P70 PS/2 - made correct cable, Rev C still won't read any images

HxC Floppy Emulator on IBM PC and compatible support
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spacecadet
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P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Thu Jun 21, 2018 11:47 pm

I've got an IBM P70 (in addition to the original PC I asked about earlier) - I saw the previous post about the cable and I also looked up how to make a cable for a standard drive for the PS/2. I did that - I cut wires 3, 5 and 6 from a standard twisted floppy cable and soldered them to a floppy power adapter to connect to the HxC. I know +12V isn't used but I figured I might use this cable for something else someday so I may as well make it like a standard floppy power connector.

The HxC is getting power and it's making all the standard noises. It also gets a signal from my computer when I try to select the A: drive. The P70 also does a hardware check when you first boot and tells you if it doesn't detect a floppy drive - the only way I could clear that error was to put the jumper block in ID2, which is supposed to be for a non-twisted cable and mine is twisted. But again, in any other position my P70 would give me a "floppy drive not found" error (601).

When I do try to select the A: drive, no matter what image I have loaded, it scans for a second and then I get a "General failure reading drive A" and "Abort, Retry, Fail?" If I retry, it scans again, then stops and gives me the same thing. I can see that the HxC is scanning the first few tracks and then going back to 0, if that suggests anything.

I've tried following the manual and I've used the HxC software to export my images to hfe. I've tried various different things in the config file too but nothing seems to matter. Any other suggestions for how to get this working on a PS/2?

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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by Jeff » Fri Jun 22, 2018 7:27 am

Hi,

Have an floppy pinout description for this machine ?

spacecadet
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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Fri Jun 22, 2018 8:59 am

This should be the pinout:

Pin Signal Pin Signal
1 Ground 2 -High Density Select
3 + 5VDC 4 Drive Type ID 1
5 Ground 6 + 12VDC
7 Ground 8 -Index
9 Ground 10 Reserved
11 Ground 12 -Drive Select
13 Ground 14 Reserved
15 Ground 16 -Motor Enable
17 Ground 18 -Direction In
19 Ground 20 -Step
21 Ground 22 -Write Data
23 Ground 24 -Write Enable
25 Ground 26 -Track 0
27 Ground 28 -Write Protect
29 Ground 30 -Read Data
31 Ground 32 -Head 1 Select
33 Ground 34 -Diskette Change

I've cut wires 3, 5 and 6 and routed them to a standard floppy power connector (with the ground leads of the floppy power connector both connected to wire 5), then connected that to the power connector of the HxC. The rest of the cable minus wires 3, 5 and 6 is going in to the 34 pin port of the HxC. And I'm using a twisted cable. I'm waiting on a non-twisted cable just to see if that works any better, but I don't have one yet.

Is there anything obvious here that I'm missing?

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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by Jeff » Fri Jun 22, 2018 9:41 pm

Please post a picture to show me how you have connected the floppy ribbon.

spacecadet
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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Sat Jun 23, 2018 4:25 am

Here's a photo of the connections to the HxC:

Image

Just to be clear since I know it's out of the photo, but pin 3 is going to the red wire and pin 6 to the yellow wire.

Thanks for any help!

spacecadet
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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Wed Jun 27, 2018 1:30 am

If it adds any relevant info, I also just tried to do the same thing with a straight (non-twisted) cable, and had the same results.

So for the record, I've tried it as the first drive on a straight cable, the first drive on a twisted cable (in the straight part) and the second drive on a twisted cable. In all cases, I've had to set the jumpers the way the computer would actually detect a floppy drive, which if I remember right was backwards from the manual in every case. (In other words, the setting for non-twisted with a twisted cable, and the settings for twisted with a non-twisted cable.)

Acts the same every time... makes the seeking noises just like a regular floppy but then gives a general drive failure. The LCD is showing an active HFE image in every case, and at this point I'm using an image I made in the HxC software itself, not a converted image from something else.

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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by Jeff » Wed Jun 27, 2018 7:21 am

spacecadet wrote:
Wed Jun 27, 2018 1:30 am

Acts the same every time... makes the seeking noises just like a regular floppy but then gives a general drive failure.
The error come right after the bios seek test or while trying to boot/read the disk ?

spacecadet
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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Wed Jun 27, 2018 8:05 am

Jeff wrote:
Wed Jun 27, 2018 7:21 am
The error come right after the bios seek test or while trying to boot/read the disk ?
The error happens when trying to read the disk. The BIOS test I can get passed if I have the jumper set a certain way, but it's "upside down" compared to the manual. Unless that was changed on revision C.

But now I'm wondering if there's something weird going on with that, because I noticed just tonight that when it's trying to read an image it always says "RB" on the LCD, not "RA" like it does at boot or in the manual. It then tries to read the first couple tracks, finds nothing there and immediately stops. Does "RB" stand for "Reading B"?

I feel like maybe somehow drive A and B are getting mixed up. I don't have a drive B and this computer doesn't come with one, so only drive A exists in the BIOS. I'm hooking up the HxC by itself (disconnecting the built in floppy) so it should just replace my existing drive A. That's why I tried both a non-twisted and twisted cable, and one with a single connector and another with two connectors. But I feel like it might be trying to read internally as drive B for some reason?

