MC240 HELP PLEASE


Ive had a mc 240 for years, its never been a problem child, loud but never a problem.

I recently brought a 2nd one to drive my mids and tweeters.

I was useing the amp the other night,and it made some clicking/on/off type noise's near the 117/125 volt switch and then near or in the the tranformers,then it just went silent.No sparks, no smoke, no shock,just silence.And thats the way it stayed ever since just bloody silent.(now this one has become a problem child.Was useing cd player into c28 into mc240 in evo 40 speakers at the time

Ive checked the cd player the preamp the speakers with a second amp they are all fine.Tubes still light up, fuse seems to ok.

The amp had just been serviced before I brought it had new caps and more,the guy I brought it of on audiogon is 100% reliable and if he says it was serviced and caps replaced then it was .

Anyone got any ideas on what the problem might be.Bye Paulie.
Thank you to all that reply .
souterncross
Ive found a fuse inside the amp, I will try to discribe it. On one end it has a spring type set up, off that spring there is very very thin copper fusewire it is now absent without leave,and I dont expect its going to return to active duty.

This looks like it may well have been an original fuse, the serial numuber is ,


313 3AG 3-2/10A 125V (this fuse is on the inside of the amp accessed by removeing the bottom plate.

Is there a substitute,I can use because I dont like my chances of finding this exact type here.

Could it really be that simple ? I hope so.

Thanks everyone Bye Paulie.
That's right - now that you mention it, there is a fuse in there. I think it is for the bias stage in case a tube goes bad.

If a fuse blows, it is because there is a problem. You will have to find the problem before you're back to normal. It sounds like you have a tube that has gone bad. But which one? That is a tough one without a tube tester... Look at each tube very carefully and see if you see anything strange. I have seen some develop black spots and/or sometimes you will see a whitish film where the vacuum was lost (near the base typically).

Arthur
Yup spot on there Athur, one tube in the very centre of the top plate glows a lot hotter than the rest Im useing nos tungsol kt66 .Im waiting on a replacement for it as I write.
Ive only been useing the kt66 for a couple of weeks now,before those I was useing svetlana c wing 6l6gc.

The kt66 sound good but they sound a bit lazy,compaired to c wing 6l6 the draw back seems to be that.
I have to drive the c wing harder for example. If Ive got the c wing 6l6 in and I ve got the volume a say 5 oclock. I would only need the volume a 3.00 with kt66 .The kt66 seem to have great mids and highs, but to me the bottom end is a bit lazy(I call them my wife).
While the c wing 6l6 seem to be a better allrounder great bottom end good mids and highs. (I call these my girlfriend).

My plan was to get my other mc240 back (from my brother no easy task) have the kt66 in one mc240, to run the mids/highs. And the other to with the c wing 6l6 in the other mc240 to run the drivers.
That way I can have the best of both worlds my wife and girl friend under the one roof all living in prefect harmony.
Tryed new fuses internal and external,it worked for about 20 minutes,until I pushed the gain up to far, the same thing happened again,clicking the silence.

My next idea is to get a new of tubes.

The problem may also be that, Im useing a 240 volt power stepdown to 117/125 volt,and that may just be high lighting a fault in amp.

Im going to have the amp fully checked out,and the power supply changed over to 240 volt power supply,while I'm at it have the amp rebuilt and a new chassis fitted at the same time .

This project will not happen to the new year, and on that note,I would like to thank ever one who responded and wish them a Merry Christmas and a happy new year.

Will let you know how it goes in the new year, after the rebuild.Bye Paulie