Hammond B3 pedals don't work, slight volume decrease in high register

[HostileAnimals]

Hello! I'm new to this page and new to owning a Hammond. I just bought a M3 and I've found a few issues with it, and I'd love to get help troubleshooting. I'm really grateful for this page as a resource, it gives me a lot of confidence to repair and maintain an otherwise intimidating instrument.

Problem I can see

• The 6BA6 tube does not light up, and neither does the 12AX7 (I'm 90% sure, but it's hard to tell with the canister around it)

Problems I can hear

• Pedals don't work (maybe due to 6BA6?)
• On all of the drawbars for both manuals, volume starts to dip at A(7); the organ needs to be full volume to hear the F#(8). 15db difference according to an app on my phone, which is not surgical but would give a frame of reference.
• One of the drawbars in the lower manual can be a little scratchy, but I'm guessing that's just a deoxit fix.

Diagnoses I've come across

• Bad capacitors. This would be a big yikes, besides rewiring my p bass from a simple schematic I have no experience or knowledge of electrical wiring, and am not really in a position to hire someone to work on it.
• Bad speaker / can't handle higher frequencies. This would be good news, my goal with this organ is to set it up with a 1/4" out and leave it in my studio, a built-in speaker is nice but not necessary.
• Maybe just replacing the tubes? This would be ideal but doesn't seem likely.

I'd love to get some opinions on what's wrong with my organ and any suggestions on next steps. Any general repair / maintenance ideas from your own experience would also be welcome.

Thanks!

[David Anderson]

Welcome to the forum.

I want to phrase this as gently and politely as possible because I have inadvertently offended people by being too blunt, but there are some statements in your post that, taken together, might discourage people from trying to help you, especially given the overall context.

By overall context, I mean that the last M3 was produced in 1964, sixty years ago. That would be the youngest M3. The oldest would be 69 years old. At this point, pretty much any electronic device that old needs to be refurbished. By 'refurbished,' I mean having someone who knows how these things work going over it from a global point of view, replacing parts known to wear out and checking other critical parts to make sure they are within specifications. A lot of people seem to have an underlying assumption that electronic parts last forever, but that's not the case. Electrolytic capacitors have a known lifespan, and past 40 years, you are on borrowed time. I sometimes describe this process as "resetting the clock." Once you've reset the clock on these things, Hammond Organs are very reliable.

Given that situation, your combined statements that your aren't comfortable doing electronic repairs and that you aren't in a position to hire someone with experience to do the work do not leave anyone considering advising you with many options. I, personally, am no longer willing to tutor people in basic electronics on this forum. There are many resources online that cover such topics, so there's no need to duplicate the effort that went into creating those resources.

If you have the inclination and aptitude, you can certainly teach yourself vacuum tube electronics and repair and maintenance procedures, but you'll have to decide if that's a learning curve you want to climb.

I can tell you that based on its position in the signal path, if your 12AX7 was dead, no signal would be getting through the amp at all. It can sometimes be hard to see tube heaters.

If the 6BA6 tube is bad, you might get lucky and restore pedals by replacing it. But there will still be other components past their practical working life. There is often a "shakedown" period when an old device is put back into regular use. For example, many years ago, I revived a long-unused mid-1960s Fender Super Reverb and made the mistake of not replacing the power supply capacitors since the amp had not had much apparent use and they tested good. (Amp still had all its original tubes, and tubes tested good.) Within a few months of being back in regular use, the power supply capacitors failed. I now know better than to make that mistake.

A speaker not reproducing higher frequencies due to some defect is an unlikely scenario.

There are a few Hammond Organ problems that have known fixes, but a lack of high end could be from so many things that anything I say would be a wild guess.

I hope this reply helps to put things in perspective. For some people owning a real Hammond Organ can be a great thing. But they are old, and we have to be honest about that and what it means, just like I have a 1947 Steinway that's showing its age.

[tmccann]

Everything David says above is spot on. There is a steep learning curve, but you can climb it if you are motivated to learn. I started a few years ago knowing nothing about tube amps, Leslies, Hammonds, etc., and I can do quite a bit with them now. I have an engineering degree (from a loooong time ago) which helps some, but anyone can learn. I do not have the decades of repair experience that some of the folks have on here, but I can still do a lot. And frequently I get help here on the forum with the trickier things. For the basics, you should search and read a lot of things on the forum and elsewhere.

An M3 is a great place to start, and there is almost nothing on them that can't be repaired with some knowledge, cleaning, and basic electronics. Here are a couple things to share to help get you started:

1) Learn and understand that there are dangerous voltages in these organs. High voltage AC and DC is everywhere, and thanks to large capacitors can still be live after the organ is unplugged. Get this clear in your head and understand how to avoid harming or killing yourself.
2) Uncle Doug has a great set of videos on how tube amps work on Youtube. From the basics to more advance details. There are many good sources on Youtube and other places.
3) You will need decent soldering equipment, a good digital multi-meter at a minimum and other tools. And you will need practice on how to use them properly.
4) A Hammond M3 is a complicated beast and a lot can go wrong. But I have found that a lot can be cured by properly doing a refresh on the AO-29 amp. Tonewheel General Hospital sells an AO-29 refresh kit with very detailed instructions with photos that is well worth the money if you are just starting out. I would add a new power cord, a fuse on the primary and a TWG refresh kit for any M3 I touch. That seems to cure 90% of ills, along with a good cleaning of connectors, sockets, tube pins, etc.

This can be a fun hobby and a great learning experience. It takes a while before it starts to click. And the people I have met here on the forum and elsewhere are great (for the most part!) and willing to share as long as people are willing to make some effort on their own.

[goffprof]

The early M-3’s manufactured prior to permanent magnet speakers are very inexpensive, often free, and are still my favorite conversion. I remove the old AO-29 amp, speaker, pedals, install an AO-28 preamp, rebuild the tonewheel generator, vibrato line box, add a lot of mods and a Leslie 122 to become a baby B-3. Even in retirement, there are always a few Hammond/Leslie projects.

Al Goff