11 Jul
2004
11 Jul
'04
4:20 p.m.
I have a couple of old 8K PET 2001s that need to be fixed.if anyone has
some extra test equipment that they no longer need I (and the PETs)
would really appreciate it!
Let me know what you have and want for it.
Even if you aren't going to VCF/East I'd pay all the shipping costs.
Looking forward to seeing you guys at VCF/East!
Thanks,
Chandra
11 Jul
11 Jul
4:39 p.m.
New subject: Unhappy HP-85
Hello all! :)
A while back, I purchased a smoking HP85.
I'm finally getting into the fixing it stage... The part in question
looks to be a transformer labelled 9100-0457 / 906933. It has a
similar, happier cousin labelled 9100-0455 / 906933. The caps are
going to be replaced, but the transformer itself has already turned
black and gooey. *Sighs* I was wondering if anyone might roughly know
the values of the fellow offhand.
Thanks very kindly! :)
Andy
5:16 p.m.
New subject: Unhappy HP-85
Hello all! :)
A while back, I purchased a smoking HP85.
I'm finally getting into the fixing it stage... The part in question
looks to be a transformer labelled 9100-0457 / 906933. It has a
similar, happier cousin labelled 9100-0455 / 906933. The caps are
Where is this part in the machine? On the PSU/printer board, the video
board, or what?
You can get the HP85 'Assembly Level Service Manual' on one of the HP
Museum CD-ROMs (look at http://www.hpmuseum.org/). Despite the name, it
does include schematics, but it won't contain transformer winding
details. You may have to work out what the transformer was from the circuit.
-tony
5:51 p.m.
New subject: Unhappy HP-85
Drat... what is wrong with me? :)
The fellow is located on the PSU / Printer board - there are three
transformers on there; it looks like the two larger ones are
identical. It's one of the two larger ones - it seems as if the two
giant screw-on caps on that board were shorted... they're going to be
replaced. Can probably rewind the transformer if I can't find
something suitable, just am feeling a bit lazy. :)
Thanks for the kind reply, Tony!
Andy
On Mon, 12 Jul 2004 03:16:31 +0100 (BST), Tony Duell
<ard(a)p850ug1.demon.co.uk> wrote:
Hello all! :)
A while back, I purchased a smoking HP85.
I'm finally getting into the fixing it stage... The part in question
looks to be a transformer labelled 9100-0457 / 906933. It has a
similar, happier cousin labelled 9100-0455 / 906933. The caps are
Where is this part in the machine? On the PSU/printer board, the video
board, or what?
You can get the HP85 'Assembly Level Service Manual' on one of the HP
Museum CD-ROMs (look at http://www.hpmuseum.org/). Despite the name, it
does include schematics, but it won't contain transformer winding
details. You may have to work out what the transformer was from the circuit.
-tony
12 Jul
12 Jul
12:08 p.m.
New subject: Unhappy HP-85
Drat... what is wrong with me? :)
The fellow is located on the PSU / Printer board - there are three
transformers on there; it looks like the two larger ones are
identical. It's one of the two larger ones - it seems as if the two
OK, I've got out my HP85 service manual. The 3 transformers on the
PSU/printer PCB are :
T1 (Lower of the 2 large ones), converter transformer from +12V to +5V
T2 (small onme), current sense transformer for +12V/-5V PSU
T3 (Upper of the 2 large ones), +12V/-5V SMPSU transformer, +6V PSU
From your description we can discount T2. Amazingly the
schematic gives
the winding details for the transformers, here you are (pin 1 is
the top
left pin looking at the componet side of the PCB -- it has a square
solder pad, pins then number conunterclockwise like an IC) (T = number of
turns) :
T1 : 2 windings
pin 1 (start) -- 27T -- pin 2 -- 27T -- pin 3
pin 4 (start) -- 15T -- pin 5 -- 15T -- pin 6
T3 : 2 windings
pin 6 (start) -- 20.5T -- pin 3 -- 5T -- pin 2 -- 17T -- pin 1
pin 5 (start) -- 15T -- pin 4
You would have to get the wire sixe by measuring the wire on the existing
transformer, and you'll have to re-use the original cores.
giant screw-on caps on that board were shorted...
they're going to be
Those are C1 and C8. C1 is the smoothing cap for the incoming supply (26V
AC, rectified on the PSU board), so if that shorts it'll take out the
mains fuse at the back. C8 is the smoothing cap for the 12V line. While
this could damage T3 if it shourted, I am suprised the PSU didn't shut
down. I'd check the rest of those PSU components very carefully (you want
to get the HP85 service manual, although you're not 'supposed' to do
component level repeair it does contain schematics).
replaced. Can probably rewind the transformer if I
can't find
something suitable, just am feeling a bit lazy. :)
They are HP custom. The only place you'll get them is from another HP85
(I know from experiece that the 9915 (HP85 in a metal case that could fit
into a rack mount kit) and the HP86 have totally different PSU
transformers. I assuem the 87 does too, but I've not worked on that yet
(a project for the near future, actually).
