Randall B100 Shutdown

[sturgis011]

I was recently given an older (not sure of the manufacture date) Randall B100 that seemed to work great. After pumping some hard driving bass licks through it, it shut down and then back on a few secs later. Alarmed, I changed a few settings (volume, compression, etc.), then went back to playing. Same thing happened again, and always came back on. After playing for about 6 hours, I found there really wasn't any consistent setting or playing style that caused the problem to occur, other than it never turned off and back on when I wasn't playing through it, so I am really lost. I don't have a problem taking it to an amp repair shop, but thought there might be something I'm just being stupid about. Hope someone can help. Thanx

[J M Fahey]

Hi sturgis.
Randalls have thermal switches attached to heatsinks, and thermal circuit breakers.
Maybe it doesn't like what you are loading it with or it's in some hot or unventilated place.
What speakers are you using?
Check your cables.
Don't use a guitar cord there.

[sturgis011]

Thanks for the reply JM. Unfortunately, I'm not an electronics genius, but do have a small amount of knowledge on the subject. The B100 is a combo amp with a single 15", 4 ohm Randall Jaguar placed in the cab below. I pulled the amp out of the cabinet yesterday, just to get a visual. The only thing I saw that bothered me was one resistor that looked like is had 'rust' (or something that looked like rust) on and around it, but otherwise everything looked fairly decent, i.e., no visual bulging of capacitors, fairly clean, etc. So, I put it back together and began playing again. Not sure if the cables I was using were for guitar or bass (didn't think there was a difference), but I used several, including different lengths, mostly higher quality. No change regarding the latter. Everything seemed to go well, except when I changed the volume or compression higher. Then it had a few problems. I turned it back down and it didn't shut down as much, but still did it occasionally. So, I'm still a bit lost. Oh, btw, the amp was sitting in the middle of the room, so I really don't think there is a ventilation problem. I am going to go to my local music store to purchase a cable just for basses sometime today. Maybe that'll be the trick. Let me know what you think. Thanx again.

[J M Fahey]

Hi Sturgis
I see you use it with the original speaker, so no problem there.
I meant do not use a guitar cord to hook *the speaker*, there is not guitar or bass specific cord to hook the instrument.
Well, with the current wave of magic surrounding everything audio, I would not be surprised.
Does your amp have an effects loop, or a pre out/power in pair of jacks?
Because that might be a caise of intermittence.
Squirt a little contact cleaner in all jacks (with the amp unplugged) and work a plug in/out to clean them.