Best, worst auction deals. (was Re: eBay vrs42?)

From: Eric Smith <>
Date: Sat Feb 12 18:19:19 2005

Roger wrote:
> To put things back on track -- what's the best classiccmp related thing
> you ever got *at a live action* (as in: not ePay)?

My best auction deal might not be considered by some to be classicmp
related. It was an Atari "I, Robot" coinop video game. This was the
first ever coinop game that did realtime 3D polygon graphics, circa
1983. It used a 6809 microprocessor for the main game logic, a
2901-based bitslice processor for the 3D math, and a bipolar gate
array for drawing polygons into a frame buffer.

It was reportedly working earlier in the day at the auction site, but
had failed by the time it was auctioned. I got it for under $200, when
I had been expecting to pay over $600. Replaced a fuse and it was
almost good as new [*].

Another candidate for best was getting two large cardboard boxes full
of manuals and schematics for late 1970s and early 1980s coinop video
games for $25.

My worst auction deal was also at an arcade auction, and resulted from
getting the auctioneer pissed off at me. The auctioneer was trying to
start the bidding on every lot at over $1000, even for things that he
would have been lucky to get $50 for. I don't know if he was
inexperienced or what. All the bidders were getting pissed off, because
he'd try to start at $1000, back off to $950, to $900, etc. It was
looking like we'd be there all day. So I started yelling out "$25"
for each lot. He tried to ignore me and keep the numbers high, but
other bidders started replying to my bid by yelling "$30", "$35", etc.
He was getting visibly more and more pissed off at me, but there wasn't
any way he could eject me. So he inserted a lot out of sequence that
was a "churro warmer" or some such crap. By rights that shouldn't have
sold at all, or should have gotten maybe $1. But he didn't describe
the lot, just called out the lot number, so I bid $25 like on everything
else, and of course I won it.

He was probably hoping I'd shut up, but I just started paying more
attention to the lot numbers, and still kept bidding $25 on anything that
didn't look too worthless. Eventually he gave up and started opening
the bidding for most items at $50, which was reasonable.

I haven't really ever gotten any good computer stuff other than
video games at a live auction. Some friends went to a liquidation
auction of a computer store, and found that people were bidding up
broken laptops and partial boxes of fanfold paper to above new prices,
so they left quickly.


[*] The "I, Robot" game, after replacing the fuse, still had two
faults which were endemic to that machine. One of the program
ROMs/EPROMs in a particular socket is very prone to going bad. At
first I thought that Atari had either used a bad batch of EPROMs
the day they were bulk programming that part, or that their programmer
was defective (underprogramming). However, then I discovered that
even machines that used masked ROMs in that position tended to have
it go bad! I checked the wiring and DC voltages to see if there was
anything obvious that could cause it to go bad, but there wasn't.
I suppose it's just one of the great mysteries of the universe.

The typical net effect of that ROM being flaky is that the coordinates
of some object verticies are out at infinity, so when displayed they have
long spikes going offscreen. The selftest does report the ROM failure.

A second common failure of "I, Robot" is that the 64K DRAMs (made by
Micron) used for the frame buffer go bad. They develop bad bits
which cause twinkly or stuck pixels, or entire bad rows and columns,
which show up as stuck-on rows and columns on the display. The frame
buffer is not directly accessible to the processor, which can only
cause the gate array to draw polygons into it. There's no way for
the program to read back the contents, so the self-test doesn't know
that there's a problem, which is OK since it's obvious to the player
or operator anyhow. Apparently the Micron 64K DRAMs were terrible;
maybe Atari got a special deal on them knowing that the frame buffer
didn't have to be perfectly reliable.

Unfortunately all the DRAMs were soldered in (which was normally the
correct way to construct video games, provided that the parts were
reliable). I clipped the pins and carefully desoldered them, then
installed eight machined-pin sockets, and stuffed them with NOS DRAMs
made by Fujitsu. Unfortunately I broke the machine in the process.
I created a solder bridge under one socket, and could not see it by
visual inspection. An HP logic pulser and current probe allowed me to
identify the position of the short, so I only had to remove one socket
to fix it.

Received on Sat Feb 12 2005 - 18:19:19 GMT

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