My friend Lawrence’s son Jacob has just been given a Baldwin Electronic Organ, model 45HP2. It’s big and old and made with vacuum tubes and point-to-point wiring (no printed circuit boards), and it has a problem: The speaker for the pedals (that you press with your feet) continually puts out static that sounds like a low-pitched crackle. It’s definitely not 60Hz hum, nor does it sound like turntable rumble — it’s very irregular in both pitch and amplitude.
Particularly vexing is that the organ was reported to work perfectly before it was moved 60+ miles in a U-Haul-type trailer. So whatever is wrong with it probably has a mechanical origin — a damaged tube, a part or connector that needs to be reseated, or a joint that needs to be resoldered.
The amplifier chassis has separate volume controls for the manual (keyboard) and pedal (footboard), and turning the pedal volume all the way down eliminates the noise. So it definitely seems to be coming from the pedal section — either a tone generator or the amplifier.
The problem would be easy to repair if it were a simple matter of replacing a bad vacuum tube, so we’ve started investigating in that direction. I had Jake swap the two 12AX7 tubes on the amplifier to see whether the problem followed the tube to the manual speaker, but no change. I should probably have him swap the 616s and 7027s as well.
The tone generators run across the upper part of the back of the organ, with a column for each note of the scale, two columns per “board.” I believe the connector at the top brings in the “requests” for that tone in each octave — probably in analog form, as a sum of all the different sources needing that pitch (for a fundamental or harmonic frequency).
The boards are presumably the oscillators, and there’s a bus (I assume the tone output bus) made of 1/8″ rods at the bottom of the inside of the cage. My guess is that the pedal tones go onto a different rod in the bus than the manual tones; but without a schematic, with the high voltages I expect are present in a tube system, and with not much time spent so far, I haven’t tried to determine which one. It’d be fruitful to disconnect the pedal tone generator output from the amplifier, to isolate the problem to the oscillator or amplifier section, if we knew which it was.
All of the oscillator tubes are identical (6SN7 GTB), and I did have Jake rotate them within all the oscillators (top two down one, bottom to top), thinking that if an oscillator tube were the problem, the nature of the noise might change if the tube were in a different position. No change so far.
If there’s anyone out there with experience with this type of thing, I’d be very grateful for any advice you want to throw my way.
The thing with old tube equipment is to check the capacitors first. I know a number of individuals who just replace all the electrolytic capacitors in this sort of equipment before even turning it on. Look very closely at the caps, and consider simply replacing all of them.
Paul, I’ve heard of that too, and it makes sense. But with the sheer number of capacitors and the point-to-point wiring, that’s going to be quite a chore. You’re not telling me what I want to hear.
I’d be more willing to do that with just the amplifier or just the tone generator, if I could isolate the problem. Any thoughts on that?
Obviously a job for signal tracing — find out where the noise is originating. Look for power supply fluctuations first, then trace the signal stage by stage, or isolate stages from each other. And don’t leave anything out. I’ve had crackling noises like this (in a radio) from a failing audio output transformer.
Mechanical… Yep, that sounds right. Tubes, capacitors, or even the transformer like Michael pointed out above. I have worked on a fair amount of this type (not this organ) of gear in the distant past. Start with logical tube substitutions across the entire organ (yes, that includes power tubes and rectifiers if is has them) and hope you get lucky. Then , signal trace and find a source for the capacitors you’re likely going to need
The problem may be related to an intermittent mechanical contact (bad solder joint, bad tube pin contact, etc.). One technique from ancient times involved tapping appropriate places in the circuit to see if a mechanical shock would induce a change in the intermittent problem (Of course, use an insulated “tapper” so that, while inducing mechanical shocks, you don’t induce an accidental electrical shock to yourself!).
Electrolytic capacitors of that era were notorious for drying out over a period of a few decades, resulting in decreased capacitances, and this could occasionally induce feedback (e.g., motorboating). However, your description of the fault doesn’t seem to indicate that is the problem.
Carbon composition resistors of that era were also prone to occasionally going intermittent. Sometimes, hitting them with a bit of “component cooler” would change their characteristics. In addition, Carbon composition resistors from that era were also notorious for drifting in value, usually upwards. However, most circuits from that era were designed so that a 20 percent change in component values wouldn’t cause problems. Usually.
