Peavey MKIII Bass Head Needs Un-Smoked

This solid state Peavey Bass head is also capable of handling mixer, equalization, and preamp roles for public address, monitor, and other sound reinforcement roles.  But power amp quit!  Can the Unbrokenstring Crew help?

The AutoMix function that Peavey developed has been discussed elsewhere in the blog.  Lots of EQ knobs here!

 

Note the graphical EQ and bi-amp capability.

 

Woah!  An Instrument System!  Ooh.  Aah.

 

On the rear panel is the power switch and speaker connections.

 

Peavey mixes and matches front panels (inputs, preamp, eq) and rear panels (ps, power amp) to build different heads.

 

As is the case with many pieces of electronics, the City of Los Angeles Fire Department approves this unit!

 

Name, rank, and serial number, please.

 

The blue circuit board at the top is for connections to the power transistors.  The I/O connections are to the left and the power supply filter caps are seen here.

 

More blue boards at the top, for power transistors.  Driver transistors are found on the square heat sinks.  Do you see the problem yet?

 

This circuitry is all preamp and tone circuitry.

 

This sucker got HOT!

 

The worst damage was to components that were near the root cause.  They burned because the transistor on the aluminum heat sink suffered an internal short circuit.

 

The heat of the electrical fault was high enough to melt solder, which happens around 650 deg. F.

 

A matched set of driver transistors were installed and the circuit board cleaned.  The destroyed components to the right have been removed and will be replaced.

 

The new parts are mounted just above the circuit board.  We can get flame-proof resistors now, unlike when the unit was built with in the 1970s.

 

More collateral damage was found on one of the blue boards.  This solder trace acted as a fuse at its narrowest point.

 

The circuit board is now cleaned up and the gap is bridged with a bit of 16awg solid copper wire.

 

Some of the power transistors were shorted as well, so all of them are now replaced with a matched set of eight.

 

These parts are still made by ON Semiconductor, the heir apparent to the Motorola semiconductor product line.

 

The electronics are back together.  The filter capacitors are original, but are still in great shape, so they remain in service.

 

And, of course, after all the components and circuit boards are in flames, the fuse finally does its job.  Of course.

 

With a new fuse, the electronics are connected again and initial tests begin!

 

This unit is back on the air!  This unit is almost hifi sound quality, with endless bottom end.  Good Job Peavey!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

Peavey MX Combo Amp Rescued from a Bad Amp Tech

This combo amp had lived a hard life and had finally quit.  Grandpa wanted his grandson to get the amp fixed so that they could jam together again.  Could The Unbrokenstring Crew bring this unit back to life?
 We begin with a quick tour of the rear panel.  The ground switch is a tip of the hat to the Old Days of two wire AC.

 

 The foot switch plugs in where the REMOTE SWITCH jack is coming loose.  This gets fixed.

 

 I’m surprised that this hadn’t ripped loose.  The whole connector wil be replaced.

 

 

 Name, Rank, and Serial Number, please!

 

 What have we here?  We found grandpa’s stash.

 

Let’s get this line cord wired correctly.  Do you know what’s wrong?

 

 The black wire goes under the brass screw. “Black on brass will save you ass.”  You’re welcome.

 

 The reverb tank connects to the main circuit board with this connector.

 

 Even after all this time, the high voltage capacitors are still charged.  Woah!  This is my discharge wand at work.

 

 Our first mystery… where does this nut go?

 

 This is a fuse.  No, you think that it is a piece of 16AWG wire, but it is a fuse.  Or, it is where a fuse goes.

 

 And here, someone was tired of the fuses falling out of the holders, or what was left of the holders.

 

 The heat from the flow of current has wreaked havoc on this solder joint.

 

 This probably smelled bad when it was hot.

 

 Now that the introductions are out of the way, we need to start replacing this nonsense.

 

 These are commercial fuse holders.  These will replace all of the preceding nonsense.

 

 The plan will be to install these new fuse holders at a spot in the circuit where they will be functional, yet out of the way.

 

 The new fuse holders are held down with a screw.  This hole is where the screw goes.  Here goes!

 

 Another hole is drilled for another fuse holder.

 

 This hole is in the center of a trace.  We won’t miss that copper.  Much.

 

 Insulating nylon nuts and bolts are used to keep the new fuse holders in place.

