Hammond Romance Organ w/leslie update: she took a plunge

[Guest]

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Hey guys, I'm new to the vintage organ scene so bear with me here,</p>

Picked up this Hammond organ, can't find a make anywhere and don't feel like opening it up to hunt one down, the model number is 126272 &amp; it's got brite foot, leslie, and isn't a tonewheel as far as I can tell as it looks mid-70s.</p>

Aside from identifying it specifically there is a steady crackling sound coming from the main cabinet, not the leslie, which is still present out of headphones when I plug in to the existing 1/4" jack. It's not very loud but would be a bit of an issue recording.</p>

 Also not sure if this is normal but with all switches set to off and the 'ss1' sound simulator off there is a very faint organ sound, all the other instruments work with normal volume levels but ironically save by using one of the ss1 presets, there is no 'organ' tone on this beauty persay.</p>

The only other issue I have with it is the slider for pedal volume only works within a narrow range towards max volume, not a real problem but it crackles like hell when adjusting and adds a slight overall noise to the existing background crackle.</p>

Any help would be great, cheers!</p>

[crossyinoz]

Re: Hammond Aurora-ish Organ w/leslie light crackling!



G'day,</P>


The organ is a Hammond Romance 126 from 1979, LSI, not tonewheel. The last numerals "272" in the model number refer to the cabinet style, in this case a contemporary theatre horseshoe in walnut.</P>


Crackle in the volume sliders appears to be a job for De-Oxit or a similar product</P>


Cheers,</P>


Ian</P>

[andyg]

Re: Hammond Aurora-ish Organ w/leslie light crackling!

[quote user="sklaz"]

ironically save by using one of the ss1 presets, there is no 'organ' tone on this beauty persay.</p>

[/quote]</p>

Not sure what you mean here. The organ tones are the Tibia/Flute and String voices on the tabs.</p>

Andy
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[Guest]

Re: Hammond Aurora-ish Organ w/leslie light crackling!



Thanks for the prompt response guys, </p>

andyg: Sorry, what I mean by that is that there is no organ instrument, there are the tabs for flute, strings, tibia etc which operate are regular volume, but with all the instrument switches disabled there is a very faint 'organ' tone. Maybe this is normal but I thought it was worth mentioning.</p>

crossyinoz: That'll definitely be the first thing I try, though it sounds like it might be something deeper than the pot sliders.. here's a mp3 I recorded of the output, don't mind the mashing around.</p>

http://www.engineten.com/comingsoon/misc/organtest.mp3</p>

At the start I'm increasing the volume pedal, then when the humming noise appears that's me adjusting the pedal volume slider. At the end I have all the switches off and there's that faint organ instrument, which returns to normal volume when I flick any of the instrument switches.</p>

Hope this helps, based on the slim amount of info I can find online about this organ I'm guessing not too popular since it's more a synthesizer &amp; missing the classic tonewheel sound. Still it looks great and the leslie effects are pretty wild, just hope I can rid it of this noise!</p>

[andyg]

Re: Hammond Aurora-ish Organ w/leslie light crackling!



I've heard the noise on other Romance organs. Seems it might be a common problem. All LSI Hammond suffer from 'LSI Disease'. Basically a combination of poor build quality, poor quality parts and problems with inter-board connectors. However, the Romances are all Japanese built, IIRC, by Nihon Hammond before they went under and got rescued by Crossy's countrymen. So, problems 1 and 2 shouldn't be so bad! That leaves the perennial problem with the interboard connectors, so while you've got the organ open and a can of De-Oxit in hand, unplug, clean and reseat every single one you can find.</p>

Hums are more indicative of power supply caps beginning to go, or grounding issues. Checking all those connectors may well sort out grounding problems, but check for anything else that seems loose. Power supply caps should be changed if they are going bad.</p>

The Romance series was launched in 1980, replacing previous models like the Dolphins etc. The 126xxx was the top model in the non drawbar range. The 272 at the end shows the cabinet styling and wood finish, yours looks way better than the fake wood ones we had over here. A nice clean organ sound, but not a range of instruments that would set the organ world alight or help Hammond stand up against the onslaught from the likes of Technics, Yamaha and Kawai. </p>

Andy
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[Guest]

Re: Hammond Aurora-ish Organ w/leslie light crackling!



