Derek92994's 700 Ser II White Oak conversion

[laatsch55]

Yep, that's the procedure bud....put bthe amp on it's back so maybe they'll fall out when they are desoldered. Gotta magnet you can hang on em as you desolder?

 

[derek92994]

Starting to feel quite ill from that vax. When I am up again will post results. Thank you Lee

 

[derek92994]

Yeah I can source a magnet

 

[laatsch55]

Take your time Darc... be well...

 

[derek92994]

Pulled all outputs from 4th row and tested one at a time, they all test around 500. But when I put them in the backplane they are all shorted again.
That was not fun.

 

[AngrySailor]

Pulled all outputs from 4th row and tested one at a time, they all test around 500. But when I put them in the backplane they are all shorted again.
That was not fun.

Any luck? Those sockets have a short to ground maybe? Maybe try pulling two outputs from the good channel and see if they act shorted in there?

 

[laatsch55]

Ok, check all resistors on the back plane, then start checking the trannies closest to the bottom of the board...get me a pic of the backplane...

 

[laatsch55]

Shorted B to E or B to C ??

 

[derek92994]

All outputs when in backplane are Shorted both C to E and C to B except bottom output which measures 224 C to B and shorted C to E
What procedure and measurement do I use to check resistors? And what do they look like?

 

[Gepetto]

View attachment 57072 View attachment 57073
All outputs when in backplane are Shorted both B to E and B to C except bottom output which measures 224 B to C and shorted B to E.
What procedure and measurement do I use to check resistors? And what do they look like?

Did you check them C-E as well when you had them out? You cannot leave out that check.

 

[derek92994]

Edited last post, had my C to B etc wrong etc

 

[derek92994]

Did you check them C-E as well when you had them out? You cannot leave out that check.

No I only went C to B, fuck. Will have to pull them out again. What should C to E measure?

 

[derek92994]

Time for breakfast, fever and chills all night, slept a lot, which is why I am up so late. Feel much better today

 

[George S.]

When you get them out, separate them by type. Then take a sharpie magic marker and number them on the silpad side. All one type are 1-12, then the other 13-24. Then print out the 2 data sheets for them so you know for certain what's what.
Make a spread sheet on a piece of paper with appropriate columns and and headings and test each one systematically.
Test all the PNPs for C-E, B-E, C-B, etc. Be consistent and write the results down for each test. Then do the NPNs. Do this assembly line like and it won't take long.
24 outputs x 6 tests per output(if you reverse the leads) equals 144 results that can be looked at with conviction. Guessing or confusion ain't gonna work.
To hard to keep it all straight any other way.
Then there's another 24 results if you have a tester to check each transistors gain.
The time spent on this will get your amp fixed faster, with less potential damage and cost.

 

[laatsch55]

C to E should be Infinity....
After the initial 3 checks, reverse leads and test again, all should be infinity except B to E, B to C... Do not install after you test....

 

[derek92994]

When you say infinity is that the same as short or when 1 displays on the meter?

 

[laatsch55]

Darc, On the PNP-21195's, Negative lead on Base, Positive on Emitter, Then positive on Collector...these 2 measurements will be .500 or so, usually .545. Then move negative to Emitter, positive on collector.

Then Positive on Base Negative on Emitter, Then Positive on Base Negative on Collector, Then Positive on Emitter and Negative on Collector.

Those are your 6 measurements per output...

 

[laatsch55]

When you say infinity is that the same as short or when 1 displays on the meter?

Infinity is NO CONDUCTANCE.... OL usually on the meter....

 

[derek92994]

Good lot of info there guys, thank you. I am about to start pulling the outputs in that row

 

[laatsch55]

The last row? By the DCP?