Getting Tandon 5.25" (TM100-4) and HxC Rev. C running at the same time...

[hails]

Hello folks, I have a "Performance Business Machine" PBM-100 running CP/M just great with my HxC Rev C using a disk image i found on the interwebs.

The old floppy drive works fine as if I do a floppy boot (with the HxC disconnected)... but try as I might I cannot get both devices to happily coexist.

I've tried lots of combinations (twisted cable, different jumpers configs) etc but I think maybe it is a configuration on the Tandon TM100-4 series drive?

I've looked at some complicated online manuals but I am not going to deny: I have no clue.....

The PMB-1000 computer comes with a Hard Drive (totally failed) and a single Tandon. So perhaps the existing Tandon is set as a single drive?

I am wondering if any of you good folks out there have any suggestions how to get a Tandon TM100-4 working with the HxC without resorting to major surgery?

cheers!
H

[hails]

Forgive my incorrect terminology does the HxC offer a way to provide termination, if the HxC is at "the end" of the cable?


cheers!

[Jeff]

Is the HxC working alone ?

[hails]

Hi Jeff - yes, my HxC works perfectly when it is connected on it's own.

[hails]

Hey Jeff - I must be getting closer!

I did manage to get both HxC and Tandon working by randomly trying the ID2 - Drive A Jumper.

As my HxC is at the end of the Twist, i believe that means "B: / DF1"

Not sure what DF1 means but it is assigned as B:

IdeallyI would like to boot from HxC, but then I would need to disconnect the Tandon.

Or I presumably need to tell the Tandon to be drive 1, right?

WOuld it be a fair assumption that right now it (the Tandon) is configured as Drive 0?

cheers!!

H

[Jeff]

Exactly. The internal drive is set as drive 0. You need to change this setting to be able to put the HxC as drive 0.
(DF1 is the Amiga name for "floppy drive 1").

[hails]

Hi Jeff - yep so... the Tandon TM100-4 has "programmable shunt socket." Below are the original FDD settings, with DS=0. I prized off the shunt and poked around with the jumpers.

After a while I stopped trying to figure this out due to my very limited knowledge, so I resorted to brute force I think I tested out all combinations and permutations on the HXC and with the DS set to 0,1,2,3 - and with/without HS jumpered, etc.

I can reliably boot from Tandon with HxC present, in one setting only. I can also boot from HxC but no Tandon, and vice versa. There are quite a few settings which allowed me to boot from Hxc, but the B: drive etc appeared to be the same as the HxC! Also in some settings I get both drive lights, but I can only boot from one or the other.

I also tried swapping the Tandon and HxC position on the cable. Tried both Tandon before the twist, tandon after the twist, Hxc before etc.

HS (head solenoid) YES
DS0 YES
DS1 NO
DS2 NO
DS3 NO
MX NO
(spare) NO
HM NO


So i am left wondering about termination. I have no resistor pack on the Tandon, I have a blank connector. So is that OK as long as the HxC is at the end of the cable? Or do I need a Termination resistor for the HxC?

thanks for the help!!!

h

[Jeff]

My question is : Is it possible to boot from both floppy drive on this machine ? I am not sure if what you are trying to do is possible without some hardware modification.