This res. gets hot even when switched off, but just in the socket. I'm
going to take pictures of the unit on wednesday, but a picture of the
teletype with the cover on can be found at
tore.nortia.no/bilder/s201002.jpg .
ASCII drawings:
(out of scale)
________________________
| | | | Blue slot with card that gets hot
| |-- |/
| | ||
|_________________| ||
| | |
|_________________|____|
____________
| |
| (14 O ) | <- large resistor
| |
| (220ko)| <\
| (300ko)| |
| | |- not sure
| etc (vr) | |
| | </
| _ |
|||||| ||||||
The resistor gets extremely hot when the 33 is plugged in.
"Athlon without its fan"-style hot.
-Tore
"Insert quote with wierd Tore-humour here"
>From: ard(a)p850ug1.demon.co.uk
>
>> Whenever I type anything I just get a left-arrow. I am blaming the
>> 1818-23/-21 for this. Shouldn't I?
>
>Maybe. Does the Model 33 work correctly when switched to 'local'? If not,
>then you certainly have problems in the Teletype. If it does work in
>'local' mode, then you might still have problems in the Teletype, but
>problems with the interface are also possible.
Hi
It is also possible that he has the wrong speed gears/motor.
A 60Hz motor will run in local with 50Hz connected but the
Baud rate to the outside will be wrong.
Dwight
>
>>
>> OK; current loop.
>>
>> Would this explain a resistor (14 Ohm, big) in the slot of the KSR would
>
>Are you sure it's 14 ohms? I remember a multi-tapped power resistor with one
>tap being about 1400 ohms in the standard current loop electronics for
>the Model 33.
>
>> get extremely hot when off this loop? Also; Hans Pufal, I would be most
>
>And I think it does run hot. When switched to local, the teletype is
>_still_ a current loop device, but the transmitter (keyboard contacts),
>receiver (the selector magnet driver -- the little module with 2
>transsitors in the Teletype electronics chassis) and a 'local' power
>supply (which includes that resistor) are all in series. A current loop,
>but one entirely inside the Teletype Model 33.
>
>-tony
Hi
I believe this is normal. According to the schematic
I have, only the motor is switched. The transformer
that supplies the current loop is still active. You
must pull the plug when working on these.
Dwight
>From: "Tore Sinding Bekkedal" <toresbe(a)ifi.uio.no>
>
>This res. gets hot even when switched off, but just in the socket. I'm
>going to take pictures of the unit on wednesday, but a picture of the
>teletype with the cover on can be found at
>tore.nortia.no/bilder/s201002.jpg .
>
> ASCII drawings:
> (out of scale)
> ________________________
> | | | | Blue slot with card that gets hot
> | |-- |/
> | | ||
> |_________________| ||
> | | |
> |_________________|____|
>
> ____________
> | |
> | (14 O ) | <- large resistor
> | |
> | (220ko)| <\
> | (300ko)| |
> | | |- not sure
> | etc (vr) | |
> | | </
> | _ |
> |||||| ||||||
>
> The resistor gets extremely hot when the 33 is plugged in.
> "Athlon without its fan"-style hot.
>
>
>-Tore
>
>"Insert quote with wierd Tore-humour here"
Hi
I think the rule is 0.5ma per cubic inch of computer
grade capacitor and 0.25 ma per cubic inch of normal
capacitor. As an example: 2" dia X 3 inch = 9.4 in^3
Cap voltage rating of 10V
use 2.2K limiting resistor and
10V supply.
Of course, if the capacitor is on a 5V rail, you'll
need to disconnect one end.
Dwight
>From: "Luc Vande Velde" <luc(a)e2t.be>
>
>For years I use a high-voltage DC power supply with current limiting for
>this. Works very fine...
>Only a few, weird designs, need the AC voltage to start.
>This is also a very safe way to repair the things (safe for the unit and the
>technician)
>
>gr.
>
>Luc
>
>
>-----Original Message-----
>From: cctech-admin(a)classiccmp.org [mailto:cctech-admin@classiccmp.org]On
>Behalf Of Robert Maxwell
>Sent: Tuesday, June 03, 2003 5:21 PM
>To: 'cctech(a)classiccmp.org'
>Subject: RE: reforming PS caps w/primary-side components
>
>
>-----Original Message-----
>>Anybody want to offer advice on reforming filter
>>caps? I'm planning to power up some stuff that
>>hasn't seen voltage in a long time. My plan is
>>to put several low-wattage light-bulbs in series
>>with the thing, to limit the amount of current it
>>will get, and hopefully allow those old caps
>>to reform instead of, say, exploding in my face.
>>...
>>Now the questions:
>>
>>Could putting the light-bulbs (or whatever) in
>>series on the primary side of the transformer
>>actually produce the desired effect? IIRC, a
>>step-down transformer divides the voltage but
>>multiplies the current. So I'd have to limit the
>>current on the primary side that much more to
>>keep the secondary current down, right?>
>>
>>Also, what kinds of things could be damaged by
>>getting less voltage than they were designed for?
