Amp went dead between sound check and show time

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Jack Napalm

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So, I take my Lynch Box today and got setup. We met the club owner around noon, setup, did a mini rehearsal. Everything was good. Got back to the club and powered up the amp and nothing. The big green light didn't come on, the tubes were cold. The pre-amp modules lights came on but nothing else. I was pissed.

Luckily our bass player lived nearby and went and got his Twin Reverb. I could at least play after making a few quick patches on my M13. I only used it for a few effects and a screamer boost. I didn't have anything set up for a good dirt patch.

Anyone have any ideas of what happened? From my limited knowledge it seems like I blew a transformer. Good guess or am I off base? Fuses all looked good. Its late. I'll be taking it to my tech on Monday.

It just pissed me off royally for the thing to go down on a whim.
 
I agree..check fuses first.
Often clubs produce ac spikes when their ice machine comes on...or anything else they have that uses BIG current.
This one reason I have indifference to clubs is because they jury rig so many electrical things..it can HURT our equipment.
I carry electrical trouble shooting gear with me to almost all my gigs. I check stuff to see if its flakey..I fix it if I can or avoid it and find another way of doing things.
Sorry to hear the amp had trouble..I hope it is nothing expensive to fix.
Please post what it was so others can be aware...
GtrGeorge
 
Well, its not the fuses. I checked all of them and the main fuse I replaced with the fuse from my Rm20 head and still nothing. The fan does come on. I'll be taking it to a tech tomorrow.
 
Jack Napalm said:
Well, its not the fuses. I checked all of them and the main fuse I replaced with the fuse from my Rm20 head and still nothing. The fan does come on. I'll be taking it to a tech tomorrow.
Click to expand...

**** man...Sorry to hear that...Always a frustrating experience...If you think of it, please let us know what the tech says...Good luck!
 
Jack Napalm said:
Well, its not the fuses. I checked all of them and the main fuse I replaced with the fuse from my Rm20 head and still nothing. The fan does come on. I'll be taking it to a tech tomorrow.
Click to expand...

Exact same thing happened to me, not once but twice. In both cases, it was fuses though.
Good luck, man. i'm sure it's not a transformer, you'll be alright. it realy sucks when that happened though.
 
My guess is that it was the mains and the two under the midi board since that's what happened to me. I replaced the mains and the fan powered up and the tubes glowed, but there was still no sound, but everything was dandy after I replaced the two under the midi board.

I keep getting different recommendations on which fuses to use, but the latest email I got from customer service said to use slo blo 400ma fuses for the power tube fuses, slo blo 1.6a fuses for the two under the board, and I'm guessing a fast acting 5a fuse for the mains since CS didn't say anything one way or the other about the mains fuse.

Good luck!
 
Tubes In a Hat said:
My guess is that it was the mains and the two under the midi board since that's what happened to me. I replaced the mains and the fan powered up and the tubes glowed, but there was still no sound, but everything was dandy after I replaced the two under the midi board.

I keep getting different recommendations on which fuses to use, but the latest email I got from customer service said to use slo blo 400ma fuses for the power tube fuses, slo blo 1.6a fuses for the two under the board, and I'm guessing a fast acting 5a fuse for the mains since CS didn't say anything one way or the other about the mains fuse.

Good luck!
Click to expand...

I can understand the 1.6 slo blo fuses for the two under the board. I think those are the heater fuses and if so they're really not even needed but the government agency that regulates this stuff says they are so you got to put them in. Heater fuses were the main cause of all the failures on the Marshall JVMs, and Marshall got a waver to hardwire them and no probs with that since. But you need the fuses. So slo-blo here.

Now for the tube fuses --- 400 mA slo-blo = NO. They should be 400 mA fast-blow, unless you don't care about your screen grid.
 
Well, looks like the board fried at the fuses on the main board that holds the power tubes. The board fried and it appears there are other resistors and contact points that took a hit from an arc. The fuses did not do their job as they were still good.

You can see pictures here:

http://www.dropbox.com/gallery/4658622/1/LynchBox?h=faaaf2

I just sent a message to the address that RD/Steve posted. We will see what my options are from here.

Mark
 
Quick Update: I received a response from the amp support email that RD/Steve posted 10-15 minutes after sending the message. I have a new board on the way.

I'll take it to my tech once I get it and go from there. Hopefully that is the only piece that is truly damaged. The other boards looked fine from the side we were looking at but the tech said its hard to say if something else happened until this piece gets fixed first.
 
Let me start by saying that Kevin Drury at Randall amp tech support has been great in working with me... But, I am very frustrated with this whole process.

It took over a week to get the board shipped to me. Kevin passed off the order and it sat in shipping for I don't know how long. Kevin finally had to overnight the board to me himself.

After taking the board to my tech he started working on replacing it and found that my impedance selector switch was blown apart. Working with Kevin again he has been unable to locate them and I have to wait until someone comes back into the office next week.

This process makes it very hard to rely on the amp in the future as a gigging amp. I just can't see putting it into a situation again where I need to rely on it over and over. I love this amp but if something happens to it there is no telling how long it will take to get it fixed and even if you can get all the parts in a timely manner. It would make a great studio amp.

This should no way be a reflection on Kevin. He has been responsive and taken matters into his own hands when others at Randall drop the ball. I can't say enough goods things about his support. I am just very frustrated with the ability to get replacement parts.
 
Jack Napalm said:
Let me start by saying that Kevin Drury at Randall amp tech support has been great in working with me... But, I am very frustrated with this whole process.

It took over a week to get the board shipped to me. Kevin passed off the order and it sat in shipping for I don't know how long. Kevin finally had to overnight the board to me himself.

After taking the board to my tech he started working on replacing it and found that my impedance selector switch was blown apart. Working with Kevin again he has been unable to locate them and I have to wait until someone comes back into the office next week.

This process makes it very hard to rely on the amp in the future as a gigging amp. I just can't see putting it into a situation again where I need to rely on it over and over. I love this amp but if something happens to it there is no telling how long it will take to get it fixed and even if you can get all the parts in a timely manner. It would make a great studio amp.

This should no way be a reflection on Kevin. He has been responsive and taken matters into his own hands when others at Randall drop the ball. I can't say enough goods things about his support. I am just very frustrated with the ability to get replacement parts.
Click to expand...

That's very discouraging. Is this something that could have been prevented with a voltage regulator? As someone else mentioned, the power in clubs is iffy at best.
 
Not the first time I've heard about issues with the impedance switch...they appear to be quite fragile in some amps....I say some amps because it's possible Randall switched parts at some point.

I think it's possible the impedance switch was breaking down and not set to what you think it was..therefore ultimately causing the problems you saw with your amp.
 
JKD said:
I think it's possible the impedance switch was breaking down and not set to what you think it was..therefore ultimately causing the problems you saw with your amp.
Click to expand...

That's what my tech said. I do switch it between 8 and 16 depending on the cab I have. Hard to say for certain but this is very likely the culprit.
 

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