>
>Subject: Re: VT-131 prints?
> From: Ethan Dicks <ethan.dicks at gmail.com>
> Date: Sat, 02 Jul 2005 15:25:41 -0500
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>On 7/2/05, Allison <ajp166 at bellatlantic.net> wrote:
>> Common VT1xx part failure. Seemed they made the video board with a
>> 50V cap where a 100V cap should be. Huge numbers of them were made
>> and failed but amazingly there are still many in use that havent.. Yet.
>> It is repairable as it cooks a cap, diode and resistor.
>
>That sounds like once someone traces down the problem, it belongs in a
>FAQ somewhere.
>
>I haven't had any failures like that, so I guess I'd like to know
>more, especially to buy a bag of 100V caps and preemptively fix some
>of my terminals (I have stuff ranging from gen-u-ine VT100s, to
>VT102s, a VT103, a VT105, a DECmate I, etc., and I don't recall if I
>have a VT125 or VT131 or not.
>
>-ethan
All qualify. It's the board in the monitor (display) that is in
question. There is a (memory test) 100mf 50V cap and it's subject
to more than that (about 70V). It was fixed in production and
who knows how many field repairs by board replacement, I once saw
a crate of dead boards 4x4x6ft full, and that was a sample. If
the cap is replaced with suitable the failure is unlikely. I
have several VT1xx and all have been fixed over 10 years ago.
Failing boards display height and linearity problems before they fry.
Allison
>
>Subject: VT-131 prints?
> From: Dennis Boone <drb at msu.edu>
> Date: Sat, 02 Jul 2005 00:57:43 -0400
> To: cctech at classiccmp.org
>
>I have a VT-131 suffering from video circuit problems. The logic
>seems to be ok -- does a self test, led dance, emits a normal beep,
>and ends with the on-line led lit. The crt filament is glowing.
>Key click happens when keys are pressed. No screen display.
>I've turned up brightness in set-up, flying blind. Haven't twiddled
>the pot yet. So far, I've just taken the lid off, and am looking
>into the still-assembled chassis.
>
>The video board has some very charred-looking spots around the solder
>pads of one component (cap? spherical white ceramic-like device with
>two stout leads) down and to the right of the brightness adjustment.
>
>The tech manuals from bitsavers and vt100.net don't give me enough
>info to identify the component in question.
>
>Anyone have prints they'd be willing to scan bits of for me? Or read
>off to me by e-mail? Or have "replace this, kid" or "you're screwed"
>specific knowledge of this scenario?
>
>TIA,
>
>De
Common VT1xx part failure. Seemed they made the video board with a
50V cap where a 100V cap should be. Huge numbers of them were made
and failed but amazingly there are still many in use that havent.. Yet.
It is repairable as it cooks a cap, diode and resistor.
The Video board is common to most VT1xx. Mine are deeply burried.
Allison
I found one of these today. Nice chassis, it's obvioulsly made for DEC
cards and has 12 Quad width card slots. However I don't know if it's
Omnibus or what. Anybody know?
Joe
Hi,
I picked up an ELL (RS 28-280) at the outlet store. It was cheap
because all of the loose parts were missing. I have the base and the
books. The PDF file on the RS web site doesn't list things in enough
detail to be able to build a list of missing parts. I'm going through
the books and trying to tally the required parts, but it's taking
hours and I'm likely to make mistakes.
Does anyone have one of these and might they have enough time to make
a physical inventory? Even a digital picture of the parts spread out
on a tabletop would be really helpful.
Thanks,
-ethan
Has anyone here successfully interfaced a SASI device to a PC at the
hardware level?
I've got a few classic systems which use SASI (or not-quite-SCSI)
controllers to talk to SASI-ST506 bridge boards and from there to ST506
type drives.
As has been documented many times in the past here, an ST506 drive has a
pretty tight relationship with its controller, and so hooking up the
drive to a different controller (say MFM controller in a PC) causes all
sorts of problems when it comes to backup.
