Hammond model 144122 Year 1983. Top set of keys fade out!!!! Help!!!

[richcrook]

So I bought a 1983 Hammond 144122 for $40. Awesome organ except that the top keys fade away about one minute after the organ has been turned on, yet they play when the full organ feature is being used. Also, they play only when the bottom keynotes are being played. Any help would be greatly appreciated.

[indianajo]

I've got a partial 246xxx schematic. If it is similar, first I would check the 770 and 771 power supply pcb's: With 9-14 as ground. J80 19 is -22 v, 15 is +22 v, 5 is +35, 1 is -35, 2 is -26, 6 is -15, 12 is +15, 21 is -12.5, 16 is -5. If you find one voltage fading with the sound, look for tired electrolytic caps or 78xx or 79xx regulator.
If those are okay, I would check the preamp mixer pcb 769. That is a page I don't have, since Richard's was working okay.

[richcrook]

Indianajo,

My head just exploded. You gotta forgive me but I have no idea what all that means. Although, I do think it's super awesome that you took the time to try to help me. Anyone else????

[indianajo]

If you really want to learn something, organs are pretty safe and understandable consumer electronics. Buy a copy of Thomas Floyd Electron Devices, the Electron flow version which I found at goodwill for $2 or some other community college electronics text. Good on basic power supply theory. Electrolytic caps in power supplies are pretty prone to failure at 40 years, since they are aluminum cans full of water sealed with rubber. Not even beer in cans is good for more than a couple of years. When the e-caps in power supplies go, they tend to take the 78xx regulator ICs with them.
Hammond PCB's are labeled with numbers like AO-1240000770, where the 770 and 771 are the power supply pcb's. If you want to read about cheap ways to replace electrolytic caps, read this http://www.diyaudio.com/forums/tubes...ube-amp-3.html although you'll have much lower voltages in a 1983 organ than a tube amp.
I've seen an Elegante or something on Lawrence Welk, it was a really superb sounding organ. By contrast I really don't like the regular organ segments on that show, which are usually something else. I hope you can refurbish this one. I put 71 e-caps in my H100 to make it sound like new. Few other people have the patience to do that. Solid state (transistor) organs, the bad caps tend to blow up other cheap stuff. Thus the book. Tube organs, it is pretty much the caps or the tube sockets.
Hope you make progress on this, the elegantes and auroras are really nice when restored. Earlier models (1975-79?) have cheesy contacts pedals and connectors, but by 1983 Andy has said Hammond had most of that straightened out.

[andyg]

Before you do anything with an LSI Hammond like this, you have to cure what many of us call 'LSI Disease'. These organs suffered terribly from poor inter-board connectors, so you open it up, unplug, clean and re-plug every such connector, one at a time. There may be a lot to do! Cleaning contacts on these connectors can be done with a pencil eraser, De-Oxit, or both. Now your Hammond is a 'Composer 144' from 1983 and it's Japanese, so should be rather better than the earlier models but you'll still need to do this.

Once done, see if the problem goes away. If so, then leave it. By 1983, the Japanese builders were using better quality components and the electrolytic caps may well by OK and the organ may well last a long time. However, Indy makes a good point about them, they don't last forever, no-one really thought people would be still playing the organs 30 or 40 years on!

So do the clean-up and report back. As you're not that technical, follow Indy's advice above, and also keep away from any high voltage areas like the power supplies, or be ultra-careful near them.

I hope that one of our other Hammond gurus, Larry, will pick up on this with some advice for you.

Andy G

[richcrook]

You guys are awesome. I'm gonna get into it this weekend. I'll check back in next week.