 

The traces in the burned circuit boards are replaced with this Teflon-covered wire.

 

 Everything is now stuffed back into place.  Not too shabby, if I do say myself.

 

Turning our attention to the rear panel, your sharp eyes may recognize this connector as a MIDI female panel connector.

 

 To keep the connector hardware in one place, some of this Thread Locker is all we need.

 

 We have the original foot switch.  It needs a new cable, with a connector to match what we just installed in the amp.

 

 This MIDI cable will be repurposed to replace the cable on the footswitch assembly.

 

 We don’t need this connector.  Instead, this end of the cable will be wired to the switches themselves.

 

 The new cable is soldered directly to the switches  Note the strain relief installed to the right of the picture..

 

 This pedal is ready for action once again!

 

 The amp is reassembled and is ready to go!

 

 The four hour burn-in test is underway.  I think we have rescued another vintage Peavey amp!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

Peavey 260 Booster Amp Needs a Boost

A local church has a rack of Peavey gear that drives their public address system.  This unit had failed.  A phone call to The Unbrokenstring Crew was all that was needed to get this unit onto the operating table.
Unlike a traditional guitar amp or stand-alone amplifier, this unit takes high level signals and buffers it to the loudspeakers.  They are often used as a means to fill in or expand the coverage of an existing system.

 

And the inputs are daisy-chain-able.

This is, of course, the volume knob.

 

Here is a tour of the rear panel.  The power switch is ‘center-off’ and, on this unit, does not switch the chassis ground to connect to one side or the other of the AC power line.

 

No tour of a rear panel is complete without a high-rez pic of the power cord.

 

And the name/rank/serial number part of our tour.

 

The AC line fuse was popped.

 

This is, correctly, a five amp slow blow unit.

 

Removing the front and rear panels permit access to all the electronics.

 

The chassis is attached to the rear panel of the unit.  Surprisingly, the power transformer is NOT fastened to the wooden cabinet, but is also attached to the rear panel.

 

These filter capacitors are good and will not be replaced.

 

This unit has a shorted rectifier.  New parts were secured, and are shown here.  Although only one rectifier is bad, the other three are the same age and have experienced the same abuse, so they will all be replaced.

 

The new rectifiers are installed.

 

Funny thing is, the new fuse looks a whole lot like the old fuse, except it is not all exploded and burned and stuff.

 

The output from my radio is amplified to a larger signal using my Marshall Stack, to drive the input of the amp at the proper level.

 

This was the point when the neighbors called the cops to complain of the noise.

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

Peavey KB4 Keyboard Amp Disintegrating

This Peavey keyboard amp works intermittently, but the modular AC outlet has completely come loose from the rear panel. Can the Unbrokenstring Crew fix this?

This unit is pretty cool, with a built-in luggage roller and extendable handle as standard equipment from the factory.

 

The modular AC plug was covered in RTV rubber.  Was this a user ‘fix’ or did it come from the factory this way?

 

Fortunately, all the electrical conductors were insulated.  Otherwise, we would have sparks.

 

User controls are on the top.

 

The ground polarity switch is a throw-back to the days of two wire electrical cords.

 

A simple mixer is integrated into the unit.

 

Name, rank, and serial number, please.

 

The panel layout allows for some space for the handle.  Good Job!

 

We removed the head from the cabinet,

 

Here is our intermittent.  This power resistor had broken free from its solder pad.

 

A circuit board trace had broken.  An Exacto knife clears away some of the solder mask to allow for a repair.

 

This crack was very small, so a good solder jumper is all that is needed here.

 

This unit appears to have been wet.  Do you see the minerals left behind after the water evaporated?

 

Here is another little blob of mineralization.  This may have been from solder flux residue left after the assembly was manufactured.  Some fluxes turn white in the presence of water.

 

This screw was loose inside the grille.  This screw holds the loudspeaker in place.  This is not good.

 

Most of the screws were loose.  While we have this unit on the bench, we should be sure that the loose screw is not a sign of a more sinister problem lurking with this unit.

 

Here is the loudspeaker in this unit.  Nice!

 

My guess is, humidity has softened the baffle upon which the loudspeaker is mounted.  These Tee nuts will be removed and new holes drilled in the baffle in different locations.  The Tee nuts will be reinstalled and we should be Good-To-Go.