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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by Jeff » Wed Jun 27, 2018 8:48 am

spacecadet wrote:
Wed Jun 27, 2018 8:05 am

But now I'm wondering if there's something weird going on with that, because I noticed just tonight that when it's trying to read an image it always says "RB" on the LCD, not "RA" like it does at boot or in the manual. It then tries to read the first couple tracks, finds nothing there and immediately stops. Does "RB" stand for "Reading B"?
yes this probably the issue. the jumper on the hxc is not in the right place. move it to the drive A part.
the hxc is able to emulate 2 drives, and you are trying to read the second one without image assigned for the hxc "drive b".

spacecadet
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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Wed Jun 27, 2018 9:02 am

Jeff wrote:
Wed Jun 27, 2018 8:48 am
yes this probably the issue. the jumper on the hxc is not in the right place. move it to the drive A part.
the hxc is able to emulate 2 drives, and you are trying to read the second one without image assigned for the hxc "drive b".
I've just set up the config file so that it's only emulating a single drive, and I've tried the jumper in *every* possible location. This PC won't work with it in the spot shown in the manual. It doesn't recognize any drive as being present; it's totally dead with the jumper there. But if I do what the manual says for a straight cable with a twisted cable and vice versa, it does recognize it and sends it commands, but just can't read from it. That's the best result I can get in any jumper location.

I did get it to say "RA" instead of "RB" by disabling the second drive emulation in the config. So now it does seem that it's trying to read from drive A. But still no luck in actually reading disks.

I did notice that pin 2 on the connector is not even with the others and is pushed in a little bit, but that wouldn't affect anything, would it? Otherwise I am just stumped. I feel like something about this machine just isn't going to work the HxC.

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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by Jeff » Wed Jun 27, 2018 9:26 am

spacecadet wrote:
Wed Jun 27, 2018 9:02 am
I did notice that pin 2 on the connector is not even with the others and is pushed in a little bit, but that wouldn't affect anything, would it?
Please post a picture of this.
spacecadet wrote:
Wed Jun 27, 2018 9:02 am
Otherwise I am just stumped. I feel like something about this machine just isn't going to work the HxC.
It is working. Set the right jumper, use a working floppy ribbon and use the right interface mode, and it will.

Please take a picture of the jumper block and post it here.

spacecadet
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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Wed Jun 27, 2018 10:04 pm

Jeff wrote:
Wed Jun 27, 2018 9:26 am
Please post a picture of this.
Here's a pic where you can see the slightly recessed pin 2:

Image
Jeff wrote:
Wed Jun 27, 2018 9:26 am
Please take a picture of the jumper block and post it here.
This shows how I have to have the jumper for the computer to recognize it when connected on a twisted cable with one connector:

Image

I also shot some video so you can see exactly what the HxC is doing, along with the PC: https://youtu.be/Is0gmaidg0w

The first boot is with the jumper in the position as in the picture - you see it makes it through the boot without errors but then has a "general failure reading drive A". On the second boot, I switched the jumper to the way the manual shows, and I get a 601 and 162 error, which are floppy drive not detected and misconfiguration error. Then I get a "drive not ready" error when selecting the A drive.

I found an IBM technical reference manual for this computer and the pinout I posted earlier for the PS/2 in general was missing one pin specific to this machine. Here's the actual pinout from the reference manual - does that pin 1 (2nd drive installed) have any potential for conflicts?

1 I -2nd Drive Installed 2 0 -High Density Select
3 0 +5Vdc 4 N/A Reserved
5 N/A Ground 6 0 + 12Vdc
7 N/A Signal Ground 8 I -Index
9 N/A Signal Ground 10 N/A Reserved
11 N/A Signal Ground 12 0 -Drive Select
13 N/A Ground 14 N/A Reserved
15 N/A Signal Ground 16 0 -Motor Enable
17 N/A Signal Ground 18 0 -Di rection In
19 N/A Signal Ground 20 0 -Step
21 N/A Signal Ground 22 0 -Write Data
23 N/A Signal Ground 24 0 -Write Enable
25 N/A Signal Ground 26 I -Track 0
27 N/A Signal Ground 28 I -Write Protect
29 N/A Signal Ground 30 I -Read Data
31 N/A Signal Ground 32 0 -Head 1 Select
33 N/A Signal Ground 34 I -Diskette Change

It's also missing the signals for both Drive Select 0 and Motor Enable 0. So I'm wondering if I should reroute wire 16 to pin 10, and wire 12 to 14? And maybe just cut wire 1? (Since it should normally just be ground anyway.)

Thanks again... feel like I'm getting closer to knowing what's going on with this.

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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by Jeff » Wed Jun 27, 2018 11:26 pm

spacecadet wrote:
Wed Jun 27, 2018 10:04 pm

This shows how I have to have the jumper for the computer to recognize it when connected on a twisted cable with one connector:
Seems fine !

Can you share the file image + cfg file you are using ?
Have you tried to clear the internal config ? (Press select without sdcard to enter the menu)

spacecadet
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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by spacecadet » Thu Jun 28, 2018 3:32 am

Jeff wrote:
Wed Jun 27, 2018 11:26 pm
Can you share the file image + cfg file you are using ?
Ok, that's attached. I did try some other things before this config (starting with the default), but now I've got it set to specifically single drive, IBM 1.44MB. The image is just very simple, just a single .exe file that I know works because I loaded it from an actual floppy before trying it with the HxC. I created the image with the HxC software in "Disk Browser" mode. All the images I've tried give me the same error but this is the one I'm testing with now since it *should* work.
Have you tried to clear the internal config ? (Press select without sdcard to enter the menu)
I did just now, and unfortunately there was no effect.

Is there anything else you can think of? It's really weird that it seems to be basically working but just isn't reading any disk images. I've also tried different SD cards, made sure a real floppy works in this machine (it does), etc.
Attachments
config_and_image.zip
(118.86 KiB) Downloaded 91 times

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Re: P70 PS/2 - made correct cable, Rev C still won't read any images

Post by Jeff » Sat Jun 30, 2018 8:07 am

After clearing all the settings to default values, do you still read "RB" ?

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