RUX50 M7522 documentation wanted

[Roland Huisman]

Can anyone help me to find hardware documentation about the RUX50 M7522 RX50 floppy controller? There must be some add on board to connect the floppy drive to the M7522. And it would be great to have some documentation about the board itself.



Thanks in advance!
Regards, Roland

 

[ftcnet]

Can anyone help me to find hardware documentation about the RUX50 M7522 RX50 floppy controller? There must be some add on board to connect the floppy drive to the M7522. And it would be great to have some documentation about the board itself..

Lou -N2MIY post makes reference to M7522 print set on microfiche documentation.

 

[Roland Huisman]

Thanks, I will ask Lou then. I wonder if he made these digital...

Regards, Roland

 

[bqt]

I would guess/assume that with the RUX50, you always used the external RX50 drives, which have a big DB-type connector. DD50 I think, but I'd have to check.
That means on the computer side, there should be a distribution panel, to which your flat cable from the controller goes. And that distribution panel also have the DD50 then. And inside the external RX50-drive you have another DD50 to flat cable, but then going to the RX50 connector.

I should have some external RX50-drives, but I don't have any RUX50. :-(

 

[erd]

I would guess/assume that with the RUX50, you always used the external RX50 drives, which have a big DB-type connector. DD50 I think, but I'd have to check.
That means on the computer side, there should be a distribution panel, to which your flat cable from the controller goes. And that distribution panel also have the DD50 then. And inside the external RX50-drive you have another DD50 to flat cable, but then going to the RX50 connector.

I should have some external RX50-drives, but I don't have any RUX50. :-(

I have an RUX50 that we had on our 11/750 in the 80s/90s for cutting floppies to send to customers. Yes. The M7522 card has a 50-pin connector on it and there's a flat cable to an external DD50 connector that poked out of the back of the VAX (just cable and connector bolted to a metal bracket in the I/O section, no circuit board). Then there was a 3m (or longer) DD50 cable to a tabletop "Leprechaun" box with a DD50 on _it_, then an internal board inside the Leprechaun box with, IIRC, a couple of ICs and a 34-pin connector, then a short, typical 34-pin cable to the RX50 drive. I think the thing you seek was inside the drive box. The CPU end just had cables/connectors.

I only recently rediscovered my RUX50 module. I'm still looking for where my docs are because people have been looking for those for years and they aren't online.

-ethan

 

[erd]

OK. Here's that transition board and the level shifter board in the back of the Leprechaun box that is the active bit between the RUX50 and the RX50. I have no idea where to get one except another table-top RX50 box.

 

[erd]

Additional information: the active electronics are only needed for "long-line" operation. Long-line is up to 40' of total cable, short-line is limited to 10' or less.

Apparently long-line was more common (almost essential, for using this with our VAX-11/750), but it's not the only way.

Jumpers W49 and W50, up by the handles, select this.

Long-line W49: in W50: out
Short-line W49: out W50: in

The controller supports up to 4 logical units (one RX50 consumes two logical units, just like on an RQDXn controller). The drive type is configured for each logical unit with the jumpers W16-W31, 4 bits each, counting backwards. First logical unit is set up on W28-W31, All 4 jumpers out means no drive for this LU.

 

[9track]

I have a PDP-11/84 with an RUX50. It just uses a simple cable (part number 70-20691-02) to connect from the RUX50 board to a DD50 bulkhead connector. The cable is obviously not the correct one for this cabinet but this is how it was connected when I got the machine. The DD50 cable then runs through a missing panel in the back of the cabinet to the external RX50 box. You can see the TUK50 connection (white) to the left of the RX50 cable (black). This is how I think the bulkhead connection should look. The last two pictures show the back and front of the RX50 and TK50.

 

[erd]

Is that cable too short to reach the back, or is it just the smaller bracket has no place to mount with the other I/O panels?

Yes, I agree, the RUX50 leaving the box should look just like the TUK50 next to it.

On machines like the VAX-11/750 or boxes like the BA23, there are a few mounting spaces for that smaller, rectangular bracket. The later, FCC boxes (and a few early ones like the 11/730) have those larger brackets with the turned up edge.

I'm sure somewhere, there's a large bracket with a DD-sized hole in it (or one can take a filler bracket and cut a DD-sized hole - easy to do with a table-top CNC)

I think there were also the larger brackets with a mounting hole for the older, smaller ones but I'm not as sure of that.

 

[9track]

It's both actually. It's too short and the bracket would not fit on the back panel even if it was long enough. I was wondering which cabinet it was actually designed for or if it's meant to be used with a different card altogether. It seems to work though.

 

[erd]

It would fit this - the back of a BA23 enclosure, but that's not the only box that had this size brackets, it was just the first example I could find.

The one you have _could_ be for a TQK50 controller (which _did_ go to the back of a BA23). That would look the same.

 

[Roland Huisman]

This gives a lot more insight about how to actually use this card. This is not going to be easy to find I think... But at least I know what I need. Thanks a lot for the pictures!

Regards, Roland