point ground simply because the left side of the board is the side closest to the star point ground itself. There is a Left to Right jumper wire on the back side of the board that effectively connects 5L to 5R.


Anyway the point of the ground optimization is that the 5L should go directly to the star point and there should be no connection to the 5R side.


Sorry for not explaining this better before Dave, Lee and I had already jumped to the optimized ground scheme (we have both done it so many times).

Maybe this is clearer for all of us now :-)

The middle picture you show is wired INCORRECTLY for the optimized wiring and can lead to ground looping. To wire it in accordance with the schematic, the switch and input jack wiring will look like this instead.

DSCN0002.jpg

You will notice NO connection to the frame of the switch, the 220K ohm resistors have been moved to an optimized location.

When you attach the normal/direct switch via the mounting screws, then the body of the switch will naturally become chassis ground. The white striped wire that you show leaving to the right side of the rightmost 3 terminal barrier strip and going to the frame of the switch and the 220K ohm resistors will no longer be needed and should be removed.
 
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Phase Linear Phanatic said:
Gentlemen, I am in understanding of the ground scheme. I think what we have hear is a simple miscommunication of terms. Since you can't SEE the amp, it's difficult to illustrate. Lee, my wording of "WOAPL board" and "Chassis" ground" COMES from the WOAPL color code schematic itself. All I am saying is that THAT is what the white wire says it is on the chart. In reality; I am to remove this white wire from the negative speaker binding posts and move it to star ground. (Its currently on 5R per the WOA color code chart). I get that. That's fine. I'll move that to the star point.


There are ALREADY two thicker grey wires running from the speaker binding posts, over to the star ground. And the binding posts are already connected with a bus wire. So cool. No need to run a new wire for that.

Ignore that question of the green/white/black wire running from the direct coupled/normal switch, over to the nearest tipple terminal block on the back wall. From looking at it, I see now it does NOT go to star ground. Rather, wired in a fashion as to do what it is supposed to do when used in direct coupled mode. Sorry.

Sooooooo really, it's just as easy as moving my white wire on the WOAPL board over to the bulk cap buss bar star point? yeah. I hope that's all it is? Again, Sunday I will get to this.

View attachment 9245View attachment 9246View attachment 9247
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Dave
What value resistors are showing on the left side of the rightmost (3rd) photograph. That is a value that I am not used to seeing.
 
Some eye candy for you conversion enthusiasts...

The way Phase Linear should have done it...but didn't
DSCN0007.jpg

DSCN0010.jpg
 
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Eye candy indeed. That's a beautifu;l thing right there...
 
I actually think it is 0.75 ohms Lee but camera color fidelity is a tricky thing...

Did Phase Linear actually use that value at one point? It does not show up in any documentation that I have. And it will really throw off the positive side current limit protection point (early clip). Of course I do not have a complete photo of what Dave is dealing with either.
 
To bad he doesn't have a scope would love to see the waveform just before clipping. I've had my hands in a few "B"s and never saw that value. I'll shoot Ed a quick E-Mail...
 
Updated PL700B Grounding Schematic

Hi Dave
I added some more detail into the area around the Normal/Direct switch to help you. This in conjunction with the photos I included in the earlier post should help you figure it out. This is rapidly turning into a complete PL700B system schematic. I am pretty sure it will end up there.

View attachment PL700 Grounding.pdf
 
laatsch55 said:
To bad he doesn't have a scope would love to see the waveform just before clipping. I've had my hands in a few "B"s and never saw that value. I'll shoot Ed a quick E-Mail...
Click to expand...

Thanks Lee, first I have seen like this. You have had a lot pass through your hands, all have been 0.33 and 0.27 ohms as far as the photos I recall of your projects.
 
Yes Sir Mr. Joe, none of that funny colored stuff---Elton John's chin!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! LMOAO!!
 
Gepetto said:
Hi Dave
I added some more detail into the area around the Normal/Direct switch to help you. This in conjunction with the photos I included in the earlier post should help you figure it out. This is rapidly turning into a complete PL700B system schematic. I am pretty sure it will end up there.

View attachment 9252
Click to expand...



Probably way past time...
 
laatsch55 said:
Yes Sir Mr. Joe, none of that funny colored stuff---Elton John's chin!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! LMOAO!!
Click to expand...

That had me rolling on the floor too Lee. I can almost picture him saying it though. A very funny guy.
 
Can you imagine if he and the Canadian hockey announcer hooked up???
 
laatsch55 said:
Probably way past time...
Click to expand...

I would LOVE to have an oscilloscope, but I can't afford a descent multimeter at the moment. I got fed up with replacing soldering irons, i broke down and bought a soldering station. Over a hundred in the hole for that this week. So yeah, nice machines like THAT are on hold. Lee......these resistors in the photo that is being blocked by my new shielded grey wire, are of the same banding as that of those 220k ohm resistors you had me remove. Now see in the pic Joe just provided where he says thats how it SHOULD look, he HAS the two 220k ohm resistors coming in from the RCA's and soldered to the RCA bar. So are they or aren't they supposed to be there?? Before i go cutting that black/white/ green wire from the switch, that goes over to the nearest triple bar on the back wall..... I will try to upload clear and more pics. Every time i try to get a close up shot, the dumb camera fuzzes out the foreground and when i move back, vise-versa so i never get a whole clear pic of the damned thing? Grrrr.... As for that WOAPL schematic I showed, I downloaded it directly from the WOA website where it says "click here on installation procedures". I guess if that is currently incorrect, maybe consider an update? If you sent me proper documentation in email, stupid windows live mail would not open excel. I do not have the program. It even cut off my adobe attachments list and I couldn't pan over to see past 7 attachments? And i know you said there were nine? So it's been a frustrating week. And to boot i just got home from work, its midnight and i have to go to bed and wake up and go back to work! Stupid job keeps getting in the way of my WOAPL project!

Point is; i believe those ARE two 220k ohm resistors there on that switch. And as you see I cut the solid wire above and below that. Leaving that banded wire going to the back wall. I will cut that also if that is an issue for ground. This means i SHOULD also remove those resistors at the switch? And move them to the RCA bar like in your pic Joe? And after that, i will remove white from 5R and go to 5L with it (just to be right) and then solder it to star ground. Am i making any sense? Or just a blabbering fool? By the way, excellent, detailed answer to my question Joe. I guess a picture really is worth a thousand words? Lol! I will try to take more pics soon.

I hope you didn't bother Ed too much Lee? This should clear things up a bit. Until I can get back to the amp...... Cannot provide more. Will try in the morning.
 
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