I was gonna suggest perhaps C61 is shorted to ground but it says you already replaced it.

Maybe start probing around and try to find where that portion of the circuit has continuity to earth.

 

Anyway I'm out I shouldn't be "contributing" to these fix it threads 

Today I had to make a parallel circuit with a variable resistor

You cannot view this attachment.

Then do some calculations etc for voltage drops and calculate how many ohms the variable resistor should be for Va to equal Vb

Then make the circuit and do it

You cannot view this attachment.


So yeah pretty boring but it's definitely helping I have to chug through this in order to get to the cool stuff.

Pretty funny the book noted "although Vo can be directly measured across A and B it is good practice to make all measurements with respect to ground"

 

That looks fantastic 

You did an awesome job.

Congrats 

I put all the knobs nuts washers etc back on my all time favorite amp

You cannot view this attachment.

They had been off since you guys fixed it.  I had planned to get around it but never did then I had an intermittent input jack and noticed how bad the chassis was rocking back and forth.

 

Hang in there bud 

Don't give up before the miracle 

If anybody can get your amp running these guys can.

Maybe post up some pics of the boards

 

Good afternoon solid state afficianados.

Hope your weekend is going well at least what's left of it.



I had a question about preparing some banana jack patch cable connectors whether or not these needed to be soldered.

The wires shown are not gonna be used they are only to illustrate the routing of the holes in the metal part.


You cannot view this attachment.

Maybe I just strip the wire insert it and screw the cap down...idk

Thanks

I'm relieved that my signal generator provided some nice traces

You cannot view this attachment.

You cannot view this attachment.

Idk why the trace from that transformer was so sketchy.

Yes sir thank you 

I decided to take a look at this on my scope

Btw here is the source of 12v ac

You cannot view this attachment.

So connecting scope probes directly to cables coming from ac source

You cannot view this attachment.

My phone was struggling to get a full trace left to right despite trying to adjust trigger etc the trace was jittery and flickering real bad

So now connect scope probes to (+) and scope ground to (-)

You cannot view this attachment.

Which I like that but when I had the scope switched to ac I had just a flat line

Then connecting scope probe to (~)

You cannot view this attachment.

So I guess everything is cool. 

I'm off to connect some other stuff to the scope and try to get a better full steady trace.

 

I decided to put a load on it...12k ohm resistor

Similar results

You cannot view this attachment.

More Bruce

 

I have a feeling Bruce says we need some capaci-taters

Thank you sir I wanted to try and replicate this scenario so I did

I had a device with taps on the back for 12v ac so I rigged it up

You cannot view this attachment.




You cannot view this attachment.

Results

You cannot view this attachment.

So...idk

I guess it's time to play some Bruce Hornsby

 

Wow nice amp 

Welcome to the forum

 

Ok guys sorry for the bo bo 

Anyhow removed the old one (no easy task) and got a new one in

You cannot view this attachment.

Seems all is good when measuring the (+) pin and two middle pins (~)

(+) pin reads about 40v DC (have no idea what it is supposed to be


You cannot view this attachment.

But when I read the middle pins I get like 16v ac but what the heck I get 20v DC

You cannot view this attachment.

I think I'll call it a night

 

Yes sir thanks I was able to find some old pics of the original part

You cannot view this attachment.

You cannot view this attachment.

 

Yes sir appears to go to

-negative terminal of capacitor

You cannot view this attachment.

-and the emitter of the tip31a on the right

You cannot view this attachment.

and a resistor

Meanwhile... experienced my first Chernobyl.

So this metronome I had removed the bridge rectifier a while back and it tested good...oh well

Put a new one in today.... thought it would be fun to hook my meter to the leads before I clipped em and read ac and DC on the different leads.

So I solder it in...crudely soldered the transformer wires back making sure I put the right ones in order.  Plug it in...I'm gathering up my meter and test leads and I hear woosh and see lots of smoke

You cannot view this attachment.

And liquid 

Later I was outside and thinking did I put it in backwards or something...or leave a solder bridge?  But looks like the orientation is correct and the solder reasonable (these pics are post meltdown)

You cannot view this attachment.

You cannot view this attachment.

Im beyond hoping this thing will be fixed but I did want to replace that part.

Meanwhile I put it on my ugly dbt after the fact yes it was glowing.