Rm100 Unceremoniously Dies

[Tube Head]

I have had several troubles with my RM100 but so far have been able to sort them out myslef. So as im practicing today I decide to turn it upand then after a minute...........Nothing. The amp is still lit up as usual but no sound, not even hiss like the cab wasn't pluged in.

I am worried that a component like the transformer is toast. My fault probably. I had a soldering iron, a glue gun and an electric heater on the same circut.

Any speculations?

 

[jmgman70]

Check all fuses,even the ones in the chassis.

 

[kbause]

did you hear/see/smell anything when you fired it up?

anything pop?

Did you check your power tubes?

 

[Tube Head]

Ive taken the amp out and I can see several fuses. They all look OK though I still have to take them out for a closer inspection.

Kbause- There was no pop smoke or smell, however while removing the tubes I did notice one of the tubes had some dark discoloration on one side that the other tubes didnt have.

Can a tube fail in this way?

 

[jmgman70]

Check the fuses with a DVM and see if there is continuity,make sure you pull them first!

 

[evhwolfie]

I had a problem with my rm4 lastnight, I didnt realize that somehow the bias got turned up all the way, blew the main fuse and a tube. I started to smell something and i was like hummm this sounds really good and that was the end of that haha.

 

[Tube Head]

I pulled 5 fuses on the inside and they all checked out fine.

 

[Tube Head]

Found two more fuses beneath the MIDI. Both were burned out. Im unsure of the value of these fuses.

Witten in them is 1.6L does this mean 1.6A?

 

[RD/Steve]

i have had situations while running a hotplate or another type of load...where the power tubes will give off some sound.

i don't know if this is the case...but i have expereinced this one more than one occasion.

 

[kbause]

Found two more fuses beneath the MIDI. Both were burned out. Im unsure of the value of these fuses.

Witten in them is 1.6L does this mean 1.6A?

This happened to me as well.

I replaced them with 1.5A because I don't have any 1.6 and its been working fine for months.

 

[Tube Head]

Can anyone confirm the specs of these fuses? I searched and found that they were 8A fuses and 10A or 12A can also be used.

kbause -- this is a lot diferent from your findings of 1.5A fuses working.

 

[guitarteck]

you can put in any fuse you want You just may not be happy when it blows up. The fuses in my lynch box buried under the midi were 1.6 amps and suggest you use those and not an 8 10 or 12

 

[kbause]

the ones in my head were most definitely 1.6 amp.

if it were 8 10 or 12 those 1.5s would have been toasted already as I've run at 80% power on multiple occasions since replacing them.

 

[Tube Head]

Problem solved Thanks!!

 

[kbause]

Problem solved Thanks!!

good to hear!

 

[Tube Head]

:x :x It did it again!

This time I was half way through the first set. I hit my wah pedal and then...once again nothing. I walked out to my car with the band still playing and grabbed my crate powerblock. Saved my *** though it doesnt sound too hot.

What is going on with my MTS? Is it caused by low voltage? What fuses should I be using? :?:

 

[Soulinsane]

If it was the same fuses under the midi board, F1G F2G, they are 1.6A 250V, located between the power transformer and the 500V B+ power supply.

It's funny those particular fuses blow and not the one on the mains AC input. I've seen something similar to that before with my RM100.

The cause could be difficult to pin point but first start with replacing the fuses and get the amp running again.

Once running again the first thing I would do is check for signs of power transformer stress. If it's getting really hot ( 115F+ ) that might just be your problem. It happened to me and there wasn't anything else causing it to heat up or blow fuses.

The problem could also be a bad part or tube that arks on occasion. Eliminate those things first but keep an eye on the power transformer.

 

[Tube Head]

I've replaced the same fuses again. After I put her back together I noticed one of the inside tube failure light had lit. I had 2 EL34's in the inside pair and 6V6's on the outsides. The EL 34 have less than 20 hours on them. The tube is fine as I remove all the tubes and placed the EL34's in the outside positions and left the inside positions empty. Sounds great now.

I think I might have a bad tube socket. Is this posible? The same socket had a failed tube in it the last time my amp died.

Also I have a loud popping sound when I switch from standby.

 

[Jaded Faith]

I occasionally have the pop from standby too. It was on a list of things I asked Randall to check when I first got it and sent it in for repairs. It still does it from time to time. Wonder what causes it?

I had the same fuse pop twice last week in practice. Noticed my Xpression in the serial loop had it's output set to around 2:00 and typically it's at 12:00. Turned it down, turned up the master volume and no more blown fuses.

 

[okstrat]

Sometimes the pop from standby is the switch arcing. I guess I've been lucky, haven't had a fuse pop yet on any of my Randall gear. Even at gigs I don't play super loud though, maybe that might be part of it.

Pete