As for contacts, you may want to invest in a bit of Caig’s DeOxit.
It’s possible that you may have a tube with the electrodes shorting, but that usually doesn’t result in an intermittent, but rather a solid (and quite dramatic) failure. It’s also possible that you may have a tube which has gone gassy, and you’re hearing the ionic conduction, but there’s nothing about moving a device that should cause that.
I’ll toss a pointer out to a group of guys who know about things like this, and see if any of them can offer any ideas.
Dave
The biggest problem with Baldwins of this era is dirty connectors and contacts. the pedaboard contact are especially prone to noise, less so the keys. I would reccoment a through cleaning of all key contact with a contact flush, followed by very light application of deoxit. The swell pot also can be noisy, remove the pot cover and apply the same technique. Clean all of the tone generator interconnect pugs, and check the 6SN7s with a good mutual conductance tube tester, reject any tubes with very low gM rating, as these will not function in the dividers. This is probably a 10-12 hour job, but the results will amaze!
Scott
Good advice so far. Since the problem may have been triggered by the move, check the microswitches. Each of the pedals has a microswitch that turns on its tone generator. One may have a dirty connection. Press each one in trun to see if that changes the noise.
Same trick with the tubes. Pull out one tone generator tube each in turn to see if its circuit is the cause. If the noise stops or changes, that circuit is suspect.
My electric organ is a Lowrey LSB bought about 30 plus years ago from an organ store that took it as trade in dead condition. Price was right. Fixed the open power resistors to get it back to life but had to clean all the key board switches for good sound. Pulled a few dropped pennies out, etc. Has a forest of 6X8 tubes for neon relaxation oscillators as well as audio and power tubes. Fun stuff to fix and play with.
Best Wishes
The first thing I’d check is the speaker. Since it became noisy after it was moved, there’s a very good chance that something has come loose and become wedged into the voice coil gap. That would not be unusual in a unit this old.
If that’s not the problem, then I’d get an oscilloscope and start probing the circuit, working backwards from the speaker to the input. Without a diagram, this is going to be a bit tough, but probing the plate and grid circuitry of each tube in the signal path will eventually locate the spot where the noise is being generated.
73, Ralph
Dave — I tapped all the tubes gently and several spots on the amplifier chassis less gently with a wooden hammer handle, with no change to the sound. I hadn’t gone probing around underneath the chassis yet, though. Sounds like I should maybe do that, still with my nonconductive stick?
Scott — I hadn’t tested the swell pot yet because I was thinking in terms of a mono organ. But since it sends manual and pedal to different speakers, it’s obviously a stereo pot, so I can have a look. It does seem to make the same noise at any position of the swell pedal, and I’m used to pots being crackly more when they move than when they’re still, but it’s worth checking.
Rich, or anyone — I’m just barely too young (and not a guitar player) to know tubes well. Should I assume that it won’t hurt the rest of the circuit to pull a tube from each tone generator? I assume I do this with the power off, then power up to test, not pull tubes when they’re hot.
Ralph — Hadn’t even thought of checking the speaker. Should be easy to do.
Anyone — On a transistor circuit, I’d disconnect the tone generators from the amplifier and see whether the noise persists (so it’s in the amplifier) or disappears (so it’s in the tone generator). I’d assume the floating input (maybe capacitor-coupled with a biasing voltage divider) would be okay. Can I do that safely on a tube circuit too?
Rich — I also like the idea of testing each pedal switch. It makes sense, and it’s something I can have Jake look at himself.
While I was outside a few minutes ago working on a new antenna, I had a thought – can you post a short MP3 or WAV file of the noise you’re hearing? That would make things a lot easier to diagnose.
Ralph, I’ve been thinking about recording and posting the noise too. I’ll see what I can get.
Since it was moved, it coudl be a cracked solder joint. But first, since it is old, unplug each tube and plug it back in to break any bad contacts from oxidations of the pins. Same for any plugs interconnecting parts of the circuits.
The idea to check the speaker for something like a metal partical in the voice coild gap was good. You can unplug the speaker and check it with another audio source.
Realize, that usually old electrolytic capacitors will result in increased hum. When they are older than 10 years, you may want to replace them.
However, this sounds like something that is akin to bad contacts, switches, corrosion on tube pins, or connectors.
