12 Apr
2007
12 Apr
'07
1:38 a.m.
Hi all --
Recently picked up a TRS-80 "Eight Meg Disk System" (model 26-4151) and
the associated interface board, with the intent of hooking this up to my
TRS-80 Model 16.
On further investigation, it appears that the 26-4151 is a Secondary
drive, which makes me curious as to whether this effort is going to be
ultimately fruitless. So, without further ado, here's the questions I have:
1. Is it possible to get this secondary drive working as a primary, or
am I up a creek without having a primary drive (or extra magic hardware
in the drive I have.)
2. If I can work around #1, I need to know the pinouts of the drive and
the controller board since I do not have a cable to connect the two.
The controller has a 50-pin edge connector and the drive has three
connectors -- 2 50-pin (labeled "Control") and one 20-pin (labeled
"Data").
a. And as a follow on to #2, where would you suggest getting the
parts and tools necessary to build the aforementioned cable? I've never
constructed such a cable, and I'll have need to do so again in the
future (need to assemble some long-ish ESDI cables for my PDP 11/73...)
Thanks for any suggestions,
Josh
12 Apr
12 Apr
7:24 a.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Josh Dersch
Sent: Wednesday, April 11, 2007 5:39 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: TRS-80 "Eight Meg Disk System" questions...
Hi all --
Recently picked up a TRS-80 "Eight Meg Disk
System" (model 26-4151) and
the associated interface board, with the intent of hooking this up to my
TRS-80 Model 16.
On further investigation, it appears that the 26-4151
is a Secondary
drive, which makes me curious as to whether this effort is going to be
ultimately fruitless. So, without further ado, here's the questions I
have:
1. Is it possible to get this secondary drive working
as a primary, or
am I up a creek without having a primary drive (or extra magic hardware
in the drive I have.)
-----
If this is a secondary drive, then No, it will not work without the primary
-----
2. If I can work around #1, I need to know the pinouts
of the drive and
the controller board since I do not have a cable to connect the two.
The controller has a 50-pin edge connector and the drive has three
connectors -- 2 50-pin (labeled "Control") and one 20-pin (labeled
"Data").
a. And as a follow on to #2, where would you suggest getting the
parts and tools necessary to build the aforementioned cable? I've never
constructed such a cable, and I'll have need to do so again in the
future (need to assemble some long-ish ESDI cables for my PDP 11/73...)
--------
IIRC, it is 50 pin straight through(to the primary enclosure)
the 8 meg units used SA1004? Drives that were very prone to failure :( the
techs at RS called it "blowing the bubble", I had an 8 meg disk unit that
got 3 new drives into it while it was under it's original and extended
warranty. On the 3rd drive they informed me that they were cancelling my
extended warranty (I was leaving the system up 24x7 with Xenix running on
it) and had terminals in everyones rooms and a modem hooked up to one of the
serial ports so we could dial out to local BBS'
http://nemesis.lonestar.org/computers/tandy/hardware/storage/mfm.html
3:25 p.m.
From: Josh Dersch <derschjo at msu.edu>
Hi all --
Recently picked up a TRS-80 "Eight Meg Disk System" (model 26-4151) and the
associated interface board, with the intent of hooking this up to my TRS-80
Model 16.
On further investigation, it appears that the 26-4151 is a Secondary drive,
which makes me curious as to whether this effort is going to be ultimately
fruitless. So, without further ado, here's the questions I have:
1. Is it possible to get this secondary drive working as a primary, or am I
up a creek without having a primary drive (or extra magic hardware in the
drive I have.)
2. If I can work around #1, I need to know the pinouts of the drive and the
controller board since I do not have a cable to connect the two. The
controller has a 50-pin edge connector and the drive has three connectors
-- 2 50-pin (labeled "Control") and one 20-pin (labeled "Data").
Hi
It sounds like you have a mismatch of things. It sounds like you have
the interface board for the 5 Meg drive and the 8 Meg drive that
has the controller in the trs-80. The 5 Meg came with the controller
in the drive board ( although, I've seen some indication that some
of the 8Meg drives did this as well ). The newer large drive had
the controller in the trs-80 box and required the two ribbon cables
of 50 and 20 pins.
It can be made to work with either a controller board from a 5 Meg
or a wd1001 board. Both have been on ebay resently but I only
see then every couple of months. Of course one can get the
controller board that mounts in the trs-80.
The wd1001 will require a little additional circuit to do address
decoding.
The controller went for a 'buy it now' but was the second time it
was listed.
Just to make sure, open up your drive box. If all that is in there
is a power supply and drive, then you'll most likely need to find one
of the controller boards. If it has a large board, then one of the 50
pin connectors was to be connected to the interface. You should
look.
a. And as a follow on to #2, where would you
suggest getting the parts
and tools necessary to build the aforementioned cable? I've never
constructed such a cable, and I'll have need to do so again in the future
(need to assemble some long-ish ESDI cables for my PDP 11/73...)
Although, I currently have a crimper tool for these connectors,
I've had good success with a vice and a couple strips of metal.
With either method, one can still mess them up. One needs
to make sure the ribbon is well aligned before the final squeeze.
Dwight
Thanks for any suggestions,
Josh
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10:06 p.m.
