"Hayelp!" 2266C problem - no sound, although still power

[Angus]

Hi guys,
After a break from my amp of a couple of weeks (we had some guests and my room had to be rearranged) I plugged into my 2266C last night. After waiting the usual three or four minutes I pushed down the standby switch and started playing quietly. After about 20 seconds though the sound suddenly vanished.

I could see the amp was still getting power as the low/high dynamic light was still illuminated, although the power light was now off.

If I turned up the master volume I could hear the slight increase in hum that indicated things were still happening - despite the lack of guitar sound.

I turned it off and had a look at the fuse on the back of the amp next to the power lead socket. I could see the fuse wire in there, and it didn't look broken, although possibly it ran across at a slight angle.

Any ideas what the problem maybe? If its sounds like a fuse, I'd appreciate the spec, as there is an electronics guy close by who may have a suitable one tucked away.

Thanks for any advice.

[Tom99SS]

This just happened with my brand new 1987x (less than 2 months old). Turned out the HT Fuse blew. Replaced the fuse with the same type (T500mA) and again same result. Replaced the fuse and the Power valves/tubes and all is well again (after a BIAS adjustment for the new valves/tubes). I knew it was the Power tubes as I tried to power on the amp with the Power tubes removed and the HT Fuse did not blow. Put the old ones back in a BANG HT Fuse blew so I replacd the Power tubes which solved the issue.

[sikter]

I guess your V1 tube has jumped out and
you need to push it back to position.
Push dem all firmly!
You can always plug your guitar to loop return and find out
if problem really refers to the preamp.

[Angus]

I guess your V1 tube has jumped out and
you need to push it back to position.
Push dem all firmly!
You can always plug your guitar to loop return and find out
if problem really refers to the preamp.

Hi, and thanks for the replies, guys.

I've never messed with the loop thing... I just plugged into the return input on the back of the amp, and got a very clean, but pefectly audible guitar tone. That part of the amp is working.

Does this imply that your V1 tube theory is probably right?

Thanks again.

[surfnorthwest]

I means there is a issue with one of your preamp tubes, easy enough to pull one and replace it.

[Angus]

I means there is a issue with one of your preamp tubes, easy enough to pull one and replace it.

Thanks Surf - Warning, imminent daft question.... Did I understand you could (carefully) remove and fit pre-amp valves with the amp powered up? My tiny brain tells me not, but I thought I heard somebody say you could.

[sikter]

Turn it off first!
Replace V1 and push all others firmly.
Turn it on and try. If still the same, repeat the proces
by replacing V2... and so on

[Angus]

Turn it off first!
Replace V1 and push all others firmly.

I think I have a problem.

I replaced V1 late on Saturday night, and then tried a couple of quiet strums. Success!

Then on Sunday, I switched it on for a proper play. All was fine - for about 10 seconds (about the same time as before) then nothing. :(

Same as before, there is power going to the amp, but no sound.

So I suspect there's a problem that is causing my amp to blow the V1 valve - but I'm only guessing.

Any suggestions, guys?


p.s.
I just thought - all this has happened after rearranging the room. As far as I know, the amp still has its original power lead, but if it had been accidentally swapped with a computer power lead, could that cause this problem?
Does the Marshall lead (UK) have any distinctive features? Thanks.

[sikter]

I doubt computer power lead would cause any problem.

[Angus]

Okay, so it looks like I'm going to be trying to find a tech, and giving him the following fault description:

"It seems to blow my V1 ECC83 after about 15 seconds of playing."


Any thoughts on what sort of work/cost I might expect? Might it be something straightforward? Forewarned is forearmed. :)

[Angus]

Okay, so it looks like I'm going to be trying to find a tech, and giving him the following fault description:

"It seems to blow my V1 ECC83 after about 15 seconds of playing."


Any thoughts on what sort of work/cost I might expect? Might it be something straightforward? Forewarned is forearmed. :)

.....so it could be pretty much anything?