Already done, years ago. Because they also sell their really great HX3 B-3 clone.
Best regards!
Thanks. Those two boards with the same part numbers as my machine are used in the R-100 with different names. Board layouts, schematic and part numbers are in the service manual.
Look for Percussion Gate Amplifier, and Alternate Percussion Amplifier.
I did not know what that board did. Someone in a forum called it a suppressor. I had to disconnect mine to get usable volume.
The board is simple enough to trace out. The one transistor is marked S667. In the old days the S-prefix meant silicon. I believe it's a 2SD667 PNP, but without the diagram I can't be sure. So it has to be traced out, then figure out how it works, then see if a PNP is appropriate. The transistor could be de-soldered to determine what it is, provided it is not damaged to the point of the inability to make a determination. Or just leave it disconnected, or make your own.
It killed most of the volume when I energized after the busbar cleaning. I had replaced the e-caps before that and it worked fine.
Now I have a dead fundamental on the Lower Manual. It looks like one contact was partially pushed in. Hope it's not a broken hair wire......
Oh cool, a contact in keyboard instead of a tonewheel problem.
If a hairwire is broken, they can be replaced by ordinary wire, plus a resistor. I think 27 ohms comes to mind, but read the other ones with a fresh battery DVM to match them- they change by the octave.
Also H100 keycombs and such are a plague on e-bay. Lots of people have scrapped them. Pity, I like mine better than the A100, but H100 are not as portable for a road band.
If a hairwire is broken, they can be replaced by ordinary wire, plus a resistor. I think 27 ohms comes to mind, but read the other ones with a fresh battery DVM to match them- they change by the octave.
Also H100 keycombs and such are a plague on e-bay. Lots of people have scrapped them. Pity, I like mine better than the A100, but H100 are not as portable for a road band.
Sorry about the duplicate schematics, in my preview I showed a left and a right half, but apparently both diagrams were complete. They are the percussion timer.
The board on the back of the keyboard chassis is the perc gate or timer.
The board in the tab box is a silence at turn on board. Just behind the vol soft tab which is the master volume.
One way designers make a silence circuit is use a jfet. A jfet reads like a pnp or npn on a DVM ohmsx2000 scale from the 3 terminals, but the two ends have a defined resistance between them that is bidirectional, say 50 or 150 ohms. That is when the voltage is open on the gate.
They use jfets to silence by feeding in the music in one end, taking it out the other, then cramming the gate up to the DC value of the feed end with DC voltage. The RC timer voltage from the cap goes to the gate, as gate goes away from the end feed voltage the volume increases.
See the DDT circuit involving a 3380 current amp IC and a jfet in Peavey PV-4C and PV-1.3K driver boards. PV-4C circuit diagram is on elektrotanya.com PV-1.3k is on eserviceinfo.com
The jfet is to the upper left. Peavey uses it to cram down input gain when the input waves are too square (crunch guitar) but Hammond I suspect just used a timer to silence the transistor containing H100's at turn on. My tube H100 the noise from the TG is much louder than anything the speakers make at turn on.
The perc gate board uses shaped DC voltage to affect the sound of the input signal to make it sound like a glock, guitar, banjo etc. Also a jfet volume squeezer. Only one voltage shape, and no variable time either. Sort of a very early ADSR board. Nicer ping envelope shape than just a RC decay though I think, there is an inductor.
If a hair wire has melted, many hammond owners recommend removing the insulating foam against the back cover. I haven't yet, it is not hot enough here in Indiana to cause a problem yet. I think foam eating wire was mostly an A100/B/C3 problem from late 64-66 when they were first using foam & probably didn't have the chemicals mixing right yet. Uncured polyalcohol chemical turns to acid from moisture in the air. But if I lose a bunch of hair wires I was wrong to not get with removing it.
While you're in there messing with the key contact wires, you might rewire the brush contact to control a midi encoder. As is they are paralleled in there to do the same thing on all 61 keys. If you bring out 61 wires you can connect them to a midi encoder, then a synth. brush busbar is the common contact.
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The reverb loop is 7 VAC out, 7 mv in, so some modification is in order to get a 2 vac in 2 vac out effect unit to work.
My tube socket was ittermittant on the 7 mv in to the EF86 tube, so I was in the mood to start that reverb loop mod. Went up to the attic to get the humming digitec Quad 4 effect unit (probably bad e-caps) and its been stolen! I haven't seen on of those on craigslist for years. Just guitar pedals. Picotech tells me that Audicity software on a PC sounds better, but a PC tower is too big to stuff in there. Plus the boot up/keyboard/display battle.
Congratulations on the keywire replacement.
I'd use midi first to get a bass drum sound. My arms aren't long enough to play a 3rd keyboard on top like all the B3 players on TV use. Plus I can make a US made Dell PC run midi synth, no need for some oriental import ****.
