Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thread

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Funny there are no capacitors on the transistor wall in the PL700B...

200 posts, it's like were up to something. Congratulations everyone.

True, but this is a hybrid, thought I'd leave em in. They are on every 400 ser I.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Ok Joe, were goin in!!!!!

 

[speakerman1]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

No I didn't know you twisted DC. Why do you do it? If you don't have a drill handy. Safety Wire pliers and a vice is pretty fast.

Larry

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Of course the cat has to help at this particular time.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

The cat always comes to the rescue when you need it most

2N5409 or 2N5410 are decent subs for the 2N3403

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Ok Joe, check me before I power on;

1L--Signal in +
2L---Signal in -
3L--Base of negative driver
4L---Collector of first negative output
5L gnd
6L---Collector bus bar of negative outputs
7L--?
8L--Emitter of first positive output
9L--base of positive driver
10L--Base bus bar of positive outputs
11L--+ 100 volts from PS caps
12L-- -100volts from PS caps

Also , where should the bias pots be ??

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

No I didn't know you twisted DC. Why do you do it? If you don't have a drill handy. Safety Wire pliers and a vice is pretty fast.

Larry

To cancel the electromagnetic field generated by DC.

 

[speakerman1]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

How if you shielded them? They emit that much?

Larry

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

These were for the power supply for the DC protect relay and they were running by everything, just a smart thing to do.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

The board is wired to the chassis, time to hook up the Variac, and Dim bulb tester, meter and scope.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Hi Lee
It appears you have the wiring correct. 7L where you show a ? is fed from the FUSED +100V rail that is effectively the bus bar that connects the collectors of the positive outputs.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Yep, figured that out while i was waiting. thank you Joe. Where should the bias pots be??

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Sorry Lee, intenet shut down and had to reboot my router. The pots I supplied in the beta kit are opposite of the outcome I wanted. Full CLOCKWISE will get you minimum bias, full COUNTERCLOCKWISE will get you maximum bias. Thus set to 2/3 way or 3/4 way to full clockwise to come in light on bias and tweak it up to the final setting. On the PL400 I modified, the final setting was nearly dead center.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

I have 3mv offset on the right channel and 85 volts DC on the left channel. DC protect works, would not activate left channel.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Time for debug it seems

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Yes indeed Joe, that's what i've been doin. No find it yet. Eliminated outputs , drivers, . bulb stays dim, no large current draw. Regulator gets real warm. No solder bridges. No shorted q1-q4. All other trans check out.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

How's your plus and minus 20V look? If the regulator is getting hot, I would suspect something there.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Let me check.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

From chassis ground with neg probe there, positive probe on middle leg of regulator 85 volts DC. Right leg + 19.78 volts DC. Left leg + 20.25 volts DC , no negative voltage on regulator.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

are you seeing this large voltage reflected at the junction of R15 and R10?

Is your bias transistor Q6 any good on that channel?