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smp
July 29th, 2014, 08:23 AM
So, I am very happy to report that I finally managed to acquire a working H8 that is in very good condition! Included inside is the original CPU board, a 16K RAM board, a wire-wrapped 32K RAM board made on a Heathkit wire-wrapping board, a "Controller Board" which I believe is the floppy disk controller board for the H17 floppy disk system, a four port serial I/O board, and a small board in the back that I believe is an Extended Configuration board.

I am even more happy to report that I removed all the boards except the CPU board and the 16K RAM board, and I have been able to verify things are running well by typing in the first test program from the Operating Manual, and I saw the "Your H8 is up and running" message. I then typed in the memory test program and that also has worked successfully (although only on 8K of the RAM - I need to find the source code so I can figure out how to extend the test to cover 16K or eventually 48K).

Now for moving on and trying more of the boards...

I left the Extended Configuration board in, just in case there are other modifications done to the CPU that now require it to be there. I managed to find operating documentation for that board today, so I will be checking out what it says and verifying the state of my machine later on.

Now for my question:
Since I have the "Controller Board," is it necessary that I go out and find an actual H17 Floppy Disk system, or can I cable the controller to an available 360K 5.25 floppy disk drive that I happen to have around? Does anyone know if Heathkit did anything funny to their floppy disk drives (like Osborne or Apple did to theirs) that requires that I get actual H17 hardware? Since I do not have the ribbon cable, does anyone have any information on what I would need to acquire or make myself? Oh, yes, I do know that I will need 10 sector, hard sector floppy disks. I actually do have some, thanks.

Thanks, in advance, for your thoughts and ideas.

smp

smp
August 1st, 2014, 03:47 AM
I got onto the Society of Eight-Bit Heathkit Computerists Google Group (SEBHC): https://groups.google.com/forum/#!forum/sebhc and I asked the same question. The answer I received was, yes, regular old 360K drives can be used with the H8.

I'll be giving this a try this weekend, and I'll post back with my results.

smp

Dwight Elvey
August 1st, 2014, 12:56 PM
If it is H17, it will require floppy disk with 10 hard sectored.
If you go to SEHBC (sebhc.lesbird.com)
you'll find code there to boot strap your disk.
There is my older code that requires DOS ( not
DOS in windows but a pure DOS boot ) or
some windows code that one of the others wrote
to do the same from the host side.
You'll still need some hard sectored disk.
If the controller you have has a Z80 on it, your in
luck as that is a soft sectored controller and you can
use more friendly methods of creating disk.
Dwight

smp
August 1st, 2014, 03:24 PM
If it is H17, it will require floppy disk with 10 hard sectored.
If you go to SEHBC (sebhc.lesbird.com)
you'll find code there to boot strap your disk.
There is my older code that requires DOS ( not
DOS in windows but a pure DOS boot ) or
some windows code that one of the others wrote
to do the same from the host side.
You'll still need some hard sectored disk.
If the controller you have has a Z80 on it, your in
luck as that is a soft sectored controller and you can
use more friendly methods of creating disk.
Dwight

Hello Dwight,

Thanks very much for this pointer and information. I found your code and I am scrutinizing the documentation. I'll have to resurrect the DOS only computer I have out in the garage for this, I guess. Anyway, I am currently trying to see if I can successfully get one of my 360K drives to work.

I have a Teac FD-55F half height drive, and a Tandon TM65-2L half height drive.

I have tried working with both of my drives, but I may have gotten further with my Tandon. Maybe it was about the same for both drives, but the one I am attached to at the moment is the Tandon.

I needed to assign the drive as DS2 in order for it to appear to the H8 as SY0:.

Working from the H17 Operation Manual, I have been able to perform the H8 memory test and the Controller memory test successfully. I also have been able to perform all of the individual SY0: Drive Interface Tests. I then moved on to the SY0: Read/Write Test. Here, the write portion of the test seemed to go successfully. I ended up with the beep and the display showing 037 127 Pc as it was supposed to. Performing the read portion of the test did not go successfully. Instead of ending up with 037 365 Pc, as the manual said it would upon success, I instead ended up with 037 306 Pc, which the manual says indicates some sort of failure.

I then entered the Drive Speed Adjustment program, and when I ran it on each of the drives, I got an acceptable number being displayed. The manual says hopefully one will see a number close to 200, and I got 212 with the Teac and 200 with the Tandon.

All this leads me to believe that I am properly interfaced to the floppy disk drive. It appears that I may not be writing properly, or, if I am writing properly, I am not reading back properly.

All of this, by the way, is using a proper 10 sector, hard sector, 40 track diskette. The diskettes I have are labeled as double density - should that matter?

Sigh. I guess it's time to break out the digital volt meter and the oscilloscope and try some of the troubleshooting activities that the manual provides.

Thanks for listening.

smp

Dwight Elvey
August 1st, 2014, 06:04 PM
As stated on the other MB, double density is not an issue.
Dwight

smp
August 9th, 2014, 11:15 AM
OK!

Through the immense generosity of a great person in the SEBHC Google Group, I have obtained some bootable diskettes for both CP/M and HDOS.

I have now verified that my Tandon floppy disk drive is working fine. I can boot up into CP/M, and I am now off and running.

Having a blast with my new-to-me H8!

smp

Frank S
August 9th, 2014, 11:42 AM
Hello SMP,
the TEAC FD-55F is an "720KB" 80 track drive.
So you have to double step the drive or choose a right drive, like an TEAC FD-55B.
Frank

smp
August 9th, 2014, 12:06 PM
Hello SMP,
the TEAC FD-55F is an "720KB" 80 track drive.
So you have to double step the drive or choose a right drive, like an TEAC FD-55B.
Frank

Thanks very much for this information, Frank.

When I looked up info on the Teac FD-55F, I was most concerned about seeing that it was a 300 RPM drive, and I completely missed the 96 tpi and 80 tracks!

You have saved me a bit of hair tearing, for sure...

smp