1 Jun
2008
1 Jun
'08
2:05 p.m.
I've got what I believe to be a complete Micron Xceed setup for a Mac SE/30.
I know these are extremely rare and thought I would pass it by you guys to
see if I get any offers. I'd really rather avoid the eBay cesspool, so
seeing what the highest offer I can get would be.
-----Original Message-----
From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org]
On Behalf Of cctech-request at classiccmp.org
Sent: Sunday, June 01, 2008 10:03 AM
To: cctech at classiccmp.org
Subject: cctech Digest, Vol 58, Issue 2
Send cctech mailing list submissions to
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of cctech digest..."
Today's Topics:
1. Re: PET 2001-8 progress... (Josh Dersch)
2. RE: Introduction (dwight elvey)
3. Re: DEC Brochures - already scanned? (Al Kossow)
4. RE: Tandy (Radio Shack) 6000 rescue (Geoff Reed)
5. Re: Introduction (Oliver Lehmann)
6. C <-> ASM translation problem (Oliver Lehmann)
7. Wang the Perverted (schwepes at moog.netaxs.com)
8. RE: Transformer repairs (Ade Vickers)
9. Thanks! RE:XT Diagnostic ROM and POSTcard (Andrew Lynch)
10. Re: Thanks! RE:XT Diagnostic ROM and POSTcard (Jim Leonard)
11. RE: Introduction (dwight elvey)
12. Re: Wang the Perverted (Jim Battle)
13. Re: Wang the Perverted (Roy J. Tellason)
14. Synertek KTM-3/80 -- 2 questions (Peter)
15. RE: Transformer repairs (dwight elvey)
16. Old style DEC 5-1/4" "pop panel" needed (will trade for 10
1/2") (Bob Armstrong)
17. RE: Thanks! REXT Diagnostic ROM and POSTcard (Andrew Lynch)
18. video game cartridges (David Griffith)
19. Re: video game cartridges (Chris M)
20. Re: video game cartridges (Mr Ian Primus)
21. Re: video game cartridges (Mr Ian Primus)
22. Re: video game cartridges (David Griffith)
23. Good Composite->VGA converters for classic computers (& video
games...) (Josh Dersch)
24. Big Board I: micro cornucopia & user disk (Enrico Lazzerini)
25. Come Work at Bell Labs! (Jason T)
26. OS/2 problems (Teo Zenios)
27. Re: OS/2 problems (Teo Zenios)
----------------------------------------------------------------------
Message: 1
Date: Fri, 30 May 2008 21:52:01 -0700
From: Josh Dersch <derschjo at msu.edu>
Subject: Re: PET 2001-8 progress...
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Message-ID: <4840D971.1030807 at msu.edu>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Dave Dunfield wrote:
RDY is being held high, which I believe is correct (my understanding
I have the AofE 2nd edn (I think it's 2nd edn, anyway), I'll take a look.
Cheers,
Ade.
No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.524 / Virus Database: 269.24.2 - Release Date: 28/05/2008 00:00
------------------------------
Message: 9
Date: Sat, 31 May 2008 09:18:31 -0400
From: "Andrew Lynch" <lynchaj at yahoo.com>
Subject: Thanks! RE:XT Diagnostic ROM and POSTcard
To: <cctalk at classiccmp.org>
Message-ID: <000001c8c320$d2ac34d0$a903a8c0 at andrewdesktop>
Content-Type: text/plain; charset="us-ascii"
Hi All,
I just wanted to say "Thank you" to everyone who helped me fix this classic
IBM XT motherboard with the Diagnostic ROM image and the settings for the
AWARD POSTcard.
Long story short, I replaced a 74LS245 and a faulty DRAM chip and now the
board boots fine.
Of course half the fun is finding what actually works, what doesn't, what
appears to be broken but actually works, what is broken but appears to be
working, etc. You know the drill, I am sure.
Fixing an old broken 16 bit VGA card which works in an 8 bit ISA slot helped
a lot. As did the old style PC/XT style floppy drive controller...
So anyway, it's fixed and I booted MS-DOS 5.0 and the Advanced IBM
Diagnostics from a 5.25" floppy disk drive. So I think we are there.
THANKS!
Andrew Lynch
PS, BTW the XT Diagnostic ROM image seems to work best when burned into a
2764 EPROM. I tried various other types of EPROM but the 2764 seems to work
best. I think IBM did some weird remapping of their custom Mask BIOS ROM...
------------------------------
Message: 10
Date: Sat, 31 May 2008 09:44:56 -0500
From: Jim Leonard <trixter at oldskool.org>
Subject: Re: Thanks! RE:XT Diagnostic ROM and POSTcard
To: General at mail.mobygames.com,
"Discussion at mail.mobygames.com":On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Message-ID: <48416468.5090300 at oldskool.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Andrew Lynch wrote:
9v
Oops! should have said 10:1 or more.
