Hammond M-162 Vibrato Cancel / Reverb I & II / Drawbars / Pedal

[RobVasquez79]

Newbie Hammond Owner Here With A Few Issues...

1. I just purchased this organ and without the Vibrato Cancel in the down (on) position the sound is grossly diminished and near non-exsistent. This is true for both manuals.

2. I cannot tell a discernible difference when the Reverb I and/or II is in the down (on) position.

3. There are a couple of drawbars that do not seem to function.

4. The right "C" pedal does not work.

5. Until I can get the M-162 serviced is there anything that I should do besides oil the generators? This organ was donated to a charity and I do not have any idea if or when, it has ever been serviced.

If anyone can help me with these issues, I would appreciate it!

[sfp1954]

Check the drawbars from the rear. After years of flexing the drawbar wires can fatigue and break off.
If all the wires are intact the drawbars may need to be taken apart and cleaned.

There are two preamp channels "A" and "B" on the AO-29 schematic. A is the normal channel (for both manuals), B is the vibrato channel.
Each has its own tube and associated circuitry. It could just be the associated tube (6AU6s) but more likely is a bad resistor somewhere.
I have an M3 with the same issue that I haven't started working on yet.
http://www.archive.org/download/Hamm...m2m3SvcMan.pdf

There are three levels of reverb I, II and I+II. The reverb has its own amp and speaker. If you're not hearing reverb try cleaning the RCA jacks going in and out of the reverb tank and amp. They are tinned and corrode easily.
Sometimes these parts get stripped out and sold so make sure the amp and 8" speaker are still there.

[RobVasquez79]

Thank you for the information. I appreciate the service manual... it is taking forever to download.

So I just went and checked and it appears that the RCA jacks are pretty clean. Is there a problem with changing to a new RCA cord?

Upon closer investigation I found two tubes laying on the floor of the organ at the Reverb Amp. There are three tube sockets on the Reverb Amp (two on one side, one on the other). I would assume that all three sockets are suppose to house a tube, and there obviously is one tube missing. I have pics available if that would help.

Another observation regarding tubes (please forgive me as I do not know the correct terminology) is that the main amp is missing a tube from the far left socket (closest to power cord).

[Bob-i]

Pics would help. It sounds like some tubes have fallen out from moving the organ around. Getting them back in the correct locations may fix the problems you're having.

[sfp1954]

See page 56 (as Adobe counts the pages) of the manual for the reverb amp layout.
The two tubes next to each other on the reverb amp should be the same model. V1 and V2 either ECL 86s or 6GW8s.
The third one near the transformer (V3) is the rectifier tube EZ81(converts AC to DC for the tubes to run on). The V stands for Valve/Vacuum Tube
The tube you mention as missing on the main amp near the power cord and main transformer is also a rectifier tube. V11 = a 5U4
I don't think the amp can run without it unless someone converted the amp to use solid state rectifier diodes (soldered inside the case) instead of a tube rectifier.

So it sounds like maybe both your amps are missing their rectifier tubes or have had them converted to solid state.
Something you definitely need to figure out before plugging anything into those sockets.

[RobVasquez79]

I can't thank everyone enough for assisting me in this endeavor. I just uploaded a video to my youtube account showing the internal amps and the console http://youtu.be/13XbruppArk. In the video I forgot to have one of the four vibrato's depressed in the demonstration, but it doesn't have any effect. Please check out the video and let me know your thoughts.

[RobVasquez79]

The two tubes I recovered from the floor of the organ at the reverb amp are both the same size and are 9 pin tubes. One says 6GW8 and the other says Hammond 31265-52 (the rest is unreadable).

[Guest]

The two tubes I recovered from the floor of the organ at the reverb amp are both the same size and are 9 pin tubes. One says 6GW8 and the other says Hammond 31265-52 (the rest is unreadable).

The 6GW8 (or ECL86, the European designation) is one of the two output tubes for your reverb amp. Assuming the other is a 6GW8 (which is not a given), you're still missing the 6CA4 (aka EZ81) tube, which appears to be the rectifier tube that the reverb amp uses. The rectifier is what turns the AC (i.e., the kind of current that comes out of the wall socket) into DC, or direct current, that the amp circuitry uses. Unless you have the correct (and functioning) tubes in place, you won't get any reverb.