-tony
11 Jul
11 Jul
5:04 p.m.
On Sun, Jul 11, 2004 at 09:20:26PM -0400, Chandra Bajpai wrote:
I have a couple of old 8K PET 2001s that need to be
fixed.if anyone has
some extra test equipment that they no longer need I (and the PETs)
would really appreciate it!
I won't be at VCF-East (and I don't have any surplus test gear), but I do
have a couple of recommendations for your PETs...
If they come up to the random-character screen (no "*** COMMODORE BASIC ***"
banner) or if the RAM reads less than you expect for an 8K machine, the
first thing I'd suspect are the sockets, the next thing are the SRAMs
themselves.
Given how hard it is to find those SRAMs, it might be easier to make a
daughter card that fits into the CPU socket that has a JEDEC SRAM socket
(for a 6116, 6264, 62256...), and use A15 as a low-true enable to put it
below $8000.
The first thing, of course, would be to check the board for proper voltages
and ripple. High ripple would mostly likely be caused by dry electrolytic
caps, given that these machines are ~25 years old.
I had an 8K PET once that I sold at least 10 years ago... it was incredibly
unreliable... I ended up putting a folded cardboard wedge under the middle
of the main board to flex it "just right" so it would come up most of the
time. I don't think it was a cold solder joint - I think it just needed
new SRAM sockets.
Once you do get them working, don't forget that BASIC 1.0 ROMs have problems
with the IEEE-488 implementation. I can't recall the nature of the issue,
but they don't place nice with most GPIB gear, not even Commodore's own
stuff. BASIC 2.0 fixed that. If you are observing disk drive timeouts
or lockups, it could be related to that.
-ethan
--
Ethan Dicks, A-130-S Current South Pole Weather at 12-Jul-2004 01:50 Z
South Pole Station
PSC 468 Box 400 Temp -89.2 F (-67.3 C) Windchill -129.8 F (-89.90 C)
APO AP 96598 Wind 10.5 kts Grid 090 Barometer 675.9 mb (10780. ft)
Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html
5:18 p.m.
New subject: Anybody going to VCF-East have cheap working Oscilloscope/Logic Analyzer to sell?
Given how hard it is to find those SRAMs, it might be
easier to make a
daughter card that fits into the CPU socket that has a JEDEC SRAM socket
(for a 6116, 6264, 62256...), and use A15 as a low-true enable to put it
below $8000.
2114s are hard to find? Are they some weird variant (speed, power)?
William Donzelli
aw288(a)osfn.org
5:31 p.m.
On Sun, Jul 11, 2004 at 10:18:32PM -0400, William Donzelli wrote:
While I think that the last round of static PETs may have had 2114s,
every one I've ever seen used 6550s, a 22 pin .4"-wide DIP...
http://www.amiga-stuff.com/hardware/6550.html
I don't know without consulting the schematics if the static PET board
depend on there being 4 chip selects, but if it doesn't, it would be
easy to make a small PCB that fits in a 6550 socket, and houses a 2114.
-ethan
--
Ethan Dicks, A-130-S Current South Pole Weather at 12-Jul-2004 02:20 Z
South Pole Station
PSC 468 Box 400 Temp -89.5 F (-67.5 C) Windchill -129.6 F (-89.8 C)
APO AP 96598 Wind 10.1 kts Grid 081 Barometer 675.9 mb (10780. ft)
Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html
Given how hard
it is to find those SRAMs, it might be easier to make a
daughter card that fits into the CPU socket that has a JEDEC SRAM socket
(for a 6116, 6264, 62256...), and use A15 as a low-true enable to put it
below $8000.
2114s are hard to find? Are they some weird variant (speed, power)?
5:45 p.m.
New subject: Anybody going to VCF-East have cheap working Oscilloscope/Logic Analyzer to sell?
While I think that the last round of static PETs may
have had 2114s,
every one I've ever seen used 6550s, a 22 pin .4"-wide DIP...
OK, they could be trouble.
William Donzelli
aw288(a)osfn.org
13 Jul
13 Jul
12:32 a.m.
New subject: CDC 9762 vs. RM02/03?
I have some conflicting info here. On one hand the literature says that
DEC rebadged the CDC9762 as RM02 and RM03s...
OTOH, the CDC has a SMD interface yet the RM02/03 has a MASSBUS interface.
Furthermore, the CDC is listed to be at 80MB, yet the RM02/03 apparently
has 67MB only.
So, which is true? I'm confused.
Thanks.
/wai-sun
10:38 p.m.
New subject: CDC 9762 vs. RM02/03?
On Di, 13 juli, 2004 11:32 am, Wai-Sun Chia zei:
I have some conflicting info here. On one hand the
literature says that
DEC rebadged the CDC9762 as RM02 and RM03s...
OTOH, the CDC has a SMD interface yet the RM02/03 has a MASSBUS interface.
Furthermore, the CDC is listed to be at 80MB, yet the RM02/03 apparently
has 67MB only.
So, which is true? I'm confused.
Thanks.
/wai-sun
The RM02/03 have als a SMD interface, but it is slightly modified.
The RM03 has a separate controller in the drive cabinet, which is
the interface between the massbus and the modified SMD interface.
Apparently, 2 or 3 cards in the card cage are modified for/by Dec
to their needs.
The 80Mb may be unformatted capacity, while the 67Mb is the formatted
capacity, but I'm not entirely sure. My RM03 still has to be used with
my 11/70.....
Ed
14 Jul
14 Jul
2:28 p.m.
New subject: CDC 9762 vs. RM02/03?
On Wed, Jul 14, 2004 at 09:38:54AM +0200, Ed wrote:
I have some conflicting info here. On one hand the
literature says that
DEC rebadged the CDC9762 as RM02 and RM03s...
OTOH, the CDC has a SMD interface yet the RM02/03 has a MASSBUS interface.
Furthermore, the CDC is listed to be at 80MB, yet the RM02/03 apparently
has 67MB only.
So, which is true? I'm confused.
Both... as shipped, the CDC 9762 is 80MB formatted; as shipped, the
DEC RM02/RM03 is 67MB from the same mechanism. The bottom of the
DEC RM02/RM03 is filled with DEC electronics that had a MASSBUS
interface on one end, and a 62-pin/26-pin interface that is *almost*
SMD. In reality, DEC made a couple of changes to the CDC cards in the
card cage in the back of the drive, so it's not trivial to take an RM02
and make it back into a 9762 unless you happen to have a set of original
CDC cards.
There's something about the logical layout of the RM02/RM03 that either
ignores some part of the drive capacity, or else it's using 13MB as
spare tracks. And it's not just on a real RM02/RM03; at SRC, we had
a 160MB Fuji SMD drive on our SI9900 controller as a system drive for
our VAX-11/750. It appeared to the VAX as a pair of RM03s, down to the
67MB available capacity (i.e., the driver wasn't patched to try to make
the 160MB drive _look_ like a single 160MB drive, unlike our Fuji Eagle,
that _was_ a patched RM05 to the system).
--
Ethan Dicks, A-130-S Current South Pole Weather at 14-Jul-2004 13:40 Z
South Pole Station
PSC 468 Box 400 Temp -75 F (-59.5 C) Windchill -113.8 F (-81 C)
APO AP 96598 Wind 11.7 kts Grid 034 Barometer 667.9 mb (11086. ft)
Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html
22 Jul
22 Jul
2:43 p.m.
New subject: CDC 9762 vs. RM02/03?
On Tue, Jul 13, 2004 at 05:32:21PM +0800, Wai-Sun Chia wrote:
I have some conflicting info here. On one hand the
literature says that
DEC rebadged the CDC9762 as RM02 and RM03s...
OTOH, the CDC has a SMD interface yet the RM02/03 has a MASSBUS interface.
Furthermore, the CDC is listed to be at 80MB, yet the RM02/03 apparently
has 67MB only.
So, which is true? I'm confused.
It's all true.
A CDC 9762 _is_ an SMD drive. DEC made some changes to the cards inside
the 9762, put it on a DEC pedestal and filled the bottom with a couple of
cubic feet of DEC electronics. Working for a small 3rd-party support
company years ago (c. 1988), I tried to "restore" an RM02 back into an
SMD device (since my boss had Unibus SMD controllers and no MASSBUS
machines), but we eventually gave up. It's not as simple as unplugging
the equipment in the bottom of the RM02/RM03 and plugging the 62 pin/26 pin
cables into a real SMD controller.
The capacities you list are also correct - the original 9762 gives you 80MB
per pack, and the same pack in a DEC RM02/RM03 gives 67MB. I do not happen
to know if it's just a difference in the number of reserved tracks for
spares, or if there is an low-level format difference.
-ethan
--
Ethan Dicks, A-130-S Current South Pole Weather at 22-Jul-2004 23:30 Z
South Pole Station
PSC 468 Box 400 Temp -95 F (-70.5 C) Windchill -135.4 F (-93 C)
APO AP 96598 Wind 9.6 kts Grid 034 Barometer 664.5 mb (11217 ft)
Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html
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