While cleaning out the pile-o-stuff I came across half a metric buttload
of DSDD 3.5" floppies. If anyone wants/needs some, I'll send 20 anywhere
in the continental US for $2.
--
David Griffith
dgriffi at cs.csubak.edu
Hi,
I'm trying to repair a couple of these units, does anyone have the printset
for them (or even just a circuit diagram)?
Many thanks
Jim Beacon.
Please see our website: www.g1jbg.co.uk
> Is that R, G, B, and composite sync, or what?
>I don't want to be appearing to 'teach grandmother how to suck eggs', but
>how are you measuring the sync frequencies? Where are you measuring them?
>waht instrument are you using? And so on....
Yep, RGB on seperate BNCs and H-V combined on another.
I'm throwing a LeCroy scope onto the SYNC output and using the cursors to measure between the
regular pulses. I pulled the graphics boardset and found one jumper (ext/int) that was
set differently from Gerhard's model (thanks for the settings!) and I swapped that, which raised the sync
frequency to 29.1 KHz.
The total waveform looks like: 29.1-29.4 KHz negative-going pulses, with 134muS square negative pulses
occuring at 66Hz (looks like it might be stuck in 33Hz interlaced mode). there are stronger negative pulses
in line with the ~29 KHz sync at 400.96 Hz, and on top of that there are 174muS blanks in the signal (at the positive end) at 2.56 KHz
-----\/---\/---\/---\/ (regular pulses) ---|_____|--- (vsync pulse, 66KHz) \/---------\ /---\/---\/ (the 2.56KHz blank and strong negative pulse)
\/
not to time scale, and the strong negative pulse was the same duration as the regular horizontal pulses. The strong negative always occured
after a blank, but not every blank.
The Display Generator board is crystal-controlled (meaning I should have pulled it out all the way before pontificating)
There is a set of jumpers on the main processor board (IP2) which are supposed to set resolution, with choices
between 60Hz non-interlaced, 33Hz interlaced, RS-170A, and European Standard. These seem to make no difference.
The jumper to select master/slave mode on the processor made a difference (dropped the sync to ~2KHz), so I know there
is a control connection between the IP2 and the graphics. I checked the DIP switches, and they function. I suppose I could try
the system with no processor and see what the default sync rate is. I'm wondering if the system (or parts) were set up for
genlock of some sort, and is expecting something it's not getting.
I'll throw the LeCroy on a Sun 3/160 and check the waveforms for comparison.
Sorry, but you might need to "teach grandmother how to suck eggs", this is both the first computer video and the first scope I've
really dug into. I found out really fast that my NTSC TV book doesn't help much. . .
> Incidnetally, I have heard of a TV set that leaked water onto the
> floor,
> and no the cause was not a vase of flowers on top of it. Any ideas?
>
> -tony
>
>
Rear projection TVs of the older sort are water cooled...
CRC
Pay for shipping and add whatever else you'd like for the following tapes,
all new.
QW5122F plenty of these!
MC3000XL Taumat format
MC3000XL
2120XLF
DC6150
DC600A
QD9120
DC9250 these are used IIRC
DC2080
MC3020XL
three TK70
two 88meg syquest
105meg 3.5 syquest
four HIFD 200meg floppy. <?>
QG15M D8 8mm tape
plenty of 2120 and 2120XL
I have a friend who has a DC100a tape with no way
to read it. Just wondering if anyone here can and
get data onto a pc.
I do have a Colorado Jumbo 250 that I have used
DC 2120 QIC-80 tapes with. But don't know
if that would read DC100a tapes.
Keven Miller
kevenm at reeltapetransfer.com
Orem UT 84097.
"Nico de Jong" <nico at farumdata.dk> wrote:
> Seems like a dead end to me, unless a working HP85 could be found.
Well I have a couple of HP-85s and HP-9915s (the embedded version of
the HP-85). I also have an HP-9825A which also uses the same type
of tape. However, if the tape was not recorded on a similar machine
it will probably not be readable by my machines.
> I don't know about TU58
yes its the same, but the TU58 uses preformatted cartridges (can't
format cartridges on its own). While the cartridges are physically
identical to the HP ones, there is no data compatibility.
**vp
Pat wrote
>You do realize that the "stuff" we talk about on classiccmp are usually things
>that aren't PC's, right?
Yep, that's why I posted here :-) - it's a SGI IRIS 3130 68020-based Multibus machine.
I'm sorry that I gave the impression it was a PC, I was just trying to not scare off
anyone who hasn't ever worked with one of these beasts but who knows about
computer video/graphics systems. I did pull some numbers from the XF86 PC modeslist
to see if what I was seeing was close to "normal", it didn't seem to be.
Jules wrote
>I suppose it's just possible that you could do interlaced 1024x768 with a
>28KHz signal, but it'd be hell on the eyes. Possibly that's the SGI's default
>though if it can't detect what monitor you're plugging into it? (scratch that
>idea if the outputs are BNC, but if the video's done over some form of
>multi-pin connector, might it not need strapping in a certain way to indicate
>display type?)
The monitor connection is 4BNC. I wasn't sure about the interlaced - it seemed that mathematically
it should be 24 KHz (48/2), but if 28KHz could be it, I'll look again.
There's a switch that's supposed to select interlaced/non interlaced. I guess next stop is to check if
that's being read properly, since flipping it doesn't seem to make a difference. I'll also try to find the crystal oscillator
(thanks, Tony), perhaps it's on the Update Controller?
I think the interlacing must be for linking it up with a TV system, since the monitor can't do 30Hz interlaced.
Standard refresh is 60Hz (per the IRIS FAQ)
Afraid I know of no details on this one - other than a rough location (Keele
uni, or at least that's where the chap who has it works), contact number, and
that any rescue is fairly urgent - it's heading into a skip rather soon.
If there's likely to be any interest, do shout - I can always phone the guy
and get more details.
cheers
Jules
