PL 700 II Clair Bros Rising from the Ashes

While I'm on the topic of dumb questions, I have found the WO back plane pcb's to fit snugly in the steel Clair Bros chassis. The T 03 screw holes in the chassis will all have to be cleared with a 15/ 64" drill. The nylon shoulder washers at the upper and lower most locations will need a 'flat' removed from the larger diameter shoulder, to clear the top and bottom of the chassis. Has anyone had to do this or is this a sign of trouble coming?
Thanks, Peter in Canada
 

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Peter , it seems most Ser II's have this clearance problem, well documented.
 
Yes sir.... I fought too many of those Ser II chassis' including the cooling fins. It's WAY EASIER with a new chassis and new fins. Unless you want to do a bunch of drilling and then risk a burr poking out shorting the whole project and laying down a smoke screen big enough for the army to use for cover for an offensive charge... I tried chamfering the cooling fin holes for the nylon standoffs, drilling bigger holes for the bias transistor mounts, and the upper board mounts.... The regular series II's require a bit of work but it seems the Clairs were worse. That's why I just bought the new chassis from Joe, and will get another one in a couple weeks when I do this other one (the 700B is tight though with several layers of paint or powder). Luckily, many of the clair's were beat up and NEEDED a new chassis. Many had ripped ears where the face plates bolt on. Too much weight to be rack mounted.
 
Peter S said:
While I'm on the topic of dumb questions, I have found the WO back plane pcb's to fit snugly in the steel Clair Bros chassis. The T 03 screw holes in the chassis will all have to be cleared with a 15/ 64" drill. The nylon shoulder washers at the upper and lower most locations will need a 'flat' removed from the larger diameter shoulder, to clear the top and bottom of the chassis. Has anyone had to do this or is this a sign of trouble coming?
Thanks, Peter in Canada
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I have done several of these. Yes the boards are snug. I had to sand a very little bit off the board once. If you do that be careful of how much you take off each side as the copper traces come close to the edge. If you take to much off coat with epoxy to seal.

As to opening To-3 screw holes I am not sure why you need to do that? It should be a 6mm hole. The nylon spacers normally are loose fit and Joe special orders them.

Adding flat to washer on edge pieces is good.

Glen
 
grapplesaw said:
I have done several of these. Yes the boards are snug. I had to sand a very little bit off the board once. If you do that be careful of how much you take off each side as the copper traces come close to the edge. If you take to much off coat with epoxy to seal.

As to opening To-3 screw holes I am not sure why you need to do that? It should be a 6mm hole. The nylon spacers normally are loose fit and Joe special orders them.

Adding flat to washer on edge pieces is good.

Glen
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Glen, because the back planes fit so tight, it causes the holes to NOT line up so good. SOMETIMES the fit is too tight. It throws all the holes off. The nylon spacers are tighter than the original TO3's. I have had where the fins are off a fair amount and everything fits like shit. The best bet is a WO chassis. I have done dozens of the clairs and they were different animals.
 
If you look close at the Clair chassis', some of the TO3 mounting holes actually cut right into the side of the chassis. Some were tighter than others.
 
WOPL Sniffer said:
If you look close at the Clair chassis', some of the TO3 mounting holes actually cut right into the side of the chassis. Some were tighter than others.
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And there was no real reason for that type of fit Perry. There is plenty of height to work with to easily stay within the 4U space height allowance. My only assumption was that they were trying to squeeze another set of chassis blanks out of the width of a standard sheet since there is no design reason for it.
 
Gepetto said:
And there was no real reason for that type of fit Perry. There is plenty of height to work with to easily stay within the 4U space height allowance. My only assumption was that they were trying to squeeze another set of chassis blanks out of the width of a standard sheet since there is no design reason for it.
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Either that, or it was how they bent them in the brake..... Joe, you should try a Rev P chassis from WOAD.... They cure all those problems..... :)
 
I junked a bunch of the Clair chassis'....... Some worked, some didn't. I kept some of your chassis' in stock just for that reason. You saved me many hours of work AND swearing.
 
Things falling into place. Everything fitting perfectly so far. One of those weld nuts may have to go. And YES, a WOAD chassis would solve this problem, but.....
 

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Spoke too soon. Looks like a die-grinder job. I'll say it for you; should have ordered the WO chassis!
 

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Just do it..... Best $115 you'll ever spend.

That, and some new speaker jacks, rca's and you'll be clean and in bidness
 
Don't be in a hurry just to save a few bucks. In the end, you'll have nice clean install and not have to fight all the issues (that's just the beginning).
 
Peter S said:
Spoke too soon. Looks like a die-grinder job. I'll say it for you; should have ordered the WO chassis!
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I think It may be ok as is. Wait till you put the back plates together and try a screw through both holes to see if they interfere. The chassis cover screw will have to be shortened for sure. You can also move the cover hole location or even leave the one screw uninstalled
 
Peter S said:
Spoke too soon. Looks like a die-grinder job. I'll say it for you; should have ordered the WO chassis!
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Peter you have to wonder what the designer at PL was thinking that day to put a non critical cover screw right above the tightest transistor mounting screw location. Makes your head explode when you see things like that.
 
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