Good Luck,
Stuart Rohre
Okay, I’ve posted an MP3 of the noise in a new blog post. It’s only fair to let you hear what you’re helping to troubleshoot, after all.
First,
The scratchiness may be caused by a tube that was damaged in transit.
switching the tubes around may not help this in the case of the 6L6′s as they maybe used in a push-pull circuit. The only way is to sub in known good tubes. This really goes for all if they have some sort of mechanical damage,microphonics,etc. as this most likely will not show up on an emission tester. A second audio amplifier used as a signal tracer would be helpful to trace the noise, besure to capacitor couple the input so that you will not damage it in case you place it across some voltage.
I know this may sound silly and too simple, but have you tried to “scrape” the corrosion of of any volume contols? Any electronic equipment of any kind can have corrosion buildup. The remidy for this is to simply adjust the volume up and down REALLY fast. I know you said the organ was in working condition before it was moved, but was the volume ever adjusted?
All –
The organ has been dismantled, and repair is no longer a concern (nor even a possibility).
I thank you all very much for your generous assistance.
Rich: mentioned he has a Lowrey LSB. I have a Lowrey FL and would like to clean the key contacts, but I’m concerned that they are quite delicate–metal springs look like they could easily be damaged by any disturbance let alone scrubbing. Any tips on the best chemicals and techniques to clean these contacts?
Frank, I just ran across this link on cleaning the aftertouch on early Roland synthesizers. Without having seen the Lowrey myself, I still suspect that their method of Q-tips soaked in acetone would help. Is that something you could do delicately enough?
If you try it, be sure to do it in a well-ventilated, flame-free environment, preferably outdoors. Cleaning the glue drip from a reattached automobile rear-view mirror was enough to get me light-headed, so be careful.
I am trying to find a replacement tone color box for a model 45 baldwin organ. Just wondering if you still have parts from the model 45Hp that you demolished.
Thnks,
Tom
Tom, I’m sorry, but I wasn’t the one to demolish it and don’t have anything salvaged from it except the tubes.
Thanks.
Tom, can you describe this “tone color box”.(picture)
I have some Baldwin parts.
Lawrence, I’ve just emailed Tom to make sure he saw your comment. If he’s still interested, I can put the two of you directly in touch with each other.
Thanks for making the offer!
Hello,
I am Rick Schiff, I live in Wichita kansas…. I just bought a Conn 650 organ and i pick it up in a few days. Do you know of anyone in Kansas that works on these organs.. Thank you much!! God Bless!!
Rick, sorry, but I’m not up on organ repair services.
I know that Senseney Music has a vintage Baldwin on their showroom floor, and their keyboard department manager might know of somewhere that does repair service.
Have one, and wonder if anyone knows how to get it in tune?
Okay, um I’m not sure if this is a great place to ask a random question, but my husband recently acquired a free Baldwin Organ. The old owner saw us scavanging it from the dumpster at our apartment and said it has suffered water damage while being stored. It worked fine for a week or 2, but now when he turns it on, it sould like an airplane taking off. It starts very quite and then gets louder until it hums at a contant volume. Adjusting the volume or pushing any of the buttons (except the power button of course) do not impact the sound at all. Any thoughts would be appreciated. I’m generally a learn by doing person, but before I take it apart I was wondering if this sounds salvagable?
Many years ago I was an organ technician working for a Baldwin outlet. The old organs with vacuum tubes often developed leaky capacitors and had to be replaced, but more often than that, we were able to restore correct frequencies by adjusting the bias on the tubes. I had an audio frequency meter specifically for organ repair and tuning. Using an adjustable resistor substitution box, I would monitor the frequency of the module in question while adjusting the resistance. Once the module came in tune, I would remove the substitution box and install a new resistor of the correct size. I was able to repair many old organs this way.
JayDee, that is so above my head. However, I too literally picked up a Baldwin OrgaSonic for free. May be stupid on my part, but will see about getting it to work. I have red power light come on, but noticed 4 vacuum tubes burned out. I suppose the first thing is to order those tubes to see if I get anything as far as sound/noise. Any other suggestions as to where to begin?
It’s been a long, long, time, so here is my best advice based on faulty memory.
