Re: can a terminal damage a computer?
- I defer to Ian's experience:
--- In email@example.com, Mr Ian Primus <ian_primus@...> wrote:
> It's going to be really rare for a terminal
> to damage a computer... beyond possibly burning out the
> 1488/1489 chips if there is something horribly wrong
> with the terminal, wired wrong, etc.
The Altair serial port blew one of those chips
at the MARCH exhibit at the MAKER fair a few years ago.
I'm unsure if it was damaged there, or before.
But it sure ruined our day :-(
> Now, there is an exception here
> if there is bad wiring in the building.
As you vividly demonstrated at VCF with your Prime :-/
Perhaps I ought to demonstrate my
fiber optic RS232 adapters.
No metal between the systems,
and it can reach over a km without repeaters!
> I had one weird occurrence several years ago
> while copying some files on an Apple IIe, however ...
> So, I'd burned out the RS232 chip in the [PC] computer.
It's a crime not to socket those chips.
The Univac is made up of hundreds, perhaps thousands of
teeny PC boards because it required constant maintenance.
Even televisions of the 70s were modular.
But now everything's surface mount
and so highly integrated into the motherboard
that the mobo is considered a FRU (field replaceable unit).
Happily, my car is not that way (yet!)
<slightly off topic>
Using a laptop/netbook/tablet (with software terminal emulation) with a USB to RS232 adapter sounds reasonably safe because the external adapter is the only thing at risk. Sadly, the Trenton Computer Fest's flea mkt is too small to offer them cheap as in years past :-(
There are 2 chips inside those dongles
- a FTDI FT232RL USB to serial adapter (or Prolific part)
but that's 5V TTL serial
(Adafruit's FTDI friend is just that chip
- a Maxim MAX232 driver/buffer for TTL to RS232 levels
with built in power supply so it's +5V only
(also available as a teeny board:
I just soldered up a RS232 to current loop adapter should MARCH need to interface to a current loop terminal.
It's not opto-ioslated but it was good enough to be a kit!
I'm unsure when or if I'll ever interface Bluetooth to that for wireless links to the vintage TTY.
-- jeff jonas
- On 04/06/2013 04:37 PM, B. Degnan wrote:
>> I have had a few computers fail while using my laptop as a terminal,think.
>> recently. Is there something a rs232 port can do to a computer to
>> cause it to fail, like the 1488/1489 drivers? Just seems odd. Corey
>> was mentioning that he had problems with his laptop after upgrading OS
>> drivers, but I have not done anything like that, I am using the same
>> Win 2000 computer I have had for years. Thinking I am just being
>> superstitious but thought I'd throw that one out there to see what others
>As other have noted, could be grounding problems. One thing I've foundgreatly useful was to put the devices on a ground fault interrupt outlet. If
there is >a ground problem then the GFI trips without destroying either the
computer or the laptop. Also using a 1:1 transformer (Isolation
>transformer) is probably not a bad idea.--------------------
But seriously, my problems are all independent of each other. I do
everything through the grounded power supply of a battery backup with surge
protector so I would think I would get bad news lights if there was a
problem. I often solder at a different station than my laptop terminal.
The 1488/1489's do die, and I have had to replace a few for sure. Better
these than other parts.
I have other devices that are quite stable with my laptop as the terminal.
I think in my case it's just the computers/devices themselves, I try to not
to short things but I am not the most dexterous.
- On 04/07/2013 09:58 AM, joshbensadon wrote:
>> Thanks everyone for your useful suggestions. I was burying the ground[raises hand] I do.
>> line in a coffee can full of dirt but I should be adding water
>> occasionally to keep it a little muddy. That keeps the electrons
>> flowing better.
> lol. On this note, I think the electric company may be giving us used
> electrons (and charging us for new ones). I have no way to verify this,
> does anyone here have an electron microscope?
However, inspecting electrons with an electron microscope is tough, because
you have to stain them for them to become visible. I once had a bottle of
stain that was made from quarks and muons, but the guy who sold it to me (who
had the oddest green scaly skin) isn't answering his phone anymore.
Dave McGuire, AK4HZ
New Kensington, PA
- --- In firstname.lastname@example.org, Mr Ian Primus <ian_primus@...> wrote:
> Later on, I happened to have the computer apart and there was a little crater in one of the RS232 line driver chips on the computer's motherboard. Interesting that I was able to blow out the chip like that, with static, on properly wired, correctly grounded machines.Perhaps the static only shorted one transistor, but if that transistor was the constant current source (now unlimited current source) for some other transistors... then it's game on!
- --- In email@example.com, "B Degnan" <billdeg@...> wrote:
>I think the best advice is to ground yourself more often. Like Ian said, he would touch metal before computer.
> But seriously, my problems are all independent of each other. I do
> everything through the grounded power supply of a battery backup with surge
> The 1488/1489's do die, and I have had to replace a few for sure. Better
> these than other parts.
> I have other devices that are quite stable with my laptop as the terminal.
> I think in my case it's just the computers/devices themselves, I try to not
> to short things but I am not the most dexterous.
I have personally seen in my professional work how some people are more likely to create a static charge. I don't know if it's clothes, physical chemistry or personality but there is a definite difference.
Before you work on that COSMAC Microkit, you better touch wood and metal!
- Josh,Unless you have a DC feed from the power co., you are not getting any new electrons , only the same ones jogged back and forth. You might, however, be sharing some with your neighbors who are on the same transformer. It might be worthwhile to invest in a whole house isolation transformer to assure that you don’t get defective electrons from your neighbors. Can’t be too careful these days.Duane
--- In mailto:midatlanticretro%40yahoogroups.com, B Degnan <billdeg@...> wrote:
> >your useful suggestions. I was burying the ground line in a coffee can full of dirt but I should be adding water occasionally to keep it a little muddy. That keeps the electrons flowing better.
> Thanks everyone for
> Sent from my PDP
lol. On this note, I think the electric company may be giving us used electrons (and charging us for new ones). I have no way to verify this, does anyone here have an electron microscope?
- Yep I had a terminal Pop the serial driver chips, but the terminal was apparently "hacked". When I found a "switch" inside that I flipped, it stopped killing drivers.
So in my case you could say the 1488/1489 drivers were not victims of normal circumstances, but of a short or mis-wiring.
In the end no biggie. I have a bunch of NOS drivers for my 3P+S, it's just my sio-A MITS serial card I'm won't risk on an unknown terminal.
--- In firstname.lastname@example.org, "B. Degnan" <billdeg@...> wrote:
> I have had a few computers fail while using my laptop as a terminal,
> recently. Is there something a rs232 port can do to a computer to cause it
> to fail, like the 1488/1489 drivers? Just seems odd. Corey was mentioning
> that he had problems with his laptop after upgrading OS drivers, but I have
> not done anything like that, I am using the same Win 2000 computer I have
> had for years. Thinking I am just being superstitious but thought I'd
> throw that one out there to see what others think.
- The PC Museum here in Ontario has an IMSAI 8080 that I plan to get operational next weekend. It doesn't have the original 8080 board and without it the front panel can't work, so I've built a replacement 8080A cpu card and loaded it with RAM, I/O, and a Disk Emulator.
Does anyone have any CP/M software I can run on it for a decent demo? Wumpus perhaps?