PL700B Damage due to multiple fast on/off cycles - Where to start ?

[mlucitt]

Hello, Thanks for the reply...
As I mentioned on a couple of my messages, I appreciate the offer of spare parts. I do not have any at the moment except for some spare 5AGX fuses. MarkWComer offered to send some parts, which I am thankful for. I am, not wanting anything for free. I am willing to send a money order via mail. As of now I don't know what will need to be replaced. I assume the drivers that drive the outputs, and with my luck probably all the outputs. I am not sure.
Eventually I will order parts, like spare outputs and I will need to replace all the capacitors in both the 700B and the pair of 400's that
are packed away in their cartons. If I get the 700B up and running, I will be more encouraged to work on the 400's too. I hope to update the control boards and replace all the component parts in all of the amps and the replace the jumbo power capacitors too. Gets pretty expensive when you are talking about 3 amplifiers, but that is my goal.. After that, I will have some experience and might be able to offer up some help to someone on this forum too !!!
BTW, I did manage to send a private reply - at least I think I did.

Thanks again,
MusicJunky

We mostly use the online parts house, Mouser (www.mouser.com) for needed parts. If you need the Mouser P/Ns, almost anyone here can help you with that. We also have a forum documents archive that lists parts you may need.

 

[MarkWComer]

Hello again!
I sent you a private message, I believe it worked at it did not show up in the regular forum.
Please let me know that you did receive it. I saw the [Start Conversation] button in the drop-down as you hover over the users name/icon
but I figured it would post a new message to the regular Forum for everyone to see. They should change that to [Send Private Message]
as it would be less confusing.

Thanks again,
MusicJunky

Got your message, yes- it’s private. Right- I didn’t understand what “start conversation” was either, but tried it because there wasn’t another option. But now we know!

 

[MusicJunky]

We mostly use the online parts house, Mouser (www.mouser.com) for needed parts. If you need the Mouser P/Ns, almost anyone here can help you with that. We also have a forum documents archive that lists parts you may need.

Hello again !

Thanks for the reply.
I haven't had much time to look around on this forum yet. I am so glad it exists and that I was lucky to find it. I am also thrilled that White Oaks
has taken the interest to offer parts for Phase Linear line. I see on ebay that Phase Linear has really jumped up in price and all of a sudden many have found or are interested. I will check out the documents archive, as I could really use a listing of replacement part numbers and where to purchase them. I have the actual PL service manuals burred in this house somewhere and hopefully can locate them. At least they have legible schematics and the part numbers and component values can be read. Most I have found on the internet are very low resolution and not clear. I will check the forum for anything that can be of use. Hopefully soon I can get started on the blown 700B, and then I probably will need some help from some of the members as far as what is the best replacement and where to purchase. I am familiar with Mouser & Allied and used to get their catalogs back in the old days when they existed.

For now, I appreciate any and all input. The guys on this forum have rekindled my interest in Phase Linear, I am really excited about attempting to service the 700B . . .

Thanks again,
MusicJunky

 

[MusicJunky]

nderstand what “start conversation” was either,

Got your message, yes- it’s private. Right- I didn’t understand what “start conversation” was either, but tried it because there wasn’t another option. But now we know!

Hello again,
I am glad the message worked !!! Now I'm already getting educated on this forum.
Feel free to drop me a message on my email and suggest a price for the parts + shipping.
Like I said I don't expect anything for free. BTW, am I correct to assume your parts would replace the outputs in the 700B ??
Would the same parts work in the 400's ?? If I remember correctly the 400's use the same outputs but lesser quantity... I don't have the schematics
on hand at the moment (We are searching thru boxes for them, LoL).
I eventually will have to purchase some extra parts to have on hand for both 700B and the 400's (while they still exist).

Thank You again,
MusicJunky

 

[MarkWComer]

Hello again,
I am glad the message worked !!! Now I'm already getting educated on this forum.
Feel free to drop me a message on my email and suggest a price for the parts + shipping.
Like I said I don't expect anything for free. BTW, am I correct to assume your parts would replace the outputs in the 700B ??
Would the same parts work in the 400's ?? If I remember correctly the 400's use the same outputs but lesser quantity... I don't have the schematics
on hand at the moment (We are searching thru boxes for them, LoL).
I eventually will have to purchase some extra parts to have on hand for both 700B and the 400's (while they still exist).

Thank You again,
MusicJunky

These transistors were pulled from a working 700 series two, they should be good. The original transistors were the RCA 410s in the pre-drivers, and PL909/XPL909 for the outputs. What I have are ON semiconductor MG21196G PNP for the outputs, the characteristics are a little different from the 909s, so biasing your control circuit will be a little different, DC offset may also change. Hopefully, someone else is watching this thread in case I’m wrong about this. Since I concern myself with rebuilds more than repairs of the old circuits I may be a little foggy on this point, I think your emitter resistors may have to change from .22Ω to .33Ω.

Yes, the 700, 700B and the 700/II use the same transistors, as well as the 400 and 400/II.

 

[MusicJunky]

These transistors were pulled from a working 700 series two, they should be good. The original transistors were the RCA 410s in the pre-drivers, and PL909/XPL909 for the outputs. What I have are ON semiconductor MG21196G PNP for the outputs, the characteristics are a little different from the 909s, so biasing your control circuit will be a little different, DC offset may also change. Hopefully, someone else is watching this thread in case I’m wrong about this. Since I concern myself with rebuilds more than repairs of the old circuits I may be a little foggy on this point, I think your emitter resistors may have to change from .22Ω to .33Ω.

Yes, the 700, 700B and the 700/II use the same transistors, as well as the 400 and 400/II.

Hello Mark,
Received the transistors you sent today!!! You even packed them properly (anti static). Now I need to find the Service Manual and some time to spend with the 700B.
I really appreciate your generosity and must say you are a man of your word. . . .

Thank You very much,
MusicJunky

 

[MarkWComer]

I really appreciate your generosity and must say you are a man of your word. . . .

Thank You very much,
MusicJunky

"Do unto others as you would have them do unto you..."
"A good name is more desirable than great riches..."
(That's my sermon for the day...)
Thanks!

 

[MarkWComer]

"Do unto others as you would have them do unto you..."
"A good name is more desirable than great riches..."
(That's my sermon for the day...)
Thanks!

I’m a turd for not mentioning this before, but others on this board have done similar to me as well. These are good guys here.