Phase Linear 400 Repair

[laatsch55]

This is obviously not the right thread for this but I have to ask. I have a couple of rebuilds in my future and I'm in the market for a new multimeter before I get started. (Landed a screamin deal on a 15 amp variac!)
Fluke always seems to be the default out there. Is the 179 a good choice and will it do what's needed for the PL rebuilds? Any other DMMs pop in your mind as a good choice? Would more than 1 DMM be a good way to go?

Thanks!

The Fluke 179 is true RMS and just a great meter in general. There are cheaper around that will do the job. Just make sure they can do ac/dc volts. resistance, diode test and cap test....

 

[Brettl]

In pic #3, the red lead is on the BASE lead, and the black probe is on the case or COLLECTOR. The other lead sticking up is the EMITTER lead. In an NPN bi-polar transistor the BASE lead should have the red probe and the EMITTER, COLLECTOR leads should have the negative probe. With you DMM in diode test mode those two measurements should be around .(point) 560DC volts.

Ok I think I have it now. Let me do these 4 tests with 3. Looks like .59 or .60 on all for the 1st test and they seem to pass the other three tests. I moved my meter to the "diode check" instead of the OHM 2M

So far these 3 look good, What will the reading be in a failure?

 

[laatsch55]

Either a dead short or infinity. You also need to reverse the leads with the black on the BASE and the positive on the EMITTER and COLLECTOR. Those readings should be infinity or NO conduction...

 

[MarkWComer]

Do you know how to test bi-polar transistors?
​

Lithium may work, if not Lithium, Depakote may be a better choice. Prozac would be like M&Ms, and I'd reserve Haldol for the schizophrenics...

 

[laatsch55]

I'm thinkin reverse-polarity.....or Aderol....

 

[Brettl]

Packages from white oak arrived today! Time to get busy

 

[laatsch55]

Amen.....

 

[NavLinear]

MEDIC

Nothing like a quick response. I'm guessing that being a bit late to the party is ok tho... My fav nurse! If you give her a hard time she may reciprocate.

I hope this helps.

 

[NavLinear]

This is obviously not the right thread for this but I have to ask. I have a couple of rebuilds in my future and I'm in the market for a new multimeter before I get started. (Landed a screamin deal on a 15 amp variac!)
Fluke always seems to be the default out there. Is the 179 a good choice and will it do what's needed for the PL rebuilds? Any other DMMs pop in your mind as a good choice? Would more than 1 DMM be a good way to go?

Thanks!

If you're looking for more than one meter I may have a couple of dated (mid to late 80's) digital Fluke meters with an ass ton of capabilities that I can part with. These have been fondled gently and are happy meters. Shoot me a PM if you have any interest.

 

[laatsch55]

Brett, did you find any bad outputs??

 

[Brettl]

My son arrived in from NY last night, a little side tracked. I will jump on it over the weekend. I had a awesome conversation with Mark from this forum yesterday and now I am just going to build the white oaks backplane also. ( need more $$$$ ) I will take the outputs and try to rebuild my 2nd pl 400 with it.

 

[laatsch55]

Once you go White Oak, there's no turning back......

 

[AngrySailor]

BTW....one of the few ways i HAVE NOT blown up a 400!!

Brett, I'm not laughing at your misfortune, but Lee, I just about fell out of my chair! I imagine you've "let the smoke out" a good few times!

I did did a similar thing Brett, I was lucky and didn't toast the amp, but a loose wire toasted a meter
Are your PL's series one? If you have/want to part with the good meter from the parts amp I would be very interested. I'm planning to WOPL my 400 soon as well and a meter is really all I'm lacking. Good luck and I'll be following your build!

 

[Brettl]

OK got the the resistors installed, here are the parts that are left. I am doing the full build, not the quasi! I know I don't have to but I soldered top and bottom.

 

[Gepetto]

OK got the the resistors installed, here are the parts that are left. I am doing the full build, not the quasi! I know I don't have to but I soldered from top and bottom.
View attachment 20581 View attachment 20582 View attachment 20583

Take your time Brett, double check each step. The amp has waited 45 years so it can wait a little longer

Looks good so far.

 

[Brettl]

Next Pictures. The C8L / C8R placement was odd but called for. Seems this is not in the accompanying photo supplied with the kit?

 

[laatsch55]

What's odd about it?

 

[Brettl]

What's odd about it?

that the build calls for it but, the picture ( supplied of finished board ) does not show it installed

 

[laatsch55]

All else fails, follow the BOM. Joe may not have updated the assembly pics as fast as he updated the boards. At times he'll add components and spaces with some experimenting in mind as well as a later component change. We have played with a lot of different component changes over the years. Some worked out and some less than optimal results. Joe told me once that a SPICE model can predict performance but not how the amp will sound....he counts on the rest of us for that info...

 

[Brettl]

Yes, that's what I did the BOM. Everything else in the picture seems exact but your explanation makes sense to me. When I'm all done I'm going to take some photos close up just to make sure you guys don't see anything wrong