I view the H100 as an analog synth, with palladium hard keys instead of the rubber pads standard in commercial synths. I've already outlived the synth I bought in 1987, and I might last 40 more years.
On the tone wire connectors, gold plate pins would be more reliable over the years. For 25 mv signals the Elco connector worked great in seismic data acquisition. Still for sale under some other name. The cool thing about the Hammond, the low voltage stuff is all soldered except those push pins and wirewraps on the preamp boards. And those can be soldered. If I put the hours of practice in to learn to play some instrument, I don't want it to **** out on me and go obsolete like the EPS did. The H100's are already 49 years old, I think they will outlast me.
My tube socket was ittermittant on the 7 mv in to the EF86 tube, so I was in the mood to start that reverb loop mod. Went up to the attic to get the humming digitec Quad 4 effect unit (probably bad e-caps) and its been stolen! I haven't seen on of those on craigslist for years. Just guitar pedals. Picotech tells me that Audicity software on a PC sounds better, but a PC tower is too big to stuff in there. Plus the boot up/keyboard/display battle.
Congratulations on the keywire replacement.
I'd use midi first to get a bass drum sound. My arms aren't long enough to play a 3rd keyboard on top like all the B3 players on TV use. Plus I can make a US made Dell PC run midi synth, no need for some oriental import ****.
I view the H100 as an analog synth, with palladium hard keys instead of the rubber pads standard in commercial synths. I've already outlived the synth I bought in 1987, and I might last 40 more years.
On the tone wire connectors, gold plate pins would be more reliable over the years. For 25 mv signals the Elco connector worked great in seismic data acquisition. Still for sale under some other name. The cool thing about the Hammond, the low voltage stuff is all soldered except those push pins and wirewraps on the preamp boards. And those can be soldered. If I put the hours of practice in to learn to play some instrument, I don't want it to **** out on me and go obsolete like the EPS did. The H100's are already 49 years old, I think they will outlast me.
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The reverb loop is 7 VAC out, 7 mv in, so some modification is in order to get a 2 vac in 2 vac out effect unit to work.
The Leslie out to a custom amp/speaker cab is a possibility. Three chip amps could be used. The bass has to be derived. Could copy the low-pass filter that it uses now. The built-in speakers are only good for recording, imo. Or send the stereo signal to a PA system.
Congratulations on the keywire replacement.
I do not know if I did the right one yet or if the resistor is close enough....
The cool thing about the Hammond, the low voltage stuff is all soldered except those push pins and wirewraps on the preamp boards. And those can be soldered.
Manipulating a pin and soldering a wire back on can break the foil. I had to jump one to where the connection goes to the next component on the back of the board to repair.
The Leslie out to a custom amp/speaker cab is a possibility. Three chip amps could be used. The bass has to be derived. Could copy the low-pass filter that it uses now. The built-in speakers are only good for recording, imo. Or send the stereo signal to a PA system.
Congratulations on the keywire replacement.
I do not know if I did the right one yet or if the resistor is close enough....
The cool thing about the Hammond, the low voltage stuff is all soldered except those push pins and wirewraps on the preamp boards. And those can be soldered.
Manipulating a pin and soldering a wire back on can break the foil. I had to jump one to where the connection goes to the next component on the back of the board to repair.
I like where the reverb tabs are to play them on the fly. To continue to use them to turn reverb on & off, I'd need to get the levels right to plug a multi-effect unit in the original RCA sockets. 7 VAC down to 2 vac out is simple, a 1k pot used as a pad with the wiper and ground end going out to the RCA jack. Coming in the EF86 could be bypassed and the effect signal coming in could go straight to the place where the ef86 plate connects to the cap to the next stage. Might be the right level, maybe some level adjustment would be necessary.
I put a gold plate tube socket in the H112 out in the country on one of the amp channels out. The 7199 socket. The channel was popping, some idiot tech had put a broken case carbon film resistor in and the voltage was popping across the windings on the dust. When I tried to change the resistor the pin broke off the tube socket. Was a real ****, lots of components mounted on that tube socket. So putting the effects unit in instead of the EF86 socket would have been a real time saver.
Fortunately high serial # H100's that you own have better tube sockets than the early units I own. I think #11211 I own has the better sockets, no popping or hissing from that one. But it doesn't have new e-caps yet, sounds like a wet kazoo.
I like the sound as is, and own a TC-10 tone cabinet if I ever need more volume to perform out. H100 don't produce higher than 7 khz so a real hifi tweeter is not necessary. Not unless I get exotic sounds with a midi unit, but that could go to my house sound system. My house sound system has 15" woofers, so splitting the bass channel off would not be necessary to get good bass.
For your .110" flag terminals you could put gold plate elco pins individually each in its own inch of heat shrink tubing, not shrunk. They have a lot of contact force as is with the cross pinch design. I'm afraid tin plate flag pins would oxide up and give you unreliable signals after a year or so, requiring reseating a few every time you play.
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