700B blew one Right channel 5A supply fuse

[62vauxhall]

Yep, a rare variant that Ed has talked about also...the 14 blank in my possession is tutned 90 deg also....I have seen the ones like Gary has....

This 14A board is date stamped May 2, 1974 and I understand the 700B was introduced that year. Maybe this board's an early example that they scrapped soon after production in favour a new & improved version.

I understand Bob Carver is expected at Innovative's garage sale this Sunday. I usually go and was thinking about taking my face plate with me and ask him to sign the inside of it.

 

[laatsch55]

Now that would be cool....ask him if he's heard about the White Oak mods.....

 

[62vauxhall]

Gary, the traces are shit and pretty easy to lift....whatever it takes to fix em. I usually lay a cut off resistor lead and bend it in the same shape as the trace and solder it in a place or two to the old one.

Is this the left or right channel?

Yes, right channel.

Good idea on the resistor lead, I used an inch of about 26GA hookup wire and snipped off the excess. I like your idea better but am not going to dick with it again unless I have to.

 

[laatsch55]

How are the measurements on the left channel? and just for shits and giggles, lift one leg of D13 and check it. They test .79-.80 in circuit both ways....

 

[62vauxhall]

Now that would be cool....ask him if he's heard about the White Oak mods.....

I will, and tell him about this site. Maybe drop your name?

 

[laatsch55]

And Joe's, sure....

 

[laatsch55]

Maybe we can talk fitz43 into taking his quasi White Oaked 700 up there. You have some rockin neighbors up there... fitz 43 and Elite-ist (Nando)...

 

[laatsch55]

And let's not forget Lyle. He has a serI 700 that's a beast and I'm packing a 3300 Ser II to send his way...

 

[62vauxhall]

How are the measurements on the left channel? and just for shits and giggles, lift one leg of D13 and check it. They test .79-.80 in circuit both ways....

Did not check D13's in circuit, should I have done that? I jumped right to lifting a leg and they were both .55 volts one direction - OL in the other.

Found the same anomaly at Q3 - voltage in one direction between emitter and collector.

Noticed that the trace hole for Q4 collector has lifted but it's still attached and I'll deal with it later.

Left channel transistor readings:

Q1
OL - red to base & black to emitter
OL - red to base & black to collector
.67 volts - red to emitter & black to base
,67 volts - red to collector & black to base
OL - red to collector & black to emitter
OL - red to emitter & black to collector

Q2
OL - red to base & black to emitter
OL - red to base & black to collector
.67 volts - red to emitter & black to base
,67 volts - red to collector & black to base
OL - red to collector & black to emitter
OL - red to emitter & black to collector

Q3
.65 volts - red to base & black to emitter
.65 volts - red to base & black to collector
OL- red to emitter & black to base
OL - red to collector & black to base
.86 volts - red to collector & black to emitter
OL - red to emitter & black to collector

Q4
.61 volts - red to base & black to emitter
.58 volts - red to base & black to collector
OL- red to emitter & black to base
OL - red to collector & black to base
OL - red to collector & black to emitter
OL - red to emitter & black to collector

 

[laatsch55]

Now that those are posted, post the measurements for Q5,Q7,and Q10....

 

[62vauxhall]

Glad I had those extra diodes. Was easier to put in new D13's than fiddle with getting the cut soldered leads back in the hole.

Q5, Q7 & Q10 transistor measurements as requested - don't think they're good.

The variable voltage readings usually climbed but would show OL briefly from time to time.

Q5 Right Channel
OL - red to base & black to emitter
.73 volts - red to base & black to collector
.56 volts - red to emitter & black to base
.55 volts - red to collector & black to base
OL - red to collector & black to emitter
.59 volts - red to emitter & black to collector

Q5 Left Channel
OL - red to base & black to emitter
.73 volts - red to base & black to collector
.55 volts - red to emitter & black to base
.56 volts - red to collector & black to base
OL - red to collector & black to emitter
.59 volts - red to emitter & black to collector

Q7 Right Channel
.55 volts - red to base & black to emitter
.59 volts - red to base & black to colletor
OL - red to emitter & black to base
OL - red to collector & black to base
.46 volts - red to collector & black to emitter
OL - red to emitter & black to collector d to collector & black to emitter

Q7 Left channel
.55 volts - red to base & black to emitter
.58 volts - red to base & black to collector
OL - red to emitter & black to base
OL - red to collector & black to base
.46 volts - red to collector & black to emitter
OL - red to emitter & black to collector

Q10 Right channel
OL - red to base & black to emitter
OL - red to base & black to collector
.58 volts - red to emitter & black to base
.59 volts - red to collector & black to base
.88 volts (varies) - red to collector & black to emitter
OL - red to emitter & black to collector

Q10 Left Channel
OL - red to base & black to emitter
OL - red to base & black to collector
.58 volts - red to emitter & black to base
.59 volts - red to collector & black to base
.80 volts (varies) - red to collector & black to emitter
.44 volts (varies) - red to emitter & black to collector.

 

[laatsch55]

Gary, I'm in the process of getting the wife's new computer and my new computer up and running today, with Jer's help. So I won't be much help today....sorry..

 

[62vauxhall]

No worries.

 

[Gepetto]

No worries.

You should draw a diagram of the original transistor orientation with the TIS devices noted in their respective locations and then a SEPARATE drawing showing how you have installed the MPS replacements.

Your earlier diagram was not clear as it mixed up the two...

 

[62vauxhall]

You should draw a diagram of the original transistor orientation with the TIS devices noted in their respective locations and then a SEPARATE drawing showing how you have installed the MPS replacements.

Your earlier diagram was not clear as it mixed up the two...

I hope I understand the request correctly and attached are two diagrams.

The first diagram I replicated from the pictorial in the manual depicting how original Q1 through Q4 were orientated, what I understood the pinouts to be and which new transistors replaced them.

The second diagram is just a re-drawing of that in my previous post depicting how the new Q1 through Q4 transistors are orientated to each other and what I believe is their pinout pattern.

Please disregard the "attached thumbnails", I can't get rid of them. The two immediately below are what I intended to post.

I can...





.

 

[Gepetto]

I hope I understand the request correctly and attached are two diagrams.

The first diagram I replicated from the pictorial in the manual depicting how original Q1 through Q4 were orientated, what I understood the pinouts to be and which new transistors replaced them.

The second diagram is just a re-drawing of that in my previous post depicting how the new Q1 through Q4 transistors are orientated to each other and what I believe is their pinout pattern.

Please disregard the "attached thumbnails", I can't get rid of them. The two immediately below are what I intended to post.

View attachment 14391 View attachment 14392



.

Very clear thanks and the substitutions are indeed oriented correctly for the NEW diagram when using the TIS devices.

 

[laatsch55]

Ok, where were we......oh yeah, D13 was ok?

 

[62vauxhall]

Yes, D13 was OK (but put in new ones), posted more transistor measurements and a couple of diagrams for Gepetto.

 

[laatsch55]

We have established that the outputs in either channel are NOT shorted correct?

 

[62vauxhall]

After posting my readings from the 410's and checking voltages at speaker terminals you suggested "a wounded Q7" or possibly others. I assumed then your conclusion was the 410 outputs were OK.