I want to White Oak a Phase Linear 400 Series I

ksrigg

ksrigg

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OK...I have (almost) everything in hand and am ready to start...I actualy have replaced the light board with the led board, and painted the bezels for the meters. I haven't soldered the board back in yet..

So what is the next task. ..I know to epoxy the sleeves with the asbestos looking wrap on them...then what is next. Is it safe for me to cut the old PCB out of the amp? I really need to be able to get it out of the way to replace the power cord and the caps, etc...I took some pics of the wiring, but don't know if it will help or not as the new layout looks different anyway..plus I have a broken fuse holder, so might as well replace them all..

When I get to replacing the transistors, are they soldered in place? Can't really tell..

Also, I know I need to replace the Bridge Rectifier. This one still has the original 25A one. I ordered a 35A and hope it is enough..

Got the variac to work, after learning they will blow a GFCI plugin...Lesson learned..

If MCM had not screwed up and left my solder station out of my order, I have a feeling I would be way farther into this thing. I really want to have the new iron to go at the BR...as I remember that solder is pretty uncooperative...

Sutton
 
ksrigg

ksrigg

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The solder station will be here tomorrow, and I should have verything but the protect circuit. I did replace the bridge rectifier today, and have the led board in place and the bezels repainted..

I'm ready to really get into this thing...
 
laatsch55

laatsch55

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Get the old board out?? Just cut each wire off very close to the board. Don't waste your time desoldering this stuff, just clip and go.
 
ksrigg

ksrigg

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I checked, and the solder I have is Kester #44. What temperature would you use for soldering using this solder, and what would you recommend for silver solder? I read that Kester says set the temp at 750...seems high to me...but I know you guys will know the answer...

IO also bought a small spool of "silver solder" at Rat Shak. Would the temp be more like 600 or where for that........or is there a way to tell....some little "secret" that is generally used?

Just trying to learn how to do this stuff..

Getting the old cord out of the 400 was a pain in the butt...I'm going back with a cord from a vacuum cleaner...should be better than an extension cord...and I am reading that BLACK is HOT....so it should go to the fuse holder, and the white should go to the solder point in the rear center of the amp, behing the PCB? The white sleeve is cool looking, but what does it do?
 
ksrigg

ksrigg

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After looking at the wire...cord....whatever, I wonder if it is thick enough to carry the current needed for this monster.The vacuum cleaner the cord came from is a 12 amp machine, but the actual wire inside the black and white plastic is not that thick..Will regular speaker wire....plain ole OFC work? I have plenty of that in various guages, from 16 to 12 guage. I also have some plugs left over from a recent project...What say you all? Extension cord rated rated fir 13 amps, the vacuum cord for a 12 amp machine, or some good ole 16 guage or thicker straneded speaker wire. I have some speaker wire that is pretty rigid too, thicker individual strands....

I know, I am OCD big time, but most of us here have to be to a certain degree...that's one reason I never get anything done.....I obsess over it all day......
 
mlucitt

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The sleeve is just to prevent any chaffing of the wire or potential melting if a component were to get too hot. The folks at Phase Linear used good point-to-point wire but they could not manage the quality control of the power cables they bought, it would be too expensive, if you could even find power cables back then with teflon or pvc insulation (rubber being more common).

You will like the flux in that silver solder much better than the Kester, less goo anfer you are done. Generally, the lower the melting temp of the solder the better for the components that are getting the heat.

I don't like the vacuum cord, but it is your call. To me it is like putting retreads on a corvette. You could go to Home Depot and buy 15' of 14GA 3-conductor cable and a nice hospital grade (look for the green dot) extra safe, heavy duty wall plug for short money...

Black is hot, run it to the fuse. Then run the white to the thermostatic switch in the middle of the amp. Although it will not matter for a two-prong cord because you can flip it over and plug it in backwards.

Mark
 
kevin

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Sutton .... Im pretty sure ive got some cord that will work fine for your amp.... remember all those short extenson cords we made that time.... ive got several of those left. they were 14 guage. black, white and green !
 
ksrigg

ksrigg

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Kevin..

Thanks man, I had forgotten about any cords. When can I get up with oy to get one? I really need it soon as that is the next thing I need to do with the amp..

Mark..

If I go with three prong cord, I'm making the assumption that black and white go the same place as two prong, but where does the green, or earth gound (or is it appliance ground) go. What do I run it to, and what is the length I need to make the cord?
 
mlucitt

mlucitt

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The beauty of making your own cord is that you can make it as long as you want. Extension cords on these amps are a bad idea, so make it long enough. There is such a think as too long but with 14Ga conductors that would be like 25 feet before it caused much loss. There is a formula somewhere but you have to know the current or the power and we don't know that for your amp yet.

The green (ground) always goes to the chassis. It is supposed to be a dedicated bonding point (scrape the paint and use tooth washers on both sides of the terminal lug) but you can probably used an existing screw or bolt. Just make sure it is making good contact.
 
ksrigg

ksrigg

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OK. I found the calculator for current loss, and as you say, it's not much with the higher guage cord. Kevin is seeing what he has. Thinks he may have robbed the hospital grade plugs from some of the cords we made up. I don't remember even making em... Man getting old sucks...

I'm going into
a
BelkinPowerConditioner....whatcha ma call it...When Larry recommended it, I bought a couple of them. They were on sale for line $150 or less. They will take 6 components each. My wife even said it was probably one of the "smartest" purchases I had ever made.

I'm going to try to attach some photos so you can see my BR and a couple of "suspect" resistors...
 

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ksrigg

ksrigg

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Top pic is my meter, os Mark or Lee when you tell me to do something...you can tell me where to set the meter. I'm pretty clueless.

Next pic is the back of the old PCB. It has some diodes and added resistors, and shows signs of having been messed with. Maybe somebody can figure out what the dude was doing. Sorry I cut the top of the board off in the pic. If you want to see a better one, let me know. I'm getting ready to cut her loose..

Third pic is of the suspect resistors. They don't appear shorted when I put the eter on them...but I'm not really sure. Does the "DC Protect Circuit" do away with thes anyway?

Last pic is of the BR with bypass caps. Yes, the connectors are soldered on the spades. This will probably result in me not getting to use the ultracool aluminum plate for holding the caps down, so I'll probably use double sided sticky tape...
 
laatsch55

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Those resistors are part of what's known as a "Zoebel" network. It's to protect the amp against really inductive or reactive loads. The DC protect board has the Zoebel network incorporated in it as you have to do away with the one on the speaker posts to mount the board.,
 
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