Phase Linear 200 rebuild

[kl0neMan]

Phase Linear 200/200B Series 1 Amplifier Service Bulletins

Perry,

Here are just a couple of the service bulletins that were issued for the Phase Linear 200/200B series 1 amplifiers.

Time permitting, I will scan a few other 200 series 1 documents which may not have been issued as service bulletins and/or were not included in the service manuals. These would include:

1.) "FINAL ASSY & SCHEMATICS 200 AMPLIFIER 402570 E VERSION"
2.) "01 ASSY, 200 POWER AMP, P.C.B PL19 65502 DWG. NO. 402555 REV NEW"
3.) "01 ASSY, 200 POWER AMP. P.C.B. PL19 23512 DWG. NO. 402555 REV D"
4.) "01 ASSY DISPLAY BOARD PL 24 60503 DWG. NO. 402558 REV NEW"
5.) "01 ASSY DISPLAY BOARD PL24 60503 DWG. NO. 402558 REV A"
6.) "PCB ASSY. SCHEM. RELAY CONTROL 200B PL31 DWG. NO. 210-0087-0 REV A"
7.) "RELAY CONTROL ASSEMBLY 200B PL31 DWG. NO. REV A"

There are a few others as well.

Ed

Did these ever get uploaded?

I am attempting to resurrect a PL200 (original version), that has apparently been worked on before.

So far I've found the following failed devices on the same channel using a bench multimeter for basic resistance checks:

1 of 2 RCA410,
1 of 2 RCA 66430
a pair of 1N4148s that were obvioulsy in series, and
a Motorola ST258 (in the same location as an RCA 66429 on the other channel.

I believe the ST258 to be Q3 on the schematic for the original version of the 200, that I found online.

Using the same method the following devices appear to be okay:
The MPSA93s at the input (Q1, Q2)
the TIS97 (Q4),
the GES 93 (Q5),
One I believe to be 1C13 (Q6 which seems to be marked as Motorola M613 S1444), and
One I believe to be 1C12 (Q7 which seems to be marked as Motorola M613 S1443).
The 1N4004 doides used throughout.
The other 1N4148 diodes.
The .68 Ohm and .1 Ohm resistors feeding the RCA410s and the RCA66430s.
Various other resistors, (spot checking).

I had to remove some of the devices from the circuit to reliably test them.

I replaced all the electrolytic caps on the amplifier PCB other than the 1uF/80V part because I do not have a replacement yet. The 100 uF 6.3V part visibly did not olook suspect, but the 47 uF 50V part appeared swollen on both the top and underneath at the seal.

I have replaced the both RCA 410's with Motorola MJ410's. I do not have a sub for the 66430s, and am unsure what to replace them with.

I understand this model has stability problems at high frequency and low impedance. and suspect this may be the reason for a prior failure. I read the service bulletin and see a 10 PF cap across Q1 and a 22 PF across Q3 on both channels. What is the recommended course of action with respect to replacing the other transisitors, and safely bringing the amp back up? ( Using a variac, DBT, etc) while looking for oscillation on the output. I would like to have more success than whoever worked on this before.

Thanks in advance,

Dan

 

[kl0neMan]

After a long hiatus, I'm back into repairing this Phase Linear 200. I decided to look at the display circuitry, and am glad I did, In there, I found a blown 220 ohs resistor on the upper right corner of the board, and a 1N4005 diode that was short circuited and someone cut out but left hanging. I have replaced both of those and rewired the conductors going to that board, because I found one of them broken. When doing this I noticed the holes for the wires were much too large for the tiny wires that they are used with. I have 8 Motorola MJ410s with date code 8239, 4 Motorola MJ15011's (MEX) with date code 8651, 10 Motorola MJ15011s with date code 7839 and a couple of RCA 66546 with date code 7748 to use in this repair if appropriate. I am also still searching for a replacement of the Motorola ST258 that was found failed short circuit. I suspect this to be a 2N3440.

Dan

 

[laatsch55]

2N3439 will work in place of the 3440, i fact it is a higher rated part.

