2027, Piezo wiring and a problem

[7 Dying Trees]

Just got holdof one of these babies, with an evo7 in the neck and apaf7 in the bridge. Luuuuurvly

Problem with it is that I have inhereted some problems with the piezo. Now this is the score:

->There is no output

Basically, I have the wiring diagram, and have fixed the wiring thathad been done wrongon the piezo.It's quite late, so I haven't traced the full signal path, but it should befine. Kevan etc have heard of this problem, asit's RichardUK's guitar that is now mine. I knew I was inhereting the problem, so I'm cool with that.

Now, some diagnostics:

->Now, I get a signal spike if the battery gets plugged in.
->As far as I can see, there are no loose wires
->Magnetics work fine

Whatwould be cool is:
->Common problems people have heard of and encountered, and how they were fixed
->What are the chances of thepreamp circuit having been damaged?How easy are they to blow?
->Piezo's, has anyone heard of them failing? What if they have?Any techniques for checking?
->How would one go about checking the preamp is still OK?
->Any pitfalls thatsomeone could have fallen intowhile wiringit up,ie, blowing components?
->How difficult/expensive willit be to get an entire new preamp + circuit board?
->Anything else anyone can think of?

Any responses, ideas, workthroughs appreciated

cheers people!

James

oh, the wood and the grain on this example is lovely. Ihave already had several "accidents" LOL!

[Rich]

The only problem I ever encountered on one was when the braided piezo wire was touching the circuit board, no signal. Rearange it in the cavity, perfect.

[7 Dying Trees]

Think the problem has been found...but sorting it out is another matter.

Basically, I think the problem is within the braided wire running from the edge to the preampflifier PCB. Basically it is shorting out with causing the piezos to be permanantly grounded.

Not only that, but als have discovered that the braided wire had no external shielding on it anywhere, resulting in most of the outer conducting braid wire being chafed away at the point where it travels from the tremelo cavity to the control cavity. This wear is due to the tremelo springs.

In any case, I think this is the problem , Which nnow raises the following question:

Is it replacable? Short of slowly shortening the wire and praying there is no way to find out where the short is, or to even find out if the lead is the problem.

why didn't ibanez think of soldering two contacts onto the actual bridge for the eventuality that this part would become damaged?

Has anyone taken apart the actual edge bridge? Where are the contacts? Does anyone know anyone in the UK who is qualified to repair this (as in:knows what he's doing, as I doubt many guitar techs have seen bridges like this)

Any other advice would be greatly appreciated.

Also, replacement trems? How hard are they to get hold of, if not impossible? Surely ibanez must be able to supply a replacement for a failed unit...?

[7 Dying Trees]

Oh, a huge amount of thanks to Kevan for sacrificing a load of his time to give me a hand going throught the wiring and helping me find the problem (or what looks like the problem) last night

cheers!

[Pablo]

James,

Is this braid just a copper grounding wire ?

It may sound dumb but if it needs to be a thick wire then you could use solderwick as a replacement.

and just get some insulating tape and wrap it round it et voila no earthing problems

I haven't looked at mine so I don't know what you mean.

If I can remember I'll bring some braid down, it helps with your soldering too !



P

[7 Dying Trees]

It's not actually an earthing problem, it's all earthed fine, problem being that that I don't think that the live signal from the piezo is supposed to be grounded...

I would take piccies, but do not have a digital camera...

Magnetics work, preamp seems to be working etc, just, that dam cable from the bridge

oh well...

[Rich]

I believe the braiding on the wire is the ground.

Of course you can order a replacement from Headstock, no, I would not expect they would have this part in stock so be prepared for a long wait. I would also expect you'd have to pay near list for the part when it does come in.

[7 Dying Trees]

Piezo's now sorted thanks to Jonathan at Feline Guitars who made some time today to have a look at it

Coolness.

Only thingnowisthe rest of the wiring doesn'tquite work as it should, but as I think the KJG mod is going in and I want a different pickup config this shouldn't be too bad as I'll have to rewire anyway

It's so sweet

[Kevan]

James-
Sorry I couldn't help more. It's tough to completely re-wire a guitar from 2000 miles away via AIM. :-)
I'm glad the local chap could help ya out...the same day I get info on that braided cable and a *basic* diagram of the actual piezo element wiring. LOL Just my luck.

Note: the 5-way switching in your 2027 is ***NOT*** JEM/UV-style switching.
Your 2027 has what's called "Special 5" (aka: J-Custom-style switching). I have a pickup chart if you need it.

[7 Dying Trees]

The diagrams would still be very usefull , especially as it is liable togo wrong again , in any case the amount of help over IM was fantastic cheers man!

Pickup wirings would be cool as wel;

Also, have you got the diagram for the KJG mod? I have to rewire the mags and stuff anyway,so...

And also Ihave to now figureout why the switch only works for the mags...

Anyone see that film the money pit?

LOL!

Cheers to anyone helping out

[Drew]

yeah, second that request for pickup wiring diagrams; i'm about to have some work done to mine. Is it on j-custom.com by any chance?

-Drew

[Kevan]

REMEMBER: The MAGNETIC pickups and PIEZO pickups are two COMPLETELY different systems.

KJG Wiring Mod Diagram:
http://jemfest.com/dewiring5.jpg

For re-wiring the magnetic pickups:
http://www.universaljems.com/tut/rewire.htm

[7 Dying Trees]

Coolness After another chat with Kevan on IM and some headscratching it transpired the switch was a bit broken, so after flipping the wiring it all works! Everything! Joy! Am now in complete heaven...

Anyone that can pick one of these up should, as untill you have you will not know how good this baby really is

Again, thanks to Kevan for helping to sort out the wiring mess and troubleshoot it into working, can't thank him enough

Who'd have though AIM could be that usefull?

yay!

[cerealk]

yay guitar fixed!!!