>
> > (Now I just have to figure out why I can't get the FDC to write
floppies correctly...)
Can you describe the problem in detail? I recall that you're using a 16FDC
with 8" drives that are not Persci brand. Are you aware that the 16FDC 8"
bus is wired differently than what is required for Shugart compatible
drives? The Persci drives did not have a TG43 signal so the write current
may be too high on the inner tracks of a non-Persci drive mated to a 16FDC
-- causing errors.
Fortunately, it is possible to modify a 16FDC to be compatible with a
couple of cuts and jumpers. I have some photos and text that describe the
mod.
Should this happen to be the problem you're experiencing, I'll upload the
mod info to a site and send the link. If not, please describe what problem
you are having in more detail.
Amardeep
"Bill Sudbrink" <wh.sudbrink at verizon.net> wrote:
> I have always found it interesting how quickly people will go chopping
> up circuit boards. Before you do this, consider chopping up a ribbon
> cable instead. Ribbon cables are cheap and easy to replace if you
> later change to a different make of drive or if you simply screw up
> making the modification. I run SA-851's on my 16FDC with a simply
> modified ribbon cable.
I have always found it interesting how quickly people comment on issues
without first studying them in depth. :-)
The TG43 signal is entirely absent from the 16FDC drive connector and no
cable mod alone can correct that. The board modification brings the signal
>from the FDC1793 through a driver to the connector so that a cable can
carry it to the drive. If you choose to operate the SA-851 out of spec, it
is certainly your right. I chose to make my 16FDC compatible with the
drive's operating requirements.
Incidentally, the Shugart SA-800/801 doesn't require TG43 and will work
with just a cable mod (or maybe no mod at all since that drive is single
sided). Almost every newer drive, including SA-851, however, will have
higher error rates on the inner cylinders without the reduced write current
controlled by TG43.
I checked out a number of vintage items that were recently found at Weirdstuff. If you're interested in any of these items, contact "Jim" at Weirdstuff (408-743-5650). If you have any technical questions regarding these items, you can contact me as I've looked them over (but didn't test)...
1. (3) New in box Hayes JT Dual Port FAX modems 14400B w/manuals and software
2. (1) Toshiba P321SL "3 in 1" Printer (missing plastic cover)
3. (1) ThinkJet printer w/GPIB interface
4. (4) Sun 68 pin SCSI Disk UniPack enclosures with auto-termination
5. (1) Macintosh Portable, Model M5120, complete with case, power supply and unused ID cards.
6. (1) New in box DEC VMS 5.4 manual set dated 26 Jul 90
7. (1) Kaypro II, S/N 61085, clean keyboard w/cable, (2) 5.25" FDD
8. (1) Manual Set, HP83480A (Digital Communications Analyzer) & HP54750A (Digitizing Oscilloscope)
9. (1) HP 85025 A/B/E Detector
10. (1) Tektronix 577 D1 or D2 Curve Tracer Service/Instructional Manual
11. (1) Intermac Trakker Antares 241X Hand Held Terminal Manual
12. (1) Heath Appliance Control, Model SL-6166-RX
I am not affiliated with Weirdstuff and receive no financial renumeration to list these items - I'd just like to see vintage stuff get a good home...
Cheers,
Lyle
--
Lyle Bickley, AF6WS
Bickley Consulting West Inc.
http://bickleywest.com
"Black holes are where God is dividing by zero"
Josh Dersch <derschjo at mail.msu.edu> wrote:
> I'm wondering if there's some fundamental problem with my current set-up
> that's causing issues here...
Are you terminating the drive bus correctly?
Hi,
Any TRS 80 gurus that can point me in the right direction with the
disk/video interface box? I recently picked one up and have it connected
to my model 100. Everything appears to be working, but when I start the
interface box, it requests a system disk. Is this required to use the
interface box, or is there a way to go right to the mode to display 80
columns and skip the boot disk in the interface box? I have the owner's
manual, unfortunately the disk is missing and it appears the disk is
required to get the interface box to do anything? Any pointers where I
might find the software?
