On 6/29/06, Jeff Walther <trag at io.com> wrote:
> >Date: Wed, 28 Jun 2006 08:26:41 +0000
> >From: "Ethan Dicks" <ethan.dicks at gmail.com>
>
> >Does anyone here know about the internals of the G3 line? I have a
> >motherboard in front of me that I'm attempting to see if it will work....
> The Beige G3 (if you're looking at a Blue & White (Smurf) MB (the
> case was B&W, not the MB), then the following advice is inapplicable)
The case for this was the Blue/White case...
> A Beige G3 could be missing any of three essential components if it
> was stripped. It needs a CPU, which comes on a 19X19 pin ZIF module.
> I doubt you overlooked that...
Indeed.
> It requires a voltage regulator.
> This is less obvious, but I bet you have that. If not, it mounts in the ~2"
> vertical slot to the left of the ZIF socket.
This does not appear to be that motherboard. I should have included
this on the initial posting, but it seems to be Apple P/N 820-0987-A.
> The battery, keyboard and mouse can all be dispensed with if all you
> wish to do is boot the machine. The battery is a 1/2AA available at
> Frys for about $6 or at Radio Shack for closer to $12.
The battery I removed is a 3.6V Li, marked ER2S (1/2AA). The nearest
place to buy a battery, any battery, is Dick Smith's in
Christchurch... the next plane is in 4 months. I'll probably either
swipe a battery from an old iMac or rig up a pack with three NiMH AAs.
Thanks for the info.
-ethan
Hi all,
I got a UNIBUS ESDI controller and I'm currently shopping for a disk drive
for it. What I was thinking of doing is mounting a bracket inside the
BA11-K and powering the disk drive from the BA11-K power supply, just using
a molex connector to one of the unused harness connectors on the power
distribution board that supplies the correct voltages.
Would doing this pose any sort of problem? i.e. violating amperage limits
etc? It would probably be something like a Maxtor XT-4170.
I have a friend who has a DC100a tape with no way
to read it. Just wondering if anyone here can and
get data onto a pc.
I do have a Colorado Jumbo 250 that I have used
DC 2120 QIC-80 tapes with. But don't know
if that would read DC100a tapes.
Keven Miller
kevenm at reeltapetransfer.com
Orem UT 84097.
I've just got hold of an old (probably late-80s) Hughes 800 projector.
It's a couple of feet long and very very heavy. Inside is a big xenon
lamp, a CRT of some kind, and some optics. It appears to work by
shining the lamp (through mirrors) onto the face of the CRT. The big
problem is, it doesn't appear to produce any video. I can hear the CRT
scan coils going. The scan pitch changes when I remove the video
source. In fact, it does appear to do all the things I'd expect when I
press buttons, but no picture comes out :-/
There is (getting vaguely on-topic) an RS-232 port and it appears to use
a TMS9900 CPU inside.
Anybody got any idea how it even works? Even better, has anyone got an
idea how to make it work *properly*?
Gordon.
Tony Duell answered:
> However, the operation of a scanner is not too complex to reverse
> engineer.
Rather you than me. The only scanner I looked inside had several
unindentifyable ICs...
> I guess that we still can't get you to accept one, even for free, without
> open hardware source.
Surely you all know me by now. I am not going to depend on something that I
can't repair.
Tony
---------------------------------------
Billy:
I'm still glassy eyed about this statement. So I thought I would tell you a
little about some work I did in the past. In OKCity, I was responsible for
all the customer support documentation on the MPI floppies, cartridge and
fixed disk drives. In the early 80's I had to do a study and recommend ways
to reduce costs - publications had become a huge cost empire within
Engineering. And whole product families were being delayed while the
elaborate manuals were written and prepared. Customers were complaining
about the enormous cost of maintenance.
So I sample polled the largest customers for our drives. It was a couple of
hundred out of 2500+. At that time, the only ones who replied that they
needed schematics were a couple of repair services. We asked on theory of
operation, app notes, etc. Same thing. None of the customers paying the
bills used any of the elaborate documentation except for the interface
specs.
The conclusion reached was that schematics were not required and they were
dropped. If any customer complained, I was to supply him engineering
drawings as schematics. No customer ever complained. (Note the word
customer - the ones who spent the money. A few third party types weren't
happy, but they were a real thorn in our side then.)
Theory of Ops was dropped. So were wire lists. Parts lists stayed - always
like to sell parts at slight markups. (Sarcasm implied.)
