Hammond H-112 Percussion Mod

[ELPFan15]

The bottom switches on the schematic, the NC switches, you leave alone. These are physically on the upper keys side of the switch (right from back) , and have a bottom & top solder terminal. On banjo you remove the wrong color wires going to the bare bussed tops (poles) and move them the the right bottom (NC)'s of the same contact. The one left alone was going to be green on banjo, wasn't it? Yellow runs over to banjo from the front of top(physical) of xylophone to the bottom(physical) of banjo as a bare wire, I'm getting too sleepy to figure that out right now.
Before doing any more modding, put guitar back to stock and see if you can get the other percussions besides banjo to work normally, as they did before you did anything. If that doesn't work, try putting banjo back to normal, though you can aligator clip lead your wrong color wires back to their terminals since you're going to take them back off again to move to the bottom of NC side. If you can't get back to normal, ask questions and I'll describe the wire order or something- I can't read it off the archive.org print, although captain-foldback.com's sliced up print might be more legible for the colors.

So I now have to figure out how to flip the switch assembly over to get to the underside? Oh well, I need something to keep me busy anyway. I'll try and restore the guitar tab.

[indianajo]

That's where the pole connected wires are going, to the NC wires that connect to the bottom terminals. Because of the rod in front that holds the plastic tabs, I don't think the switches will flip over. I've been thinking the easiest thing to do is unbundle the wire harness at the back, undo the twist ties and unscrew the big cable clamp. Then trace the bottom NC wires out to a place where you can reach them. Then extend or replace the top pole wires to make them long enough to reach a handy spot on the NC wires. Then skin the insulation off the NC wires with a knife without cutting them, wrap the pole wires around them, solder, and insulate with electrical tape. Scotch 33 tape from electrical supply/mcmaster.com stays stuck, lumberyard & HarborFreight tape come unwrapped.

[Bobmann]

Getting to the bottom of the switches is not that much trouble...look at this:
(start at 6 minutes, the first part is fluff)
http://www.youtube.com/user/bobmann1...28/XnRKTzUjxgY
Then look at part 2, the first couple minutes:
http://www.youtube.com/user/bobmann1...27/wOGa-iQ37DA

You may be able to get to the terminals you need just by removing the back of the switch panel.

Bob

[ELPFan15]

That's where the pole connected wires are going, to the NC wires that connect to the bottom terminals. Because of the rod in front that holds the plastic tabs, I don't think the switches will flip over. I've been thinking the easiest thing to do is unbundle the wire harness at the back, undo the twist ties and unscrew the big cable clamp. Then trace the bottom NC wires out to a place where you can reach them. Then extend or replace the top pole wires to make them long enough to reach a handy spot on the NC wires. Then skin the insulation off the NC wires with a knife without cutting them, wrap the pole wires around them, solder, and insulate with electrical tape. Scotch 33 tape from electrical supply/mcmaster.com stays stuck, lumberyard & HarborFreight tape come unwrapped.

Ok, I'll try that. Thanks.

[ELPFan15]

Well, the percussion is indeed working, and, although it doesn't sound like the right harmonic when on, the 3rd harmonic drawbar(2 2/3', right?) doesn't work, and I think that is supposed to happen, right? Either way, it's closer.

[indianajo]

Theoretically, the 3rd harmonic drawbar should work as normal, and you get an extra burst of 3rd harmonic when the percussion timer is on . Did the 3rd harmonic drawbar stop working all the time, or just when the banjo or xylophone percussion tab (the ones altered?) are on? The drawbars on the main schematic go out the regular way through .5 ohm resistors to a transformer on the upper left then off the the preamps. They also go through this percussion set of switches to the tops of a mixing transformer on the percussion gate and amp assy, and when the percussion switches are down the keyed harmonic goes through the NC sides of the switch to the bottom of the mixing transformer. I think this weird arrangement is maybe to prevent pops when you turn percussion on or off while playing.

[ELPFan15]

Only when Banjo is on. It sounds like I get somewhat of a boost of the harmonics on Banjo when it's on.

[indianajo]

Glad only banjo messes up 3rd drawbar. There are 3 yellow wires going to xylophone and banjo switches (third harmonic perhaps?), and some internal tie wires in bare wire that run to the bottom instead of the top, so I'm going to have to unbundle my harness and figure out how exactly it is wired. One in, one out, one?? There is more yellow wire there than on the schematic, perhaps one of them is the drawbar wire. I'll have to figure out which of the 4 connectors on the back is in from TG, and which two are out to the perc chassis, and what to do with the extra one that won't damage third drawbar setting.

[ELPFan15]

Glad only banjo messes up 3rd drawbar. There are 3 yellow wires going to xylophone and banjo switches (third harmonic perhaps?), and some internal tie wires in bare wire that run to the bottom instead of the top, so I'm going to have to unbundle my harness and figure out how exactly it is wired. One in, one out, one?? There is more yellow wire there than on the schematic, perhaps one of them is the drawbar wire. I'll have to figure out which of the 4 connectors on the back is in from TG, and which two are out to the perc chassis, and what to do with the extra one that won't damage third drawbar setting.

I'm not working on it on the 4th anyway, have to do party preparations.

[ELPFan15]

Alright, back to work. I've opened it up to fix a vibrato problem, so why not go ahead and finish the mod while the switches are exposed? It turns out the high harmonic I was hearing was 8th harmonic(according to the preset wire chart on the back of the harp). Maybe if I cut those wires off, and leave the 3rd harmonic, I might hear it a little better.

But, this harmonic(like 3rd at the end of chimes) has 3 wires. Should I tape all of these wires together, or just certain ones?

[indianajo]

The keyboard-partner.de schematic shows only banjo uses 8th overtone (white). You should be able to remove the NO wire and connect it to the NC wire to let the overtone flow through. Of course there may be more wires than shown on the schematic, like yellow, so good luck.
What vibrato mod? I was going to put a different size pulley on the scanner for celeste to give it a slow leslie vib to complement the fast stereo vibrato it already has on dual vibrato, but only on the one I might try to sell. I like slow celeste for the classical organ pieces I mostly play.
Won't be much help rest of month. Car has been 5 hours without dripping antifreeze out the oil plug- I might have fixed the front cover leaks. If so, I'm headed to the country to mow until it rains or I can't stand the chiggers anymore. Course I haven't proved the carburator quit leaking gas or the heads quit leaking antifreeze or vacuum yet- just the front cover.

[ELPFan15]

I'm not modding the vibrato, I'm trying to get it to work right. I'll try moving that wire

[ELPFan15]

And, now none of the percussion triggers. I only moved the green wire. ?????

Just tried it again with the replaced wire. Now it's still got 8th harmonic. At this point, I have no idea what I'm doing wrong.

[ELPFan15]

Alright, it's working. After all of this, it's finally working. 2nd harmonic percussion and the vibrato still need work, but I finally got it working.