M-60 New Post Wiring

milo63

Everett, WA
Subscriber
A ratty M-60 with the usual busted speaker terminals, upper corner post separated from the circuit board and a lot of plastic is missing.
I thought (my first problem) that it would be easy to pop some binding posts in 3"x8" plate and run the wires directly to them. Who needs a circuit board?
Wrong, the circuit board is more complicated than I thought, as I'm sure you guys know.

Wisdom?

Thanks (again).
 
Its not really that complicated. Looks can be decieving.
 
Let me poke at it again. Initially I thought six speaker wires and a seperate common ground for L/R sides.
 
Thank you once again for your time and sharing your experience.
I have to dig myself out of another self-inflicted junk pile (jewels are ADS L300C and Kenny KA-8100).

Gotta take it all.. Need a big organ speaker with bad surround?
 
Blown up print of the speaker wiring schematic*, reading glasses, flashlight, a couple of beers and I have it sussed.

One question remains, I don't see any visible capacitors but I do see pretty solder spots over holes where caps would be on the schematic. Are they internal to the board?

Many thanks for the Mouser link, I get overwhelmed with options when I try to find stuff.

*Thanks hifiengine.com
 
I don't see any visible capacitors
Maybe there not there. I was looking over the schematics. I forgot I had a parts carcass
I just did a visual inspection.
Nope, there not there.
Sweet.. Makes it even easier.
 
Maybe there not there. I was looking over the schematics. I forgot I had a parts carcass
I just did a visual inspection.
Nope, there not there.
Sweet.. makes it even easier.

WOOT!!!
Happy fourth, sir.
 
Garage therapy day.
I dug a piece of aluminum out of the scrap bin at work and got busy.

The notch on top is for the rear cover screw. I had to estimate size and sheared it a bit bigger than needed.

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Check that the positive posts are not shorted to the neg posts with your meter before powering it up.
 
For those following along at home, don't follow me, I'm lost.

Later last night I put my meter to the traces of the board and came up with this:

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As usual, my "assumption" was flawed and I have to redo it.
 
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I'd be looking at the yellow and white wire . Its going to both ground and positive "C" in your diagram.
 
I'd be looking at the yellow and white wire . Its going to both ground and positive "C" in your diagram.

It's very strange but that's how the board is laid out.

I plan on rewiring to that diagram and doing a DBT prior to the money shot. Trying to make my diagram jibe with the official schematic makes my head hurt.

All my jacks are isolated from ground.
 
I have a M-60 here thats all torn down. Give me and hour.
 
Your right. Doing some confusing switching with the A,B,C speaker select switches. Press on..:D
 
Due to speaker C being placed in series with either speaker A or B.

There you go, thinking...
I was trying to figure out how to truncate the wiring to one set of speakers (who needs three?) but gave up.

I broke a banana terminal so I'm on hold until delivery. Plenty of other projects to occupy my time....I don't have time for a job, too many projects to work on.
 
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