 

Some black nail polish will camouflage the new fastening hardware.  You do have black nail polish, don’t you?  Doesn’t everybody?  Hint: This also makes good thread locker.

 

OK, now for the IEC power jack.  This unit has mounting ears, so we won’t rely on friction or glue to keep it in place.

 

As an added bonus, this IEC jack has a built-in noise filter.

 

The hole in the chassis was enlarged to accommodate the new jack.  This hand grinder is adequate for the job.

 

Yep!  Just fits.

 

Now we will bore the steel panel to accommodate the mounting hardware.  This will be SO much better than glue!

 

This doesn’t look too bad, does it?

 

All of the original wiring goes straight onto the new IEC jack.  This is better than factory!  Hot glue was apparently used at the factory to secure the switch and the old IEC jack to the rear panel.  So that answers that question.  Shame on you, Peavey!

 

Here is one last look of the internals before we reassemble the head.  The mixer is at the bottom and the power amp and power supply is at the top.

 

This unit is literally ready to roll!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

Peavey Mark III Bass Head – Busted Controls

These sturdy old bass heads turn up in pawn shops and Craigslist from time to time. They soldier on for years, sometimes making music for decades. This unit came in for some minor repairs and a Million Mile Checkup. Let’s get to work!
This unit has LEDs for the power indicator and a clipping indicator, or something called “Compression.”

 

From the school of ‘crank it up and rip the knobs off’ we have a knob that has been ripped off.

 

Most of these Peavey heads usually consist of a preamp, mixer, and/or EQ assembly behind the front panel, and a rear panel that holds an amplifier and power supply.  The transformer is bolted to the case in the middle.

 

We need to get to the circuit board, so all the knobs and nuts come off.

 

This unit was built in the era of the Plastic Potentiometer Shafts.  Grrr…

 

A few screws keep the panel and circuit board flat.

 

More screws go into the magnetic parts holder.  We are almost there.

 

Here, at last, is the circuit board.

 

Potentiometers that stand off the circuit board like this are sometimes called ‘spider’ pots.

 

These other controls are fine.  The values 10K and 50K refer the resistance, and the letter ‘B’ implies that the taper is linear.  An ‘A’ letter implies an audio taper control.

 

The Alps company made these in Brasil.

 

Here is the new replacement part, with a metal shaft!  If this were my unit, I’d replace them all with metal shafts.

 

The plastic shaft broke off inside this knob.  A few minutes with an Exacto knife is all it took to reclaim the knob and cut my thumb..

 

The new control is soldered into the circuit board.  The factory workmanship on this assembly is pretty good.

 

Back together it goes.

 

With the knobs in place, you can’t tell that anyone has been here.

 

One last look as we reassemble the unit…

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

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

 

Peavey 1810 Bass Enclosure Crossover Doesn’t (Crossover)

Most of what you see in this post works well. However, a crossover network inside the speaker cabinet doesn’t work at all. Could the Unbrokenstring Crew sort out a solution that would put this cabinet back to work?
Here is some file old hardware from the 1980s.  This cabinet has an eighteen inch subwoofer underneath two ten inch loudspeakers.

 

Behind this panel is found a crossover network that routes the input signal to the proper destinations.  The crossover automatically routes the really low frequency stuff to the 18 inch loudspeaker and the rest is routed to the ten inch loudspeakers.  Or, you can specify which signal goes to which driver using the BI-AMP jacks.

 

The sheet metal screws hold this circuit board in place.  An inductor plugs into the pins in the center of the picture.

 

The input jacks are seen in this view.  The capacitor is part of the crossover network, and has been replaced.  As this is in a high powered audio network, the electrolytic capacitor is a non-polarized variety.

 

We can examine the circuit side of the printed circuit board to figure out the schematic for this assembly.

 

This inductor is cooked.  Unfortunately, this part is no longer available.

 

An examination of the inductor may give us some clues that we could possibly use to fix it and use it again.

 

This component can take the place of three different inductors, thus the three wires.  Any two wires yield a different inductance.  Unfortunately, the insulation is thoroughly cooked.  No salvaging this guy.

 

The functions of each ‘net’ on this circuit board is labelled with a felt tip marker.

 

For this particular model of crossover, the inductor wires we need to use are indicated by this inductor symbol.

 

This is an inexpensive crossover kit, with similar specifications.  We can harvest this inductor for use in the crossover.

