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guys i got my AD50VT 2 years back & ever since it has been running a 'going dead' problem.. the damn problem is intermittent & it happens just when u really need it to deliver.. it has ruined two gigs & innumerable practise sessions.. have given it for repairs to 3 different shops (including the one i bought it from) & they're just clueless 'cause as soon as the amp gets to the shop, it just freakily stops malfunctioning, like as if there's some ghost inside it that hides away seeing the doctor!! & each time i get the amp back from repairs with the tag "working ok"!!
the problem started well into the warranty period & has been there on & off.. sometimes it just won't sound at all, no matter how many times i reboot it.. sometimes it goes dead after 5,10 or 15 mins (altho the power LED still glows) & then i turn the power off/on & it again works for some minutes.. i have even changed the valve, but the problem persists..
& i m totally lost here 'cause i can't get it repaired & i can't get it sold (who'll buy such a sucker?!).. i'm just stuck with it till the rest of eternity blaming that day when i went to the shop with my hard earned money to get me a brand new 'vox' amp!!! :(
if anybody else got this problem & also figured out the root of it, PLEASE HELP!!!
This might be just a dry solder joint where a solder joint is breaking/reconnecting intermittently, possibly contracting/expanding as the amp heats up & cools down. A careful check of all main solder joints might be worthwhile.
Chances are you won't be able to see a bad solder joint. best to reflow everything on the main power board. Next time it happens, plug in a set of headphones to it and see if you hear anything. It may be the power chip going. It may be a bad headphone output jack, too.
Have you cleaned the headphone jack?
You'll be amazed at how often this is overlooked, even by techs, as most do not realize the signal is in series through the headphone jack on these amps.
guys, what am i telling u!! the damn thing works fine in the shop floor.. it has happened 3-4 times now.. now if it does not break up in front of the technician, how the hell is he supposed to fix it!! he can go on checking all soldering joints & phone jacks, but the problem has to happen in front of him first!! it's a freaky situation..
these guys, what they do, they just connect a radio or deck to the amp & let it run at moderate volume throughout the day.. i have tried to make them understand that a continuous guitar attack is much different on the amp than a radio signal & that they should test-check it likewise.. but as it is with these local techies, they just don have the time for such an in depth analysis, neither are they ready to come up to our rehearsals one day to see the actual ordeal happening.. & in the end, i am the sucker with an imported amp that does not work..
First, stop yelling at those trying to help you.
Second it is not our fault or the amp's fault if the techs in your area are inept.
Third, listen closely.
Fourth, HAVE YOU TRIED CLEANING THE HEADPHONE JACK?
hey, i wasn't yelling at u guys man.. i know u all r trying to help me.. those were just distress complaints..
the amp's at the shop, not with me.. will call up the technician & ask him if he has done that..
You could test it with a volt meter, to find where the signal breaks up
well i tried everything, the repair guys tried everything & ultimately its back home sitting finely at an obscure corner where i plan to keep it for the rest of my life for i know that i won't even be able to sell it.. thank u Vox.. we have moved onto a Boss pedal..
Did "everything" include spraying the headphone jack with electronic contact cleaner/lube and then working a plug in and out several times to clean the contacts, loosen any crud, and distribute the lube?
Secondly, if you have receipts or work orders showing that you tried to get it fixed during the warranty period and that they were unsuccessful, Vox may be able to help you. Did you take it to a Vox dealer for repair?
Voxman, what do you think about this?
yes, all that.. btw i strongly feel that the 2nd post in this thread might be the cause.. unfortunately, it happens only when there are no repair guys around!! i know how i sound but thats the truth.. bad luck..
right now i am having some guy carve a very nice "RTP" for the vox.. :D
"it happens only when there are no repair guys around!!"
Chances are, if it's happened more than once to you, it'll happen during a proper diagnostic check-over by a qualified tech. Unfortunately, some techs don't take the time to adequately test the gear they have for service. Turning it on and letting it run under no-load conditions won't bring on every intermittent problem, any more than resoldering a couple of connection points will correct all the ignored points.
"Authorized Repair Facilities" aren't always the BEST facilities, whether because they're overloaded with work or because they just don't have adequately trained techs. One has to shop carefully for a repair facility and it's important to take the advice of the tech when it's offered. If they need the gear left there for a few days (and in a case like this, they probably will), leave it and give them time to check it over carefully. This is a good reason to always have a backup amp/guitar/etc. Rome wasn't built in a day and an intermittent problem in electronic gear isn't necessarily going to be found by an untrained tech or by one who isn't given adequate time to investigate every possible cause. More experienced techs probably won't require as much time to find a problem but it isn't always a quick job.
I have yet to have any problems with my AD50VT (and it's been worked very hard) but I experienced a problem similar to yours with a bass amp from "another manufacturer" and the "Authorized Warranty Repair facility" had it for a month, replaced the wrong part and sent it back unrepaired. A local tech found the problem in about a minute - improper soldering of a connector at the factory. Sometimes it just works out that way.
9 out of 10 times this is a headphone jack or headphone circuit board problem;
http://www.valvetronix.net/forums/vt-headphone-test-circuit-t4237.html
