M3 sound went south instantly.

[Aardman]

Hello,</p>

I found a sweet deal on an M3 a couple of months ago, and after using WD-40 to clean the squealing tone wheels and completely re-oiling it, it's been working like a charm since then - really enjoy it, until today.</p>

Up to this point VERY occasionally, like maybe once in four or five times it was fired up, it would occasionally emit a little crackling when pushed - sort of like the sound lightening would make on an AM radio. This was slight and would only happen once or twice, so I didn't particularly worry about it.</p>

Well, today is something else entirely. Now when you start it up, first you hear a loud 60 cycle hum and LOTS of crackling - after about 20 seconds a 2nd hum kicks in, and the two together make the organ sound very much like a car with a slightly bad muffler idling. During all of this it's crackling like mad and none of the switches or the volume pedal setting has any effect on the noise in the least. In fact, it still plays through all this din, but it's pretty much unlistenable. VERY occasionally the hum and crackling will let up, for, say, about three seconds, and the organ will sound like normal - then it starts in again.</p>

Very nasty sounding and very depressing. I've been in the habit of playing this instrument daily as it sounds, or sounded anyway, so good.</p>

I HOPE this is something minor that I'll be able to address.</p>

Any help appreciated!</p>

[jimmywilliams]

Aardman,</P>


I'll let the Hammond guys chime in with the specific details to help you as they know more about these organs...</P>


But, I would strongly recommend that you stop using the organ and not use it until the problem is fixed. You may have bad filter capacitors or rectifier, and other problems that could have cascaded down from that. Continuing to use the organ like this is dangerous. A very loud hum usually means serious trouble and further damage to the equipment, and possibly overheating/fire, can result - head it off at the pass by NOT using the organ until it is repaired. I may be wrong about the specifics of your problem, so I'll let the others take over from here.</P>


- jim</P>
<P mce_keep="true"></P>

[Aardman]

Actually, I might have figured out some of the problem.</p>

</p>

While it was on and making it's noise I started tapping the tops of the tubes on the back and I noticed that I was getting a audible response from one of them. I shut the organ down and pulled the one tube - in the poor light I THOUGHT it said it was a 12AX7, a tube I happen to have a few extras floating around here, so I got one, put it in, and the organ became playable again - well ALMOST.</p>

It has a very faint grumbly noise that can be heard when the volume pedal is all the way down.</p>

Actually, once I had better light and after I'd already put the 12AX7 in and started it up, I noticed that the tube I pulled was actually a 12AU7A - oops. I don't know enough about tubes to know what the difference is between them, but I wouldn't think I should run it with a substitute tube.</p>

I've shut the organ down and am wondering if I should just replace all the tubes.</p>