> Try Dataterm in Woeburn, Massachusetts. I have a nice ASR-33
> teletype that I bought from them last year. They also used
> to service them and they might have spare parts.
Woburn, MA.
I grew up in the next town and didn't know of them. Do they sell much
retro gear?
Has anyone any explicit knowledge and / or experience of a
TK70 tape drive on a PDP-11?
In respect of the media, does anyone know of any explicit
differences between a TK50 (CompacTape) and a TK70
(CompacTape II)?
Memorex used to have a page listing all DLT physical and
magnetic characteristics. At the time, I was unable to
see any differences. I did find some data starting
with DLT III media, but not for TK50 / TK70:
http://www.data-storage.co.uk/tape/quantum/media.htm
Can anyone at classiccmp help answer these questions?
My personal experience over the last 15 years using a
TK70 on a PDP-11 under RT-11 is that regular TK50 media
(CompacTape) have always been successfully used (over
100 TK50 media) with the TK70 tape drive (after the TK50
media are bulk erased if they were ever placed into a
TK50 tape drive - if they were completely unused, they
worked immediately).
Sincerely yours,
Jerome Fine
--
If you attempted to send a reply and the original e-mail
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Check to see if the armature for the selector magnet is vibrating or
"buzzing". If it is, there are 2 computer grade caps in the call control unit that
have to be changed. Very common problem on 33's.
Hi all
David Holland said :
>Hardcore Computerist(?) once published an article on how to deprotect
>Wizardry I. (If anyone happens to have/know of that article, I'd kinda
>like to arrange get a copy of it (Xerox/Scans are fine) for nostalgia
>sake.. - yes, I did spend many many hours as a teenager putzing w/
>Wizardry I's protection scheme)
Me too! (translation: I'd love to see the article, and yes,
spent many hours pussling over that tickety-tick-tick
thing the head did...)
Remember Zardax?
W
Tom Jenning's account of getting his Nova up again made me go back to
my Nova MP/200, a 2901 bitslice based machine.
With the machine came a DG6095 diskdrive, on which i did not find any
info.
It looks identical, inside and outside, to Tom's 6070 drive.
Questions :
- anybody know for sure that the 6095 is just the Euro version
(220V/50HZ) of the US 6070 drive ?
- Anybody has a spare pack ( fat chance, I know )
- and failing that would RL02 packs fit ( if so, how many sectors )
- and do I really need to dismantle heads and fixed platter to clean
them ? ( I believe I know the answer to that...)
Jos Dreesen.
I saw the following notice on the Heath listserver :(. Unless there is
more than meets the eye, Agilent does not come out of this looking like
a very worthwhile company.
************
Please visit the following site for the letter from Agilent.
http://bama.sbc.edu/images/Letter%204-18-05.pdf
>From: "Paul Koning" <pkoning at equallogic.com>
>
> jim> If they are switcher power supplies, they tend not to react very
> jim> nicely to having a solid state inverter feed them.
>
>I don't believe that.
>
>Without PFC, a switcher begins with a full wave rectifier. If you
>feed a square wave into that, it will be happier than it was with a
>sine wave, not less happy.
>
>With PFC, the analysis requires more knowledge than I have.
>
> paul
>
Hi
For the square wave inverters, they have a flat line
square wave of 115V RMS and peak.
AC rectification as seen on most switchers use
a simple voltage doubler that doubles the peak voltage
that is around 160v on a sinewave. This means that
if the inverter was intended t run lights, it will
have too low a voltage for a switcher input. If
it was intended for a switcher input, it would burn
the lights at too high of a voltage.
Swithcers don't like to run at low voltage.
Dwight
It was written...
>>> Hello.
>>>
>>> Can be possible to obtain in some place image disks of the Apple II
>>> Pascal
>>> or UCSD Pascal por the Apple II ? I'm searching a copy to play a little
>>> in
>>> the Apple II Oasis Emulator.
>>>
>>> Thanks in advance
>>> Sergio
>>
>> ftp://ftp.apple.asimov.net/pub/apple_II/images/utility/programming/apple_pa…
>>
>>
>> Just a little while back I also posted asimov's mirrors.
Does anyone know who runs that ftp site of apple stuff?
Jay West
You can build your own rotary phase converter from an old 3 phase motor. And 3 phase motors can be some of the cheapest to get second hand.
It seems that a three phase motor will not start if a phase is missing, but if it is running it will continue to run if a phase is removed. The combination of the energized windings and the spinning rotor will have the effect of creating the third phase, although this is not an efficient state of affairs.
In my home machine shop I first used a bank of capacitors to help synthesize the third phase. The bank of WWII tin caps was adjusted until the lathe motor was running with the least buzz.
Then I added a three phase chipper. The first time I slammed the lathe from forward to reverse with the chipper I was surprised that the lathe reversed and the strain of reversing it could be heard in the chipper motor.
Then I added a three phase grinder to the setup. But when the grinder was used alone the cap bank was the wrong size and the motor had a terrible buzz in it. So I released the drive belt on the lathe and turned on the lathe motor. Bingo! The buzz in the grinder was gone!
So in this configuration I am in essence using the caps to start the lathe motor as a rotary phase converter for the grinder.
Hope this helps,
Mike Gemeny
>
>Subject: Re: small valves and RE: OT
> From: ard at p850ug1.demon.co.uk (Tony Duell)
> Date: Wed, 27 Apr 2005 00:49:28 +0100 (BST)
> To: cctalk at classiccmp.org
>
>However, there are plenty of other people reading this list, who might
>come across similar sets. I would hope they might now realise that the
>chassis could be live.
Ah, threin lies the reason. However good point.
People here play with power in the form of higher voltages, also in
the form of high energy. Some of those computer supplies designed
to pump out dozens to sometimes hundres of amps of power posess
the capability to melt off a ring (and the encircled finger), watch
or cause a splatter of melted metal in the eye. Trust me, I have
been been to 1500volts and back due to fools around me and their
pointing fingers. I've also seen what an 80amp regulated power
supply can do to a 1/4" shank screw driver. That little ditty
vaporized in a nice UV rich arc. Had me seeing spots for a
week(welders burn). Oh and the guy fixing it was quick state he
had unplugged it. So yes, a reminder for those listening is far
>from out of order.
>[1] The presence of a mains transformer in a valve radio does not imply an
>isolated chassis!. It was not unhead-of for the transformer to be to
>supply the heaters only, with the HT coming by half-wave rectifying the
>mains, thus giving a live chassis. Some UK sets even had the heaters in
>series, runn from the mains via an autotransformer...
Yep, that too!
I might add that something "grounded" can be more unsafe until your
sure there is NO POTENTIAL differences. I got dinged in NYC one
fine day due to a mere 65vac differential in grounds between the
12th and 14th floor. And they couldn't understand why the RS232
drivers were being fried all over the place. Seems equipment
ground wasn't.
Electrons are our friends, they have a dark side too. Always play
nice and use proper technique. Failure to do so really can take
the fun out of it.
Allison
