PL 200 Series Two Repair - What about those cute little caps?

[Mr. Pink]

Hi everyone,
I'm a total novice to amp repair and electronics in general. I'm working on a 200 series two amp that blows the negative (-) supply fuse on start up.
I have a soldering iron, a DMM, lots of hand tools, a service manual, and a brain. I'm pretty much learning as I go.
My copious research so far has led me here. This seems like the place.
Anyway... I've pulled one of the modules for easier access and tested everything I can test. Found some bad diodes, resistors, and transistors. At least two of the output transistors on the one board I've pulled are shot. I understand those have to be replaced in pairs.
I'm making up a parts list of things to order in the hopes of replacing the bad, keeping the good, and trying to get this puppy up and running. I'm learning all about the DBT so as not to fry my new parts!
My questions are about the capacitors on the two main boards. Do I ignore them until I try to power up? Power up, test and replace as needed? Replace them without testing since I'm already working on the finer points of soldering (and they're old)? If replacement is the obvious answer should I match the original electrolytics or change to film?
Thanks in advance for any corrections/guidance.

 

[mlucitt]

All the electrolytic capacitors on those boards, as well as the main capacitors in the power supply are at least 40 years old. The life expectancy of those vintage capacitors is 15-20 years before they dry out or start leaking. Replace them all with modern electrolytic capacitors (we like to use Mouser Electronics, they seem to have a good variety of parts for the Phase Linear amplifiers), no need to replace them with film, they are not part of the signal path.
If you can find a 10-15 amp Variac (autotransformer) to use in conjunction with your DBT, that will help to determine if there are shorts in the unit. You can bring the Variac voltage up slowly and watch the DBT, if it starts to get bright, back the voltage down and keep searching for the cause of high current flow.

 

[Mr. Pink]

Thanks for the fast reply! As a follow up related to buying replacement parts, I've read that caps should be the equivalent storage value (or close) and the same voltage or higher when replacing. How about transistors? Eg. Q7 needs replacement. It's a Tis97. Mouser says it's obsolete, and another site I was on showed 31 equivalents! Which specs are the most important when it comes to transistor replacement?

 

[laatsch55]

How many TIS-97's do you need?

 

[Mr. Pink]

I need 2. I'm taking readings in circuit. Is that bad practice?

 

[laatsch55]

Well, it can tell if you are shorted or open..

 

[mlucitt]

Lee has a supply of obsolete parts. He is Mr. Obsolete...

 

[laatsch55]

True dat..

 

[pennysdad]

I've got one of these, still all original, running in bridge mode [using an external thingie].
It powers my old JBL 380 sub most admirably.
The good thing about these was they came with the relays as standard. I don't think they ever did it with anything else.
Just thought I'd mention it.
[... yes, just passing, thought I'd drop in and say "Hi Lee".]

 

[laatsch55]

GEORGE!!!!! God bless ya!! How ya doin???

 

[pennysdad]

Where do I begin???? I'm ok I guess. Jeez it's been a while. Time just slips by so quickly.
I got a call from Darcy the other day out of the blue, and so here I am.
He told me about his WOPL. So sad.
Still have my Clair Bro. 700 but not game enough to run it up any more, even tho' I did get it rebuilt only 3-4 years ago.
But I do still run and like my 200 II as I mentioned earlier.
So, you still breathing? Me too... Good news then.

 

[derek92994]

Still have my Clair Bro. 700 but not game enough to run it up any more, even tho' I did get it rebuilt only 3-4 years ago.

DC Protect is for Sissys

 

[pennysdad]

DC Protect is for Sissys

I wish my 4x 10" JBL's knew that before my 400 let go in my JBL L36 and L40. Jeez that hurt.
Almost irreplaceable, but after over 12 months of searching I finally found some.
You can get external 'add-on' relays now for less than US$20 on the 'Bay. Just add a 12VAC supply. Too easy.

 

[pennysdad]

Anyway, the 200 II is quite a little tuffy as long as they got lots of air.
Mine worked for almost 2 years as part of a bi-amped stage monitor system running the horns.
There were 5 of 'em partnered up with 400 II's.
Only one 400 died. That's pretty good for rock n' roll.

 

[laatsch55]

Darcy's 700 is a minor fix, and we are slowly walking him through it. It'll be fine. Good to see ya George. Real good.

 

[pennysdad]

Thanx Lee.

 

[derek92994]

Darcy's 700 is a minor fix, and we are slowly walking him through it. It'll be fine. Good to see ya George. Real good.

I gave him a kick up the ass and said get the fk back onto phoenix ya hermit

 

[derek92994]

Darcy's 700 is a minor fix, and we are slowly walking him through it. It'll be fine. Good to see ya George. Real good.

Lee, Bills keep coming in, Im trying to get a variac but I just have to keep waiting and doing overtime. Im at peace with it all, and have backup amps, Im glad the jamos are efficient.

 

[derek92994]

How big does the variac have to be? In VA please

 

[laatsch55]

You guys are 240 right? 10amps at 120 is 1200 va. 240 at 5 amps is 1200 va..