Dwight
Got out my
ancient oscilloscope and did a bit of probing and got a
little more info:
On power up, the CPU reset line is held low for ~1 sec, then goes high.
At this point if I look at the address/data lines, I can see a very
brief burst of activity and then nothing at all (it's during this
activity that a few characters on screen change). After this activity,
all address lines are high. IRQ & NMI lines are high. CPU is being
clocked throughout all of this, clock rate seems to be correct.
Assuming that it is clocked and has been reset correctly, there are
generally only two reasons that a CPU stops running (fetching opcodes):
1) It is being held in a hardware wait state.
Check the state of the RDY line on the 6502 and if it
is asserted, backtrace through the circuit to find out why.
from reading 6502 specs indicates this is held low to
halt the CPU...)
2) It executes an instruction which causes it to stop
Usually a HALT instructionor of some sort or other, there are sometimes
undocumented opcodes which cause this behaviour as well - A bit of
net searching should turn up details on the undocumented opcodes.
There are generally two reasons why a processor would execute an opcode
to shut itself off:
1) On purpose
Usually while waiting for an interrupt - given that you PET hasn't
even cleared it's screen, I doubt this is the case.
2) By executing "random" code
Can be caused by:
- Bad ROM - actual code gets corrupted
- Bad RAM - stack failure results in "return" to random address
- Bad bus buffers - hardware failure resulting in corruption in the
address or data buses.
- Bad decode logic - no device or multiple memory devices being
selected when only one should be.
I've seen a least two 2001's with bad ROM chips. And a number of PETs
with bad RAM - I'd suspect one of these two.
On a whim, I ran the machine without any of the ROMs installed and I get
identical behavior to what I was already seeing (brief CPU activity,
then nothing). I suspect the CPU is just reading garbage and
something's broken between the CPU & RAM. The CPU's probably halting
on a bogus instruction... I'm going to do some investigation in that area.
Thanks for the suggestions...
Josh
If you have a storage scope, you should be able to
trigger on the
SYNC signal at the CPU and catch the last few opcode fetches - walking
the data and address bus signals and writing them down will reveal
the last opcode executed and the address from which it was executed.
Alas, I don't. My 'scope's an ancient Tektronix 561A. Works great,
but
it's pretty simple. (And maybe a bit underpowered for this particular
task...)
Look at the opcode that was executed to see what
exactly caused the
CPU to stop.
Try this a couple of times and see if the CPU is always stopping in
the same place. Scope the select lines and note *which* ROM was
selected for the last opcode fetch, or in the case of a "wild" access,
which ROM was selected last before it stopped.
If the address where that opcode was fetched in within the ROM, get
the PET rom binaries and see if it's "supposed" to be there - a bit
of disassembly around that address should tell you if the code is
real code, or some random bit of data that the processor wandered
off into. If you can read the PET ROMs (I made an adapter to stuff
them into my homebuild EPROM programmer) you can compare against the
binaries to check the entire ROM content - The PET roms are not standard
pinouts - but you can make an adapter to put a normal ROM in the
socket - IIRC I needed a TTL chip to provide an extra select - I've
got photos on my site of a PET that I had to repair this way.
If the address is NOT within the ROM, trigger on the ROM select and
see what the last opcode executed from ROM was - if it was RTS or
RTI I would strongly suspect a RAM problem. It might also be a jump
indirect (same suspicion). As above, look at the code contained at
this address and see it if "makes sense" as a valid place to be
executing.
With a decent scope you can get several fetches on the screen, and
therefore determine the opcode/address for the last few instructions
executed - If you can't get any of that to make sense, try single-
shot trigger and capture the first few instructons executed - see if
they make sense and match the ROM.
With a bit of poking around you should be able to determine what the
processor is doing at the time it went insane - hopefully at some point
the "ah-ha" light will go on.
Regards,
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
------------------------------
Message: 2
Date: Fri, 30 May 2008 21:01:27 -0700
From: dwight elvey <dkelvey at hotmail.com>
Subject: RE: Introduction
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <BAY138-W40430C54E60BC3EB282BEFA3B90 at phx.gbl>
Content-Type: text/plain; charset="Windows-1252"
From: roger.holmes at microspot.co.uk
Date: Fri, 30 May 2008 21:09:13 +0100
To: cctalk at classiccmp.org
Subject: Re: Introduction
On 30 May, 2008, at 18:00, cctalk-request at classiccmp.org wrote:
---snip---
Message: 9
Date: Fri, 30 May 2008 17:11:02 +0200
From: Oliver Lehmann
Subject: Introduction
To: Classic Computers Mailing List
Welcome Oliver.
