rm100 tube failure help

[belias]

Hi, great to find this forum. I'm happy to say my first ever tube amp is an Rm100. Sounds Great. But now comes my first experience with tube failure, lol. Wondering if anyone can give me some tips.
I noticed a "tube failure" light on tube #2, which is odd because I haven't really used it that much yet. I borrowed a voltage meter from work and followed the directions in the manual. My tubes are the Ruby 6L6's that came in it.
With the DC section of the meter set on 200M, my readings are: T1)50 T2).2 T3)33.5 T4)43.2. To me, these numbers seem out of whack.
Another thing i've noticed is that the "top" light on tube #1 seems dimmer than the other three. By top light, I mean that each tube seems to have two illuminating points, one towards the top, the other towards the middle to bottom, if ya get me?
One other note: when I bought it roughly over a year ago, the whole system blew out shortly after I plugged it in for the first time. The local repair center fixed it quickly...I think they said they replaced the main board or something, but didn't know exactly what caused it.
It sounds fine now, but with this tube thing, I don't want to use it and risk damage.
Any help is greatly appreciated.

 

[JKD]

Hi, great to find this forum. I'm happy to say my first ever tube amp is an Rm100. Sounds Great. But now comes my first experience with tube failure, lol. Wondering if anyone can give me some tips.
I noticed a "tube failure" light on tube #2, which is odd because I haven't really used it that much yet. I borrowed a voltage meter from work and followed the directions in the manual. My tubes are the Ruby 6L6's that came in it.
With the DC section of the meter set on 200M, my readings are: T1)50 T2).2 T3)33.5 T4)43.2. To me, these numbers seem out of whack.
Another thing i've noticed is that the "top" light on tube #1 seems dimmer than the other three. By top light, I mean that each tube seems to have two illuminating points, one towards the top, the other towards the middle to bottom, if ya get me?
One other note: when I bought it roughly over a year ago, the whole system blew out shortly after I plugged it in for the first time. The local repair center fixed it quickly...I think they said they replaced the main board or something, but didn't know exactly what caused it.
It sounds fine now, but with this tube thing, I don't want to use it and risk damage.
Any help is greatly appreciated.

It sounds like the tube in socket 2 is blown..could be a bad tube or could be it blew out because the bias was too high.

You may have to replace that tube.

You need to bias your tubes, ideally those readings should be within +/- 5% of each other.

The RM100 makes it easy as there is a bias adjustment for every tube right there on the back of the amp.

I know a guide has been posted before about how to bias an MTS and am sure someone will chime in.

 

[belias]

hey thanks for the response. It turned out the problem was just a fuse, but I will readjust the bias to what the manual recommends.
quick question: I went to radio shack, but they didn't have that specific "250mA fast blo" fuse.
I picked up a few other similar ones:
fast acting .5 amp 250v gma
fast acting .315 amp 250v gma
fast acting 2.5 amp 250v gma
Will any of these work? They didn't have anything 1/4 amp (as I'm assuming 250mA might be?)