 

Here are a few details, listed on the end of the box.

 

This inductor is has a laminated bar core.

 

We can remove this inductor from the circuit board and use it in the Peavey circuit.

 

The back side of the donor network is covered with some self-adhesive foam rubber.

 

The foam sticks really well!  But now we have access to the solder joints that need to be unsoldered.

 

The mechanical mounting scheme is VERY robust for this heavy part.  We can use all of this in the Peavey circuit.

 

These white plastic caps are handy to hold the mounting nut and to insulate the exposed iron core.

 

We will use the original circuit board as a template for finding and marking places to drill new mounting holes in the Peavey circuit board.  We can search around for a practical mounting location.

 

The mounting holes are marked.  Away We Go!

 

One end of the inductor is electrically wired here.

 

The other end of the inductor is wired here.

 

We will make lock the threads of the mounting screws with this stuff.

 

The thread locking compound is thin enough to seep into the threaded fasteners and lock them.

 

Now, we can reassemble the crossover network assembly.

 

The original inductor was mounted in the foreground.  This doesn’t look to tacky, does it?

 

One last look before it disappears into the enclosure.

 

The panel is ready for reassembly into the enclosure.

 

No.  Wait.  We need a new gasket between the I/O panel and the cabinet enclosure.  This self-adhesive foam strip material is just the ticket for this application.  Note the mitered corners.  Because I’m OCD like that.

 

Holes for the mounting screws are cleared with the Exacto knife.

 

OK, NOW is one last look at this assembly.  The wire pairs go to the loudspeakers in the cabinet.

 

This system is pretty awesome.  Everything tests out at full power.  Life Is Good!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

Peavey Artist Combo Amp Refurb

This Peavey Artist combo amp was WAY too distorted to suit even the most extreme metal head. Could the Unbrokenstring Crew look into this and put this unit back into service?
First, a tour.  You can have two channels, or a mix of the two ‘Automix’ inputs.  This was a ‘thing’ back in the day.

 

The other controls are straight-forward.

 

The standby switch is in the front, whereas the AC power on is in the back.  Actually, I like this because if both power switches are in the back, half the time I switch the wrong one.

 

The AC line duties are all squared away on this side.  The City Of Los Angeles has their own version of UL.  That’s the yellow and red sticker.

 

The right hand side of the rear chassis has the ins and outs for this amp.

 

These are all Peavey-branded tubes.  They are all in good shape and will stay in this amp for now.

 

So we put a clean sine wave in, and this is what we get out.  The positive power supply is weak.

 

An overall gut shot shows power on the left, preamp on the right, and power amp on the bottom.

 

These capacitors have begun to swell and push the seals outwards.

 

We have signs of overheating.  These resistors handle power distribution and are somehow related to our problems.

 

The other power supply has a cooked resistor as well.

 

Here I am just documenting all the plugs and wires so I can get them back in the same place.

 

These capacitors are also bulging and will be replaced.

 

Time to remove the power supply board and work it over.

 

This circuit board holds the tube sockets.  We have an intermittent short to ground under this assembly.

 

At first I thought that the short was under the tip terminals of these jacks, but that was not the case.

 

I am going to pull this assembly out and look it over as well.  The blue, red, and brown wires are high voltage.

 

The blue capacitor in the upper right is the ‘death cap.’  If it shorts, 115vac is connected to the chassis.  Not good if you ever touch the amplifier.  Fatal if you touch the amplifier with one hand and grab a microphone with the other hand.

 

This circuit board is supported by the tube sockets.  All four sockets will be unsoldered.

 

Out this guy comes.

 

Here is our short circuit.  These are component leads from parts installed on top of the circuit board and soldered from the top.  I guess if the excess length is out of sight, then it is out of mind.

 

Here are some of the parts on the top side.  I don’t think these were replaced in the field, but rather it came from the factory with the untrimmed leads.  Sloppy.

 

However, wires that are too long are easier to deal with than wires that are too short.

 

I am cleaning up the bits of crap in the bottom of the chassis, using some sticky tape as a way to capture the crap.

 

I have installed new bleeder resistors and new capacitors on this assembly.  That big blue resistor is a high voltage dropping resistor.  This part is fine and will not be replaced.  However, those are not made anymore, and I have some of the last remaining stock of the OEM resistor.  You’re welcome.

 

Everything gets trimmed and cleaned up before reassembly.