The system runs a Z8001 with 3 MMUs and
Z80-peripherial ICs (PIO,
SIO...)
It also has 2 SIOs for 4 terminal connections, and one PIO to
connect the
WDC. The system also has two furhter PIO chips to establish a
connection
to the 8Bit system. The system runs with up to 4MB of DRAM but it
might
run with more RAM with self-made RAM modules.
When I retire I might get around to getting myself a Z8001 system if
there's any still around by then. I am kept busy at work programming
Apple Macs and at home restoring a 1962 mainframe computer (ICT 1301)
and restoring/maintaining my old cars (2 Daimlers, 2 Rovers, a Land
Rover, a Jaguar and a BMW).
Hi
One can still get a Olivetti M20 but mose I've seen come up on
the Italian eBay. These don't have a MMU but instead use a ROM
to decode segements. It is limited to 512K of RAM.
It does have one segement where the data and instruction are
mapped to two different physical memories, giving a total of
128K within one segement.
The M20 can run the version of CP/M that DRI came up with.
It has a C compilers as well asn an assembler. It can also have
a hard disk connected but the original controllers are hard to find.
It is software compatable with the WD1000 controller. I use
a TRS80 controller and a ST251 drive. I did need to modify
the code to deal with stepping differences between the original
olivetti drive and the ST251. I just use the auto stepping.
Dwight
_________________________________________________________________
Give to a good cause with every e-mail. Join the im Initiative from
Microsoft.
http://im.live.com/Messenger/IM/Join/Default.aspx?souce=EML_WL_ GoodCause
------------------------------
Message: 3
Date: Fri, 30 May 2008 22:44:26 -0700
From: Al Kossow <aek at bitsavers.org>
Subject: Re: DEC Brochures - already scanned?
To: classiccmp at classiccmp.org
Message-ID: <4840E5BA.1040005 at bitsavers.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Wow, that must have been a brutal scanning job.
Paper cutter and a sheet feeder.
Biggest challenge was dealing with thin paper.
I've switched to a different brand of scanner that
can handle it better now to deal with the data
books.
------------------------------
Message: 4
Date: Fri, 30 May 2008 23:34:33 -0700
From: "Geoff Reed" <geoffr at zipcon.net>
Subject: RE: Tandy (Radio Shack) 6000 rescue
To: "'General Discussion: On-Topic and Off-Topic Posts'"
<cctalk at classiccmp.org>
Message-ID: <078801c8c2e8$63aea410$6a01a8c0 at liberator>
Content-Type: text/plain; charset="US-ASCII"
I still miss my tandy 6000 I had several years ago... very nice box as long
as you had spare HDD's for the external storage unit.
------------------------------
Message: 5
Date: Sat, 31 May 2008 08:41:27 +0200
From: Oliver Lehmann <lehmann at ans-netz.de>
Subject: Re: Introduction
To: cctalk at classiccmp.org
Message-ID: <20080531084127.dfbaf4a6.lehmann at ans-netz.de>
Content-Type: text/plain; charset=US-ASCII
dwight elvey wrote:
It is software compatable with the WD1000 controller.
I use
a TRS80 controller and a ST251 drive. I did need to modify
the code to deal with stepping differences between the original
olivetti drive and the ST251. I just use the auto stepping.
Dwight
Can you tell me a bit more about this? I can connect MFM drives to my WDC
too but I've problems with ST251-1 while ST251-0 are working. I think
that the -1 is probably somewhat different then the -0 but I'm not sure
where to look at in the WDC firmware (source is 86K) for what to
change...
http://pofo.de/P8000/misc/sources/EAW/Firmware/Firmware_-_MON16-WDC/WDC/wdc.
firm.s
I can switch something in the firmware from 40MHz to 41,4MHz but neither
this helps nor do I know what this means....
--
Oliver Lehmann
http://www.pofo.de/
http://wishlist.ans-netz.de/
------------------------------
Message: 6
Date: Sat, 31 May 2008 13:00:15 +0200
From: Oliver Lehmann <lehmann at ans-netz.de>
Subject: C <-> ASM translation problem
To: cctalk at classiccmp.org
Message-ID: <20080531130015.2f61d66d.lehmann at ans-netz.de>
Content-Type: text/plain; charset=US-ASCII
Hi,
As I promissed here comes my first question ;)
While writing several C files for the WEGA/ZEUS kernel out of the
disassembled objects (with unresolved symbols marked as external) I came
across a piece of code I can't get to reproduce when compiling C.
The original object contains:
0006de: 35a2 0004 ldl rr2,rr10(#$0004)
0006e2: 9424 ldl rr4,rr2
0006e4: 0704 7f00 and r4,#$7f00
0006e8: 5d04 8000 0004 ldl $8000+$0x4,rr4
I tried to reproduce it:
ipc.ip_addr.l = *(unsigned long)(uap->addr.l)&0x7F00FFFF;
Which generates:
0008 35a2 0004 59 ldl rr2,rr10(#4)
000c 0702 7f00 60 and r2,#32512
0010 5d02 8000* 61 ldl _ipc+4,rr2
0014 0004*
which looks for me functional the same...