At that time two other trends were starting. First, most products no longer
needed card cages. ICs allowed all the logic of a drive to be on one PCB.
And we certainly did not want end users mucking up those boards by trying to
repair them. (Also, many of the circuits were tuned in PCB fab; swapping
out an IC wouldn't always fix the problem. It had to be tuned to be
optimum.)
Second, the first ASICs were used; I believe the first ones for us were on
the 8" products. Physical size and board space were suddenly critical. The
shrink to the 5.25" Wren series was really tough for engineers who were used
to designing individual boards bigger than the entire Wren.
So - the MPI official policy was to no longer provide documentation. The
customer did not demand it, wasn't willing to pay for it. With ASICs and
single board drives, we didn't want them to repair the units. The customers
were pleased with the change - they were able to reduce their maintenance
staffs, their spare parts costs and their cost of ownership. I'm cutting
out a long section out here about the reliability of replaceable components
vs limiting connections, adjustments, power etc. It is the same argument
used on anything electronic.
The point to all this is that a series of conscious deliberate decisions
were made to prevent what Tony wants to do: repair to a component level.
Repair cost money, was unreliable and required massive support. The world
would only pay for cheaper product. The ASPs for disk drives moved from
$3000+ to sub $50 in 15 years while the capacity went from 16 MB for Wren I
to a terabyte today. A repairable drive was a luxury that nobody would pay
for. And as time has proved, was unnecessary.
Since that time, more than 20 years, Tony Duell is the only person I've met
who insists on repairing his personal work system to the component level.
Everyone else, wants it to be cheap and reliable. And that includes the
most fanatical military buyer.
What's next? My last three employers all had long range programs to get the
entire drive electronics and interface down to one piece of silicon. And
they want to eliminate the connectors as much as possible. Hard drives will
be soldered to PCBs before the end of the decade. Optical drives are a
little harder because of the form factor. They will achieve one piece of
silicon, but it will probably be mounted on the OPU and have a 4 wire serial
interface.
As everything moves to SOC (System On A Chip) designers become firmware
engineers. And already, there are plans to make firmware easier and more
modular. The goal here is to have the system design itself from a few high
level instructions.
I understand Tony's feelings - I've encountered similar viewpoints many
times in other fields. But it makes me sad, because he can't share a lot of
the fun with us. We can't send him scanned manuals and he can't send us
some of the work he has done. And what about photos from our conventions,
videos of the speakers, software that is on CDs not floppies? The exchange
of knowledge that bonds the rest of us is lost with Tony. And he has lots
of knowledge that we would enjoy seeing.
Billy
Hi Folks,
Has anyone got a set of Workbench 3.1 ROMs they'd be willing to part with
for less than epay and internet vultures want for them? My A4000 needs them
so I can install OS3.9 and get instant accelerator action :)
Cheers!
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?
Anyone happen to have this? It's what the IMP16 board uses, and I'd like to
see if I can build an adapter for my programmer to read the data out of the
ROMs before I get rid of the boards...
(I suspect it's a 3-rail device, but the address and data lines are TTL, so
hopefully I can make them appear as 2Kx8 devices* to my programmer)
(* The smallest ROM my programmer knows about is a 2716 single-rail device)
ta
Jules
Well, I got my 11/34 working, it comes up to a console and it all works
great.
I have a second M7800 card but I'm not real sure how to configure the
address and interrupt vectors on the card. I did figure out that:
A. I have the 4.608 mhz crystal, allowing me to do 9600 baud with it.
B. I removed the two caps that were in place according to the manual "FOR
110 and 150 BAUD ONLY"
C. How to set the 9600 baud rate for both send and receive
D. How to set 1 stop bit, no parity, and 8 data bits.
So I'm good to go with it except for two problems:
1. When it is put in to replace the DL11-W (which would be much easier to
reconfigure later, what with its switches), it causes the machine to halt at
173524 on powerup (this also happened before I removed the two caps, so it's
not that).
I just want to set this thing up as the serial console, for 9600, N/8/1.
Can someone help me out?
Thanks
Julian
Hi all,
I got a UNIBUS ESDI controller and I'm currently shopping for a disk
drive for it. What I was thinking of doing is mounting a bracket inside
the BA11-K and powering the disk drive from the BA11-K power supply,
just using a molex connector to one of the unused harness connectors on
the power distribution board that supplies the correct voltages.
Would doing this pose any sort of problem? i.e. violating amperage
limits etc? It would probably be something like a Maxtor XT-4170.