Did the organ work at all before it was moved? If so, then you are probably correct regarding a mechanical problem. A close visual inspection with a magnifying glass to detect broken solder joints may be the first thing.
Also, in my experience, organs in churches suffered rodent damage — chewed wires that may now be touching something they shouldn’t, feces that shorted out components, speaker damage, etc., — a thorough visual check may point to some problems.
That said, are the four bad tubes in the power supply, or a tone module? If the latter, are they all on the same module? I assume that these tube filaments are not wired in series, i.e., when one goes out, all tubes in the same filament string are out.
If the filaments on a few tubes do not light, check them with an ohmmeter to make sure they are bad, or switch them with others that do light up. If they light up in other sockets, then you have something else wrong in the circuitry — could be as simple as a dirty tube socket. Don’t just switch tubes out in a wholesale fashion however. Doing so could throw the tuning off if a circuit is actually working.
With no sound at all, I check the power supply voltages — if they are down, the electrolytics would be my first choice for replacing, along with any paper caps that are in there. And check the speaker(s) -speakers gather dust over the years and get “clogged” — the quit working because diaphragm can’t move, although it may crackle as you mentioned in your post. Dust can often be just blown out with a vacuum or one of those compressed air dust blowers — but be careful because too much air on those old speaker cones can put holes in them.
IF the power supply output voltages look ok — and if I remember correctly — each tone module operates independently. You may try: 1)turn off the power 2)unplug one module 3)turn on the power and see if others begin working. Caution: removing one load from the power supply may cause voltages to rise in the other modules — and you don’t want too much voltage to the modules. You can test this by monitoring the power supply voltages with one module unplugged. If the voltages remain stable, unplug the next one — but continue to monitor the voltage and stop if the voltages begin to rise.
A service manual would really come in handy..if you don’t have one, maybe you can find one on line…I don’t know if the Baldwin company would be able to provide you with one. In a pinch, you may be able to draw a rough schematic yourself by looking at the wiring and noting the tubes’ pin numbers and components attached to them. This is a very labor intensive process and it’s easy to mislabel something. This would be my last resort.
To summarize:
-1 Visually check for rodent damage, cold/broken solder joints, or chewed wires that may be shorting out the circuitry.
-2 Check speakers and controls
-3 Check the power supply, and recap it if the voltages are missing or low. (As a standard procedure, I would replace any original electrolytics and paper caps — and be prepared to replace the paper caps in the tone modules, but I would not do a wholesale replacement – once the power supply looks ok, and you have all the tubes lit, try recapping just one tone module.
-4 Check tube filaments of those tubes you see are burned out.
-5 Check each tone module by the isolation procedure I outlined above.
And be careful….ensure the organ is turned off/unplugged when you are doing visual inspections.
You have an interesting project there. I would like to hear more as this progresses. I hope I have helped at least a little, but it’s difficult not seeing the organ — even then I don’t know if I could fix it.
One more thing…do you have a vacuum tube manual? The manual will give you pin layouts and approximate voltages you should see on them. If you don’t have one, I can copy pages from mine and email them to you.
I don’t even know the exact model. There is not a stamped plate under the lid, or inside the case. There is however a number stamped when lifting the lid, on top of the unit. 52-24928 or 52-24828 (it’s smudged just a bit). I do not have a vacuum tube manual, but I’m searching high and low via internet.
If you have something that may compare to this model, I’d be so grateful.
Is there any way I can send you photo’s of this organ?
I don’t have any organ schematics, and the store I worked for 30+ years ago is long out of business. 45HP2 should be enough to identify a schematic. Not sure what the numbers you cited are – could help identify the unless they are part numbers
Here’s an organ repair site I found http://www.pugetsoundorgan.com/baldwin.html.
Here’s a site offering schematics. The 45C – 45H2 may be close enough to the 45HP2 to work with. You can contact them first and ask before you buy. http://www.geocities.com/justradios/baldwin.html
From looking at the photos, I see this model uses 6L6, 12AX7, and 7027 tubes. Any others? Power supply tubes? If you give me the complete list, I will get out my tube manual and send you some specs on them.
This site offers you to chat live with a 45hp2 service expert. If you contact him, please let me know how it works out.
Which site has the live expert chat?
