Przem's Phase Linear 700 Series II White Oak Conversion

[laatsch55]

Board time....

 

[laatsch55]

Right side done...

 

[laatsch55]

Board wiring done, tie up a few loose ends then it's time to nut up and plug this F*&^%$ in!!


One thing I lack is a 240 volt variac, however it does go to 140, that should be enough for the board to regulate but maybe not enough for the DCP relays to click. It will tell me if I have problems before we go with the full 240.....

 

[laatsch55]

All fuses checked and in, board isolated, voltmeters hooked to the outputs, fingers crossed....

 

[gadget73]

Very cool. If you find yourself in need of a step-up transformer, I think I can lay my hands on one for you. We permanently decommissioned a couple of dead heaters at work, and they were powered from step-down transformers. I know they were fed from 277 but I'm pretty sure it also has a 240v input tap and a 120v output. Wire it backwards and you've got 120 in and 240 or 277 out. Not sure the amperage offhand but the transformer itself is pretty close in size to a stock PL 700 transformer. Let me know if you need it, and I'll dig it out of the ceiling.

otherwise you could really cheat and use a couple of extension cords plugged into outlets fed from different buss lines in your breaker box. Hot to hot should give 240v. If you get 2 on the same buss, it'll be 0v. Thats not really a safe way to do it, but it does work in a pinch.

 

[P.L.F.]

Another WOPL 1000 to be born soon... A Big Time!

Lee, ALL fingers are crossed....

 

[laatsch55]

Power supply problem.....electronics on the boards are fine, I did something wrong on the transformer wiring.....I'll post a schematic...

 

[laatsch55]

Very cool. If you find yourself in need of a step-up transformer, I think I can lay my hands on one for you. We permanently decommissioned a couple of dead heaters at work, and they were powered from step-down transformers. I know they were fed from 277 but I'm pretty sure it also has a 240v input tap and a 120v output. Wire it backwards and you've got 120 in and 240 or 277 out. Not sure the amperage offhand but the transformer itself is pretty close in size to a stock PL 700 transformer. Let me know if you need it, and I'll dig it out of the ceiling.

otherwise you could really cheat and use a couple of extension cords plugged into outlets fed from different buss lines in your breaker box. Hot to hot should give 240v. If you get 2 on the same buss, it'll be 0v. Thats not really a safe way to do it, but it does work in a pinch.

I have 240 going to the rack, and I have run this amp in 240 mode before tearing it down. This is just on initial power up that I'l be limited to 140 from the variac...

 

[laatsch55]

On the transformer primary wiring I have yellow/blue and brown to mains in, then I have blue and yellow/brown tied together on the terminal strip for the 120 feed to the fans...this is where I dscrewed up, I need the blue or yellow/ brown , either one for the 120 feed , but not both hooked together.....the other leg for the 120 feed comes off the yellow/blue....I need to isolate either the blue, or yellow/ brown and leave the other tied to the terminal strip...

 

[laatsch55]

But I wouldn't get 240 that way....

 

[P.L.F.]

Lee,
What if for the initial testing you wire primaries as for the US power supply voltage, i.e. in parallel. Then before sound testing in the rack the primaries are rewired in series?

 

[laatsch55]

Power supply checks out fine with no rail fuses in. Negative rail is fine. I have a problem with the B+ rail...troubleshooting now...

 

[laatsch55]

This is kicking my ass...

 

[P.L.F.]

Sorry Lee, cannot assist you that much - I'm traveling these days. I took some pictures of the PS wiring for 240VAC compatibility and here the are. First two are of the same gear you have on your bench. The two other are of my PL700II fully comp, also 240VAC wired. I hope it'll help a bit...

 

[laatsch55]

That part of it is fine Przem, it's something to do with one of the boards, I may have damaged one shoehorning it in there, but not totally sure yet.

 

[laatsch55]

If it is one of the backplanes , how do you feel about a new chassis? I have one sitting here but it's not black. It's the prototype and you wouldn't be charged for it . In fact the price still stands.

 

[P.L.F.]

If it is one of the backplanes , how do you feel about a new chassis? I have one sitting here but it's not black. It's the prototype and you wouldn't be charged for it . In fact the price still stands.

I don't mind Lee. Only don't want it gets corroded over time. But probably while using the amp at home it won't be the case anyway...? So let's go ahead...

Are you afraid that one of the backplanes is too tightly fixed, too close to the chassis?

 

[laatsch55]

There is no clearance and I can't get any without compromising the board. I had to pull the board in with the output mounting screws and a couple of the threaded standoffs pulled in instead of the board moving. They didn't move much but there are 4 layers to that board and there may be some internal damage I can't see. I have tried every test I know to isolate an external problem and I can't find one. I have contacted Joe to see if there's some things I can do to determine IF there is some internal damage.
So I was getting your approval to go with the new chassis in case it's needed. I would think that chassis in a home setting would outlive you. If not send it back in 5 years and I'll put a new anodized black one back in it for nothing. I have to use it on something just as well be yours. I was going to use it on D2's 700 but Joe has more...your call.

 

[JustMike]

Morning guys.
I just thought maybe one of these methods might work for the chassis in a pinch.
I used this old method of Blackening on many old Harley parts.
Here is some info: http://www.mmsonline.com/articles/do-it-yourself-cold-blackening

The other is how about gun bluing?
Both of these could be done in house.

 

[laatsch55]

Not a bad idea Mike, but that's for ferrous metals, the new chassis' are aluminum...and they are beautiful and with everything Joe does, they are the best of what they are. Laser cut, tig welded corners, PEM nuts and machine screws for the covers and slightly larger internal volume and slightly deeper for better clearance of the meters.
The 2 prototypes are not anodized in case there has to be any changes before he makes a production run....

Somebody has to be the first, just as well be Przems...as he needs a chassis......I could probably make this one work, but I'm worried about the long term reliability with a compromised board....and one must consider a board compromised if you take any material off of it. Granted, I didn't take off much and should have taken off more, but those 100 volt DC pads are close enough to the edge as it is and then have that distance lees AND then the board touching the chassis doesn't seem like a long term, trouble free option...yeah, maybe an untreated chassis will corrode in 20 years, but by then Przem or I won't really care...we'll be rockin with God and his million watt WOPL....