I also tried:
ipc.ip_addr.l = *(unsigned long *)(uap->addr.l)&0x7F00FFFF;
Which generates:
0010 35a2 0004 60 ldl rr2,rr10(#4)
0014 1424 61 ldl rr4, at rr2
0016 0704 7f00 62 and r4,#32512
001a 5d04 8000* 63 ldl _ipc+4,rr4
Which looks "better" but isn't the same as the original because the
adress of rr2 gets loaded into rr4 first, not rr2 itself.
I'm a bit lost because I tried several different */&-pointer stuff to get
this as it is in the original object without success. the elements
ip_addr and addr are both of type saddr_t which is declare as follows:
typedef union
{
caddr_t l;
struct
{
unsigned left;
unsigned right;
} half;
} saddr_t; /* segmented address with parts */
rr4 itself gets later overwritten in both codes - my code and the
original object - it is not reserved for an internal C-variable. Maybe
someone from you can help me here?
--
Oliver Lehmann
http://www.pofo.de/
http://wishlist.ans-netz.de/
------------------------------
Message: 7
Date: Sat, 31 May 2008 07:49:45 -0400 (EDT)
From: schwepes at moog.netaxs.com
Subject: Wang the Perverted
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <Pine.LNX.4.58.0805310740230.15648 at moog.netaxs.com>
Content-Type: TEXT/PLAIN; charset=US-ASCII
My name is Bob and this is my first post.
What caused me to join this discussion group was a wang computer that
came into my possession that had two 5 1/4 diskette drives, one
internal and the other external.
It seemed to require its own peculiar start up disk and I suspect it
would have to be a formatted 160 or 180 kbit job.
Finding out information on this thing only seemed to lead to dead ends.
I cannot get greater specifics as I stored the thing in an inconvenient
place when I took it off the workbench.
respectfully
bob schwier
------------------------------
Message: 8
Date: Sat, 31 May 2008 14:12:56 +0100
From: "Ade Vickers" <javickers at solutionengineers.com>
Subject: RE: Transformer repairs
To: "'General Discussion: On-Topic and Off-Topic Posts'"
<cctalk at classiccmp.org>
Message-ID: <045701c8c320$0ae50490$0b01a8c0 at solutionengineers.com>
Content-Type: text/plain; charset="windows-1250"
Tony Duell wrote:
OK, let's
talk failures ;) If you've got any links which give a
sensible description of how a switcher works, I'd be most grateful.
I don;'t know of any useful on-line info. There's a pretty
poor article in this month's Elektor magazine (which might
give you some idea), and there's a reasonable description in
the _second edition_ of The Art of Electronics (a book which
you ought to have anyway...) Long story short, I replaced a 74LS245 and a faulty
DRAM chip and now the
board boots fine.
The DRAM I could probably figure out myself, but how did you determine
the 74LS245 was at fault? (I, too, have a 5150 that won't boot)
--
Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/
Help our electronic games project: http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/
A child borne of the home computer wars: http://trixter.wordpress.com/
------------------------------
Message: 11
Date: Sat, 31 May 2008 07:45:00 -0700
From: dwight elvey <dkelvey at hotmail.com>
Subject: RE: Introduction
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <BAY138-W24D5E879AF7B158451474FA3B90 at phx.gbl>
Content-Type: text/plain; charset="Windows-1252"
Hi
My German isn't that good. If the step rate is the problem,
I did see a couple routines that were creating steps. One
was RAMP.
Setting the controllers step rate is always done on just one
port. I forget which. All you should really need to do is find
all the out's to that port and set the step to the auto rate.
For my code, it was only in two places.
Dwight
From: lehmann at ans-netz.de
dwight elvey wrote:
http://pofo.de/P8000/misc/sources/EAW/Firmware/Firmware_-_MON16-WDC/WDC/wdc.
firm.s
It is software compatable with the WD1000
controller. I use
a TRS80 controller and a ST251 drive. I did need to modify
the code to deal with stepping differences between the original
olivetti drive and the ST251. I just use the auto stepping.
Dwight
Can you tell me a bit more about this? I can connect MFM drives to my WDC
too but I've problems with ST251-1 while ST251-0 are working. I think
that the -1 is probably somewhat different then the -0 but I'm not sure
where to look at in the WDC firmware (source is 86K) for what to
change...
I can switch something in the firmware from 40MHz to 41,4MHz but neither
this helps nor do I know what this means....
