#1
hey guys, i don't know if i'm posting in the right place to be honest, but i haven't noticed a troubleshooting section so i figured i'd try here, anyways on to the problem.

as stated in the title i have a Randall RG50TC tube amplifier, as of yesterday it stopped producing noise, i had finished a quite lengthy jam session, probably 3 hours or so in length, but that being said i wasn't pushing very hard volume wise.

anyways, today i turned the amp on, waited the usual length of time it takes for it to warm up, flipped it out of stand by and got no sound, after about 10 minutes or so of waiting i switched to my other guitar, still nothing.

i have not yet tried another instrument cable, although that is on the list, but i just have to wait until tomorrow so i can get a hold of my buddy's known good cable

back to the issue though, what i have noticed is that the fuse in the back panel is still good, the wire is in tact, and does not appear to be damaged in any way, and the lights in the power on switch, as well as all the indicator lights on the faceplate and foot switch appear to be functioning normally, but no matter how long i leave the amp turned on, there is no sound output and the tubes do not appear to be warming up in any fashion, no heat output, and definitely no glowing of any kind (i am aware that they do not need to be glowing to be functioning though).

i'm curious as to what else i can do to try to narrow down the issue further if i try this known good cable and it still doesn't work.

so far i have tried 2 known good guitars (one has recently had the pickup swapped, perhaps that could be a factor?), checked the fuse, and tried using the amp with and without the foot switch plugged in

and tomorrow i will be trying a known good cable

but yeah, is there anything else i can do diagnosis wise to try and narrow down the issue further before just outright sending it off to a repair shop?

thanks in advance.
#3
Quote by 311ZOSOVHJH
I would replace the power tubes and ALL of the fuses and try again.


so basically what you're saying here is that i should be replacing all 6 of these guys here...



of which there are the 2 EL34's on the left (power tubes i would imagine?) and then the 4 other guys on the right of those, the 3 to the left either being more tubes or possibly fuses and the last on the right in the metal case being another tube or fuse? as well as the fuse in the back panel?

now that i look at them they do seem to be noticeably burnt or charred looking, although i don't know if that's a normality or not
#4
Yeah the 2 - EL34 power tubes. Order a matched set. I'd go with JJs. A place like www.eurotubes.com or www.dougstubes.com. As far as fuses go, the fact that the amp and lights come on tells me that the mains fuse is probably fine. That is the one you looked at. Some amps have additional fuses. Most tube amps do. There is something called a HT (high tension) fuse in some amps. That is there strictly to protect the power tubes. You can try the power tubes first and see what happens. If any lights up super bright, shut it off an take it to a tech. Also, the inside of a tube amp can hold lethal voltages even if unplugged. Do not go poking around inside the amp, but that is probably where the HT fuse is.

PS - your tubes look normal. If the tops where white or clear - THEN I'd be concerned.
Last edited by 311ZOSOVHJH at Oct 5, 2013,
#5
also you should check each fuse on A dvom to know for sure. Pay attention to see if one is a sloblo or standard, they are NOT changeable.

If you have contunity when you check the fuse, the fuse is fine. If not then replace.
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#6
UPDATE: i've pulled the electronics out of the amp and checked all of the fuses i could find as well as every solder and connection i could lay eyes on, everything seems to be fine, at this point i'm just going to clean every connection and solder i can and replace the tubes, if that doesn't work, then i'm probably going to just replace my amp entirely.

mainly because i don't see a point in paying 500 dollars to have some guy look at my 500 dollar amp, especially when i can get an equal or probably even a better quality amp for that price now anyways as this one is a few years old now.

thanks for your input guys.
#7
Did you get the new instrument cable?
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#8
yeah sorry, i forgot to mention that i tried that as well, same thing, no matter how long i left the amp on there was no output of any kind, not even the slightest bit of heat output from the tubes