 

[kl0neMan]

2N3439 will work in place of the 3440, i fact it is a higher rated part.

Thank you. Any advice on the others I have? As stated in my earlier post I intend to use Motorola MJ410's in place of RCA 410's. I was unsure about what to do with the 66430's. Can I use MJ410s for those two, or something from that pile of transistors I mentioned before?

Dan

 

[laatsch55]

I'll have to ask and see what the 66430 is rebranded from..

 

[kl0neMan]

Thank you again sir.

I am happy to be working on these restoration projects again. I was able to retire, just before the pandemic hit here. I am 'hunkered down, and refraining from venturing out, so these things give me a way to productively occupy my time. I need some success stories about now. So far, I got my TEAC X-1000R, a Carver C4000 and a few other things going again.

Dan

 

[laatsch55]

Amen...

 

[kl0neMan]

I ordered a pair of the 2N3439 transistors, as well as replacements for the electrolytic on the LED Meter display PCB. Subtitutes for the 66430s are the lone holdout part for this one. I also ordered a the of Lubriplate ES-DS to use on the X-1000R when I open it back up next time.

 

[laatsch55]

Jeez, I'm brain dead, use MJ 21196 for the outputs...

 

[kl0neMan]

Okay. It is my understanding that the RCA 66410 were the outputs and I was going to replace them with MJ410s. Is this not correct?

huh?

Sorry for the confusion... The post got truncated somehow and I hopefully fixed it here...
Thank you for the photos. My eyes are so damned bad I cannot read the part numbers of the devices from my phone. I will look again at them from my computer..

 

[kl0neMan]

huh?

Even on the large display and zoomed the part numbers are a bit difficult to read. They appear to be MJ21195G (inner pair) and MJ21196G (outer pair). Is this correct? ( I have Qty 4 of both parts in a shopping cart at Mouser's online store...)

 

[laatsch55]

Yep, that would be correct for a full comp amp. Where are the MJ410'S going?

 

[kl0neMan]

Yep, that would be correct for a full comp amp. Where are the MJ410'S going?

Now, I’m confused. The amp was originally a quasi complementary design as far as I know. Was originally placing the MJ410s where the 66410s were, and was looking for a sub for the 66430s. Then saw the photos of board with the MJ parts. Have no idea how to proceed.

 

[kl0neMan]

Tonight's finding - a shorted diode in the power supply bridge. Glad I did not apply any real voltage to it. Both Electrolytics "Seem" okay - ie. they are not shorted, bulging, and appear to hold a charge when tested with a DVM for whatever that is worth.

 

[laatsch55]

I'm confused too. If you have 95/96 pairs it's full comp, and would not need a 410driver..
Thev410 is a TO-3 isn't it?

 

[kl0neMan]

The original parts were RCA devices, with 66410 and 66430 part numbers. A parts place crossed the 66410s with MJ410's but had no sub for the 66430. I saw the MJ21195G (inner pair) and MJ21196G (outer pair) in a photo of PL200 module, but it it apparently NOT like the ones I am attempting to repair. There is a number written in blue sharpie on the component side of mine - 04-45-478.

On the foil side is
PL19
23512

Dan

 

[laatsch55]

I'm not that familiar with the 200.. never worked on one, 300, 400 and 700 but no 200.
Are the MJ410's a TO-3 ?

 

[kl0neMan]

huh?

Looking at the photos of the PL-200 you did. Were those transistors substitutes for the original series or for something later?

 

[kl0neMan]

I'm not that familiar with the 200.. never worked on one, 300, 400 and 700 but no 200.
Are the MJ410's a TO-3 ?

Yes, they are TO-3 cases. Here are photos of the modules in my unit. The one without wires attached and having gray-colored insulators has the original transistors installed as placeholders so they may not be in the correct positions. The module with the wires still attached and having orange-colored insulators has the original transistors in the original locations.
U

 

[laatsch55]

Ok, that's a quasi comp. You can sub MJ 21196 for the 66430's. Just be sure to replace all the 4430's in ther same channel, Don't mix the 66430's and 21196's..