--
Oliver Lehmann
http://www.pofo.de/
http://wishlist.ans-netz.de/
_________________________________________________________________
Give to a good cause with every e-mail. Join the im Initiative from
Microsoft.
http://im.live.com/Messenger/IM/Join/Default.aspx?souce=EML_WL_ GoodCause
------------------------------
Message: 12
Date: Sat, 31 May 2008 09:57:15 -0500
From: Jim Battle <frustum at pacbell.net>
Subject: Re: Wang the Perverted
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Message-ID: <4841674B.6090709 at pacbell.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
schwepes at moog.netaxs.com wrote:
My name is Bob and this is my first post.
What caused me to join this discussion group was a wang computer that
came into my possession that had two 5 1/4 diskette drives, one
internal and the other external.
It seemed to require its own peculiar start up disk and I suspect it
would have to be a formatted 160 or 180 kbit job.
Finding out information on this thing only seemed to lead to dead ends.
I cannot get greater specifics as I stored the thing in an inconvenient
place when I took it off the workbench.
respectfully
bob schwier
Bob,
Wang made many different computers of the course of three decades. Can
you say which one you are talking about? Or some information that might
help narrow it down?
------------------------------
Message: 13
Date: Sat, 31 May 2008 11:17:47 -0400
From: "Roy J. Tellason" <rtellason at verizon.net>
Subject: Re: Wang the Perverted
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <200805311117.47464.rtellason at verizon.net>
Content-Type: text/plain; charset=iso-8859-1
On Saturday 31 May 2008 10:57, Jim Battle wrote:
schwepes at moog.netaxs.com wrote:
Those disk formats sound like their "PC" with single-sided drives, 8 or 9
sectors / track offhand...
--
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
------------------------------
Message: 14
Date: Sat, 31 May 2008 17:32:36 +0200
From: "Peter" <peter.lofstedt at bahnhof.se>
Subject: Synertek KTM-3/80 -- 2 questions
To: <cctalk at classiccmp.org>
Message-ID: <000001c8c333$8dbecfa0$0300a8c0 at HemPC>
Content-Type: text/plain; charset="us-ascii"
Hello
I have an KTM-3 with power module, thermo printer and floppy drive.
How can I come in touch with people that are interested in this classic
hardware?
Kind Regards
Peter Lofstedt
Home +46 243 60655
Cell +46 70 6368475
Peter.lofstedt at ericsson.com
------------------------------
Message: 15
Date: Sat, 31 May 2008 09:15:45 -0700
From: dwight elvey <dkelvey at hotmail.com>
Subject: RE: Transformer repairs
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <BAY138-W24BE1707FABC9FD2B0BBBBA3B90 at phx.gbl>
Content-Type: text/plain; charset="Windows-1252"
My name is Bob and this is my first post.
What caused me to join this discussion group was a wang computer that
came into my possession that had two 5 1/4 diskette drives, one
internal and the other external.
It seemed to require its own peculiar start up disk and I suspect it
would have to be a formatted 160 or 180 kbit job.
Finding out information on this thing only seemed to lead to dead ends.
I cannot get greater specifics as I stored the thing in an inconvenient
place when I took it off the workbench.
respectfully
bob schwier
Bob,
Wang made many different computers of the course of three decades. Can
you say which one you are talking about? Or some information that might
help narrow it down? From: dkelvey at hotmail.com
To: cctalk at classiccmp.org
Date: Fri, 30 May 2008 20:47:47 -0700
Subject: RE: Transformer repairs
was
From: javickers at solutionengineers.com
---snip some ---
>
> My apologies - I previously stated that all T's were fed from the same AC
> input, but that's wrong. Mea culpa, my memory is rapidly fading, and I > going from memory...
>
> You can probably follow things from the schematic better than I can from
the
> circuit board, however:
>
> The T3 transformer is fed via Q1 from one side of C7. I'm guessing that
Q1
is what's
generating the pulses?
Hi Ade
No, Q1 is on the secondary side of T3, not the primary. IC1 generates
the pulse that go through T3 and cause Q1 to turn on for the short pulses.
I'll try to walk you through how this particular supply works.
---snip-- some more
>
> Can remove T1 from the board & conduct an isolated test? If I connect a > battery (with a lightbulb in series, say) across
the primary, would I
expect
to see a pulse
of some kind come out of the secondary if it is working
properly?
It is unlikely that you'd see anything more than a small spike on a scope
The T1 seems to have about a 100:1 ratio or more.
Let me try to describe how this supply works. This should help you fix it.
First, T2 provides power to IC1. IC1 monitors the 12 volts out through
R14, VR2 and R12 network. If it is more than 12 volts, IC1 will sorten
the pulse on time to T3. If the voltage is too low it will increase the
pulse
width.
