My amptech saw my dead RM100. He was startled. DESIGN FLAW!

[skunky_funk]

Remember I posted a thread asking for help on my dead RM100. To make a long story short, I kept blowing HT fuses (used to be 250mA and replaced them with 315mA), and eventually, two 1.6A internal fuses blew. Replaced the two 1.6A fuses with 2.0A ones, and then, my amp had a spark. The pic above shows what happened.

My amptech is here and is STARTLED. WHY DID RANDALL/EGNATER DESIGN THOSE HIGH VOLTAGE TERMINALS BESIDE THE GROUND? Look at the pic... the brown wire with the spade connectors is connected to the output tranny. You're talking about 400V around the ground. Once that arcs (shorts), you're in for trouble.

The same thing happened to the red wire. Sparks due to arcing. Now I had them jumpered direct to the tube socket.

He was surprised about the design flaw of the RM100. Oh well. I still love it though.

 

[Bewitagos1]

Remember I posted a thread asking for help on my dead RM100. To make a long story short, I kept blowing HT fuses (used to be 250mA and replaced them with 315mA), and eventually, two 1.6A internal fuses blew.

I didn't get the courtesy of a blown fuse, interesting how close yours burned up in proximity to mine. Half volume on the master is when mine went "tits up" as was aptly coined in my WTF thread.

Question. How many of you folks crank these amps beyond half-way?

 

[oathinc]

Same thing happened to my rt2/50 but i dont feel like fixing it maybe ill sell it as is

 

[Julia]

Question. How many of you folks crank these amps beyond half-way?

75% to dimed here.

 

[Mailman1971]

I run the master at about 75% as well. then control the overall volume on from the module.

 

[RIP STUDIOS]

Was your Bias to High? or did you over load Fuses meaning use to high of a fuse ? i talked with Voodoo Amps on this. They suggest bigger Transformer so that doesnt happen. The RM100 needs bigger Power Tranny. The George Lynch comes with Mercurys. But Upgrade the power Transformer and you will get a lot more power and better sound...

 

[tonymustang302]

I run the master at about 75% as well. then control the overall volume on from the module.

Dan, have you tried the way i was running my amp as i posted in a thread?

Max out the volume on the module and then put the master to what you want. Totally changes the character of the module and makes it more controllable and less compressed.

 

[Mailman1971]

I run the master at about 75% as well. then control the overall volume on from the module.

Dan, have you tried the way i was running my amp as i posted in a thread?

Max out the volume on the module and then put the master to what you want. Totally changes the character of the module and makes it more controllable and less compressed.

Cool, thanks for the info Tony. I havent really played with it too much. Sad isnt it? haha.... I will give that a whirl this afternoon. Supposed to have a band session. Going to rip it up. Loving that new Hairy Brown Eye module that I had Dave friedman mod.
Thing is a beast for any 80's hair/heavy metal. 8)
My Pete modded 1086 should be home this week. NOW THAT.....is tone to die for! The "Be all....End all" for me is that Monster Pete makes out of the 1086. :twisted:

 

[Bewitagos1]

Was your Bias to High? or did you over load Fuses meaning use to high of a fuse ? i talked with Voodoo Amps on this. They suggest bigger Transformer so that doesnt happen. The RM100 needs bigger Power Tranny. The George Lynch comes with Mercurys. But Upgrade the power Transformer and you will get a lot more power and better sound...

I'll be honest, in my situation, I took the amp out of the box and turned it on, seven minutes later it was dead. Its my understanding (limited as it may be) that the bias function was for tube longevity, in other words, biasing the tubes hotter may make it sound more "Killer" but tube life is drastically shortened. I can also understand the rational of a bigger Trans, when you make demands on electronic components with an inadequate power source, you run into a brown-out situation and it becomes anyone's guess as to what could occur. As we all know, electrons by nature are seeking the quickest source to ground. The master volume in our situation is the faucet, the more you "open" it up, the more electrons are excited and get in line to exit. Increased electron flow creates heat in areas of resistance, and somewhere in this scant explanation of electron theory, resides our collective problem.

Jimmie

 

[Nightdare]

i talked with Voodoo Amps on this. They suggest bigger Transformer so that doesnt happen.

basicly they're saying:
"after buying a randall, you need to rip out the tranny for a better one or it blows up"

I would like to hear what Randall themselves think about building amps like this in that case

 

[Jaded Faith]

You really have to keep in mind that many people use these amps trouble free every day with no issues what so ever. Most of the time if you are reading it in a public forum like this, someone had an issue and is seeking opinions and advice. How often do you read "hey my amp is/has been flawless for "X" amount of time and I was wondering why?"