Perfect, it's definitely in great condition physically and there's little wear on the anything externally.. thankfully I grabbed the organ from a local church for free so spending a bit of cash to fix it up is not an issue. I'll order some de-oxit and get my father to help look at grounding issues since he's an electrician. The service manual is on ebay so I might pick that up as well, it's unfortunate somone doesn't collect them in PDF format along with descriptions though, there are a fair amount of enthusiasts out there it seems. Anyhow I'll be sure to take photos and scan the manual if I find one since documenting these more obscure models is worthwhile, without the knowledge available on this forum I'd be hard pressed to find info outside of contacting actual organ techs.</p>

Thanks again and I'll update when I get to taking it apart! </p>

[Guest]

Re: Hammond Romance Organ w/leslie light crackling!



Well the honeymoon was short, I managed to fix the crackling by moving the sliders rapidly back and forth for a while and the organ was sounding great for a few hours. I was playing with the bass arpeggio functions when it just stopped making sound. Tried resetting all the switches, powering on and off and nothing. Ahhh I knew it was too good to be true...</p>

The organ had been on for maybe 3 hours and towards the end it was playing with a fair bit of bass in the sound so I'm thinking something was rattled? </p>

That being said I get no response on any functions save the power light. There's a 'memory key' function that mechanically holds down keys on the bottom manual and even that does not function anymore.</p>

When I power it on I hear a click from around the power supply and that's it other than a very low hum from the cabinet.</p>

From what I've ready I wonder if this could be one of the LSI cards being shaken loose or a power/capacitor problem? This organ had been in storage for up to a year and was moved via truck about an hour on its' side which the organist who played it for the church said shouldn't be a problem. Were there maintenance procedures I should have followed prior to starting to hammer down on the thing or just a case of old connections that need to be deoxified? </p>

 I'm going to leave it for an hour in case it overheated? But any help would be great, thanks guys.. </p>

[andyg]

Re: Hammond Romance Organ w/leslie light crackling!



I believe that the power light in the switch is just a neon that glows when the switch is closed. All that shows is that there is mains AC getting to the switch. If nothing at all is working (does the leslie spin?) then I think you may have either an internal fuse blown or power supply problems. Hard to diagnose at a distance.....</p>

There's nothing you could have done prior to playing it, and moving the organ on its back shouldn't really have done anything bad, except maybe dislodge some connectors.
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Time to open it up and have a look for anything obvious. Our usual forum warning applies. You're looking around the power supply and there are lethal voltages in this area so be careful. We'll help in any way we can, but don't take on anything that you are not 100% sure of. We'd normally advise you to call in a tech, but in this case that service call would outweigh the value of the organ, which is realistically not much more than zero, even fully working.</p>

I hope it's something simple enough to fix, so you can have a bit of fun with it.
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[Guest]

Re: Hammond Romance Organ w/leslie light crackling!



Thanks Andy, thankfully you were right.. it was a fuse on the main power supply, there's a top and bottom one -- both 1A 250V slo-blo which I was just able to replace today. Though the one I had didn't have that coiled spring on the one end for what that's worth. Only the top one seems to blow.</p>

Anyhow sure enough after playing for about 20 minutes it went again. Frustrating especially after I found out I can plug my guitar directly into the phono-in on the back and have friends jam while I make a bass-line using the Hammond.</p>

So maybe this is a symptom of something else wrong in the power supply? Both times I was playing loud on and off, possible an issue with the old wiring not being able to handle maxing out?</p>

As much as I hate to, I could try running it off the 1/4" output through my home stereo for a while in which case I'd know it was an issue of powering the speakers.</p>

As always the sage advice on these forums is appreciated, cheers! </p>

[andyg]

Re: Hammond Romance Organ w/leslie light crackling!



