*tap* *tap*
I tried posting to the list a few weeks ago, don't think it worked.
I saw on http://manx.classiccmp.org/details.php/47,13105 that the SDK-51
assembly manual's not available as a scan, so I scanned my copy, which is
taking up space.
So, anyone interested in the scan, and anyone interested in the original,
which I will otherwise (shock, horror, but I really need to get rid of
stuff) chuck.
W
David Riley wrote:
>Ooh, another place I can find 4116s cheaply (even more so than Jameco).
>Wish I'd known about this place when I was fixing my Defender boards!
I replaced the 4116s in my Apple with 4164s. OK, it's not original (you
should have seen the mix of 4116s that came out of there) and you only use
a quarter of the chip but it doesn't need all those pesky voltages and they
run cooler too.
W
I'm not able to get this one, but hopefully someone on this list may be
interested in it. Tnx!
g.
---------- Forwarded message ----------
Date: Sat, 14 Jan 2012 01:18:10 -0000
From: pauls1950 <paulstephens at Q.com>
Reply-To: TRS-80 at yahoogroups.com
To: TRS-80 at yahoogroups.com
Subject: [TRS-80] Re: Model I for sale
I thought I had it taken but it fell through so here is a list of what I have:
TRS Model 1 , converted to level 2 16K,original CRT, expansion interface, modem, two original floppy drives, cassette, assembler programming tapes and docs, several boot disks, LDOS, TRSDOS, NEWDOS etc..., Tech manual (scematics and diagnostics), programming manuals.
I tried booting it today for the first time in 15 years?? and although the CRT lights up I don't get any output to it - with and without the expansion interface connected so it is in need of repair (either the monitor or the video circuitry in the CPU.
I am asking just $100 for everything but whether I get any money for it or not it either gets a new owner or it goes to be recycled.
I am in Seattle you can contact me by phone at 206.725.0881 or by email at paulstephens (at) q (dot) com.
Please someone take this system - all hardware is original RadioShack.
Paul
--- In TRS-80 at yahoogroups.com, "pauls1950" <paulstephens at ...> wrote:
>
> I have a 1978 model I with expansion interface, two floppy drives, lots of manuals and software. This is a complete system and documentation. I am moving and never use it anymore so I need it to go to a good home.
> contact me at paulstephens at ... or 206.725.0881 if interested.
>
> Paul
>
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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hi guys,
I've released a new version of the DiscFerret interface library and
microcode. This is libdiscferret v1.5, with microcode release 0x0028.
The reason I'm declaring this an urgent update is because in an
earlier release of the microcode (possibly back to the initial
release) introduced an extremely nasty bug...
This bug WILL corrupt the data read from the disc if either
* An index pulse arrives at the same time as a flux transition, or
* The counter overflows immediately before a transition.
In either of these cases, the flux transition will be dropped, and
either a Counter Overflow or an Index Trigger byte will be stored instead.
For extra bonus points, the counter overflow logic made it absolutely
impossible to represent a counter value of 127, or a multiple thereof.
These would cause an overflow store... followed by another count up.
The transition would be completely ignored.
This basically means that any disc image created with any microcode
release earlier than 0x0027 (i.e. libdiscferret 1.4 or earlier) should
be considered unreliable and not an accurate representation of the
data on the disc. These images should be discarded and the discs
re-imaged.
To resolve this problem I have:
1) Re-engineered the data coding format and the disc-reader logic to
prevent a counter overflow or index store from causing a missed transition
2) Completely rewritten the testbench to remove the stupid mistake
which allowed these mistakes to slip through the net in the first place.
3) Changed Magpie (the disc image reader) and Merlin (the analyser)
to create "DFE2" format files. Attempting to load a "DFER" image into
Merlin will work, however it will warn you that the data may be
inconsistent.
I've screwed up bigtime here -- a tool designed for data preservation
should most definitely NOT have had bugs like this. I can't believe I
screwed up the design so badly, and I've been cursing at myself since
the bug was reported on the DiscFerret IRC channel (#discferret on
irc.freenode.net) last week. An even more subtle bug in the test bench
code rendered all my tests pointless (basically: the test_fail()
function would cause the testbench to abort with a 'success, tests
passed' code).
The aforementioned test benches have now been rewritten from scratch
in a way which will hopefully prevent this kind of thing from
happening again. Yes, I am doing both positive and negative testing,
and testing the testbench framework.
I've left the "torture test" testbench running for several hours with
various types of input waveform, including some which would cause
timing violations on other parts of the circuitry (specifically, the
input filters). No timing violations or data errors were detected,
even under these challenging (and in some cases outright impossible)
scenarios. The output data matches the hardware model and my
specification documents *perfectly*.
No doubt some vendors of similar products will take this opportunity
to take a dig at me and my product. Whether they choose to act in this
highly unprofessional manner is entirely up to them. However, please
bear in mind that my code is available for peer review, and I accept
submissions of code from others (and bug/feature requests). The bug
tracker (Mantis) is open to the public. How many other projects like
DiscFerret operate with this level of transparency?
