26 Aug
2007
26 Aug
'07
4:35 p.m.
Brent Hilpert sayeth:
I've had a few problems with mine, mostly failing
semiconductors, all of
which have been unusual and difficult to replace/substitute, although I
was quite pleased when I found the 4004 inside.
I'll say. It's basically a 4004 microcomputer system in there, so it's no
surprise the support chips have been hard to track down.
I presume you have the manual, which has the schematic
and a listing of
the base code firmware.
Yes.
I suppose it's conceivable the 1702 firmware
EPROMS are losing their
contents.
I didn't consider that possibility and don't want to :) But it might be
correct. These are pretty old by now.
I have taken dumps of the contents of the ones in
mine, if of interest.
I have another I can try out. But yes, I would probably want to re-burn
the EPROMS if they have rotted out.
(Is this a new toy or something you know was working?
Also, out of
interest, which personality module do you have plugged in?)
A new toy, but I assumed it worked. I hope the other one is good at
least.
This one has the 2716 plug-in, which is perfect because that just happens
to be what I need it for currently. When I pull the other one I'll let
you know what module it has. I believe I have also an 800 model,
something like that, but a third unit for sure.
If you haven't used the unit before, you do have
to press one of the
LIST/DUP/VER/COPY keys initially to get anything to display on the hex
LEDs (initially blank on power-up), although I expect you've banged on
all the keys already.
Oh yes, they got thoroughly exercised.
IIRC, some of the communication adapters if plugged in
(serial¶llel
D plugs) may cause the unit to appear hung.
Interesting. But nothing is plugged into those. Interestingly, the
serial interface is current loop, for interfacing to a TTY. That feature
really dates these things :)
If all the power supplies levels are OK I suppose the
next thing would
be to 'scope for multiplex/keyboard scan activity to see if the
processor/firmware is functioning.
Or just try the other and hope it works. I unfortunately don't have time
for troubleshooting :(
--
Sellam Ismail Vintage Computer Festival
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26 Aug
26 Aug
4:53 p.m.
On Sunday 26 August 2007 16:35, Sellam Ismail wrote:
Speaking of which, I'm remembering running into current loops in some early
hardware (tht Heathkit H-11 I built back in 1978 for one example), but they
seem to be all but gone, even though you can run a whole lot more wire with
one of those than with rs232. Wonder why that is?
I guess they were put into use originally because of teletype machines?
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
IIRC, some of
the communication adapters if plugged in (serial¶llel
D plugs) may cause the unit to appear hung.
Interesting. But nothing is plugged into those. Interestingly, the
serial interface is current loop, for interfacing to a TTY. That feature
really dates these things :) 
27 Aug
27 Aug
3:33 p.m.
Sellam Ismail wrote:
As you can see from the manual there are two RS-232 serial interface options
but they require the appropriate firmware EPROM being present and a small
adapter which plugs into the parallel(!) plug. My unit had the firmware but I
didn't get the hardware adapter, but it turned out to be quite simple to build
an adapter with a MAX-232 chip.
This may all be more than you want to deal with right now if you are just
trying to program some 2716s but if you really want to know what your units are
capable of you need to look at the labels on the installed firmware EPROMS and
correlate them with the options codes/list in the manual.
Brent Hilpert sayeth:
(It's worse than that, in addition to all the 4004 family chips there are
other 'standard function' chips in odd format: some Signetics TTL that don't
match directly to 7400 series and which have a habit of failing; the data
buffer is composed of type 6508 CMOS RAM chips. Even the LEDs on the 2716
module, which look like ordinary individual LEDs, turn out to have internal
current-limiters so you have to add a resistor if replacing them.)
Speaking of the Signetics chips, if you wish to take the time on a crap shoot,
here's one thing you might wish to try to repair the 2716 module:
The problematic Signetics ICs are type 7234(mil-spec)/8234(commercial) (they
are just TTL quad 1-of-2 tri-state muxes but different pinout/control from
7400 types). I have had 2 or 3 of these ICs fail in my unit. There are 2 of
them in the 2716 module. You might try scavenging two from the non-working
base unit and replacing them in the 2716 module to see if it then functions in
the good base unit.
Note: in idle-state with no 2716s in the MASTER/COPY ZIF sockets the 8 data
LEDs on the 2716 module should be ON (open-circuit default to high).
I've had a few problems with mine, mostly
failing semiconductors, all of
which have been unusual and difficult to replace/substitute, although I
was quite pleased when I found the 4004 inside.
I'll say. It's basically a 4004 microcomputer system in there, so it's no
surprise the support chips have been hard to track down.
IIRC, some of
the communication adapters if plugged in (serial¶llel
D plugs) may cause the unit to appear hung.
Interesting. But nothing is plugged into those. Interestingly, the
serial interface is current loop, for interfacing to a TTY. That feature
really dates these things :) 
4:43 p.m.
Glen Slick wrote:
If you just need to program 2716's you could pick
up a BP Microsystems
EP-1 for less than $20 off of eBay.
