Roadking (1) Gone bang!

Well not actually bang......

Hi Gang, I was at rehearsal tonight and all of a sudden the volume just dropped and sound quality went to 5h1t.
This was across all 4 channels and I use either the 6L6's or EL34's depending on the channel so as all channels were affected i'm guessing it's not just one of the valves affected (coz if a 6L6 had gone "bang" surely the channel only using EL34's would still work ok?).
Any idea what could've gone wrong? I don't intend to try and fix it myself, just want to make sure I don't get taken for a ride when I get it repaired.

Cheers!

stueyd said:

Well not actually bang......

Hi Gang, I was at rehearsal tonight and all of a sudden the volume just dropped and sound quality went to 5h1t.
This was across all 4 channels and I use either the 6L6's or EL34's depending on the channel so as all channels were affected i'm guessing it's not just one of the valves affected (coz if a 6L6 had gone "bang" surely the channel only using EL34's would still work ok?).
Any idea what could've gone wrong? I don't intend to try and fix it myself, just want to make sure I don't get taken for a ride when I get it repaired.

Cheers!

Click to expand...

This has happened before...
I don't know all of it, but in the ones I looked in, the DC filament supply for the preamp had failed.
There are several updates for this amp.
And according to mesa, some of the updates are free.
So it's best to take it to an authorized service center, and get all the updates installed.

Could be a preamp tube. Some of them (V1, loop buffer, phase inverter) would be in the signal path for every channel.

If it is the DC filament supply, then you won't see red glow in any of the tubes. You can tell visually if that is the problem. Look carefully, sometimes it is quite difficult to see.

If the filament supply died,there would be no sound at all.The easiest and safest check for you to do is get a known to be good preamp tube and one by one sub them till you find it.If that doesnt work you'll have to take it to a tech,if you dont like what he says/charges,shop around.

stokes said:

If the filament supply died,there would be no sound at all.The easiest and safest check for you to do is get a known to be good preamp tube and one by one sub them till you find it.If that doesnt work you'll have to take it to a tech,if you dont like what he says/charges,shop around.

Click to expand...

The DC is REDUCED, and the signal is weakened.
You constantly jump to conclusions, based on assumptions.
AND your assumptions are so far off base, nobody with your skill set could "ever" repair a guitar amp...
(perhaps by random luck and guessing)
That is the sign of a very inexperienced technician.

I answered questions.
You are just here to attack posters. I hope you enjoy yourself.

No,you dont know me at all.You said the dc filament DIED.In what country or what sort of broken english does that mean REDUCED.You need to get your drill out and remove the carbon from between your ears.I made no attack,I merely pointed out your stupidity.

stokes said:

No,you dont know me at all.You said the dc filament DIED.In what country or what sort of broken english does that mean REDUCED.You need to get your drill out and remove the carbon from between your ears.I made no attack,I merely pointed out your stupidity.

Click to expand...

Yes every forum on the internet has a goofball.
I just found the one in THIS forum.

What country are you from?

Easy tigers!
Let's keep it friendly.
FYI - When I looked at the valves they were "on" but I reckon only a fraction of the brightness they normally would be.
I'm agreeing the preamp area sounds like the culprit.
Unfortunately the amp is way out of warranty and the authorised service dealer is about as far away as you can possibly get from me (in the UK).
Luckily there's a highly recommended non-authorised Boogie repair man locally and I gave it to him today. I'll let you know what he comes back with...
At some point I guess it might be worth sending it away for all the updates? Any idea what updates are actually performed?

stueyd said:

Easy tigers!
Let's keep it friendly.
FYI - When I looked at the valves they were "on" but I reckon only a fraction of the brightness they normally would be.
I'm agreeing the preamp area sounds like the culprit.
Unfortunately the amp is way out of warranty and the authorised service dealer is about as far away as you can possibly get from me (in the UK).
Luckily there's a highly recommended non-authorised Boogie repair man locally and I gave it to him today. I'll let you know what he comes back with...
At some point I guess it might be worth sending it away for all the updates? Any idea what updates are actually performed?

Click to expand...

The DC filament supply crapeth. The filament voltage is reduced, and so is the amplification of audio.

I noticed that first.
I have no idea what all the updates are. What I do know is that Mesa told me that several of the updates were done for FREE.

They won't give you the schematic. They won't give you a list of the problems, or updates.
So, it is FAR better to send it to the authorized service center.
Otherwise, your local tech will be faced with reverse engineering a VERY complex amplifier. It's absolutely not worth it.
The Road King is by far, the most complex of tube guitar amplifiers. There IS no amp more complex to repair, anywhere.