Thanks, Win
------ Original Message:
Date: Mon, 9 Jan 2012 12:04:41 -0500
From: Win Heagy <wheagy at gmail.com>
To: cctalk at classiccmp.org
Subject: TRS-80 Model 100 disk/video interface box
Hi,
Any TRS 80 gurus that can point me in the right direction with the
disk/video interface box? I recently picked one up and have it connected
to my model 100. Everything appears to be working, but when I start the
interface box, it requests a system disk. Is this required to use the
interface box, or is there a way to go right to the mode to display 80
columns and skip the boot disk in the interface box? I have the owner's
manual, unfortunately the disk is missing and it appears the disk is
required to get the interface box to do anything? Any pointers where I
might find the software?
Thanks, Win
-------Reply:
No, unfortunately you need the disk to load the required firmware into both
the DVI and the M100 and I don't believe anyone has taken the time yet to
figure out how to image/restore that format.
Send me your address off-list and I'll send you a copy.
You might also want to join the 'Model T' mailing list:
http://www.bitchin100.com/
And of course there's *THE* place for everything M100/102/200-related:
http://www.club100.org/
mike
Time to thin the herd - I have a number of DEC machines that are free to
a good home, though beer fund donations will be accepted. Available for
pickup in central Berkeley by appointment, or I may be able to deliver
to some parts of the East or South Bay at my convenience. I'll also take
them to a Mailboxes Etc equivalent to be packed and shipped if you
really want to pay for that...
Here's what's on offer:
DEC 3000/300LX - Alpha 21064, can get to PROM monitor on all of these
#1 - 32MB RAM, 1 x RZ25L HDD (~500MB)
#2 - 256MB RAM, 1 x RZ25L HDD (~500MB)
#3 - 160MB RAM, no HDD but bracket is included
DECstation 3100 - MIPS R2000, don't have MMJ or video cables, can't verify
#1 - Can see VSIMM and 4 SIMMs, no HDD
DECstation 5000/133 - MIPS R3000?, no graphics, no response on the DB25
serial ports
#1 - 32MB RAM, 1 x RZ25L HDD
VAXstation 3100 m38 - don't have MMJ or video cables, can't verify
#1 - Can see 2 RAM daughterboards, no HDD, 8 bit graphics board?
#2 - At least 1 RAM board, 1 x RZ23E HDD (100MB?), 1 x RX23 floppy,
graphics board
First come, first served based on email.
--/Steve/.
<smj (a) crash (d) com>
On 1/9/2012 6:31 AM, Bill Sudbrink wrote:
> Josh Dersch wrote:
>> (Now I just have to figure out why I can't get the FDC to write
>> floppies correctly...)
> Which FDC? I've had trouble with the original 1793 controller chips
> (the early programmed ones with the painted over window on top) going
> bad on a couple of 16FDCs I have. Replacing with a newer hard programmed
> plastic package chip and then recalibrating the data sep circuit solved
> a bunch of problems. The 4FDCs tended to just be "twitchy". I think
> there was a known problem with the controller chip used on them.
Right now I have both a 16FDC and a 64FDC to play with (one is on
loan). I'm using Dave Dunfield's RDOS transfer utilities to upload the
"INIT" software into RAM from a PC. From there I can initialize
floppies (single-sided, single-density), and this appears to work -- it
goes through all 40 sectors (5.25" drive) and the drive steps and no
errors are reported. Then INIT attempts to write the filesystem to the
drive and it fails (it's a "Home Error" on Track 0, Surface 0, Sector 8,
if I recall).
Ignoring that and using the RDOS utilities to attempt to write a disk
image fail similarly ("Err-H 34" IIRC).
I've tried a pile of different disks and three different floppy drives
-- a Tandon TM-100 (300 RPM), a modified 1.2M 5.25" drive that runs at
300RPM, and a standard 1.2M drive (360RPM) and all three fail in exactly
the same way. (I don't currently have an 8" drive I can wire up, I need
to build a cable...) I've also tried swapping the cable out, and both
the 16FDC and the 64FDC fail identically.
I'm wondering if there's some fundamental problem with my current set-up
that's causing issues here...
- Josh
