Hardcore Techies Please Help / Rm 100KH Problem

[T-BONE]

So I was Jamming last night full volume and all of a sudden nothing. Not a spec of signal to my cabs. All tubes, tube fuses, pre tubes all checked out. I tore the head apart and found two sidexside blown fuses under the Midi board.(if thats what you'd call it). Its the hidden two. They are F1.6L 250v's.
Two ?'s.
I am having trouble tracking those down locally so is there any alternative ones I can put in. I know they are fast blowing and I can get the slow blow ones easily enough but I don't want to mess anything up. And two is this a common occurrence, just there time to go or is there a chance something is happening or I did something. I am pretty proficient with amps but not the in depth electronic stuff. I don't even know what those fuses are for. I assume some type of output stage but 1.6 is really nothing, no? Any help with this matter would be totally awesome.
Thanks.

 

[T-BONE]

Well just in case any one was interested Randall got back to me fast. Heres what there tech said
" The fuses under the MIDI board are the HT fuses which supply the output tubes. They usually do not blow for no reason. Most likely there is a bad output tube."
Maybe that'll help someone else out also.
Turns out it was a broken fuse in my power tube slot. Must have blown the internal ones. All fuses replaced/ All is better now and the tube is fine.
And for anyone who may not have known this, the failure light only lights when the head is in PLAY mode not standby. Most of you probably know this but I did not.

 

[GuidanceOfSin]

Did you talk to someone at Randall? Where did you find the replacement fuses?

The RM100LB I sold to my buddy popped a fuse and he said he can't find replacements anywhere. I went over to check it out and found one of the fuses on the back had popped. All the others seemed fine (internal fuses as well). It's weird though, the amp powers up except there no sound and the main power indicator light doesn't come on. None of the tube failure leds were lit either.

Anyway, I send an email to Randall, just wondering if you had direct contact info...

 

[T-BONE]

Well I found my fuses at radio shack. I just e-mailed randall customer support and they got right back to me. I also blew a power tube fuse(the ones in the back you can get to). The fuse was actually broken and the light never lit. Then it went through and blew my internal output fuses. Those are fast blow 1.6 250v and radio shack had em. My amp says to replace the external fuses with fast blo 400ma 250v fuses but the manual says 250ma 250v. Radio shack oddly enough had 315ma (.315) fuses which have worked out just fine and my amp is cranking again. If you get no sound at all and the amp powers up fine I would bet money its those 2 internal fuses under the midi board.
Just my 2 cents. I just roll with the punches like everybody else. Its good to know Randall gets right back to ya with the answers.
Good luck.

 

[jdr94]

good info. i'm havin a similar problem. blew out the F1G position, but before takin the head apart i checked all my external fuses and all were fine with the voltmeter. can anyone suggest somethin else to look for before i replace the fuse?

 

[Mattfig]

Bump....Having the same problem with F1G and F2G....What fuses will work? Anyone know?

Edited to add mine is not a KH version though I doubt that matters....

 

[eyeball987]

There was a fuse thread around here a couple years ago that explained most of this. From what I can remember, Bruce and Rob gave some good input. I will see if I can track it down.

 

[Mattfig]

There was a fuse thread around here a couple years ago that explained most of this. From what I can remember, Bruce and Rob gave some good input. I will see if I can track it down.

Thanks....I've been digging too...The ones I use flash as soon as I power up so I know I have something wrong...Just can't find what's going on....

Thanks for the help!

 

[Mattfig]

1.6 Amps 250V 5x20

For anyone's future reference...

Thanks Anthony!