The other components around IC1 provide time constants for the pulse
frequency and filter of response time of the regulation. IC1 also has
a current monitor that looks at R11. If the voltage across R11 is too
high it will turn on a circuit to stop the pulses to T3.
Now, lets look at the high voltage side. As Tony has stated, you can't see
much on a scope because of the fact that everything is following the ac
input.
Where you'd want to connect the ground would blow
a fuse, unless you
ran differential or as I suggested, use an isolation transformer.
First the input AC goes through the filter network of L1 and some
capacitors.
It then goes through a full wave rectifier, causing a
DC voltage to be
developed
on C7. You should measure this voltage with an
ungrounded meter. You
should
see about 300volts across C7. If not, something is
open in the input
circuits.
If, as you say, you see pulses on T3's primary
side, it must be in the
bridge
rectifier is open. The voltages measured relative to
ground have little
meaning.
T3's secondary is connected to the emitter and
base of Q1. The pulse
will cause Q1 to turn on for a short time. Since this is a short
pulse,T1's
secondary will see a voltage spike as well.
This will forward bias the leg of D6 from the transformer to L2, charging
C14. When the pulse is gone on T3's output, Q1 turns off. This turns
the top leg of D6 off.
Because some energy is now stored in L2, the bottom leg of D6 will
now conduct, further charging C14. It is this voltage that feeds back to
IC1 to change the pulse width going to T3 and on to Q1.
This completes the 12 volt part of the supply.
The 5 volt output is completely supplied from the 12 volt line. If there
is
no 12 volts, there is no 5 volts.
The 12 volts powers IC2 that sets the regulation of the 5 volt output.
It is directly connected to the transistors that switch the DC from the
12 volt line to the 5 volt.
IC2 turns on Q4 and Q3 for a short amount of time. This causes
current to flow in L5 and charge C21. When IC2 turns off Q4 and Q3,
L5 will still have some stored energy, causing D7 bto conduct, further
charging C21.
IC2 monitors the voltage and adjust the pulse width to keep the
output at 5V, in the same way as IC1 did.
Besides testing the voltage across C7, as I suggested earlier ( being
very careful not to electricute one self, you might also unsolder Q1 and
see if it is shorted.
This supply is also unique in that the 5 volt part runs from the 12 volt
side. It would be possible to connect a 12 volt bench supply to the
12 volt output leads ( with the mains not connected ) and see if the
5 volt output works OK.
That is all I have for now.
Dwight
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------------------------------
Message: 16
Date: Sat, 31 May 2008 11:13:21 -0700
From: "Bob Armstrong" <bob at jfcl.com>
Subject: Old style DEC 5-1/4" "pop panel" needed (will trade for 10
1/2")
To: "'General Discussion: On-Topic and Off-Topic Posts'"
<cctalk at classiccmp.org>
Message-ID: <004101c8c34a$0290a810$07b1f830$@com>
Content-Type: text/plain; charset="us-ascii"
I need a DEC, old style, "pop panel" blank rack panel that's 5 1/4"
high.
I'd be happy to trade for a 10 1/2" pop panel if that helps anybody (heck,
I'll trade for two - I've got several of the 10 1/2 panels).
Thanks,
Bob Armstrong
------------------------------
Message: 17
Date: Sat, 31 May 2008 15:49:11 -0400
From: "Andrew Lynch" <lynchaj at yahoo.com>
Subject: RE: Thanks! REXT Diagnostic ROM and POSTcard
To: <cctalk at classiccmp.org>
Message-ID: <008b01c8c357$65d30b40$a903a8c0 at andrewdesktop>
Content-Type: text/plain; charset="us-ascii"
Andrew Lynch wrote:
Long story short, I replaced a 74LS245 and a faulty
DRAM chip and now the
board boots fine.
The DRAM I could probably figure out myself, but how did you determine
the 74LS245 was at fault? (I, too, have a 5150 that won't boot)
--
Jim Leonard (trixter at oldskool.org
<http://www.classiccmp.org/mailman/listinfo/cctalk> )
http://www.oldskool.org/
Help our electronic games project: http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/
A child borne of the home computer wars: http://trixter.wordpress.com/
-----REPLY-----
Hi,
The old fashioned way; I used an oscilloscope to compare the inputs and
outputs of the bus transceiver. One of the buffers was dead and all of the
outputs on one side looked "funny" so I desoldered it and replaced it with a
new one. Of course, the IBM PC/XT motherboards have few sockets so
desoldering and replacing the chip was awful. I tried to nicely desolder it
but ended up destroying the chip and cutting it out.
One thing I really like about VG, NorthStar, Kaypro, and Heath is almost
their entire motherboards are socketed. Yes, I know direct soldered chips
are technically more reliable but they are a PITA to replace when they do
fail.
Thanks and have a nice day!
