700B serie 1 faulty

[66stanger]

Hi,

I use a PL4000 with 700B S1 on JBL 250Ti CE.
Since last week, the left channel is faulty, low level listening and important pink noise and after no sound and the needle on level meter is @ max like this forum header...
The amplifier is stock with PS capacitors replaced.

I didn't opened yet, I thread to know your opinion.
I have the complet set replacement components (PCB driver & output transistors)...

Thank you in advance for your opinion.

 

[laatsch55]

All the 5 amp rail fuses good?

 

[ksrigg]

I hope 66stranger didn't go in for the repair without your help, Lee. Danger, danger ....

 

[laatsch55]

It could happen....

 

[Gepetto]

It could happen....

And far too often does...

 

[66stanger]

All the 5 amp rail fuses good?

In fact, I not checked.
The right channel; it's good.

I know, I played with the fire... but you what is it ? It's so good... I'm a 700B addict now... :-///

It's grave Dr ???

 

[laatsch55]

What is DC offset on both channels?

 

[66stanger]

What is DC offset on both channels?

0 on left (faulty channel) because the fuse (3.15A fast) is dead and 0.022V on right (good one).
The other fuses are good.

I must to replace the fuse and I will let you know...
On the schematic, there is not the VU meter section...
Why is it on max level ?

 

[laatsch55]

Probably a shorted output....but that doesn't jive with t he 0 volts of DC. What driver board does this amp have?

 

[66stanger]

Probably a shorted output....but that doesn't jive with t he 0 volts of DC. What driver board does this amp have?

Yes, it's probably shorted...
Normal the 0V, there is not fuse
The speaker fuse in dead on this channel...

I'll see that.
I must to remove the 700b of my stand... not cool :-//
And I'll check output trans with the driver...
It's the time to replace the complet set... with 21196...
and the PCB driver from Joe...

To be contiuned...

Thanks

 

[Northwinds]

Good luck with this Brother, welcome to the board. Folks here will help you get your 700 singing again. They are remarkable amps and with Joe's goodies inside, are way beyond what Bob Carver envisioned

 

[derek92994]

Has Bob Carver ever listened to a 700b with the new boards? What were his comments on it?

 

[laatsch55]

Not YET....

 

[derek92994]

Not YET....

Damn!!!

 

[66stanger]

700b... after several months... -:/

Hi guys,
I'm back after several months... :-/

No time to work on the 700b...
I am so addict...
I can't wait more...
This amp is so good...

My orignal transistors are PL909, I can't find the datasheet...
The MJ21196 have the same pins ?
I saw several photo on the web and there are different positions in the back.
Anyway, what is the position on the 21196 on the radiator ?
Any pictures ?

I've 700B rev.1

Thank you,

 

[laatsch55]

All TO-'3's have the same pinout. The bottom row should be different than the other 5 rows. Got some pics of the back of that bugger?

 

[laatsch55]

If an output blows and causes a fuse to blow, there is usually something else wrong...

 

[jbeckva]

If an output blows and causes a fuse to blow, there is usually something else wrong...

Heheh.. I hold the record on number of outputs blown up in one zap...

 

[laatsch55]

Yes.....you do!@!

 

[66stanger]

All TO-'3's have the same pinout. The bottom row should be different than the other 5 rows. Got some pics of the back of that bugger?

OK, just to be sure.
Thanks.

What do you use as output protection ?
Relay ?


=> jbeckva
Record of the blown up ?
You are shareholder at Onsemi ?

I will work on 700b this week end...

Is there many 700b on the forum ???