How could I test a junky little practice amp that might be fried?

[Zut8083]

Hi,

I have a quick, and perhaps trivial question- "How do I test a potentially fried practice amp that didn't cost that much, but I'd rather not spend cash now if I can avoid it?"

Relevant data:
1) It's an old Behringer BT108, so...it's kind of an "economy" amp/paperweight, but is useful enough.
2) The amp was turned off when it got a surge, but was plugged into the wall socket and, thus, was grounded.
3) The surge current from a poorly grounded heater into the gold shroud of a monster cable plugged into the unit.
4) As mentioned elsewhere, I bridged said current by holding the instrument cable and brushing the heater.  I may have mambo'd while the current went into the amp, but there was no Korean BBQ/Teppanyaki smell.  Again, and fortunately, I was neither dinner nor the show.
5) I am not a precision instrument, so I cannot accurately guess the extent of current/voltage that was fed into the amp (maybe 20 V and unknown amperage), and I don't know if it cooked the amp's innards somewhere.
6) I am not sure where to/how to/if I should measure the circuit with a multimeter to determine if it functional.  I also don't want to zap myself again because my wife is gonna get really pissed at me.  Per doctor's orders, I am on an all new, low-mayhem diet.
7) I am also presently *really* cheap and don't want to damage anything else that costs much cash in testing this unit.
#8) Do you guys have suggestions beyond, "quit all effort designed to save your new ottoman, get a $50 mixer as a DI receiver for a bigger amp, and run headphones from it or get a proper little headphone practice amp", or, as Don Rickles once said, "why don't you get a horse and live in the mountains, and stop bothering people?"  I already got those covered, so, again, I wonder, what more clever and sophisticated suggestions y'all might offer to investigate the amp's integrity while adhering to a low-mayhem diet and lifestyle.

Thanks in advance.  Have a good weekend.  Cheers.

[jwright9]

Something to consider.

Behringer gear isn't far from garbage to begin with even when it is working properly.

On a scale of 1-10, 1 being garbage and 10 being excellent quality gear that will last forever if taken care of, working Behringer equipment is a 3.5, MAYBE a 4.
Non-functional Behringer gear is thus right at about a 1.5.

If you are a marksman, I'd say to use it for target practice.
Or, maybe take out some pent up anger on it with a hammer.
Could be fun!

At least more fun than trying to resurrect a zombie.

Just my 2 cents.

[lbpesq]

Have you tried using it since the mishap?  Do you know it is no longer functioning or are you assuming such? If you haven't tried it yet, you might want to use a wireless system, if you have one or can borrow one, just to be extra safe.

Bill, tgo

[gtrguy]

You can build a cheap gizmo where a common light bulb is placed in the line and in a box or enclosure, and then there is an outlet to power the amp. If the bulb stays dim when turned on or plugged in to the amp, the amp is sucking power and has a short. I bought all the parts for mine at the Goodwill Outlet Store for a buck or two.

[Zut8083]

jwright9-

True.  But better to know whether I have a bad bass amp, or whether I have a cat hutch in the making.  Besides, like I alluded to, I am trying to be frugal now to be wonderfully impractical later.  And I was waiting for your love of Behringer products to appear, like Martin Brody announcing Bruce by saying, "I think we're gonna need a bigger boat!"  Nice.

Bill-
It's totally an assumption as I have not dared to plug in a bass for fear of the unknown.  I figure if it was not fun for me, it wasn't fun for the input->third prong circuit in the amp, and I am only looking to suss that out so I don't myself up for a small fire.

The wireless system is a great idea and probably the best way to do it, plus a fire extinguisher, but I don't have a wireless system, and most rudimentary analogue 4 channel mixers with a XLR input, plus an XLR cable, would run less than a decent used system.  I still really like your idea, though  Thanks.

I mean, you are right, I need signal generation with a big fuse and/or physical separation from an instrument sending the signal.  It would also conceivably work to dial in a monotone signal to test the path's integrity, but I have no such input device on hand, and I believe that professional grade/laboratory modules are expensive. 

I wish I still had a Speak-and-Spell; that might work to mimic a bass signal strength (~1-1.5V).  Maybe a cheap radio, a tape recorder, or the children's toy that assigns animals with their noises?  If it were to destroy the bass amp in the process of testing it, at least it could be funny if I were to have a burned out chassis.

Anyhow, these are very helpful ideas.  Thanks, fellows!

[Zut8083]

gtrguy-

That's pretty freaking clever!  I am going to look into that, it's elegant and cheap; thanks!

[xlrogue6]

New ones are $79.95. Behringer products are not designed to be repaired (especially not the low end stuff). I fix musical electronics for a living, I won't take Behringers in, neither will the vast majority of techs I know. Even if you just want to learn about electronics, this is not a good place to start.

[Zut8083]

OK.  So, what I am sensing here, as a consensus from those members most acquainted with this particular electronics package...is that this practice amp is probably like the last 10-15 minutes of "Old Yeller", and that any "Young Yeller" would be better off as a non-disposable electronic commodity, especially as a part of a low-mayhem lifestyle? 