The software update is available to download, free of charge, from the
usual download source:
http://www.discferret.com/
(click the Downloads link on the left hand side).
As always, if you have any issues with your DiscFerret, please feel
free to contact me -- either by email, the DiscFerret mailing list, or
on IRC (philpem on irc.freenode.net).
Thank you all for your time.
- --
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
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Does anyone have an electronic dump of the Basic-11 paper tape for the
PDP-11? I am looking for Version 007A that was released 10/22/70.
The id of the paper tape is:
DEC-11-AJPB-PB PDP-11 BASIC V007A 10/22/70
Many thanks!
--barrym
> The 12/7 uses a Z80 processor with 2 Z80-DMA chips, one ot read in
> characters from the host, the other to send them to the printhead
> ciruirry. I nthe 700, the DMA chips are effecively each replaced by a Z8.
> In both cases there's a correction PROM fro the printhead chracteristics
> to correct the pin fire timin, programemd for that particular printhead.
> Yes, they're that precise.
I wonder how they measured the printhead characteristics for the
correction PROM.
Did you have to replace that PROM if you changed the carriage motor, for
example?
/Jonas
>> environment. They were built like tanks. The print head used a patented
>> "flexhammer" system, instead of pins the dots were made by leaf springs
>> which had their ends bent over and shaped to a little square point. The
>> springs were held bent off the paper by solenoids, which de-energised to
>> print the dots, whereby the spring would shoot forward against the paper
> What happened wehen the power went off? Presumably all the springs hit
> the paper. Did this mean you could damage the head by moving paper/ribbon
> with the ppwer off? And how did the springs get back to the soenoids when
> the pwwer was turend on again? (were the solenoids powerful enough to
> attract the leaf prings back?)
No, as a previous poster mentioned, below the head was a little rubber
bladder that pushed the head against the paper when printing, normally
it would be angled slightly away from the paper. The head ran across the
paper supported by the usual bearings running against a bar at the
bottom IIRC, and a solid bar that ran across the paper at the top. I
seem to remember that many printers of the time supported the top of the
printhead against a wire, and using a bar instead was said to be a big
advantage. To print, the head would be pushed against the paper by
filling the bladder with air. I don't think there was a compressor in
the printer, IIRC just some sort of solenoid in the bottom of the
printer pushed against another bladder. The two bladders would have been
connected with a little tube that moved with the head. My memory is not
too clear about the details here.
So what would have happened is that all the magnets in the head were
energised, the bladder was expanded and the head run across the paper
while working the magnets and springs, at the end of the stroke the
bladder would be released and the magnets de-energised while the paper
moved, and the process repeated while the head went back across the
paper for the next line of dots.
It was quite fast as well. We had the two colour version but used all
black ribbons which were cheaper, IIRC there was a DIP switch to say
whether the ribbon was red and black or all black. IIRC the ribbons were
rather like typewriter ribbons, on reels, and you would have to thread
the ribbon through the mechanism. The ribbons would come with a pair of
plastic gloves so that you didn't have to get your fingers dirty.
>> You would love one, I'm sure I would if I could find one and if I had
> Indeed it appears I would...
>
>> room for it... Absolutely the nicest printer I have ever seen.
> Hmm.. I think for dot matrix printers that honour has to go to the
> Sanders 12/7 (or maybe the 700) machine. This is a 7 pin dont marrix
> printer that is so well made that some fonts use 8 passes of the
> printhead -- and it is worth doign that. They do things like justifying
> text, lining up columns, etc.
>
Ah, but I haven't seen one of those ;-) It sounds quite amazing.
Another nice printer I have come across was a Qume daisywheel printer,
it was connected to the PDP-11/40 at the department of applied
electronics at the university, which I used for my master's thesis. They
had the manual for it, which included the circuit diagrams and technical
description. Lots of analogue servo mechanisms.
/Jonas
Does anyone have an idea of what color "Hazeltine Green" (phosphor) is,
or might be, or where that info could be found?
My question is regarding web and programmatic simulations of green
phosphor monitors. (in an attempt to be somewhat accurate and also have
them look "right")
-- Quinn
I have two working Defender board sets that I'm almost ready to start building cabinets for. I'm scoping out new power supplies (I have the linear ones they came with but no giant transformers for it; I've been using PC power supplies but would like to use something with no moving parts). Does anyone know the approximate rail requirements for it? They don't seem specced in the drawings/theory of operation manuals anywhere. An old 230W AT power supply seems to work fine, but I don't think I need anything that heavy-duty.
I know the 5v is going to pull a lot because it's used for most of the logic, and the regulated 12v and -5v are probably somewhat heavy since they power the sense amps for the 24 4116s. As far as I can tell, the unregulated 12v is only used to power the audio amp and the -12v (unregulated) is only used for the negative reference on the audio DAC; am I missing anything? I haven't measured current draw per rail yet, mostly out of laziness (and missing a few sizes of .156" plugs).
BTW, the Apple color monitor they sold with the IIgs works great as an arcade monitor in a much smaller size if you can set the sync polarity correctly. Fortunately, Defender has solder jumpers for selecting that.
- Dave
