Looking for advice on a 1967 Vox Beatle head to get it up and running

[Jam]

My Dad got a 1967 Vox Beatle head and he said it wont turn on so I got and I was gonna start working on and before I power it up I didn't know if there was a good order of testing to start at? It does have all the original Cap's too and maybe replace them before I get to far on it. Thanks for any info

[vintagekiki]

1967 Vox is oldtimer. It's very easy for some caps to dry up.
In order not to get unnecessary damage during the first inclusion build your own current limiter for protection when repairing and testing.

http://www.bristolwatch.com/load_lamp.htm

https://www.youtube.com/watch?v=HQ2ZTFspYvA

https://www.youtube.com/watch?v=wRFRwOnLsZI
Current limiter for protection when repairing and testing electronic equipment


When servicing an amplifier, try to stay as far as possible the original state.
This means that only defective parts need to be changed.

Vox schematics is here:
https://music-electronics-forum.com/showthread.php?t=9222

[olddawg]

This is not an amp for someone to “learn” on. They are very difficult, ponderous, and intimidating for even good experienced working techs. Unless you have the proper skill set you should have the “right” shop that specializes in old SS VOXs look at it. There is no magic bullet.

[66tele]

I agree with olddawg. Most amp techs won't even touch a Thomas Organ era solid state Vox amp due the build issues and time involved in repair and restoration. Not an amp for a newbie to learn on!
Go to R.G. Keen's website http://www.geofex.com/ ......the most knowledgeable guy on these amps that I know. He has written a very good book on the subject that will give you an overview along with white-papers on specific models for further depth. With these in hand you [B]might [B] get an amp tech to work on your amp. But bear in mind that it will be expensive.

[R.G.]

First of all, kudos to you for trying to keep these old timers out of landfills. They're unique amps and I'm very fond of them.

You're getting good advice. Fixing these amps requires some electronics technician skills. They are not learner amps. Here are some pics to show you what you'd be getting into.
http://www.geofex.com/images/The%20N...he%20Beast.jpg
http://www.geofex.com/images/Working...%20chassis.jpg

The fundamental issues are as noted above, the design uses something like 80 off-board wires back and forth to controls, jacks, and switches inside the preamp. The wires are solid-core and thin, so they tend to break off at one end or the other if you flex them. And you have to flex them to get under the PCB to solder/unsolder caps.

And you do need to replace caps. Electrolytic capacitors have a built-in decay mechanism which makes them slowly, slowly get less capable of holding off DC voltage until one day they start leaking badly. This happens on a scale of five to twenty years. A 1967 amp's capacitors are easily 50 years old now, so they're ready for the trash can.

It's a demanding job for a skilled tech; many of them won't touch it, just as 66tele says. But some will. I know a couple of techs who have successfully revived these. And it will be expensive, largely because of the sheer number of hours of skilled labor that have to be spent. A good tech can't make a decent living at much under $50 an hour for bench repair time, and the good ones get more.

In addition to looking at the Thomas Vox content at geofex.com, you might want to also look at thomas-vox-repair.com, which is where I'm now placing the more specific Vox amps info. There are more repair tips there, as well as some Thomas Vox specific parts and so on.

I'd be happy to help you or a tech with email or phone assistance as well. I love them amps, and I hate to see them get trashed.

[dmeek]

I haven't seen a Thomas Vox amp recently but years ago I saw them regularly. Most problems were caused by leaking electrolytics. Those black axial ones are particularly bad.
Just replace them all for starters.

And as mentioned above this thing is a rats nest. A certain amount of care and manual dexterity is necessary. It might help to take some close-up photos of the circuit boards
before you start in case wires break and you don't know where they went.

[vintagekiki]

Principle US Vox Amplifiers by the Thomas Organ Company detailed are processed at:

http://www.voxshowroom.com/us/amp/index.html

For each amplifier there is a layout that carries the tag A Look "Under the Hood"
Schematics can be found at:

https://music-electronics-forum.com/showthread.php?t=9222, and has over the web.

Vox electrical parts:

https://www.partsisparts.net/catalog/vox-electrical-parts

https://www.mojotone.com/Electronics_1

http://www.hotroxuk.com/amp-parts-service-equipment-294-0.html

https://www.amprepairparts.com/newitems.htm

http://www.banzaimusic.com/Electronics-c-1664/

May I be very curious, about whom the Vox Beatle Head is model?


http://i.imgur.com/bsA7odJ.jpg