Guitar amp box replacement

[Jack Crow]

Hi all,
This one took some work to get this close to right.

First off I am not a musician and do not pretend to have any skill other than a music consumer.

One of my co workers (Earl) has a side business doing exactly that.
He is a whiz with old amplifiers, but not so much with this kind of work.

So he gets in a repair one day.

Seems the little electronics boxes some companies install in their guitar's tend to go bad.
Mostly from people installing the 9V battery backwards.
This blows the internal op amps out. The oem's don't always use industry marked parts, so repair becomes nearly impossible.
Think of it this way.
Let's say you go to the auto parts store and say you want an oil filter for a 1972.
The helpful counter guy will say a 1972 what? You tell him that is all you know, there are no nameplates on the car.
Your going to get 'a look'. Electronics guys try not to do that to our parts vendors.

Years down range the OEM part is no longer available.
Spare boxes are long out of production.
Time to upgrade or replace the instrument.

You also need to understand that these boxes are cheap.
The replacement part was less than $20.
It's making it fit is the true pain in this job.

This client managed to break the box in their guitar, then screw up it's innards with a soldering iron.
The results were ugly and I don't want to share them here.

This is a nearly perfect 3D printer task.
A custom made adapter from old to new rev parts.

Just for the record I had to make use of 'recycled' parts from the OEM installation to make this one work.
I can't make springs or rubber gaskets. That is outside the skill set.

So I offered to make an adapter for the new box to fit the opening in the guitar.
This was not easy.
Tasks that are worth doing are rarely easy.
It was a time to develop new skills.

Earl found this replacement box marketed under the name "Fishman". Seems to have good write ups in the trades.

Anyhow based on mechanical measurements of the remains from the OEM part I was able to adapt the Fishman to the opening.

Check out this first photo.

What your looking at is a bunch of things.

The injection molded part is the new Fishman Box.
It is held to the adapter by four small screws.
The lower adapter is about 55mm deep.
This is to allow the mechanism to swing up for battery replacement and back into the guitar body again.

Sticking out of the old unit were these flat springs.
Was able to reuse these to mount the new adapter box.
These (when installed in the instrument body) compress the adapter box to the body.
There is a small contour gasket visible as well, this allows the flat of the Fishman to fit the shape of the instrument body.
12-9-2017 016.JPG

Same as above but the far side.
You may notice a missing spring.
The client could not find it.
Earl will have to magic one up somehow.
12-9-2017 017.JPG

This is where the connections come from.
The black wire Im told is for a vibration sensor.
It picks up the strings sounds and pipes it to the electronics in the module.
The white connector is for an output to for external amplification.
Remember the whole thing pivots up so I had to leave plenty of room to prevent wire snags.

12-9-2017 018.JPG

The last photo shows the bottom plate.
I use it to stitch the fairly light weight adapter into a robust whole.
The attach screws are the 'outer four', they connect the bottom to the adapter box.
The inner screws are were the flat springs are attached.
I make use of the springs shape/ torque (?) to hold them flat to the inside of the box and the tabs on top to hold to the guitar body.
12-9-2017 019.JPG

This project was a bear.
Went through a lot of revisions just to make it all line up right.
Reverse engineered the old part to make the new part fit.
The rule was I could not change the opening in the side of the guitar.
Something to do with the 'sound' of the device.

Real glad this one is 'in the can'.

More when I know more.

Jack Crow aka Radio Mike in VB

[RetireeJay]

I really appreciate your sharing your adventures in making practical parts!

[Jack Crow]

RJ
Thanks for the kind words.

My first exposure to 3D printing was many years ago.
We used it to make explosives holders for electronic weapons applications.

Plus any number of "G" class jobs for a national lab.

So the idea of making cute stuff was never a goal.
Seemed like a lot of technology to make a D & D figurine.
Couple that with a nearly total lack of art skills, I will stick to what I understand.

Fixtures, holders, insulators, laser targets, parts for UAV's.
All kinds of useful practical stuff.

Life has a flip side.

Yet I have more or less have failed to grow up.
Toys still have an appeal.
I won't even try to evade the subject.
The day I do 'grow up' it will be time for dirt nap.

Since I got the Simple Metal working, I have made some cute things.

Like that LED night light that morphs colors.
My DDS has one for his kid, and I have the other in my bathroom.
It's a happy thing to have in the smallest room in the apartment.

Found an STL for 'Borg Cube' on Thingverse that was huge, reduced it to about 2 inches square, not it's not so threatening.
It rests on top of this computer. If it trys to assimilate me, I will toss it into traffic and let a Honda run it over.
Resistance is tread pattern.

Ever read comics as a kid?
There are adult comics (comix) as well.
One of my favorites is called Buck Gadot Zap Gun for Hire.
Being one of the worlds 'gun nuts' means I have an interest in all kinds of arms.
Energy weapons too.
There is always a danger when translating from Art to real life.
Nothing is exact in art. Everything has dimension in real life.
Bucks' gun is called "Junior".
Been noodling around with an edition of Junior for my very own.
It is not ready for prime time.
It fails my 97% rule.
As a rough sketch it's fairly good.
The key parts are in place, the dimensions need tweaking.
What good is a zap gun that won't zap?
One of the electronics dealers has a special on photo flash modules from disposable cameras.
Want to add one of them to the thing, so that when the trigger is pulled, a dazeling pulse of light will come out. (blink away the blue spots)
Will need to rework Junior to make room for the flash tube, electronics, battery house, reflector, and light guides.
Plus an on/off switch, trigger, and ready light.

The goal is to make it as close to a 'hero' prop as possible.
Even have a pelican case picked out to transport it in.

Been thinking of model rocket parts.
Even tried to make some fin assemblies.
Still don't know how to do a conical section for a nose cone, that will come in time.

Sometimes we don't forget the toys we had as a kid.
Have a killer idea for making an N Gauge train set built into my living room coffee table.
Track bed, bridges, and overpasses all fabed on the 3D printer.
Most serious model rail guys are into ultra realism. Good for them. Let them make museum quality exhibits. I want fun and functional.
What if I went the other direction. Something not tried yet?
A fantastic railroad of an ultra modern life.
A town of the future stuff. Buildings, rolling stock, loco's.
Stealing ideas from Issac Asimov, Bradbury, and others.
The whole thing running in silence under a half inch of plexi.
Automated controls so that two or more trains do not run into each other.
Randomized routines to make use of sidings, switches, cross overs. Perhaps semi automated changes of rolling stock and locos.
Even track signals that work.

Made a few 'do nothing' boxes. They can be fun.
All kinds of stuff to make the ham radio hobby a little better.
Silly fan holders.

With the 'fun' items I am learning new skills. There was no attempt to 'make money' on this guitar project.
But I learned things, and that is much cheaper than 3 credits in college.

Hope I did not bore you.

Keep it sane
Time to practice snoring.
Jack Crow aka Radio Mike in VB