You have a fault that seems to blow the fuse when things have literally warmed up. Power Supply? Maybe, but I couldn't tell you what it was, but maybe someone, one of our engineers, will come up with some ideas.</p>

Andy
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[Guest]

Re: Hammond Romance Organ w/leslie light crackling!



Hi Sklaz,</p>

Since this is a solid state organ, it won't be as full of lethal voltages as an older tube Hammond, but heed Andy's advice anyways. Does the fuse only blow when its being played? How does it look after it blows; is it just an open wire inside like a bad lightbulb, or did it splatter and blacken the inside of the glass tube? If its the latter, the fuse has been detonated by a sudden short, so there is likely a chance that a power device, like perhaps one of the output transistors in the power amp, has gone thermal and is going into avalanche (momentary dead short). Try replacing the fuse and turn it on and just let it sit for a day or so without playing. If the fuse blows anyways, it may be an electrolytic cap going leaky in the power supply filter. If, however, it stays up, then you start playing it and it goes again, it could be what I suggested earlier about the power amp. I've seen guitar amps go this way and its a very frustrating thing to debug since the offending device doesn't actually die outright, it just hiccups every so often under stress (i.e.: driving a load and dissipating power). One way to see if its a thermally triggered problem is to open the back and have a fan blow air onto the innards while you play it. If it stays up, its a good chance that its a thermal problem, which is often the trademark of a bad semiconductor. Also look at the tops of the electrolytic capacitor cans in the power supply, or at the ends of any axial units on a PCB. A leaky cap that would draw enough power to pop a 1A slo-blo fuse at line voltage would show definite signs of heat expansion. For instance, the flat top of a can may show a definite rounded bulge (just before it becomes a confetti maker ;-). </p>

These are some simple pointers. Given that the organ plays right up to when the fuse goes, its not some major problem that will cost more than the organ is worth, but you could spend a great deal of time chasing this one down. Good Luck!</p>

expiano
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[Guest]

Re: Hammond Romance Organ w/leslie light crackling!



Thanks guys, I make sure I've got a hand in my pocket and wear gloves if I'm poking around on the power supply board so I should be alright! As the fuse has only blown twice it's hard to say re: it going due to playing.. but again it ran for close to 8 hours initially and the only thing I can think of that changed was that I was playing louder. This time it took much less time, around 20 minutes, before it blew. But again the volume was pretty loud at times so that could have been it again. </p>

The fuse didn't blacken the inside, only a small break in the wire so no serious current overload happening there. I do get the sense that it's something with the power amp as you mentioned.. though wouldn't the fuse on the power amp board blow as opposed to the power supply board?</p>

Also I'm having some friends over tonight &amp; our local electronics shop isn't open at night..would it be ill advised to run a wire through the first of two adjacent fuse slots and keep a fuse in the second just to show them the organ for an hour?</p>

Otherwise can't find any bulges on the caps, they're mainly axial (I'm assuming that means laying on their side vs standing up) but all the internal hardware seems immaculate, barely any dust even. I'll pick up some more fuses tomorrow &amp; try leaving it on for a while, maybe there'd be some value in disconnecting the leslie which attaches to the power supply via a control board that has a port for another external leslie on it to try to isolate if it's an issue powering both speakers? </p>

Regardless I'll post some pics of the two power boards later tonight as soon as I steal my brother's digital camera in case there's something I'm missing.</p>

Thanks again! </p>

[Guest]

Re: Hammond Romance Organ w/leslie light crackling!



