It is currently Mon Mar 16, 2020 2:52 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 4 posts ] 
Author Message
Post subject: EVH III 50 watt switching back to clean on its own!!
Posted: Sun May 28, 2017 11:10 am
Offline
Hobbyist
Hobbyist

Joined: Sun May 28, 2017 11:01 am
Posts: 2
Hi,

The title says it all.
Had a recording session yesterday and the 50 w EVH amp was switching back to clean randomly either from the red channel or the blue. It happened more in the early stages of use. After two hours it stopped switching.
No foot switch was being used.
Any insight would be appreciated,

Thanks,
Ernesto


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: EVH III 50 watt switching back to clean on its own!!
Posted: Tue May 30, 2017 5:29 pm
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1023
http://www.evhgear.com/support vietnamese version. If you have this version, the first thing to try is to clean the switch inside the footswitch jack. Squirt in some plastic safe cleaner an insert a plug 25 times to exercise the internal switch.
After that, it gets deep.
The switching logic is controlled by a microprocessor.
If the effects switching is still working, it's probably ok.
When you describe a problem that appears after warmup, its probably a bad solder connection.
I would look closely at the soldering on the U2 regulator. It supplies 15.6 volts to the switching circuits and the processor. It also supplies power for the preamp tube filaments.
Frankly, this part of the power supply looks overloaded. The fuse is rated for 4 amps. The U2 7815 regulator is a 1 amp device that can be pushed to 2 amps. The 3 filament lines consume @1/2 amp each. That doesn't leave much to drive the processor and the relays in the channel switching circuitry. Not to mention the channel lamps.
Your amp is a ROHS compliant amp with solder that is lead free.
The easiest approach I would take is to resolder the entire amp and see how it does.
It may very well fix the amp and prevent future failures from this unreliable solder.
If not, you have eliminated the most common cause of failure.
If the problem persists, I would try some freeze spray on the processor and see if that makes a difference.
On the original 5150, Ive seen the jfets give lots of problems. These are different.
Good luck.


Top
Profile
Post subject: Re: EVH III 50 watt switching back to clean on its own!!
Posted: Wed May 31, 2017 11:54 am
Offline
Hobbyist
Hobbyist

Joined: Sun May 28, 2017 11:01 am
Posts: 2
Thank you very much for your info!
I just left the amp with Mike Franceschini at Classic Amp Repair in North Hollywood and I printed out what you said and he kept the paper, very cool.
He knows Eddie VH's tech so he's gonna ask him.
By the way, I have the Mexican version. 8)


Top
Profile
Post subject: Re: EVH III 50 watt switching back to clean on its own!!
Posted: Thu Jun 01, 2017 8:54 am
Offline
Professional Musician
Professional Musician

Joined: Thu Aug 07, 2014 3:25 pm
Posts: 1023
While the signal chain in this clone is faithful to the original, unfortunately, the Fender channel switching circuitry is completely different than the Peavey version.
The use of a microcontroller in the Fender ensures that only the original Peaveys will make it to their classic era.
Let us know how it works out.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: