My latest acquisition came in today, a Mac IIci, that I wanted to use as an OS 6.08 machine with a Daystar Turbo 040 (68040/33) accelerator. Anyway after cleaning up the system and installing the OS I put the card in and loaded the drivers and all was fine (very fast booting). After about 15 minutes I had to reboot for driver update and the system would just bomb during boot (about where the control panel for the Daystar card would want to load). I took the card out and notice there was a capacitor missing on the back with a nasty looking black burn mark. So I started looking around inside for the burn metal part and notice I did not smell or see smoke or little capacitor parts (its a surface mount with no numbers on it). Doing a little digging in my picture archive I verified that the card which I have never used before (which is why I wanted a IIci since it works in that model) was sent to me in this condition.
So what I want to know is how the thing functioned at all without the cap (burnt carbon acted as a capacitor in some way)? and what caused it to stop working.
If anybody have an original Daystar Turbo 040 33Mhz card with the cache on a separate board could you let me know (if possible) what value C54 s supposed to be? The cap looks to be tied into one or two legs of the oscillator chip that controls the CPU (Ecliptek EC1100 16.667Mhz 93-10).
I kind of want this working again since it will be a long time before I find another one at a great price.
Thanks
TZ
>
>Subject: Re: CompuPro floppy controller differences
> From: "Dave Dunfield" <dave06a at dunfield.com>
> Date: Fri, 08 Sep 2006 22:35:38 -0500
> To: <cctalk at classiccmp.org>
>
>> Is there any practical difference between the CompuPro Disk 1
>> and Disk 1A that would prevent a 1A disk from working on a 1? I have a line
>> on a Disk 1 controller but only have access to 1A disks from Dave Dunfield.
>
>I have a Disk-1A up and running in my Compupro box - unfortunately I do not
>have a Disk-1 to test with. I do however have manuals for both controllers.
>
>>From what I can tell on a cursory readthrough - the Disk-1 and the Disk-1A
>are very similar, but not identical:
>
> - The Disk-1A appears to have some functions available in the write side
> of some registers which were read-only on the Disk-1 - these seem to
> control features that had to be set by switches or board modifications on
> the Disk-1.
>
>- The Disk-1 has a bit-bang serial port which has been dropped on the 1A.
>
>- The difference is NOT the difference between a 765 and a 765A - both
> manuals list the 765A as the NEC FDC.
>
>- The 765 and motor control registers appear to be in the same place on
> both controllers.
>
>I have a set of original Cromemco CP/M diskettes, and the labels do NOT
>mention anything about a specific floppy controller board - my guess is that
>the disks would boot and run on either controller. (But as noted above, I
>cannot confirm this, so it is just a guess).
>
>Dave
You missed one item, different eprom and contents. The differences there
include boot code for 8088 and in very late 1A version 68000. They are
essentially the same, though of the two the latter 1a is prefered.
Allison
Is there an equivalent to CTRL-ALT-Delete on the C64 so you don't
have to turn it on and off every time you want to run a new program?
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
I'm looking to offload an IBM 360 front panel in order to focus more on my
core collection.
A good picture can be found at:
http://www.parse.com/~museum/misc/index.html
I collect PDP-8's mainly, so I'm looking to get a straight 8, and 8/S, or an
8/L. Now, I realize that the front panel is probably not worth a straight 8
or an /S, (but might be worth an /L), so I'm willing to pitch in some cash as
well, or other items (lots of spare cards, misc electronics, whatever). Let
me know what you have, and where you are located. I'm at Kanata/ON/Canada
postal code K2M 1C5.
Probably best to take this offlist to rk at parse.com
Cheers,
-RK
--
Robert Krten, PARSE Software Devices
Realtime Systems Architecture, Consulting, Books and Training at www.parse.com
Looking for Digital Equipment Corp. PDP-1 through PDP-15 minicomputers!
>
>Subject: Re: CompuPro floppy controller differences
> From: "Dave Dunfield" <dave06a at dunfield.com>
> Date: Sat, 09 Sep 2006 08:39:24 -0500
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>
>> You missed one item, different eprom and contents. The differences there
>> include boot code for 8088 and in very late 1A version 68000. They are
>> essentially the same, though of the two the latter 1a is prefered.
>
>Yeah, I ment to mention that ... And hand-in-hand with it, the boot option
>switch settings on the 1 are different than the 1A (no 8086 modes for
>example).
The 8086 mode is only a preset to a block of eprom for booting, same for
others.
>Q: Are the controllers similar enough that the boot code from the 1A will
>work in the 1 - ie: If Rich wanted to run an 8088/86 CPU could he put
>the boot code from the !A into the 1 and boot the system? (He might have
>to put in just the mode he wants in an accessable "slot" in the 1A ROM
>space)
Yes, the basic control floppy registers and addresses are identical.
The DMA also behaves the same. However it means burning a new eprom
as the 1A used a larger prom.
NOTE: the caveat is the booter also knows what size floppy is used
(8 or 5.25) as well as what CPU in the case of the 1A there are 16
different possible S1 settings for booter. The late 1As could
boot 8085/88 card, z80, 8086, 80286, 68000, 32016.
Allison
>
>Subject: CompuPro floppy controller differences
> From: "Richard A. Cini" <rcini at optonline.net>
> Date: Fri, 08 Sep 2006 19:36:32 -0400
> To: "'General Discussion: On-Topic and Off-Topic Posts'" <cctalk at classiccmp.org>
>
>All:
>
>
>
> Is there any practical difference between the CompuPro Disk 1
>and Disk 1A that would prevent a 1A disk from working on a 1? I have a line
>on a Disk 1 controller but only have access to 1A disks from Dave Dunfield.
Generally none. The 1A has an different boot rom (boots more cpus and IO
combos) and no serial (bit bang port).
The difference of the 765 vs 765A will not be a problem for C-pro disks.
If it concerns you you can put a 765A in a disk-1 with no other changes.
The rest of the differnces in the two boards are small, though of the
two I prefer the 1A as it has a lot of small fixes on the same basic
design.
Allison
>
>
>
> Thanks.
>
>
>
>Rich
>
>
>
>Rich Cini
>
>Collector of classic computers
>
>Lead engineer, Altair32 Emulator
>
>Web site: <http://highgate.comm.sfu.ca/~rcini/classiccmp/>
>http://highgate.comm.sfu.ca/~rcini/classiccmp/
>
>Web site: http://www.altair32.com/
>
>/***************************************************/
>
>
>
>Subject: Re: PDP-8m Console Switch Problems - fixed!
> From: Don North <ak6dn at mindspring.com>
> Date: Thu, 07 Sep 2006 00:49:17 -0700
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
> Cc: cctech at classiccmp.org
>
>None of the databooks I have ever seen actually show the gate level logic
>for the internals of the 74x175 or 74x174; they are only black box diagrams.
>So it is not clear to me that the outputs are unbuffered/bidirectional.
>They certainly seem to be for Signetics (see below) but my lab tests cannot
>verify this for any other mfg.
I have old databooks sets that go to the gate and some cases
transistor level.
>I have pulled totem-pole outputs forcibly high or low before, but
>have always used an external series current-limiting resistor to limit
>the override current to a 'safe' value.
For pullup a current limit is advised, for pull down it's not needed
as the pull up device is current limited already.
>Well, I am seeing something very different here. I built a breadboard
>with the circuit under question: 74x175 device, 470ohm to +5V on MR~,
>CLK and Dx inputs forced to ground. I connected voltmeters to the
>Q and Q~ outputs, and then tried forcing Q and Q~ alternately to ground
>to see if I could change the state of the device.
>
>I had a number of devices to test, here are the results:
>
> DATE
> MFG DEVICE CODE RESULT
> --- ------ ---- ---------
> TI 74175 87 FAIL, shorting Q~ to gnd never changes Q to high
> SGS 74LS175 82 ditto
> TI 74AS175 87 ditto
> SIG 74S175 84 PASS, with 470ohm pullup to +5V on Q req'd for Q0-Q3
> SIG 74S175 76 PASS, Q1-Q3 work w/ no resistor, Q0 requires 470ohm
>
>For the failed devices, I tried with no pullup, and 100, 470, 1K, 4.7K
>pullups to +5V on Qx. No value of pullup made any difference. Shorting
>a Q~ signal (at ~4V) to ground never changed Q (at ~0.4V) to a HIGH.
It the MR/ is not in the correct state (may need pullup) I'd conclude
you have some bad parts. Especially the TI[I have the most data on those]!
>> I'd give the 7404 the hairy eyeball! A quick test is socket a '175
>> with the Q and /Q output pins floating and using a jumper to ground
>> make it flip [It WILL NOT IF MR/ is asserted, you can bend out the
>> MR/ pin to avoid that.]. Then test the '04 for input changes output.