Fair enough.  I think that may be smarter than an apartment or driveway fire.  Thank you, guys.

[lbpesq]

I'd at least plug it in and see what happens.  There may be nothing wrong with it (other than being a Behringer - though, in all fairness, I have a Behringer iNuke NU4-6000 four channel power amp, 440 watts per channel at 8 ohms, that I use to power four passive floor monitors.  It works quite well - so far, especially considering the cost.)

Bill, tgo

[StephenR]

A friend of mine accidentally burned down his parents beautiful old historic house on Long Island by leaving his effects pedals plugged in and unattended, electrical fires are no joke, your amp sounds like it is ready for retirement. A fire or electrocution would not qualify as a low-mayhem lifestyle...

[Zut8083]

Bill-
I worry there may be a small defect in the operation that could evolve into Stephen's comment regarding an abrupt problem.  I might try to suss out what parts are OK while trying to expand my rig back to a full speaker enclosure, and use the 15" (?) speaker as a slave output.

Stephen-
In all seriousness, I agree that the loss of a home is not funny, I meant no offense to you or to anyone that you might know who has experienced that.  I have had homeowner emergencies, some with voltage, some with fire, some with exploding hotwater heaters (2), and all "bad luck" which I do not wish to entice further, no again, experience its aftermath. 

I am sorry if that flip summation of what fortune seems to occasionally follow me around has offended you.  However, I fully agree with your point that limiting the damage that a potentially damaged electronic unit can do is prescient, but if it is at all salvageable for anything, it may be useful, or it may not. 

I think you may also agree with me that time is the most valuable thing being considered here and rehashing a decade old practice amp that served me well may not be quite so efficient as finding a new solution that can be delivered safely.

Thank you both for your input.

[StephenR]

Hey Zut, now worries, I didn't experience any offense reading your posts so not sure what you are referring, too. My comment about a low-mayhem lifestyle was supposed to be funny and a riff on some of your comments above, hard to "do" humor in an internet post. The point of my previous post is that electronic stuff should not be left plugged in and unattended even if turned off and seeming to be problem free. It already sounded like you are wise enough to not plug the amp in again unless you are sure it is going to be safe, how to ultimately know it is 100% safe remains the unresolved part.

Hear you loud and clear about your time being valuable and agree that perhaps time spent on finding a new solution would be better spent than trying to resurrect a ten-year old $80 amp. Hope you can find a quick, cheap, solution. Meanwhile it sounds like the speaker in the cab is still usable so not a total loss.

[Zut8083]

Stephen-

It was indeed funny, but I was also saying to myself while reading it, "Is this as funny as I think it is, or am I glossing over something that would make me even more of an insensitive jerk?  Damned handsome, but still insensitive."  I too worry about the power consumption of the line, and will shut things down if I leave because of that worry.  I am terrified, irrationally maybe, also that if the amp's circuit or its resistors are damaged, so firing it up will go beyond nuking the little Teutonic terror, but also eat bass electronics, albeit passive ones. 

That's why Bill's suggestion to separate the instrument from the amp was a great one, and everyone cautioning me to just walk away from a disposable amp, or to invest as little money and effort as possible to test it are right is probably right to solve the problem, and leave the bastidge to be investigated later.  It's probably time to pull out my old AH300, and invest in a pair of cans with a metric buttload of resistance (I think the manual specifies 60 Ohms, but I'd have to check); that is probably most convenient at this point, having reviewed the advice presented in this thread.

And hey, being a Trace Elliot, I could get some black light posters for my bedroom, possibly some essential oils, some potent potables at the ready, and playing could be more "dynamic" than through my old blackbox of tinny doom, and it'll be like high school/college.  After I check with my wife.  I think the only thing I have to remind myself of is that I will be extra careful/mindful to maintain a mayhem-free lifestyle by not plugging the headphones into the effects send jack or the power amp output jack.  That will be a major inflammatory problem, and I would totally be the guy to do that.  I feel like I should probably audition to be Spinal Tap's next drummer, sometimes.

Thanks again, you guys!  And if the Behringer is indeed toast...if I remove the speaker and the backing, and I have a cat hutch/scratching post ready to go.  Not a total loss!  Peace to you, and have a great weekend.

Cheers,
Zut

[peoplechipper]

Does it smell burnt? if yes, scavenge for parts and give to the cats...if not. plug it in with a cable and short the cable; get a sound and it lived...even if it's hooped you won't get the voltage dance! so you'll be fine, don't panic...

[xlrogue6]

Can't hurt to plug it in and turn it on. If it doesn't turn on, the fuse is probably blown. It's probably mounted in a clip on the PC board, replace it with a fuse of the specified amperage and try again. If the replacement blows, you're done--or, more accurately, the amp is done. If the fuse blew due to a power line anomaly, the amp will probably work again and be fine.