Andrew Lynch
------------------------------
Message: 18
Date: Sat, 31 May 2008 13:13:41 -0700 (PDT)
From: David Griffith <dgriffi at cs.csubak.edu>
Subject: video game cartridges
To: cctalk at classiccmp.org
Message-ID: <Pine.GSO.4.55.0805311312100.3718 at helios.cs.csubak.edu>
Content-Type: TEXT/PLAIN; charset=US-ASCII
I know that some of you here have an interest in vintage video games. How
many of you would be interested in getting together a pool to make new
Atari 2600 and Vectrex cartridge cases?
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
------------------------------
Message: 19
Date: Sat, 31 May 2008 13:28:16 -0700 (PDT)
From: Chris M <chrism3667 at yahoo.com>
Subject: Re: video game cartridges
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <913257.48853.qm at web65511.mail.ac4.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
how would you intend to do this? You'll need someone
to machine a die, and subsequently someone to do the
injection molding. It's not rocket science (although
I've never done it). But I'm not volunteering...
Dies are very expensive by the way.
--- David Griffith <dgriffi at cs.csubak.edu> wrote:
I know that some of you here have an interest in
vintage video games. How
many of you would be interested in getting together
a pool to make new
Atari 2600 and Vectrex cartridge cases?
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people
normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
------------------------------
Message: 20
Date: Sat, 31 May 2008 13:36:53 -0700 (PDT)
From: Mr Ian Primus <ian_primus at yahoo.com>
Subject: Re: video game cartridges
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <601034.32883.qm at web52702.mail.re2.yahoo.com>
Content-Type: text/plain; charset=us-ascii
--- On Sat, 5/31/08, David Griffith <dgriffi at cs.csubak.edu> wrote:
I know that some of you here have an interest in
vintage
video games. How
many of you would be interested in getting together a pool
to make new
Atari 2600 and Vectrex cartridge cases?
I've made up many Atari 2600 cartridges, and I've never had a hard time
finding used carts to recycle for the casing. There are enough Pac-Man, ET,
and Space Invaders cartridges out there for decades of homemade carts.
Besides, even if you had new cart cases made up, you'd still need the boards
from used carts anyway. Unless, of course, someone
makes those again too.
Vectrex, on the other hand, is a different beast. Not a lot of Vectrex carts
out there. Now, if you make up cases for those - I'll buy some - provided
that someone sends me a Vectrex, that is... <grin>
-Ian
------------------------------
Message: 21
Date: Sat, 31 May 2008 13:37:25 -0700 (PDT)
From: Mr Ian Primus <ian_primus at yahoo.com>
Subject: Re: video game cartridges
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <861748.41180.qm at web52711.mail.re2.yahoo.com>
Content-Type: text/plain; charset=us-ascii
--- On Sat, 5/31/08, David Griffith <dgriffi at cs.csubak.edu> wrote:
I know that some of you here have an interest in
vintage
video games. How
many of you would be interested in getting together a pool
to make new
Atari 2600 and Vectrex cartridge cases?
I've made up many Atari 2600 cartridges, and I've never had a hard time
finding used carts to recycle for the casing. There are enough Pac-Man, ET,
and Space Invaders cartridges out there for decades of homemade carts.
Besides, even if you had new cart cases made up, you'd still need the boards
from used carts anyway. Unless, of course, someone
makes those again too.
Vectrex, on the other hand, is a different beast. Not a lot of Vectrex carts
out there. Now, if you make up cases for those - I'll buy some - provided
that someone sends me a Vectrex, that is... <grin>
-Ian
------------------------------
Message: 22
Date: Sat, 31 May 2008 13:43:30 -0700 (PDT)
From: David Griffith <dgriffi at cs.csubak.edu>
Subject: Re: video game cartridges
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <Pine.GSO.4.55.0805311339590.3718 at helios.cs.csubak.edu>
Content-Type: TEXT/PLAIN; charset=US-ASCII
On Sat, 31 May 2008, Mr Ian Primus wrote:
--- On Sat, 5/31/08, David Griffith <dgriffi at
cs.csubak.edu> wrote:
Atariage.com sells various types of PCBs for the 2600, 5200, 8-bit, and
Coleco
I know that some of you here have an interest in
vintage video games.
How many of you would be interested in getting together a pool to make
new Atari 2600 and Vectrex cartridge cases?
I've made up many Atari 2600 cartridges, and I've never had a hard time
finding used carts to recycle for the casing. There are enough Pac-Man,
ET, and Space Invaders cartridges out there for decades of homemade
carts. Besides, even if you had new cart cases made up, you'd still need
the boards from used carts anyway. Unless, of course, someone makes
those again too. Vectrex, on the other hand, is a different beast. Not
a lot of Vectrex
carts out there. Now, if you make up cases for those - I'll buy some -
provided that someone sends me a Vectrex, that is... <grin>
The Vectrex consoles themselves aren't that hard to find.