As your video also shows, the rectifier tube on the other (i.e., main) amp is missing, too, which is really odd. Because, again, the rectifier is what converts the AC to DC so that the organ can function. Since the organ is actually emitting sound, it's possible that someone converted it to "solid state" by soldering in a rectifier diode (a component that you can buy from almost any electronics supplier or Radio Shack for less than a dollar) in the power-supply circuit to replace that rectifier tube.

But that modification won't be apparent until you actually unfasten the screws that secure the amplifier onto the cabinet and examine the underside of it. That's where the electrical components are soldered. Obviously, you should never do this unless the unit is unplugged! So go ahead and unplug it, undo the screws on the larger amp chassis, flip the chassis over, and take a nice, clear picture of the area where the missing tube is. Post the picture and we can direct you from there.

Personally, I don't know how sound the solid-state modification is, and if I were you, I'd much rather have the tube itself, since that's how the circuit was designed to operate. And I'm a little troubled by that popping sound you noted in your video. It could be the result of the hack job someone may have done on the power supply. To me, that sounds like a resistor that's getting overheated. So, I would recommend that you not run the organ until you get this sorted out.

Cheers,

Aaron

[Guest]

I just purchased this organ and without the Vibrato Cancel in the down (on) position the sound is grossly diminished and near non-exsistent. This is true for both manuals.

I've got the same problem on my newly purchased M-101. I started a thread on it in the electronics forum, and someone gave me a good tip on how to fix it. Chances are, you're going to need to do some under-the-chassis work on this one. How are your soldering skills? :)

[mange656]

Rob, I am located in Crestview. I see you plucked the M-162 that was in the Pcola craigs list. Nice pick. The reverb amp looks like an AO-44. There are two variations of that reverb amp (minor component changes). The rectifier tube for it is easy to get. The power tube 6GW8 is a combination pre amp tube + power amp tube (like a 12ax7 or 12au7 and an el84 in the same tube). Those are not produced anymore. Not looking at the schematic right now but you also have a at least one transistor in there that can fail causing no or low output if it goes bad.

The power cord has electrical tape on it. That could be a warning sign that it needs to be replaced. Is it cracked and brittle? If it is, make sure to unplug the organ any time it is left unattended. Don't want to burn down the house or get someone zapped.

Send me a private message if you are looking for parts or tubes etc... I may be able to help you out there. I have a functioning Leslie 110 not the prettiest thing in the world that would get you a real Leslie. I also have a Leslie 26-1 kit on ebay. If you don't want to add a leslie, then there are some options to get the organ into a simulator by building a line out box and correctly adding it into the organ.

Since it looks like the rectifier tube is missing and the organ runs, your AO-29 amp has been modified. Please be careful if you go underneath that amp. Stock tube electronics are dangerous enough but modified electronics add to that problem. I am guessing there is no documentation of the mods (simple as they are) to let the next technician know what was done. And you never know how good or bad the last tech was.

Thanks

Andy

[sfp1954]

The two tubes I recovered from the floor of the organ at the reverb amp are both the same size and are 9 pin tubes. One says 6GW8 and the other says Hammond 31265-52 (the rest is unreadable).

That number is the hammond date code. 3/12/1965 I believe.
It probably is the other 6GW8. Does the layout inside the tube look the same?

The center cover on the main amp is for the shielded lines with the signals from the manuals and other places. There is one labeled underneath as A (the non-vibrato mix) and B (vibrato mix).
Under the cover on the left is where the AC is distributed to the power switches and the motors.
The main AC cord should be replaced ASAP and it's a good idea to add a fuse.

I see a lot of rust near the empty rectifier tube socket on the main amp. I wonder if the socket became unusable and that's why someone modified the amp.

[Guest]

Since it looks like the rectifier tube is missing and the organ runs, your AO-29 amp has been modified. Please be careful if you go underneath that amp. Stock tube electronics are dangerous enough but modified electronics add to that problem. I am guessing there is no documentation of the mods (simple as they are) to let the next technician know what was done. And you never know how good or bad the last tech was.