 

The power supply board has new caps everywhere.

 

The Ty-Wrap was my idea.  These big parts need some mechanical support, but I’m not big on lots of hot glue.

 

The original power resistors were way out of spec, so these new parts are higher wattage to take the abuse.

 

These caps on the preamp board were replaced.

 

As was this guy.

 

These were the overheated resistors that we saw earlier.

These new resistors are actually more robust than the parts they replaced.  And they are flame-proof.

 

We are back on the air!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

Peavey Stereo Chorus 212 Head Stuck In Mono

The owner of this amp was so anxious to get it fixed, he removed the chassis from this Peavey Stereo Chorus 212 combo and even helped load it!  The amp plays, but only one stereo channel is operational.  Can the Unbrokenstring Crew help?

A quick look of the front panel shows the inputs and the normal (clean) channel controls.

Did you catch the missing knob?  The Unbrokenstring Crew will find a replacement, which is no small thing because these are no longer available new and are only available from spares or salvaged from a non-working unit.

This amp uses a digital signal processing (DSP) module to make all this audio magic.

Interestingly, the DSP module creates two unique audio signals (stereo) from a single mono input.

The ground lift switch is on the front panel, which is a nice touch from many other designs.

This dual OPAMP is non-functional.  However, this is not the root cause of the missing stereo signal.

This is the DSP module in this amplifier.  We have only one audio stream as an output from this device.

A piece of cardboard serves an an insulator so that the bottom of the DSP assembly can be probed.

Here is where the DSP processor outputs both audio as a stream of ONEs and ZEROs.  We are OK here!

This chip processes the two DSP streams in a manner similar to a successive approximation analog-to-digital converter.

The bit streams are split using an analog switch.  Here is the output of the switch assigned to the working channel.

And this is the output of the switch on the non-working channel.  Time to change the switch!

Desoldering today is performed with a traditional iron, rosin flux, and copper braid.  This keeps solder balls to a minimum.

The circuit board is cleared of excess solder and flux.

The new MUX chip is available through the usual sources.

With the tweezers, the new MUX chip is oriented properly on the circuit board pads.  See the tweezers?

After soldering, the workmanship is inspected with this hand-held microscope.  The high-powered white illuminator is on the left, and the black cylinder next to the big IC chips is the optical microscope itself.

Any remaining solder flux is removed with alcohol.  The rag gives the dissolved mess somewhere to go.

Both channels are operating at full power.  The knob is coming from an eBay auction.  When it gets here this head is ready to return to the eager customer!

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

Peavey Citation MK IV Two Channel Guitar Amp Head Repair

Rod had this Peavey head kicking around and thought it was time to put it to good use. However, it didn’t work at all. Could the Unbrokenstring Crew work its magic and bring this road warrior back to life?
A quick scan of the front panel shows that the input circuit sports the sort of flexibility that the Peavey Marketing Department loves to explain to anyone who would listen…
Each channel has independent gain, and a master volume to Rule Them All.  Effects can be inserted via the front panel.
On the rear panel, we have parallel speaker jacks and the usual ground/no-ground power switching.  Peavey often married different front panels, which contained preamp circuitry, to different rear panels, which carried power and audio amplifier components.  The ‘series’ number goes with the power amp, not the front panel.  We Got This.
Name, rank, and serial number, please.
Pulling the front panel, we see that all of the components are mounted on one circuit board.
I took a few pictures to be sure that the wiring and cables were returned to the same spot when we are through.
The cable to the right is just wired to the power indicator.  The other two carry signals.
This is a better view (to be sure that they cables are properly oriented on their pins.
The front panel is free of the rest of the unit.
All of the controls and switches will be cleaned so this assembly comes completely apart.
We can now clean and lubricate everything now.

 

Can you spot the broken solder joints?
Someone has been here before!  This needs to be cleaned up, too.
The Blue Shower is a good cleaner.  The DeoxIt contains a lubricant for the potentiometers.  Good Stuff!
Back Together it all goes!
This screw hole was stripped out.  First, we will soak the stripped hole in the wood with this wood hardener.
Next, a birch dowel is cut to partially fill the hole.  The dowel reduces the apparent diameter, allowing the screw to hold.
With the stripped hole repaired, we are back in business!
This unit plays very well, and all the controls and switches are Like New!

 

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626