>>I could imagine hard disks spinning too little to
>>lift the heads from the surface, for instance.
>>(This is moot, because there are no hard disks
>>in any of the equipment I'm looking at.) How
>>about CRT's? Could too little deflection make
>>the beam hit something it shouldn't? Anything
>>else?
>>
>> Thanks,
>> Bill.
>
>Bill,
> (1) Don't use a light bulb - they have a very low resistance when cold,
>and will cause the inrush you're trying to avoid. The best recommendation
>I've seen is to use a "variac"-type variable transformer to reduce the
>powerline going in. Start at minimum, and turn things up slowwwwly, watching
>current draw. Beware gotchas like LSTTL drawing heavy current at around 2.1
>volts supply. Actually, with a meter across the capacitor supply, stop at
>about one volt, so any semiconductors in line can't get terribly excited: if
>there's no apparent short as things stabilize, turn the voltage up.
> (2) CRTs aren't a hazard from undervoltage (I ran a sick Zenith TV on
>85VAC for years using a Variac). It's overvoltage that causes X-Ray risks.
>Just to be safe, disconnect anything mechanical, to avoid problems like the
>hard-drive one you mentioned - some types of motor overheat if undervolt-ed.
>
>Bob "HW-Hacker" Maxwell
>How many people do you know that sawed their computer in two?
Hi Joe,
>I'd like get a copy if you have it. I'm running into a couple of
>oddities when I try to operate it. It's working but not the way that I
>expected and I don't know if I'm doing something wrong or what.
I remember being slightly confused by the operation of the bus analyser too.
It didn't really seem to make sense to me for some operations - I was never
sure if it was broken or that was just the way it worked.
I think that these things tend to be a little flaky / sensitive - I ended up
constructing a single analyser that sort of worked from three analysers that
didn't.
>Steve Robertson ran into the same problem when he tried to use it to
>study the disk operation as part of writing an OS for the HP 1000. He did
>get some usefull info but only 32 bytes of it!
That's right, the internal memory buffer in the bus analyser is only 32
bytes.
You can either set it up to store 32 bytes from the bus or (I think), if you
have the patience, you can manually (in binary) store 32 bytes in the memory
and then have the analyser clock them out onto the bus.
>I'm currently investigating another option.
>NI make a GPIB+ card (ISA or PCI) that acts as both a GPIB controller and a
>...
>codes. I'll let you know how I get on.
I've now had a chance to take a look at the NI GPIB+ cards in some detail.
With the proviso that these cards only work under Windows 98 se or earlier
and windows NT, they seem to be an excellent solution to seeing what is
going on on an HPIB bus.
The software can be set up to monitor all events on the HPIB bus, control
lines, data lines, control words, data words etc. The card can also be set
up to passively monitor the bus and add time stamps to the captured bus
events.
The only limitation to the number of events that can be stored in a capture
file appears to be how much memory/disk space the capture machine has.
The capture files can be exported in a text format and dumped into Word /
Excel for further processing.
>I have (had?) a card like that but NI no longer supports it and I
>haven't been able to find any docs or software for it.
If the card is a GPIB+ Controller/Analyser then the software is available
for NT / Win98 - you need version 1.7 of the GPIB controller software from
the NI website.
>I have something else that might be usefull. It's Bus Analyzer module
>made by HP that works with one of their logic analyzers. You plug the LA
>pods directly into it (no wire leads) and it has sockets for RS-232, HP-IB
>and one or two other standard interfaces. With it you can use a LA to grab
>the data, disaasemble it (if you have the the disassembler), save it, send
>it to a computer, etc. I've never tried to use it since I don't have the LA
>(HP 1631 IIRC) that it works with.
For me, after looking at the GPIB+ card it seems to be a 100% solution - I
am very impressed with it - only the slightly ageing software lets it down.
Peter
_________________________________________________________________
It's fast, it's easy and it's free. Get MSN Messenger today!
http://www.msn.co.uk/messenger
For years I use a high-voltage DC power supply with current limiting for
this. Works very fine...
Only a few, weird designs, need the AC voltage to start.
This is also a very safe way to repair the things (safe for the unit and the
technician)
gr.
Luc
-----Original Message-----
From: cctech-admin(a)classiccmp.org [mailto:cctech-admin@classiccmp.org]On
Behalf Of Robert Maxwell
Sent: Tuesday, June 03, 2003 5:21 PM
To: 'cctech(a)classiccmp.org'
Subject: RE: reforming PS caps w/primary-side components
-----Original Message-----
>Anybody want to offer advice on reforming filter
>caps? I'm planning to power up some stuff that
>hasn't seen voltage in a long time. My plan is
>to put several low-wattage light-bulbs in series
>with the thing, to limit the amount of current it
>will get, and hopefully allow those old caps
>to reform instead of, say, exploding in my face.
>...
