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Can anyone lend/send me a copy of the Allen 081-7031 schematic for the MDC main board, 904-5665 ? Trying to figure out the keying/stop connections for this, before I acquire the board. ( I'm well aware of the limitations of the MDC's :-) ) TIA for any help.
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If you are able to get this, I sure would like a copy.Mike
My home organ is a Theatre III with an MDS II MIDI Expander.
I also have an MDC 10 Theatre spinet. -
To my knowledge, there isn't a schematic available for the MDC main boards. And sadly, there isn't a whole lot of information left on the tech site about the MDC models. I do have a service manual, and might have a diagram of some kind in there that would help. What model is the organ? As you may know, there were at least two types of main boards used in the MDC series over their lifetime. If I have one that is useful to you I can send you a scan.John
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Sorry to be out of the loop right now. And elderly family member passed away this week, and the out of town funeral is next week. On top of that, there is a LOT of stuff to get ready for Holy Week at church, family coming in to visit next weekend, not to mention a few service calls that can't wait! I think you all know what I'm talking about. As soon as Easter is behind us, I'll dig through the MDC manuals and see if I have a diagram that might help.John
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jbird604, taking you up on your offer, hoping your schedule has quieted down a bit.
What I got was: (the other MDC board was sold to someone else)
MADC Allen Organ Board MDC2 421-2704C 904-5665 081-7031
Any help with diagrams on the keying and stop connections will be much appreciated! TIA
BillComment
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Bill,
Yes, things are settling down somewhat, now that Easter is behind us. Just about wore me out before it was over, but I'm recovering. I was in the shop the other day and noticed that the MDC manual is still on the shelf. I'll take a look at it tomorrow and see if there is anything useful.
The Allen tech site only shows that the MDC-2 board was used in the MDC-42 and -52, the largest and only AGO models of the MDC series. The MDC-2 is not radically different from the MDC-1 board, but it does have a couple more stops and perhaps some other slight changes. The two boards are not interchangeable though. I found a couple of things on the site that might be helpful to you in figuring it out. Here are PDF's that you might look at while I'm searching for more drawings.
One of these is the stop wiring diagram for the 42/52 and shows the stops going to J95 on the MDC board. The other is the keyboard wiring diagram (and it is marked as being for the MDC-20 and -30, but other MDC models probably used identical keyboard connections), and it shows the keyboard wires also going to J95.
It looks like all stop and keying lines go to J95 and are internally linked to J96, which connects to the Preset Board and some other external parts.
Here are the files:
mdc42-stop-wiring.pdf
MDC-keyboard-wiring.pdfJohn
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There is literally nothing more in the service manual than the two diagrams I shared. Documents on the MDC series were limited and obscure.John
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Thanks, John, and sorry to hear that. By any chance would you know the connections on P175 and P176? P176 has 4 pins and only pin 3 seems to be connected. P175 has 6 pins and all seem to be connected. Again, this is on the MDC-2 board.
R, BillComment
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Here's a pic of the power supply connection chart. It shows J175 and J176 to be voltages from the power supplies to the MDC board.
John
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