Hi all --
Recently picked up a TRS-80 "Eight Meg Disk System" (model 26-4151) and
the associated interface board, with the intent of hooking this up to my
TRS-80 Model 16.
On further investigation, it appears that the 26-4151 is a Secondary
drive, which makes me curious as to whether this effort is going to be
ultimately fruitless. So, without further ado, here's the questions I have:
1. Is it possible to get this secondary drive working as a primary, or
am I up a creek without having a primary drive (or extra magic hardware
in the drive I have.)
I believe you've got problems... The host interface board is pretty
simple, I think, just buffers and an address decoder. It talks (8 bit
parallel data bus, register select lines, etc) to the controller board
mounted inside the primary drive cabinet. This controller talks to the
drives by an interface somewhat similar to ST506 (I don't think it _is_
ST506, though.), in that there's a control cable that links from the
controller to all the drives and a separate data cable from the
controller to each drive.
The controller board can handle up to 4 drives, the one mountedin the
primary cabinet and up to 3 more secondaries
Without the cotnroller board (which is, IIRC, similar to a Western
Digital thing), you are not going to get it working.
-tony
13 Apr
13 Apr
2:07 a.m.
From: ard at p850ug1.demon.co.uk (Tony Duell)
Hi
Tony is most likely right but the interface is compatible w/ ST506, I'm
currently
running a ST251 as a 10Meg drive on the TRS-80 controller ( not
in a TRS-80 invironment ).
As I stated, the WD1000 will work fine but needs a simple address
decoder. It may not work with the lights and switches on the cabinet
but it will work with the drive.
If you like, I can find a seller ( not ebay ) that has several WD1000's
for sale. I have no idea the price but they are suppose to be working.
Dwight
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Hi all --
Recently picked up a TRS-80 "Eight Meg Disk System" (model 26-4151) and
the associated interface board, with the intent of hooking this up to my
TRS-80 Model 16.
On further investigation, it appears that the 26-4151 is a Secondary
drive, which makes me curious as to whether this effort is going to be
ultimately fruitless. So, without further ado, here's the questions I
have:
1. Is it possible to get this secondary drive working as a primary, or
am I up a creek without having a primary drive (or extra magic hardware
in the drive I have.)
I believe you've got problems... The host interface board is pretty
simple, I think, just buffers and an address decoder. It talks (8 bit
parallel data bus, register select lines, etc) to the controller board
mounted inside the primary drive cabinet. This controller talks to the
drives by an interface somewhat similar to ST506 (I don't think it _is_
ST506, though.), in that there's a control cable that links from the
controller to all the drives and a separate data cable from the
controller to each drive.
The controller board can handle up to 4 drives, the one mountedin the
primary cabinet and up to 3 more secondaries
Without the cotnroller board (which is, IIRC, similar to a Western
Digital thing), you are not going to get it working.
-tony
14 Apr
14 Apr
10:26 p.m.
Thanks for all the responses to my questions regarding my problem -- I
think I understand the situation a bit better now; just to make sure,
since the terminology (mostly around "controllers" vs. "interface
boards," etc...) seems to be used somewhat loosely, I'll attempt to sum
up the discussion so that I can eliminate any confusion on my behalf...
So... a complete Model II/16/6000/etc. hard drive setup (for the 8mb, 8"
drive -- I'm ignoring other potential configurations at the moment)
would consist of the following hardware:
1. The proper host interface board (this is the card that goes in the
Model II/16/etc. cardcage)
2. The actual hard drive controller (which lives in the primary hard
drive enclosure)
3. One or more SA1004 8" hard drives (in primary/secondary enclosures)
What I have at the moment is 1 & 3; since my drive is a secondary drive
I lack #2. (And I did double check, to make sure -- my enclosure
contains the drive and a power supply, but no controller board.)
From the responses I've received I get the impression it's possible to
substitute a hard drive controller for a 5mb TRS-80 hard drive for #2 --
I do happen to have one of these (I have a Model 4 external 5mb drive
with a broken drive)... if it is possible to do this, can anyone provide
details on how it's done?
Thanks once again,
Josh
15 Apr
15 Apr
1:01 a.m.
From: Josh Dersch <derschjo at msu.edu>
---snip---
From the responses I've received I get the impression it's possible to
substitute a hard drive controller for a 5mb TRS-80 hard drive for #2 -- I
do happen to have one of these (I have a Model 4 external 5mb drive with a
broken drive)... if it is possible to do this, can anyone provide details
on how it's done?
Thanks once again,
Josh
Hi
It might be simpler to remove the hard drive from the 8 Meg box and install
it
in the 5 Meg box.
As I recall there were a number of wires that were connected directly to the
5 Meg drive.
These essentially connect the front write protect switch and drive the light
on the front
panel. I believe these can be ignored. The power and signal cables are the
same.
You might need to check the drive select jumper on the 8 Meg to match the
first
drive. The 5 Meg controller should connect to the interface card. There is a
site that
has manuals for the 5 Meg drive including schematics. I've misplaced the
pointer
for it but it is the one with all of the TRS80 manuals.
Dwight
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ard＠p850ug1.demon.co.uk -
derschjo＠msu.edu -
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