WOPL update for PL400

BlueCrab said:
I removed the transformer today to treat the rust that was beginning to form on it. Each of the four KEP nuts and washer were badly corroded, so those are being pitched and I bought new at the local ACE hardware store. I pulled out the four 1/4" mounting bolts, sanded off the worst of the rust, likewise on the transformer itself, and then treated them with rust reformer. Looks almost new. I had planned on painting the transformer, but the reformer did such a nice job, I don't think it needs it.

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Don’t forget to use plastic washers and shrink tubing or the straw method to isolate the 1/4” bolts from the chassis.
 
I'm afraid I don't follow. What's the advantage or point of isolating the 1/4" bolts from the chassis? Originally they were not. I don't see an electrical reason. Is it to reduce mechanical vibration?
 
BlueCrab said:
Appreciate the input and this is what I'm looking for - pros and cons. Given that they replace slo-blow puts the nail in the coffin for the DC. But for the AC main, I may do it for the reasons I stated above.

Interesting what you state concerning arc flash problems, since all the aircraft systems on which I worked most of which are 28vdc and many handle far greater current than this amp, I've never come across this. Pilots and mechanics routinely use these circuit breakers as switches, so those CBs get cycled thousands of times. Not to say they don't go bad - they do - but I haven't heard of this. Learn something new everyday.
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So their Pro's and Con's are OK but mine aint???
 
Ha ha. Thought I was going to get a lot of stick for refurbishing a PL400. Your pros and cons are always welcome.
 
BlueCrab said:
Ha ha. Thought I was going to get a lot of stick for refurbishing a PL400. Your pros and cons are always welcome.
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I'm a 400 fan too,good little amps. 75% of the time I'll have a 400 on the horns....but...when it's time to get radical I will put a 700 on em...
 
I don't know if Lee put some extra juju in mine but it is still one of the most detailed amps I've heard.
 
Nope, standard WOPL Fish...could have been the background vibrations...
 
Stripped the chassis down to nothing - cleaned everything. Plan is to build the WOPL PL14/20 card first. Then build up the backplane without the transformer just to make it easier to move around. Then install transformer and rebuild power supply and test it before connecting it to anything. Once I'm satisfied with the power supply, I'll follow the route suggested in the instructions for bringing up the controller and backplane. Oh, and somewhere in there I'll add the relay protection circuit.
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I planned to replace the power cord since its condition was looking poor. Initially I thought I'd put on a 3 prong plug with an earth and tie it to the chassis and float the amp's ground from the chassis. This would provide safety and shield the amps innards. But then the amp can't be plugged into any of the preamps I have, which only take two pronged plugs - and only two pronged plugs that are not polarized.

What have others done?
 
I use two prong plugs and file the wide one down if there is one.
 
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