I played around today, checking for rodent chews, etc. Things look pretty good so far. I turned it on, let the tubes warm up and found 2 power tubes NOT working. One is a 6L6GB. I’ve been advised by Fl. company that with that one burned out, the sound will not work. Speakers look pretty good too. I have ordered the 2 tubes and will have them Monday. I have also contacted MusicElectronics (who posts on this site) that may have what I’m looking for in terms of the operating manual and service manual. I have printed your advice and will use it as a check list. I appreciate your help and look forward to reading more information about the Baldwin OrgaSonic. I finally found (it was hidden on the side covered in dirt) the printed stamp with model info. It’s a Model 51P, Serial # 51P-24948-B1.
This site has a live chat link but I am not sure it is workng. I found a different one the other day but can’t locate it again. Sounds like you have made some progress. Please let me know how ithe nre tubes work.
http://www.maybenow.com/Can-you-Please-help-identify-a-part-for-the-Baldwin-OrgaSonic-51P-q24000835#
Hello JayDee:
I have replaced the burned out tubes and it works. Now I have the same ‘static’ in some of the keys. So, I don’t think it’s the speakers creating the problem. The static is primarily coming from the E key, all octaves and both manuals. I’m guessing that the contact is dirty from sitting ‘who knows where’ for many years. Any suggestions for me?
Progress!! Congratulations!! The static most likely is being generated by dirty contacts as you say. If you can get to the contacts themselves, one quick trick is to rub them lightly with a pencil eraser, then blow or vacuum the eraser residue away from the contacts. (just be careful not to bend any of the contacts). If access to the contacts is not easy, you can find contact cleaner spray at electronic supply houses. Another possibility may be dirty plugs/sockets where the tone generator modules plug in or any other plug/socket that the circuity routes through. Again, thorough cleaning usually takes care of such problems. Please let me know how you make out.
More progress. I managed to see how each panel is numbered, then found the E & D# stamps. I removed those tubes, they are the original by the way, and cleaned the contacts. The E keys are now free of static. Yippee.
The volume pedal works great too.
I have 2 more situations. Maybe you can suggest something here. The pedals. The C works good. D intermittanly mostly not, E is ok. F intermittant, G very good. A so so, B so so, High C not at all. Good news, all of the # black pedals work. I have removed the cardboard pedal cover (in the bacK)
I checked and all wires are soldered well. I blew out the dead spiders and heavy dust. Not sure where to go next. I don’t want to get anything out of whack! ha! Any suggestions?
I think the last thing that I don’t understand is the Percussion keys. If I press any of them in a downward position, they play the same pitch. I can’t imagine that being correct. I thought I’d try to clean any contacts for those, but I don’t have a clue where.
You can imagine how excited I am about this working. It’s actually in very good shape. Looks like someone must have cleaned out the spare bedroom and dumped it for a poor sucker like myself to bring home.
By the way, I now have the copies of the original owners manual, and the service manual. I’ve been playing it this afternoon, without the pedals.
Ok….getting better all the time… As for the remaining problems, it sounds like you have done all the right things to track them down. The intermittent pedals sounds like contacts. Sometimes pressing them repeatedly and quickly several times will clean those contacts, but you may have to dig deeper there. The high C that does not work at all could also be a contact problem, but is more likely something more involved — broken wire, bad component, or even a wire that has lost its insulation and is touching the chassis grounding out the signal. The Percussion keys playing the same pitch sounds like a component problem but I really don’t know — maybe one of them is stuck in the down position and thus is overriding the rest? Even if the key itself looks like it is in the up position, the switch under the key may be stuck. Repeatedly moving each key several times may improve this problem. I don’t remember the mechanics of the percussion keys and how they activate the switches, so I’m afraid I’m not much help here either. The fact that you have the manuals is a big plus. If you are still stuck after reading this, do you know a local technician (he doesn’t necessarily have to be an organ tech) who can help you trace the schematics and isolate the problems? I applaud your tenacity, and look forward to any other questions/results you may have….
Rome wasn’t built in a day. Concerning the pedal layout, the pedals are held by nuts.
1. Are those just to remove the pedal or do they control anything with the sound. Thought I’d remove and see if I can clean them.
2. The springs have little red felt pads, a couple look very deteriated, what purpose do they serve? Thought I could make new ones.