And what if you don't use ebay?
Anyhow the point is fix it -- not toss it out.
All I want programed is 28C16's EEPROMS and I can't find a
low cost burner for that around.
IF COST .LE. $100 THEN CALL SPEND_IT(INCOME)
Ben alias Woodelf
5:14 p.m.
On Aug 27, 2007, at 4:43 PM, woodelf wrote:
Then create an account and use it. ;)
If you just
need to program 2716's you could pick up a BP
Microsystems
EP-1 for less than $20 off of eBay.
And what if you don't use ebay? Anyhow the point is fix it -- not toss it out.
All I want programed is 28C16's EEPROMS and I can't find a
low cost burner for that around.
IF COST .LE. $100 THEN CALL SPEND_IT(INCOME)
I don't remember the specifics, but does a 28C16 really require
any special voltages or pulses for programming? I seem to recall
that they aren't difficult to program, but I could be wrong.
-Dave
--
Dave McGuire
Port Charlotte, FL
Farewell Ophelia, 9/22/1991 - 7/25/2007
5:23 p.m.
On 8/27/07, woodelf <bfranchuk at jetnet.ab.ca> wrote:
Glen Slick wrote:
If the point is to fix an existing programmer, then fix it. If the
point is to program a 2716 (for example) it might be quicker and
cheaper to buy a used programmer.
If you need to program a 28C16 parallel EEPROM it appears it would be
pretty simple to build a circuit to do that, at least for something
like the Atmel 28C16 part which only needs a single 5V supply unless
you want to Chip Clear.
If you just need to program 2716's you could
pick up a BP Microsystems
EP-1 for less than $20 off of eBay.
And what if you don't use ebay?
Anyhow the point is fix it -- not toss it out.
All I want programed is 28C16's EEPROMS and I can't find a
low cost burner for that around.
IF COST .LE. $100 THEN CALL SPEND_IT(INCOME)
Ben alias Woodelf
6:53 p.m.
Glen Slick wrote:
If you need to program a 28C16 parallel EEPROM it
appears it would be
pretty simple to build a circuit to do that, at least for something
like the Atmel 28C16 part which only needs a single 5V supply unless
you want to Chip Clear.
That is what is frustrating at the moment, the few designs I have seen
on the web is about 3 chips and a zip socket.But alias the only low cost
one I have seen is from the UK, and the VAT and shipping will kill me.
I may breadboard up one, but I am not sure if I will use 28C16's or
2732A's yet.
Ben alias woodelf
PS.
That programmer must have cost a fortune to have 4004 in it.
I had a EPROM programmer once in a Z80/S100 bus cpu kit about 1982
( 2 slots?) but the it was lost in moving years ago. Also it I think was
toasted with a homebrew power supply failure. I have seen alot
of 8080 systems talked about very little on kit computers on the net.
28 Aug
28 Aug
2:42 a.m.
All I want programed is 28C16's EEPROMS and I
can't find a
low cost burner for that around.
IF COST .LE. $100 THEN CALL SPEND_IT(INCOME)
Ben, can't you use a willem type programmer?
www.willem.org
Greetz from Brazil
Alexandre
4 a.m.
Alexandre Souza wrote:
I tend to avoid that part of the world since getting the
Canadian dollar to them is my problem. I can do it but
not for small priced items. I need a AC adaptor and
a case too. That would bring the cost from about 85 Euro
to $125 Canadian. With shipping and other costs I am guessing
at $175 Canadian. I am looking at a $190 (US) programmer
All I want
programed is 28C16's EEPROMS and I can't find a
low cost burner for that around.
IF COST .LE. $100 THEN CALL SPEND_IT(INCOME)
Ben, can't you use a willem type programmer?
www.willem.org from the states if i decide to to buy a programmer. I
only
need 4 (e)eproms burned for my microcode so I may buy 2732A's
programmed from some where in the USA.
That is a nice programmer but I on the wrong part of the
globe.
Thanks again.
Greetz from Brazil
Alexandre
7:51 a.m.
I tend to avoid that part of the world since getting
the
Canadian dollar to them is my problem. I can do it but
not for small priced items. I need a AC adaptor and
a case too. That would bring the cost from about 85 Euro
to $125 Canadian. With shipping and other costs I am guessing
at $175 Canadian. I am looking at a $190 (US) programmer
from the states if i decide to to buy a programmer. I only
need 4 (e)eproms burned for my microcode so I may buy 2732A's
programmed from some where in the USA.
That is a nice programmer but I on the wrong part of the
globe.
These programmers are sold everywhere, take a look on ebay. But you can
build your own, there are schematics, I even built one before I had my Elnec
Beeprog. Single faced board!
6174
days inactive
6176
days old
10 comments
7 participants
participants (7)
-
alexandre-listas＠e-secure.com.br -
bfranchuk＠jetnet.ab.ca -
glen.slick＠gmail.com -
hilpert＠cs.ubc.ca -
mcguire＠neurotica.com -
rtellason＠verizon.net -
sellam＠vintagetech.com