MPC60 SCSI board schematics

I need your help. Does anybody have the schematics or a drawing, even hi-res images of the top/bottom MPC60 scsi board with visible traces? I have a couple LSI controller chips here and wanted to diy one for my old mpc60. Any help is much appreciated.

-B

Have not seen any schematics, as it is not an Akai product, it was not included in the Akai schematics.

A high res photo of the top is not going to show all the traces, as I think some are hidden under the components.

I think that the clone SCSI board makers had to pull the components off of an existing SCSI board, or at least trace them out to see where they go.

There isn't really much to the SCSI boards though, so it shouldn't be too difficult.

I have a clone SCSI board out at the moment, I can get some detailed photos of both sides happening in the next couple of days, if you don't find any elsewhere.

SimonInAustralia wrote:Have not seen any schematics, as it is not an Akai product, it was not included in the Akai schematics.

A high res photo of the top is not going to show all the traces, as I think some are hidden under the components.

I think that the clone SCSI board makers had to pull the components off of an existing SCSI board, or at least trace them out to see where they go.

There isn't really much to the SCSI boards though, so it shouldn't be too difficult.

I have a clone SCSI board out at the moment, I can get some detailed photos of both sides happening in the next couple of days, if you don't find any elsewhere.

That would be awesome. Your right there isn't much to it, I could probably figure most of it out if I could see the majority of the circuit so any pics would be great!

Pics of a SCSI board are on my blog. Not super hi-res but it should be enough to get you started.

http://www.mpchunter.com/scsi-interface ... ai-mpc-60/

MPCHunter's photos are of an original Marion SCSI board.

These are of a clone...

Great, thanks guys!! Can you tell me what value the 3 resistor networks are? I'll make a guess on the caps .33uf and 1n4148?

SimonInAustralia(or anybody else who has a scsi board on hand and a mulitmeter or probe), any chance you could check a few points on it for shorts/connections for me? I've had a bit of free time and have already laid out a bulk of the board based on the photos. I just have a couple questions that could probably be answered with a little multimeter probing.

on SN74HCT573:
I'm assuming pins 12/13/14 go to gnd or are NC? Do any of the other pins connect to any each other under the chip?(multimeter probe for shorts).

on the CD74HCT139:
I've got pins 1/3/4/8/9/10/13/15/16 mapped,
Pins 2/5/6/7/11/12/14 are wildcards, I assume some would be connected under the chip due to the nature of the circuit... or possibly to connected to (gnd or vcc , but thats doubtful) or NC(once again a multimeter probe for shorts)?

Anyway, if anybody has a chance and would be willing... I'd really be grateful for the confirmations or additions, and I'll finish laying out the board.

On the clone...


All 3 blue ceramic capacitors marked 104Z (I think, that shit is tiny as). So 0.1uF +80/-20%


3 x passive SCSI terminator resistor networks marked...

8X-4-221/331L
•(Bourns 'B' Logo)B10253

...so 8 pin SIP 221,331 ohms.


Other component, diode?, can't see what it's marking are (that shit is too tiny for my eyes).

skylab001 wrote:SimonInAustralia(or anybody else who has a scsi board on hand and a mulitmeter or probe), any chance you could check a few points on it for shorts/connections for me? I've had a bit of free time and have already laid out a bulk of the board based on the photos. I just have a couple questions that could probably be answered with a little multimeter probing.

My Fluke multimeter is at work, but I think I have a shitty Radio Shack multimeter here somewhere.

What software are you laying it out in?

I would like to see if it can be made to fit on a 14cm x 4cm board, to fit in an ASQ10.

Also, check the Stratos Technology MPC60 SCSI board.

He has made some changes, including a 50 pin IDC header, instead of the standard 26 pin IDC header, for easier connection to internal SCSI devices, without needing 26 pin IDC or DB25 to 50 pin IDC adapters, has an extra power connector to take power off for a card reader, and is using an active SCSI terminator IC.

http://artmix.com/MPC60_SCSI_IF.html

skylab001 wrote:I just have a couple questions that could probably be answered with a little multimeter probing.

on SN74HCT573:
I'm assuming pins 12/13/14 go to gnd or are NC? Do any of the other pins connect to any each other under the chip?(multimeter probe for shorts).

On the SN74HCT573 Octal D-Type Latches...

1,8,9,10 to Ground
12,13,14 are NC

Nothing else connected to each other under the chip, that I can tell.

skylab001 wrote:on the CD74HCT139:
I've got pins 1/3/4/8/9/10/13/15/16 mapped,
Pins 2/5/6/7/11/12/14 are wildcards, I assume some would be connected under the chip due to the nature of the circuit... or possibly to connected to (gnd or vcc , but thats doubtful) or NC(once again a multimeter probe for shorts)?

On the CD74HCT139 Dual 2-to-4 Line Decoder/Demultiplexer...

2,8 to Ground
1,15 connected
3,13 connected
5/6/7/11/12 seem to be NC

14 on CD74HCT139 to 16 on SN74HCT573

So under chip on CD74HCT139 seems to be 2 to 8 (ground), and pin 16 of SN74HCT573 coming under to 14.

Nothing else connected under chip that I can tell

SimonInAustralia, thanks so much for checking those chips, I knew there was something under the CD74HCT139, I just didn't want to guess. The stratos is a nice board, the 25 to 50 pin is a good idea. Is there a reason in particular you think he used the extra SCSI auto termination chip? I was just planning on doing the board exactly like the marion and that clone, seemed the quickest and easiest way to get it right. There could be a little room to play with the size though. I'm laying it out in Eagle.

On L5380PC SCSI Interface Controller...

Diode anode seems to connect under large IC to pins 27,31

11 to ground

skylab001 wrote:The stratos is a nice board, the 25 to 50 pin is a good idea. Is there a reason in particular you think he used the extra SCSI auto termination chip?

Not sure, though I think I read a reason somewhere, just can't remember where.

Maybe so that the termination can be disabled, if the SCSI interface is connected in the middle of the SCSI bus, with a terminated internal SCSI device, and a terminated external SCSI device?

Maybe this is where I read a mention of the active terminator, doesn't go into any detail...

http://www.ebay.com/itm/301064131675

Stratos Technology AKAI MPC60 SCSI Interface Card, CF AztecMonster built-in possible

Stratos Technology SCSI Interface Card KIT for AKAI MPC60/60II. This is able to expand SCSI Interface of MPC60/60II.
All new designed (not dead copy). Accurate performance depends on Active Terminator, 50pin internal SCSI cable and sure GND point.
Made in Japan.
CF AztecMonster Built-in KIT (Optional) makes CF memory card as MPC60/60II internal HDD.
Demension (SCSI PCBA) : 80 X 150 X 12.5 mm
Weight : 150g
Including installation manual, cable, screw spacer.