Most techs will not want to work on it.
Most techs do not have the tools or experience to do it correctly.
Causing damage to the circuit board is a frequent possibility...
The average tech will spend many many hours attempting to understand it.
Most techs stay away from working on it.

When you buy a Mesa ROAD KING amp, you are committing to have Mesa authorized techs service it.
The information you need is kept a secret. And this secret is deliberate.
It's like owning a Ferrari.

If you want an amp that is easily serviceable, by the local tech shop,
Then buy a Marshall or a Fender.
If you want "easy" --- you picked the wrong amp.

You can possibly save your self the expense and aggravation of sending it out for repair by trying the preamp tube substitution method I mentioned.90% of problems with mesa amps can be fixed this way.It probably tells you this in your user manual.The only way to know if there is a problem like the filament supply is to open it up,unfortunately my volt meter doesnt work via text,as someone elses does.If you know how to use a meter you can easily check that by putting a meters leads in pin 9 and 4 or 5 of any preamp tube socket.Otherwise get a good preamp tube and sub V1 first,and move down the line and see if that helps.It is more common in high gain amps for preamp tubes to crap out,they put more stress on the tubes than normal gain,Fender type amps and the preamp tubes made today are less reliable than the old ones.Try it,it is the first step in isolating the stage the problem is in,very simple and as even mesa will tell you the most common problem with their amps.

It's ALIVE!

In case anyone was curious...
The amp guy traced the problem to a relay.
Apparently there's loads of 'em in a Roadking and one had failed. He replaced this and all was good.
However he checked everything else out and found a preamp tube was on the way out and that got replaced too.
Not too expensive a repair and nice to have a "health check" on the amp.

Time to rock!

Good to hear you got it fixed.The relay affects the channel switching,nothing to do with the original symptom you posted.That was the preamp tube causing the volume drop and sound quality issue.

stueyd said:

It's ALIVE!

In case anyone was curious...
The amp guy traced the problem to a relay.
Apparently there's loads of 'em in a Roadking and one had failed. He replaced this and all was good.
However he checked everything else out and found a preamp tube was on the way out and that got replaced too.
Not too expensive a repair and nice to have a "health check" on the amp.

Time to rock!

Click to expand...

So I guess it was NOT the DC filament supply then.

I think someone owes stokes an apology :wink: :wink:

Dom

Ha!Thanks Dom,wouldnt hold my breath on that,tho.

stokes said:

Ha!Thanks Dom,wouldnt hold my breath on that,tho.

Click to expand...

"I don't know all of it, but in the ones I looked in, the DC filament supply for the preamp had failed."

That's what I said. The ones I looked in, the DC had failed.
I do not owe anybody an apology. Least of all, you.

soundguruman said:

stokes said:

Ha!Thanks Dom,wouldnt hold my breath on that,tho.

Click to expand...

"I don't know all of it, but in the ones I looked in, the DC filament supply for the preamp had failed."

That's what I said. The ones I looked in, the DC had failed.
I do not owe anybody an apology. Least of all, you.

Click to expand...

Every board has a jerk, i think i just found him.

soundguruman said:

"I don't know all of it, but in the ones I looked in, the DC filament supply for the preamp had failed."

Click to expand...

Dom

soundguruman said:

stokes said:

If the filament supply died,there would be no sound at all.The easiest and safest check for you to do is get a known to be good preamp tube and one by one sub them till you find it.If that doesnt work you'll have to take it to a tech,if you dont like what he says/charges,shop around.

Click to expand...

The DC is REDUCED, and the signal is weakened.
You constantly jump to conclusions, based on assumptions.
AND your assumptions are so far off base, nobody with your skill set could "ever" repair a guitar amp...
(perhaps by random luck and guessing)
That is the sign of a very inexperienced technician.

I answered questions.
You are just here to attack posters. I hope you enjoy yourself.

Click to expand...

It would seem you are the one to "jump to conclusions".You immediately jumped to the conclusion that the filament supply failed,if it failed,the tubes would not operate the signal would not pass.You then backpedal and say you meant "reduced",I dont buy it.I explained a simple procedure that would have led the poster to fix the problem described without taking it to a tech.Your solution was a case of guessing,but not lucky.Nothing in the original post would point to a "failed" filament supply.And dont go telling me you meant "reduced".Failed and reduced are two different things.People come here to hopefully fix their amps,many have little experience.Your answer was to take it to a tech because its some major failure.In the other thread I had it out with you,you did the same thing,when again the first step would have required a tube sub to trouble shoot,which any novice can do.But you tell the guy to remove his circuit board and take a drill to it to remove some imagined carbon.