Guitar Intermittently Dies - Help Appreciated

[lbpesq]

I have an Alembicized Strat-type guitar I built with an Alembic Strat set and added 3-Way Q switch.  Here's s link to the thread about it:

https://club.alembic.com/index.php?topic=16621.msg167889#msg167889

It has served as my #1 player for several years without any problems.  Lately, however, it has completely died without warning while I'm playing.  Unplugging the cable at the guitar and then plugging it back in seemed to fix it.  This happened twice at my last gig.  I tried jiggling the plug at the jack, but the connection seems solid.  I tried a different cable, but the issue still happened. I hate intermittent problems.  They are always the toughest to track down.   Any suggestions?

Bill, tgo

[jazzyvee]

What jack leads are you using? i had problems with my guitar and bass cutting out when using the moulded plastic jacks, with or without the device that is supposed to hold it in tight. The plastic made the jack marginally too short to completely fit in the socket. I cut them off and used metal neutrix and that works better. They fit with a satisfying clunk.

Yours may be a different issue.

[adriaan]

If the same thing happens with different cables, assuming the cables also have (slightly) different plugs, and the same cables do not have the same issue when plugged into other instruments, then the common factor must be inside the instrument. Is anything not fastened quite well enough around the jack?

[StephenR]

Other than jiggling the jack and thinking it felt solid have you examined the actual connection? One of my luckiest gigs was back in the late 90s at Yoshi's with the Broken Angels. For many years I had always brought a spare bass but for some reason that night I only brought my Modulus. We did the soundcheck and everything was fine but when I walked out on stage for the show my bass was completely dead. I freaked out, unplugged then replugged my bass a couple of times and it came back to life. I managed to finish the show. The next day I opened the back up and one of the wires to the input jack was barely touching it and basically had no connection anymore. That may have been the only show in the last 40 years that I went to with only one bass, I wasn't going to let that happen again and have never had a bass fail on a gig again either but I am ready if it does. FWIW... I had a similar thing happen with the spare car key which I kept in my wallet for years and the one night I left it home locked the keys in the car after a gig, it was snowing and the car was running. Police managed to get into the car for me...

Unless your op amp is about to fail I suspect a wiring issue somewhere or it could even be the battery connections or a wonky battery. Agree that intermittent problems are the worst to deal with. Good luck sorting it out.

[dannobasso]

Could be unrelated but my Alembic equipped Strat HSS had issues with the shielding causing the guitar to cut out a bit here and there. I had the luthier who put it together for me (Alembic wired the pickguard for me) he double checked and fixed the shielding in the cavity issue. We used shielding paint like Alembic does in their cavities.
Good luck on your trouble shooting.

[mica]

Always check for a defective battery even if you just put a new one in. You would be shocked at the defect rate in 9V batteries - I should know we use a TON of them here.

The1/4" jack could be the issue. If you were using Switchcraft connectors on your cable I wouldn't look to the jack, but TBH so many 1/4" cable connectors are out of spec they can degrade the jacks. Can you take off the backplate and watch the cable insert in the jack? take a look at the connections and see if they look suspect.

Make sure that all the solder sides of the board are clear of any shielding.

And as Adriaan said, a near failing IC can cause output issues - but look at the connector first.

[lbpesq]

Thanks for the suggestions, everyone.  I opened up the control cavity and eyeballed it while I was checking the battery before the gig.  Didn’t see anything wrong.  I’ll double check the battery, the shielding, the jack, and the wiring more closely when I have time.  Until then, it’s not leaving the house.   At one point at the gig last Saturday, the guitar died when I stepped on the switch for my envelope filter for a lead.   Not a good feeling on stage!   I guess this is an opportunity to spend more time on some other guitars.

Bill, tgo

[cozmik_cowboy]

Not leaving the house?  Gee, hope you can scrounge up a fill-in until you get it sorted........

Peter

[xlrogue6]

Even if the jack feels solid, it's possible that the plating on the contacts is worn or oxidized. Can't hurt to replace it. Even Switchcraft jacks can have this issue, especially after years in your #1 guitar.

[keith_h]

You might try carefully spraying a little contact cleaner like DeOxit in the jack and exercising it in case the battery contacts are oxidized or dirty. I don't know how the blade switch is built but if it is open I would see about cleaning it too. In both cases I would remove the part from the guitar and make sure there was something underneath the part to stop any excess spray from hitting the finish.

[gtrguy]

9mm gun cleaning brass brush is a good fit for the 1/4 inch jack and works well to clean one. However, I think you have another issue at fault here.

[cozmik_cowboy]

9mm gun cleaning brass brush is a good fit for the 1/4 inch jack and works well to clean one. However, I think you have another issue at fault here.

I have had good results with a .22  caliber brush.

Peter