VOGONS


First post, by Gonzolenfox

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Hello there,
I have a question about the breakout box for the MPU-IPC.
The user Dellamorte has mentioned in this thread below, that the BOB for MPU-IPC-T is not compatible with the MPU-IPC Controller card, because the hex inverter is still integrated in the BOB, not on the controller card.
Roland MT32 & Roland mpu-ipc-t

Well, I have one of these MPU-IPC Controller Card, but no BOB.
So, my question is: Would it be possible to make a cable adapter for only Midi out with a integrated hex inverter, so you can use it for MT-32?

Has anyone the schematic of the MPU-IPC with BOB?
I found only the schematic of the MPU-IPC-T:
https://www.ardent-tool.com/sound/MPU-IPC-T-circuit.jpg

Or maybe has anyone the BOB and can take some pictures, so I could see, which components are in there and where to where the wires going?
This would be amazing.

Thanks and best regards
Stefan

Reply 1 of 6, by keropi

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It is better to have the box of the mpu-ipc rather than having the ISA interface: the whole Mpu chipset is inside the box making the ISA matching card just a simple interface to ISA .
For the ipc-t the chipset moved to ISA card and the box is just the ports more or less.
So in your case unless you find that Roland box the ISA card is nothing more than a few logic chips and thus not able to do any mpu work.

You can find a photo of the box electronics here: https://nerdlypleasures.blogspot.com/2013/06/ … intage.html?m=1

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Reply 2 of 6, by Gonzolenfox

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Hi keropi,
Can it be, that you mean MPU-401 and not MPU-IPC?
On my Card there are also the Roland Chips, like the MPU-IPC-T, See the picture.
Apparently it should suppose to be missing the hex inverter.
(Instead on the position of IC3 (74LS08) on my card, there is IC12 (74LS04, hex inverter) on the MPU-IPC-T)
This is the upper IC near the DSUB25 Connector.

Reply 3 of 6, by cyclone3d

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Doa search for the wiring for the MCB-1 and and MPU-IPC. It might be possible to make an adapter for an MCB-1 to use it on the MPU-IPC.

I'll pull the cover off of my MCB-1 when I get home and take a gander at it to see if there is a hex inverter.

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Reply 4 of 6, by keropi

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ah sorry I was thinking of the older model with the large breakout box...
I have no idea for this variant ...
maybe you can work out where pin12 goes and add the potential missing chip and test if this works (maybe you need to add a LS04 and the rest of the passives after that)

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Reply 5 of 6, by cyclone3d

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Can you get a better picture of the front side as well as the rear side that show the traces clearly?

Also, closer up pictures of the card wod be helpful as well. The chip markings bearing clearly readable will help
Maybe take pictures that split the card in half.

The vogons forum will kill picture quality. Saving them at 85% quality will keep the forum from butchering the quality.

The chips are pretty readable as-is, but the clearer the better. The traces being clearly visible for both side of the board will be very helpful.

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Reply 6 of 6, by Shponglefan

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I have an MPU-IPC and break out box. I just popped the box open and took a couple pics (front and back) of the circuit board.

It does have a hex inverter, plus an optocoupler and other components. Not a super complicated circuit to reverse-engineer and recreate I imagine.

The attachment MPU-IPC bob circuit top.jpg is no longer available
The attachment MPU-IPC bob circuit back.jpg is no longer available

For reference, a shot with the box with the labels for each connector.

The attachment MPU-IPC box.jpg is no longer available

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