Peavey Bandit Combo Amp Refurb

David found this fine old Peavey combo amp in a pawn shop for almost next to nothing. Could the Unbrokenstring Crew resurrect it?
This saga begins on a cool Saturday morning in the Guitar Center Pasadena parking lot.  If you look closely, you can see right through this unit.  Literally.  What are we getting ourselves into this time?

 

Electrically, this unit is mute.  No sound comes from it.  But, as the story is told, this amp languished in the barn for years so we have to expect the worst.

 

Name, rank, and serial number, please.

 

This part number goes to a Peavey Spider loudspeaker.  This is gonna be fun, as you shall soon see!

 

The grille is off.  This poor thing is a mess.

 

If a rat gets hungry enough, it will eat anything.

 

Perhaps it was not tasty enough, as the rats left plenty of bits of uneaten loudspeaker cone behind.

 

The brunt of the rat nasty-ness was taken by the reverb tank cover.  We need to clean this up right away!

 

The spring reverb tank is in perfect condition.

 

The tank cover did its job and kept this reverb tank in a pristine condition.

 

Pledge furniture polish contains solvents and emulsifiers that are excellent for cleaning Tolex.

 

The nice lemon-y scent is just the thing to counteract the barn smell.

 

The bottom of the unit is a mess, though.

 

The amplifier electronics are on the bench.  The unit is upside down.  The reverb tank connector is to the left.

 

The bottom cover comes off.  We need to go over this unit with a close eye for damage due to humidity and dust.

 

Perhaps moisture (rat urine? mouse-ture?) has seeped under the solder mask and attacked the copper on the circuit board.  Everything gets a bath.

 

The top side of the electronics is pretty filthy, as we might expect.

 

The circuit board is free of the chassis.  Everything is being scrubbed with water, alcohol, and compressed air.  The switches, jacks, and controls are cleaned, flushed, and lubricated.

 

Tracing signals, this guy is bad.  This IC is replaced from stock.

 

I want to clean up around the cases of the transistors.  The heat sink is at zero volts while the transistor case is at +70 volts or so.  The dirt may bridge across the insulator.  Not on my watch!

 

These power transistors are just fine.  They are also super-rare.  Luckily, I won’t have to replace these.

 

But they sure do clean up good!

 

The transistor on the left is already installed.

 

We use Wakefield heat sink grease on power devices at the Unbrokenstring Shop.  Old Skool.

 

The original mica insulator is reused.

 

This is actually quite messy, but is a thing of beauty when I do it.

 

Both sides of the washer are coated with compound.

 

The whole stack is installed as shown.

 

While we are here, some of the solder joints could use some attention.

 

This amp is now delivering 75 watts into 8 ohms.  This chassis is Good To Go!

 

Back in the case it goes.

 

These jacks are on the rear of the unit.

 

The knobs press on.

 

This guy goes in the trash.  Wait?  Aren’t we going to recone it?

 

No.  We don’t have to recone.  Peavey Spiders are available without the magnet.  No tricky alignment issues here!

 

When the magnet was removed from the old loudspeaker, the magnetic gap was cleaned and then sealed shut with tape.

 

Once the old magnet is aligned, three screws hold it in place.  We’re done!

 

This is the new loudspeaker, seen from the front.

 

A rear view shows us the cleaned cabinet and reverb tank cover.

 

The loudspeaker looks new, because it is new.

 

The grille was cleaned up and is seen here, reinstalled.

 

The refurbed chassis slides in from the rear.

 

These washers go underneath the trim plates thru which the chassis screws extend.  Don’t leave these out!

 

These big trim pieces are metal, coated black.

 

And these, boys and girls, are how the chassis is suspended inside the cabinet.

 

Installing this trim piece is all that is left to do.

 

David is really tickled with his like-new Peavey Bandit!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

 

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