Rob,

Andy raises a good point. If you've never done any electronics work before, or you don't feel comfortable doing it, it might be best to leave this job to a qualified repair person. If it were just a matter of replacing a couple of capacitors or something, that might be different. But in order to tackle this job, you'll need to be able to read a schematic and do some soldering. Besides, you've also got the vibrato problem to deal with. It might be best to just take it to someone for service.

By the way, I enjoyed your other videos. Nice playing!

Aaron

[mange656]

Rob,

Andy raises a good point. If you've never done any electronics work before, or you don't feel comfortable doing it, it might be best to leave this job to a qualified repair person. If it were just a matter of replacing a couple of capacitors or something, that might be different. But in order to tackle this job, you'll need to be able to read a schematic and do some soldering. Besides, you've also got the vibrato problem to deal with. It might be best to just take it to someone for service.

By the way, I enjoyed your other videos. Nice playing!

Aaron

Ditto on the videos!!

The vibrato problem could be one of your 6au6 tubes. You can swap those two tubes and see if the problem follows the tube. IE if the vibrato position worked but non vibrato did not and after the tube swap the vibrato didn't work but the non vibrato did you have a very weak or dead tube. Easy fix buy a new tube. If the problem did not move then more testing is in order. Does the tube for the non working portion have a filament / heater glow.

I am an electronic technician. That is why I provided the advice on modified electronics. If you have ever worked on a used car to fix a problem and discovered a Disney Engineering repair (jury rig, Mickey Mouse etc...) that you had to completely redo then you know what I am talking about. Most folks know enough about mechanical stuff to suspect some is not above board. I am local, I did the foldback mod on my M3 upper manual and the bass mod as well. I have spare parts etc...

Keep the beast running and give a shout if you want a second opinion on something. My M3 and M103 both had frozen TWGs. Notes that wouldn't play and in the case of the M103 I had to rebuild the bass pedal wiring harness because wires had been broken where they passed thru the lower shelf where the amps are located. I could have spliced it but only four wires were complete. Fun stuff. If you don't know how to solder there are sites that will show you how. Remember practice on something other than your Hammond first. I have been soldering for over 30 years and I will still practice before I commit to my Hammonds to reduce the chance for an error.

Andy

[Guest]

Keep the beast running and give a shout if you want a second opinion on something.

Andy,

I think he should have the amp checked out before he continues to run it. I have very little faith in the "solid state" mod that was done on the amp. An improperly functioning power-supply section can wreak havoc on the rest of the circuitry. Just my $.02.

Having said that, I wish Rob were local; undoing the previous tech's mess and getting it back up to snuff could be fun. Plus, he could give me some pointers on my playing. :)

Aaron

[mange656]

Andy,

I think he should have the amp checked out before he continues to run it. I have very little faith in the "solid state" mod that was done on the amp. An improperly functioning power-supply section can wreak havoc on the rest of the circuitry. Just my $.02.

Having said that, I wish Rob were local; undoing the previous tech's mess and getting it back up to snuff could be fun. Plus, he could give me some pointers on my playing. :)

Aaron

Aaron, I agree completely on having the amp checked out before he continues to run it. As a tech I have seen some real butcher jobs. The organ was listed in the Pensacola Florida Craigslist and there are US Navy trained technicians there on active duty as well as retired because of Naval Air Station Pensacola. The job could have been done at the highest level or butchered. If the tech just wired in the diodes using the 5u4 socket then it could easily be reversed. BUT... the socket should have been covered and some form of warning on or adjacent to the socket identifying the modification for future technicians / owners of the organ. The problem here is not knowing who did the mod and how good they were.

I like you like Hammond organs. Restore them and play them.... nothing like them will be built again. My M3 is a 1959 it's older than I am. It will be around after I am gone. Thats quality.

I will have to go back and watch the video to see if I can see anything else going on. The power cord is another area where the old Hammond organs have issues. Replace it with a new one for safety reasons. What lurks below that electrical tape. cracked casing or exposed copper?