Resurrecting a very old (2011) thread about PPS-4/1 - I'm looking for
data sheet on the mm76E - the pinout in particular - as I am trying to
sketch out the schematic of a home pinball game that used the MM78 CPU
and the MM76E for memory.
Bitsavers and everyone else has the sheet for the MM76EL which is the
40-pin version of the original spider chip and those pages talk about
how the EL does not require as fussy a voltage for Vss.
Anyway, if anyone has this data I'd appreciate it!
Thanks,
John :-#)#
On 2011-10-31 1:29 a.m., Eric Smith wrote:
> Benjamin Sølberg wrote:
> > So if you multiplex 8 leds you need 8 times the peak current to keep
> the
> > same luminance ?
>
> 8:1 multiplex requires 8 times the peak current to get the same
> average power. Years ago I saw some claims that with multiplexing you
> can use lower average power for the same perceptual brightness, due to
> retinal persistence. However, I've seen other people claim that this
> is not true. It would be entertaining to set up a double-blind test
> and find out.
>
> Too late now, but those keyboards were actually standard Keytronics
> ones, and not at all hard to repair.
>
> -tony
>
I'm fairly certain that the MG-1 I have is one of the Stern Hall machines
mentioned earlier.
But in re "standard Key Tronic"... The one here is certainly a
foam-and-foil capacitive device like a Key Tronic keyboard is, and surely
the mechanism is basically identical (as are its repair methods). It still
works --- for now. But the pads aren't little round tablets like the usual
KT fare but instead squares with one of the corners notched out (think: the
shape of Utah, but squarer). I do not look forward to those pads degrading
further and expect it may be necessary to get some kind of custom die punch
fabricated in order to produce replacements.
I can't easily retrieve the name of the keyboard manufacturer at the
moment, but I wonder if anyone knows more about this odd shape of
capacitive pad.
--T
>
Hi there!
Long shot here, I know, but does anyone on here have an IBM SP node, especially an earlier (non Power 3) Thin Node with MCA? But really any SP owners here at all?
Thanks!!
-Ben
Hi everyone,
According to historians, and I consider myself one, let us consider what
classic/vintage computers were: The 1970s saw the three amigos: Apple II,
TRS-80 and Commodore PET and the OS was DOS and its ilk + CP/M. The 1980’s
saw the Dells, HPs and many others with MS-DOS & IBM PC-DOS from QDOS. We
saw this and behold ’bring on the clones’(I just had to say this!) The era
of old computers saw one generation building on the shoulders of giants who
designed these wayback computers(with apologies to Wayback Machine).
Today’s PCs and ARM machines are just the latest iteration of this
theory(by the way not mine).
Happy computing
Murray 🙂
Greetings Restorers,
I think a number of us have wanted to restore software that's only
available as a scanned listing from a line printer. The original
printout probably wasn't the best typographic quality, and scanning
doesn't improve it.
As a first pass, OCR with tools like Adobe Acrobat can easily produce
a rough draft of the content in text form, but it takes almost as much
work to correct the many "typos" as it does to simply re-type the listing.
It seems like, with all this high-tech AI processing around, it
should be possible to take advantage of the limited character set, fixed
fonts, and restricted grammar that one might find in a listing to
resolve more of the ambiguities in character recognition.
Does anyone have an approach that's more efficient than generic OCR
and a long process of correcting typos on every line of code or comment?
Thanks
/guy
One of the greatest joys of classic computing was running what you wanted
on your own computer. What has happened in the intervening years? Have
‘software walls’ created a computing environment that benefits software
gate-keepers(owners of computing technology) by monopolizing creativity,
freedom to program and establishing a defacto ‘true ownership’. Will the
future be this or will it be more like the earliest years of
microcomputing?
Murray 🙂
I have recently acquired a Flexowriter. It looks very much like the one shown on this page - https://moca.ncl.ac.uk/iomedia/pt4.htm
The identifying points are
- blue color keys
- tape punch and reader (both appear to be 8 bits)
- white and red lamps on the front panel beneath the Friden logo
The serial number plate shows F_V as the model and S P E C as the coding.
Is anyone familiar with what this model is? What does the coding refer to?
Peter
I have a Connectix camera with a small 8-pin mini-DIN connector. The
pin placement looks like RS-232. All it says on the label is that the
FCC id is LKD1. The only thing I found about it online called its a
Macintosh camera. Logitech bought the Quick Cam from Connectix in 1998
but I can't find much more about it, or even if it's the one with FFF
id LKD1. Do you want it?
With all the talk going on, I ordered some ButtonWorx 4mm keypad
repair buttons to fix my old Technics stereo rubber dome remote and it
seems to work good as new. Now I just have to replace some capacitors
in the receiver itself.
-----------------------------------------From: "Daniel L via cctalk"
To: "General Discussion: On-Topic and Off-Topic Posts"
Cc: "Daniel L"
Sent: Sunday November 30 2025 5:40:55AM
Subject: [cctalk] Re: Conductive material in rubber dome
Well folks, it was a false alarm. My wife was looking at my open
switches and told me to zoom in with my camera. It turned out that it
wasn't the dome itself. The dome had left just enough residue on the
switch contacts to prevent consistent usage. So I sprayed excess
contact cleaner and a qtip and cleaned it vigorously. Voila, all three
switches work perfectly.
It took a better part of five hours to do all of them. I figure this
would likely happen again. And I was concerned the self adhesive
version would break off during use but, no. The material in the domes
is self adhesive. The dome material was also cast to be quite flat.
I didn't have to use any of the new bits since it's still in shipping
from amazon. But, I have them in stock because there are a number of
100s I will be refurbishing for resale at some point.
I'm glad the wife looked at it with her eagle eyes. I would've torn
off the original stuff and it wouldn't have worked. I would have
kicked myself.
I also replaced the leaky battery on the mobo so she's ready for
modifications! Looking forward for this project.
Daniel
sysop Air & Wave BBS
finger calcmandan(a)bbs.erb.pw
On November 26, 2025 5:04:11 AM PST, me--- via cctalk wrote:
>I just acquired a TRS-80 model 102, my first of that model.
>
>Everything is great other than three keys. The 2 keys works
intermittently, q, and [ don't work. Having checked the schematic, the
keys have no commonality on the circuit.
>
>Before I pull the cap off the switch, I know that the rubber dome
inside has material on the inner part that meets with the silver
contacts to complete the circuit. I'm told this material will wear out
or lose conductivity.
>
>I reflowed the solder joints on the pcb and this didn't help. Other
people have simply replaced the rubber dome from another dead 102's
keyboard. But, I'd rather attempt applying new material inside that
dome.
>
>I'm hoping there is an inexpensive and mainstream solution I can buy
at home depot or something.
>
>Any tips?
>
>Daniel
>sysop | Air & Wave BBS
>finger | calcmandan(a)bbs.erb.pw
I am playing around with VMS 5.4 on a simulated microvax 3100 and want to
get decnet running.
The install media I have found is for decnet 4.0 end-node but it doesn't
install. Vmsinstal complains
about symbols not being defined and I am guessing I have the wrong version
for VMS 5.4.
Does anyone know of a decnet version that will work on VMS 5.4? I can't
seem to find one.
Thanks,
- Peter