>>
>>
>> Allison
>
>The 7404 on the output seems OK, as is the rest of the downstream logic
>(the priority encoder). I measured the input currents required on a
>suspect '04 input to set the output high and low and they are well within
>spec (about +20uA for input high, -0.7mA for input low). With the 74S175
>out of its socket I could set all the 7404 inputs H/L and observe the
>downstream priority encoder outputs were just as expected.
That's good.
>I have about 15 of the 1984 Signetics 74S175s, I tried all of them in
>the console board socket; none of them worked, even a little bit, with
>no pullups added.
I'd pulse them slow with Q/ connected to D and see if they toggle.
I suspect you have a bad run of old chips. I just tossed a few tubes
of mid 80s NOS parts as they apprently died of silicon rust [moisture gets
into the plastc and they die].
>So I added 470ohm pullups to +5V on the 74S175 Q outputs to 7404 inputs.
>Everything started working as would be expected. The switch decode logic
>is now 100% functional.
You have something really messed up with those 175s your testing.
>My thought is that the output pullups on the 74S175 Q pins are trying to
>pull those outputs high fairly strongly (10mA load) but the Q output can
>still drive a valid low (it is a 20mA schottky driver). This pullup
>'preloads' the output, so that a kick on the QB~ (by shorting to gnd)
>gets the Q output moving high, the resistor keeps it moving high, able to
>override some smaller internal driver trying to keep the output low.
>At least that is the only rational explanation I can think of right now.
Sounds like you have some '175s with the upper device fried in the totem
pole outputs.
>Just the 7404 by itself is a -1mA low, +40uA high load; not very much.
Unless it has an input with high leakage to Vcc or ground, i've seen both.
>In any event, the fix is simple (three resistors really, but I'll add one
>on each of the six used outputs). Turns out all the original logic chips
>appear to be good (I had removed the original 74S175 intact for testing).
>
>Thanks to everyone for all the suggestions and helpful hints.
Put all the parts on a header and plug it in rather than mess the board up.
Allison
All:
Is there any practical difference between the CompuPro Disk 1
and Disk 1A that would prevent a 1A disk from working on a 1? I have a line
on a Disk 1 controller but only have access to 1A disks from Dave Dunfield.
Thanks.
Rich
Rich Cini
Collector of classic computers
Lead engineer, Altair32 Emulator
Web site: <http://highgate.comm.sfu.ca/~rcini/classiccmp/>
http://highgate.comm.sfu.ca/~rcini/classiccmp/
Web site: http://www.altair32.com/
/***************************************************/
I did some basic diagnostics on the system. First, checked the
superficial stuff like the cable. The Berg has a strain relief attached
and all wiring looks solid at that end. Also checked the head lock
which was indeed in the lower (free) position however I observed the
head suring loading and it does indeed retract properly ... when the
LOAD key is out the heads retract immediately to the parked (fully
retracted) position. When a fault occurs, heads pull back as well.
True, the unit was transported without the head lock in place - any
ideas on possible misalignments?
When the BOOT switch on the limited-function panel (or the BOOT key on
the console) is pressed, the FAULT light blinks momentarily, the READY
light goes out momentarily, and the disk is restored to the original,
ready, state. When the cartridge is loaded, the heads move from the
parked state to engage the disk. During the fault the heads pull back
to the parked state and are then restored to the disk again.
When the bootstrap is stepped, the READY light never does blink (stays
lt), nor does the FAULT light! Which leads me to wonder why? Checked
the ROMs on the 8317 board - they are labelled '469A2' which I can't
seem to track. Bootstrap option switches are set as SW1: 2,4,8 ON, SW2:
1,6 ON so with the older ROMs one would expect a TA8-E device (obviously
different or these ROMs). Can I verify the bootstrap code easily?
Now, when I do step-through the bootstrap I have loaded (at address 1 -
the one on my web page), the address is seen to step through as follows:
1,2,3,27,30 (with AC=0004), 31,33,34,27,4,5,27,30,31,33,35,1 at whch
point it repeats in an endless loop. It seems to fail, then, on the
read header function (at which point I did the diagnostics I had
outlined finding the DCRC error after which I did a get status.
I'd be grateful for any further ideas you might have on the subject
otherwise it might well be 'get out the scope' time!
Thanks .... Mark
Professor Mark Csele
Niagara College, Canada
300 Woodlawn Rd., L-8
Welland, ON, L3C 7L3
(905) 735-2211 x.7629
E-Mail: mcsele at niagarac.on.ca
URL: http://technology.niagarac.on.ca/people/mcsele
Author of "Fundamentals of Light Sources and Lasers", Wiley, 2004