Sklaz,</p>

So its loitering at the edge rather than suddenly jumping into overload, according to the fuse. There's several reasons the power amp fuse doesn't go; the amp fuse is typically rated to pop on a short circuit overload, or the fuse may have been previously replaced with a higher rating one, or the fault may not be in the power amp. The fact that it goes when you play it loud does however suggest a power amp issue. It's possible that as the amp warms up from power dissipation, its DC bias may be drifting enough to cause it to draw a higher idle current (understand that its about 50% efficient so if its putting 15Watts into the speaker, its also dissipating 15Watts of heat). This can happen if certain components have aged and leakage currents have crept up. Another possibility, depending on the amplifier topology, can be the output capacitor if it has one. A single rail amplifier, that is, one with a single DC polarity power supply, will need an output capacitor since the output stage is biased to idle (zero signal point) at a voltage that's 1/2 of the main amp power voltage. The output capacitor is subjected to the full AC current of the speaker signal and is a highly stressed component in the signal chain. If that capacitor goes leaky, and I've seen a few that have, some of the DC voltage its supposed to block will be applied directly to the bass speaker voice coil and draw a constant power from the supply ON TOP OF the electrical power being consumed to produce the acoustic output of the speaker. The summation of the two power drains over a sustained period of time produce an average line input current that exceeds the fuse rating by some percentage, say around 10-20%. The fuse wire slowly heats up and finally breaks open, rather than vaporizing and splattering metal all over the inner surface of the fuse barrel. </p>

So how do you debug this. First, if it is a single supply amp, it will have a single power rail to the amp section of around 35-40VDC if its a 20Watt amplifier. The output capacitor will be an electrolytic of typically 470uF to 1000uF and has a direct connection to the speaker live wire. The other wire, the speaker return, will have a direct connection to chassis Ground. You can check all this with an ohmmeter with the organ POWER OFF. Now, with a voltmeter connected across the speaker and set to DC, say around 10-20V range, you should not see anything more than perhaps 0.01V or less when the Organ is on. Leave the meter hooked up and play the organ loud for 10 minutes or so, not to the point of popping the fuse but just getting up there. Stop for a few seconds and check the voltmeter; if you see a reading exceeding 1V, the output capacitor needs to be replaced. If there is no DC, the capacitor is OK and there may be a bias problem deeper into the amp. While the amp is still hot from having just played, with power on, CAREFULLY measure the DC voltage (w.r.t. chassis) at the other end of the output capacitor and note it down. Then, CAREFULLY measure the DC voltage at the amps power fuse; the voltage on the output capacitor should be roughly 1/2 of the voltage measured on the fuse. If its significantly off, like at 1/3 or 2/3 of the main DC fuse voltage, that could indicate a bias problem and may be the reason the amp is taking more power than it should.
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For a dual supply amp, which are common in higher end hi-fi amps but less so in Organs and guitar amps, there is no output capacitor. The power supply provides both a positive and negative voltage to the amplifier, and the chassis ground voltage sits in the middle at 0 Volts. The test, however, is similar in that you look for the absence of DC voltage across the speaker. If you see significant DC (over 1V) in a dual supply amp, that means that the bias point has drifted and the problem is buried within the amp. This is the same problem as with the single supply amp bias voltage being away from the 1/2 supply voltage point. </p>

If you measured DC across the speaker, then, unless it is the output capacitor leakage in a single supply amp, you're looking at a more complex debug procedure to find out why the amp is drifting off its bias point. One quick, preemptive action that can be taken is to replace ALL the smaller electrolytic capacitors on the amplifier board, since they are the least reliable components within the system and have a useful service life of around 20-30 years if they aren't subjected to a lot of heat. The big main supply capacitors will not cause the amp bias to drift, but the little inter-stage coupling caps and emitter bypass caps can definitely have that effect. That approach is a relatively cheap exercise and has restored several power amps to perfect working order for me in the past. The caps to suspect the most are the ones that have been neglectfully located right beside a heat dissipating component like a transistor or power resistor. Generally, one only finds stupid layout errors like that on PCB boards that have been designed off-shore by less experienced persons (I hesitate to call them Engineers).</p>

Hope that helps,</p>

exp
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