>Now the questions:
>
>Could putting the light-bulbs (or whatever) in
>series on the primary side of the transformer
>actually produce the desired effect? IIRC, a
>step-down transformer divides the voltage but
>multiplies the current. So I'd have to limit the
>current on the primary side that much more to
>keep the secondary current down, right?>
>
>Also, what kinds of things could be damaged by
>getting less voltage than they were designed for?
>I could imagine hard disks spinning too little to
>lift the heads from the surface, for instance.
>(This is moot, because there are no hard disks
>in any of the equipment I'm looking at.) How
>about CRT's? Could too little deflection make
>the beam hit something it shouldn't? Anything
>else?
>
> Thanks,
> Bill.
Bill,
(1) Don't use a light bulb - they have a very low resistance when cold,
and will cause the inrush you're trying to avoid. The best recommendation
I've seen is to use a "variac"-type variable transformer to reduce the
powerline going in. Start at minimum, and turn things up slowwwwly, watching
current draw. Beware gotchas like LSTTL drawing heavy current at around 2.1
volts supply. Actually, with a meter across the capacitor supply, stop at
about one volt, so any semiconductors in line can't get terribly excited: if
there's no apparent short as things stabilize, turn the voltage up.
(2) CRTs aren't a hazard from undervoltage (I ran a sick Zenith TV on
85VAC for years using a Variac). It's overvoltage that causes X-Ray risks.
Just to be safe, disconnect anything mechanical, to avoid problems like the
hard-drive one you mentioned - some types of motor overheat if undervolt-ed.
Bob "HW-Hacker" Maxwell
How many people do you know that sawed their computer in two?
Hi, I have a DEC RL02, supposedly removed from a working system.
Anybody want it? Anybody want to offe a few $$$ for the wear and tear on my
back?
It's a heavy beast, so expect $45 or so shipping cost
in the USA.
Regards,
George
-----Original Message-----
>Anybody want to offer advice on reforming filter
>caps? I'm planning to power up some stuff that
>hasn't seen voltage in a long time. My plan is
>to put several low-wattage light-bulbs in series
>with the thing, to limit the amount of current it
>will get, and hopefully allow those old caps
>to reform instead of, say, exploding in my face.
>...
>Now the questions:
>
>Could putting the light-bulbs (or whatever) in
>series on the primary side of the transformer
>actually produce the desired effect? IIRC, a
>step-down transformer divides the voltage but
>multiplies the current. So I'd have to limit the
>current on the primary side that much more to
>keep the secondary current down, right?>
>
>Also, what kinds of things could be damaged by
>getting less voltage than they were designed for?
>I could imagine hard disks spinning too little to
>lift the heads from the surface, for instance.
>(This is moot, because there are no hard disks
>in any of the equipment I'm looking at.) How
>about CRT's? Could too little deflection make
>the beam hit something it shouldn't? Anything
>else?
>
> Thanks,
> Bill.
Bill,
(1) Don't use a light bulb - they have a very low resistance when cold,
and will cause the inrush you're trying to avoid. The best recommendation
I've seen is to use a "variac"-type variable transformer to reduce the
powerline going in. Start at minimum, and turn things up slowwwwly, watching
current draw. Beware gotchas like LSTTL drawing heavy current at around 2.1
volts supply. Actually, with a meter across the capacitor supply, stop at
about one volt, so any semiconductors in line can't get terribly excited: if
there's no apparent short as things stabilize, turn the voltage up.
(2) CRTs aren't a hazard from undervoltage (I ran a sick Zenith TV on
85VAC for years using a Variac). It's overvoltage that causes X-Ray risks.
Just to be safe, disconnect anything mechanical, to avoid problems like the
hard-drive one you mentioned - some types of motor overheat if undervolt-ed.
Bob "HW-Hacker" Maxwell
How many people do you know that sawed their computer in two?
I guess that's me!
I am quite busy. In a few months (3) I have my own
"PDP-11 garden house" (3,5 x 8 meters) just for PDP-11's.
Then www.pdp-11.nl will see some new info.
On http://home.hetnet.nl/~tshaj is a link to www.pdp-11.nl
and to my StarShip project. Again, in a few months time,
I will start new developments ... indeed time is a problem.
The 'StarShip Simulation' of Dilithium Press is the Bible,
but, as it should, use it for inspiration and do not follow
it like a fanatic :-)
- Henk.
BTW. Megan, I have sent you the 68020 assembler source code
of the kernel which supports task start/stop/suspend/resume
and time-wait and semaphore-pend calls. Ever ported it to
PDP-11?
> -----Original Message-----
> From: Megan [mailto:mbg@TheWorld.com]
> Sent: dinsdag 3 juni 2003 15:46
> To: cctalk(a)classiccmp.org
> Subject: Re: Display of first networked personal computer
> game returning
>
>
> I have a copy of the 'StarShip Simulation' and have also often
> thought about rendering some code...
>
> alas, not enough time...
>
> I do know that there is someone on the net who has been trying
> to actually build the hardware for a starship simulator and has
> been basing his code on the 68000... I'm not sure where his page
> is or if he reads CCMP.
>
> Megan