3. When you say contacts, I assume I need to clean the metal L shaped wires. They are very dirty, rough feeling. I’ll be cleaning them up today.
We do not even have a piano tuner here. The piano guild makes special arrangements for a tuner to come 150 miles to tune their piano’s. We haven’t had our church organ repaired in quite some time, and I think he came from Dallas, 6hrs. I’ll just be at the mercy at this blog for now. Take mercy on me! Ha. I’m sure I’ll have this repaired in no time.
Update! I figured the contacts were the L shape wires. So, I took a Q-tip and swabbed them with alcohol. Nothing, so I took rust remover and started cleaning them. A ton of rust/corrosion came off. They are bright and shiny now and ALL play well. (shooting off fireworks)
The last thing to figure out are those Percussion keys. I’m not sure what they’re supposed to do, will ask the organist at church. However, I fooled around with them, switching them off and on as you suggested. They still are playing a sound when each are pressed down. Do you happen to know which tubes in the back are for them? I think that I’ll pull them all and clean them because doing that to the E tube worked.
1. I believe the nuts just hold the pedals in place. If the service manual has a parts breakdown, you can check to see what parts are involved and how they connected before you disassemble anything. Be careful when you remove one — make a note of where all parts — washers, etc, belong.
2. As I recall, the felt pads are either bumpers to keep the springs from bouncing once activated, or to avoid any extraneous mechanical noise when the springs move (probably both).
3. The wires are indeed the contacts and giving them a good cleaning should help greatly. Also clean the surface that they touch when activated. Just exercise patience so you don’t inadverdently bend any.
I am trying hard to visualize exactly what all that looks like, but it’s been too long for me to dredge up the memory.
I’m getting into guessing terroritory here, as I am in no way musically inclined, but I do know that a piano, for instance, is a percussion instrument (hammers hit strings) if the percussion keys have something to do with emulating piano features, such as the decay time of the notes as piano pedals do?
Does your organ have a “percussion chassis? ” This would be a separate electronics module used to produce the percussions ordered by which percussive key you press. I would look for that first….
thank you for taking the time to help me. I’ll get the schematic out and see what I find. I’m sure this might be a few days.
I have two guesses about the percussion keys, based on what I have on my (working) Hammond and on a Crumar clone of the Hammond.
The first is harmonic percussion, which adds some harmonic overtones to the beginning of the note when you press the key. It adds the higher-pitched sounds into the note for just the very beginning, making kind of a “plink” sound at the beginning of the note. It sounds vaguely like a mallet striking a xylophone or marimba, and can be used to accentuate a staccato effect.
The second is noise-based percussion on the Hammond clone, which does much the same as above but adds a bit of noise instead of overtones related to the key being pressed. It sounds more like a “ksh” sound, and I think it’s supposed to emulate the key click of a Hammond key closing the contacts. I don’t have much use for it myself.
On both the Hammond and the Crumar, the percussion effect is controlled by one or two toggle switches that turn percussion on and off for the entire manual (or both manuals?). (I think the Hammond has two different percussion switches for different sets of overtones.) They certainly wouldn’t (shouldn’t) be making a noise continuously when switched on.
I hope that gives you some ideas about what to expect from the percussion; and congratulations on getting so far with the repairs already!
That does help. When pressed in the ‘down’ position the VibraHarp, Harpsicord, etc., play a continuous sound. When pressed “up’, they don’t. I’m currently cleaning all tubes in the Percussion section. (can’t hurt). I love problem solving!
This has made such interesting reading. I am purchasing a Baldwin 3-Manual Drawstop C-601 Classical Analog Organ (serial no. F-1071-B). I understand the organ was working recently andwas moved to a shop where it has not been touched. Before I start it up, should I follow some of the recommendations stated above. Would you give me some advise of how you would recommend prepping the unit for power up.
I understand the unit does not have a “transposer”. Will this cause the unit not to work? I’m curious as to the function of this “transposer”.
Also, I wondered if this organ has a reputation of having quality sound?
We have a Baldwin Electronic model 5A and very interested in trying to find out where the kinks are.It is in working condition but does have some notes that do not play and one that sticks until disconnected..
From reading other comments I think the first job is cleaning it thoroughly,tube by tube..is that correct?
Am searching for the manual and schematic..where??
Many thanks
Lou Ann