TRS-80 Model II

From: Lawrence Walker <>
Date: Tue Feb 24 09:35:32 1998

On 23 Feb 98 at 23:28, Ward Donald Griffiths III wrote:

> Lawrence Walker wrote:
> > There is a circular hole, but it accesses the drive locking
> > (parking) mechanism. It seems to be like SCSI with 2 50-pin
> > A B Control sockets and 3 A B C 20 pin Data sockets . I have a
> > 50-pin line terminator pack for it. The drives have a label saying "
> > this unit contains a line terminator " Haven't opened them up yet.
> > On the front panel a lock-key turns power on or off. I' ve only one
> > key but it seems to work with all 3. It has 2 buttons one labelled
> > Protect and one labelled Active. Possibly illuminated (haven't fired
> > them up yet.)
> Those are 8.4MB drives. Not SCSI, not even ST-506. Those are 8"
> Shugart mechanisms in there, 4 heads by 256 cylinders. I forget
> how termination worked in those units (haven't seen one in action
> in at least 12 years). And yes, the write protect switch and the
> active light are illuminated when in use. The number of times I've
> wished I had a hardware write-protect switch on a PC...
> When the drives are in use and the active light is blinking, those
> drives make the friendliest little chirping noise.
> > The II itself has a cage for 8 cards occupied by 5 cards, card 1 has
> > cables leading to 2 female DB25 "serial port A B' ,card 2 has a
> > cable to the int. fdd and one to a M 34-pin parallel printer port,
> > card 3 is for the ext. hdd , the like-new card 4 has no cables looks
> > like a memory card and card 5 is hard-wired to the CRT board.
> > Do you know whether it had some sort of fdd select jumpers ?
> > I'll switch cables and see if it will boot off the ext. fdd.
> Quite a few were sold, which became a serious problem a couple of years
> later when most of them were dropping like flies. Tandy's parts
> contract with Shugart was one of the worst deals they ever made. At
> least the 5/12/15/35/70 MB drives were standard Tandon units and if
> need be could be replaced with other vendors' drives, assuming a slight
> change to connect the drive logic to the write-protect switch.
 Well I finally fired up the HDDs and they appear to be functioning.
BUT , there seems to be no data cable pins on the M.II itself. It
seems strange since there is the ext. connector built in to the
chassis for the control cable. I checked out the HDD controller card
and there was nada nor could I see any 20 pin connectors anyplace
else. Were the data sockets only for sharing data between the HDDs ?

ciao larry
Received on Tue Feb 24 1998 - 09:35:32 GMT

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