Hence driving the SASI side of things (and preserving the drive/bridge
board relationship) would seem like a sensible move when it came to
backing up data. In theory data could then be restored to a replacement
drive if/when the original dies via the same method.
Presumably inventing a simple SASI board to hang off a PC parallel port
(say) is a lot easier than mucking around with the equivalent for floppy
drives - or is the data rate still likely too low to cause timeout
problems within the bridge board's firmware?
I've got several Acorn, Torch and RML machines which use bridge boards
and in most cases the tools needed to back up and restore data have long
since vanished off the face of the earth (my RML fileserver's a
particularly important one as it seems to be the only one left in the
world)
cheers
Jules
At 07:13 02/07/2005 -0400, you wrote:
>All:
>
> Does anyone have a copy of the Solid State Music V1B video board
>manual that they'd be willing to make a scan of (or make a copy of so I can
>scan it)?
Hi Rich,
If by chance you are referring to the SSM VB1B video board... I have the manual
available on my site. Go to "S100 cards" near the bottom of my main page, then
scroll down to the SSM section, and click the "1.4M PDF" link beside the listing
for the VB1B.
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
All:
Does anyone have a copy of the Solid State Music V1B video board
manual that they'd be willing to make a scan of (or make a copy of so I can
scan it)?
Thanks.
Rich
Rich Cini
Collector of classic computers
Build Master for the Altair32 Emulation Project
Web site: http://highgate.comm.sfu.ca/~rcini/classiccmp/
/************************************************************/
All:
I want to get the Turnkey Monitor running on my 8800b. I have a VG
PROM/RAM board (which has 1k of RAM and an EPROM programmer) and some 2716
EPROMS. I made an adapter so I can use 2716 chips in the 2708 sockets. So
far, so good.
I configured the board for $C000, no RAM and all other jumpers per
the default for the board with the following exceptions:
(1) "Use PRESET or POC for power-on/reset jump" The defaultis for
the POC signal to be connected to the reset circuitry on the VG PROM board.
The other jumper option is to connect PRESET to the reset circuit on the VG
PROM board. This is now set for the PRESET line to be connected to the
board's POR circuit. I don't have a schematic so I don't know what this is
doing exactly.
(2) "Phantom generated if power-on/reset" This disables other memory
boards on reset so it can respond to the CPU reset jump to location 0
(making the board an auto-start board). I cut this jumper.
(3) "Jump to PROM/RAM board if power-on/reset" This causes the board
to respond to the CPU jump to location 0 on RESET. I set this jumper to the
equivalent of disable.
With this configuration, I can't EXAMINE or DEPOSIT to/from any
location. When I remove the board, the Altair responds normally, so it
definitely is this board.
Does anyone have any experience using this board in an Altair (or
other non-Vector) system? What's a working configuration for this? Does
anyone have a spare generic ROM board I can buy/trade for?
Thanks.
Rich
Rich Cini
Collector of classic computers
Build Master for the Altair32 Emulation Project
Web site: http://highgate.comm.sfu.ca/~rcini/classiccmp/
/************************************************************/
In a message dated 6/30/2005 12:22:29 AM Eastern Standard Time,
chenmel at earthlink.net writes:
This past weekend I picked up an old PS/2 machine. It's a Microchannel
system, a Model 65sx (I think). The only thing missing in it is the
hard drive. It has one of those 3-1/2" drives with the full-length
card-edge connectors on it, I think 50 pins wide or so, that provides
all connections including power.
I would like to get it up and running just to have around as another
working system (also got a Compaq Portable III at the same auction for
$10 in a leather case!). Any suggestions where I could find such a
drive easily? Is this machine's HD interface an ST-506 variant, EISA,
or what?
---------
8565 is a 386DX-25 I think with a SCSI controller instead of ESDI that the
model 60 used. Take note of what adaptor cards are installed. This machine is a
floppy based reference disk instead of using an IML partition so you will
need to build a reference disk with all the adf files on it. If parts are
needed, I can help with whatever is needed.