I have had all of the MTS line except the RM20 at one point and currently have 2 RM100's. One I bought used with several known issues upfront (Randall fixed it for free and it was out of the warranty period) and the other was used and in great condition (I upgraded it with a MM OT). Both are flawless performers (as were all 4 of my MTS rigs through the last 3 years) and have never once let me down with 2 rehearsals a week and 2-6 gigs a month. I also gig confidently without a backup.

Just food for thought.

 

[Mailman1971]

+1 0n that. I have owned several MTS amps and only one had a "problem" where a fuse came loose inside of it. But there are always going to be a few lemons in anything you buy. Amps, cars, etc....
Overall I have had great dealings with Randall and their products. I thought I blew it up once when the bias went too HOT.....scared the crap out of me, but just blew a fuse and tube. But things happen. I have found TONS of great advice on this forum and ANYTIME I have even the smallest problem/Question I toss it out here and members have always helped me out. Even the Randall Reps have helped me in the past. great company to deal with.

 

[jmgman70]

On a side note,the Customer service has been incredible!!!I emailed them about some parts and WITHIN a week they were at my Door!!!!FTW!!!

 

[gtr31]

I think the Lynch line has the same transformers ?

if they use Mercury thats news to me can anyone confirm this?
I thought they were Heyboer clones to spec.

The fuse issue has ALWAYS come up a 250 slo blo seems to have a lot of problems at higher volume and hot bias .
they should be 400 or 500 ma I believe especially with the el34 of kt88

 

[Bewitagos1]

You really have to keep in mind that many people use these amps trouble free every day with no issues what so ever. Most of the time if you are reading it in a public forum like this, someone had an issue and is seeking opinions and advice. How often do you read "hey my amp is/has been flawless for "X" amount of time and I was wondering why?"

I have had all of the MTS line except the RM20 at one point and currently have 2 RM100's. One I bought used with several known issues upfront (Randall fixed it for free and it was out of the warranty period) and the other was used and in great condition (I upgraded it with a MM OT). Both are flawless performers (as were all 4 of my MTS rigs through the last 3 years) and have never once let me down with 2 rehearsals a week and 2-6 gigs a month. I also gig confidently without a backup.

Just food for thought.

Confidence. Thats what I'm hoping for and why I posted my concerns here. If I thought the RM100 was a P.O.S. I'd invest my time and money elsewhere. Had the same issue with a Triaxis I bought back in 92. Called Mitch Faber at Mesa, he told me the component that burned up was in a circuit that didn't contain the oomph to burn up the 1/2 watt resistor that was charred beyond recognition. After he shared the resistance value, I replaced it and never had a issue with it again. Of course that was back in the dayz before the Internet networking capabilities that we enjoy today.

I'll figure it out and share my findings with you all. Think if the limitations that have been shared here by you all and how cutting edge modded circuitry and upgrades have become common trade. You all should commend yourselves for the progression of an already amazing piece of technology.

Jimmie

 

[Julia]

I think the Lynch line has .... Heyboer clones to spec.

They do.

 

[KillTone]

After reading this thread I am a little worried.

I have a questions on the power transformer - how hot should it get? I had a gig last night with my RM100. We played for about 3 hours modules at about 1:00 master at 12:00. I did not check how hot it was immediately after playing, but about 15 minutes after I shut the amp off I put my hand on the PT and it was still very warm.

Second question: If the PT is getting too hot will it effect the volume of the amp?

 

[Julia]

First what is "too hot?" Of course if the paint is blistering it's too hot.

The transformer can get very warm. It's also quite large, so it will take time to cool down. Let's just say it will take longer to cool down than your tubes. Although I have to say it doesn't get any hotter than the output transformers on my powered monitors.

I'm not going to worry about it.... My amp is under warranty. Anything major screws up it's going back to Chicago, and I'm back in Peaveyland until it gets fixed. I don't trust the locals to fix anything anymore.

After my experience with the JVM, I am SOOO glad I didn't do the C83 cap mod everyone was raving about. Mods void warranties. I needed mine. It's how I ended up here.

 

[KillTone]

What is "too hot" - I guess that is really the question. I don't know much about electronics - just as much as being a player/tone tweaker requires.

 

[Bewitagos1]

What is "too hot" - I guess that is really the question. I don't know much about electronics - just as much as being a player/tone tweaker requires.

If the circuit is designed with adequate protection, i.e.; fuses; circuit breakers; etc, not hot enough to blister the paint on the transformer or discolor the leads coming from the transformer, but hot to touch, nonetheless. In high output transformers, over time, I've seen the copper "pushed" right out of the wire. The end of the wire becomes non-conductive at the point of termination and several inches have to be trimmed back and re-soldered. Thats only a tempoary fix and most likely the entire Trans needs to be replaced or rewound.

Jimmie