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
------------------------------
Message: 23
Date: Sat, 31 May 2008 14:01:46 -0700
From: Josh Dersch <derschjo at msu.edu>
Subject: Good Composite->VGA converters for classic computers (& video
games...)
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Message-ID: <4841BCBA.1070109 at msu.edu>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Anyone out there use a composite->VGA upscaler for their classic
computing and/or gaming needs?
I've been looking to shave a bit of space off my workbench and just use
a single SVGA monitor instead of that and an old composite monitor. I
picked up one of these: http://www.amazon.com/gp/product/B000XXZQWQ and
while it works great for certain systems (the C64 and NES, for example)
it gets really confused by the composite signal coming from other
systems (like the Apple II and Sega Genesis) and is unusable with them.
Anyone have any recommendations?
Thanks,
Josh
------------------------------
Message: 24
Date: Sat, 31 May 2008 23:07:53 +0200
From: "Enrico Lazzerini" <elazzerini at interfree.it>
Subject: Big Board I: micro cornucopia & user disk
To: <cctech at classiccmp.org>
Message-ID: <4818CE87016296C3 at jack.mail.tiscali.sys> (added by
postmaster at tiscali.it)
Content-Type: text/plain; charset="us-ascii"
Hi at all,
i'm looking for all articles and software for the big board I.
( <http://en.wikipedia.org/wiki/Ferguson_Big_Board>
http://en.wikipedia.org/wiki/Ferguson_Big_Board)
There was a magazine called Micro Cornucopia
( <http://en.wikipedia.org/wiki/Micro_Cornucopia>
http://en.wikipedia.org/wiki/Micro_Cornucopia)
Some issues are scannered here below:
<http://www.aceware.iinet.net.au/acms/BooksByManufacturerList.asp?lngManufac
turerId=980&strManufacturerDescription=Micro+Cornucopia>
http://www.aceware.iinet.net.au/acms/BooksByManufacturerList.asp?lngManufact
urerId=980&strManufacturerDescription=Micro+Cornucopia
The issues i'm looking for are from the 1st to the 22th.
There was also an DRI Archive of the Big Board user disk.
I'm looking from the #1 to the #20. They contain sw utilities bios lists and
all about this OLD SBC.
I thanks to all would be help to rebuild all info around this board.
Enrico - Pisa - Italy
------------------------------
Message: 25
Date: Sat, 31 May 2008 20:04:48 -0500
From: "Jason T" <silent700 at gmail.com>
Subject: Come Work at Bell Labs!
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID:
<51ea77730805311804p2f484f8ax68e70637697458ce at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Some great shots of old terminals and other mysteries of the Labs here:
http://www.youtube.com/watch?v=ZHBHEWyZ1Xw
What are the terminals Greg Chesson is using around the 2:30 mark?
------------------------------
Message: 26
Date: Sat, 31 May 2008 23:09:30 -0400
From: "Teo Zenios" <teoz at neo.rr.com>
Subject: OS/2 problems
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <002e01c8c394$e91c20d0$c600a8c0 at game>
Content-Type: text/plain; charset="iso-8859-1"
Anybody happen to have disks for OS/2 2.1? I tried installing it today on my
PS/2 65SX and disk #8 is bad. not sure if anything past that is good or not.
Also I tried installing OS/2 1.1EE onto the same machine but fdisk could not
find any drives. Since that machine is SCSI does OS/2 expect ESDI drives?
TZ
------------------------------
Message: 27
Date: Sat, 31 May 2008 23:55:59 -0400
From: "Teo Zenios" <teoz at neo.rr.com>
Subject: Re: OS/2 problems
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <004601c8c39b$69c9a8f0$c600a8c0 at game>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
----- Original Message -----
From: "Zane H. Healy" <healyzh at aracnet.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Saturday, May 31, 2008 11:38 PM
Subject: Re: OS/2 problems
At 11:09 PM -0400 5/31/08, Teo Zenios wrote:
>Anybody happen to have disks for OS/2 2.1? I tried installing it today on
>my PS/2 65SX and disk #8 is bad. not sure if anything past that is good or
not.
Also I tried installing OS/2 1.1EE onto the same machine but fdisk could
not find any drives. Since that machine is SCSI does OS/2 expect ESDI
drives?
More likely MFM or IDE, I've never run 1.1EE, however, I ran 1.3 on an IDE drive. Which is older, OS/2 1.1EE or the PS/2 65SX?
1.1EE is a year or two older then the 65SX. Just seems odd DOS FDISK had no
issues finding and formatting the drive but 1.1EE kept giving me errors.
End of cctech Digest, Vol 58, Issue 2
*************************************