[Coladam] eBay auction

Daniel Bienvenu newcoleco at yahoo.fr
Sun Jun 14 03:12:33 CEST 2009


So, it can be reasonable to think that this thing is to test the super games before making them into tape format? If so, my wild guess in a previous message was partially right!

Daniel

--- En date de : Sam 13.6.09, Geoff Oltmans <oltmansg at bellsouth.net> a écrit :

> De: Geoff Oltmans <oltmansg at bellsouth.net>
> Objet: Re: [Coladam] eBay auction
> À: drushel at apk.net
> Cc: coladam at adamcon.org
> Date: Samedi 13 Juin 2009, 20h43
> I agree with your assessment. It is
> clearly as you say though, a  
> 68701, 1k sram, and an address latch and inverter. This
> appears  
> numerous times in the ADAM design for ADAM Net. I agree,
> didn't see  
> any evidence of the LM339 and associated circuitry (which
> would  
> definitely involve some inductors as well).
> 
> I wonder if there's any of this circuitry underneath the
> ribbon cable.  
> It is rather large.
> 
> The puzzling thing to me is that some of the chips appear
> to be some  
> interface chips to/from the Z80 bus/expansion connector,
> which of  
> course you wouldn't/couldn't need for a simple ADAM Net
> device. Near  
> the expansion connector, I make out two 74LS138s (3-to-8
> decoders), a  
> 74LS125 quad tri-state buffer, and a 74LS175 quad D flip
> flop.
> 
> I believe the small 8 pin chip is an LM347[?]N. Most likely
> an op-amp.
> 
> There's an RCA CD4057BN(?) which is described as a 4
> channel analog  
> mux/demux with logic level conversion. I can't make out the
> chip above  
> that.
> 
> I'm tempted to ask the seller to identify each chip.
> 
> eBay is not difficult to use. You can set up an account
> easily and  
> you're good to go. As Joe mentioned, the best strategy for
> winning an  
> eBay auction is to wait 'til the last possible second and
> place the  
> max bid you're willing to accept. There are a variety of
> reasons for  
> this:
> 
> 1. eBay uses a proxy bidding scheme. What this means is
> that if I want  
> something, I can place a maximum bid and eBay's system will
> bid up to  
> that amount on my behalf. So, for example if the current
> bid stands at  
> $10, and the current high bidder enters a max bid of $15,
> you come in  
> and say bid $14 max, the original high bidder will still be
> the high  
> bidder at $15. I would have to bid up one step above the
> original high  
> bidder's bid in order to have the high bid. Another
> example, if the  
> current bid was $10 (with a max of $15) and I bid a max of
> $30, the  
> high bid would go to me at $16.
> 
> 2. Knowing 1, we can see that anybody can simply "bid up"
> an item by  
> whittling away at your max bid by placing incremental
> smaller bids up  
> to (and possibly) beyond your max. I bid $11, the original
> bidder goes  
> up to $12. Then I bid $13, the original bidder bids $14,
> and so on.  
> This can include sellers who either have a second account
> set up (or a  
> buddy) to bid up items they feel aren't selling for what
> they should.
> 
> 3. Knowing 2, there are "sniper" bidders and/or special
> software that  
> will wait til the last 30 seconds or so of the auction to
> place either  
> a max bid, or whittle away at your max until they just
> surpass it.  
> This gives you little opportunity to counter bid and they
> win the  
> auction.
> 
> Clearly the best bidding strategy for eBay is to wait til
> the last few  
> seconds of the auction, and place the biggest bid you're
> willing to  
> pay. This gives you the best chance of paying the lowest
> price and  
> winning an item.
> 
> I would like to see the guts in person (or higher res
> pics), beyond  
> that though I'm unwilling to pay what this would ultimately
> go for I'm  
> sure. It would be a nice piece to have for a collection,
> but I'm  
> unsure what additional information can be gleaned about the
> ADAM  
> architecture by having it.
> 
> 
> On Jun 13, 2009, at 3:34 PM, Rich Drushel wrote:
> 
> >
> > On Fri, June 12, 2009 8:26 pm, Frances and/or Richard
> Clee wrote:
> >
> >> Meanwhile, the series of disassembled, closeup
> pictures is posted so
> >> perhaps Rich or geoff or Dale or someone can
> figure out what the damn
> >> things are, and if the better interests of the
> Adam community  
> >> suggest we
> >> pursue them.
> >>
> >> So will those who know please speak up?
> >
> >     Okay, now that my brain is
> clear (turns out I was in the onset
> > stages of a migraine when I was writing last time,
> eventually my  
> > vision
> > almost went out and my head was exploding for a few
> hours, ask Rin how
> > much sense I was making at the time), and I have had a
> chance to  
> > examine
> > the disassembly photos, here is what I think:
> >
> > (1)  The most informative photo is the one with
> the diagonal color  
> > ribbon
> > cable, since that exposes much more of the underlying
> circuit  
> > board.  I
> > will refer to this photo in subsequent points.
> >
> > (2)  The large 40-pin ceramic DIP marked "TAPE
> SIM", with its  
> > associated
> > chips (TTL logic 74LS273 and 74LS00, 2 static RAMs
> 2114) and metal  
> > oscillator
> > crystal, is clearly is 60701 microcontroller (EEPROM
> version of the  
> > 6801),
> > suggesting that the board is an ADAMnet device. 
> Somewhere around  
> > should also
> > be an LM339 quad comparator, a 14-pin DIP, which was
> always part of  
> > the ADAMnet
> > interface.  Possibly it is under the multicolor
> ribbon cables.  If  
> > it is absent,
> > then whatever the board originally did, it cannot in
> its present  
> > state be a
> > functional ADAMnet device, because the LM339 sits
> between the  
> > ADAMnet bus and
> > the 68701 -- it would never get any ADAMnet inputs.
> >
> > (3)  The circuitry in the vicinity of the added
> DB-37 connector,  
> > especially
> > the blue rectangular trimpot (i.e., high-precision
> variable resistor  
> > with
> > a tiny adjustment screw sticking out horizontally),
> suggests to me  
> > that
> > maybe the original board was a prototype for a disk or
> tape drive.   
> > I have
> > looked at the extant schematics
> >
> >     http://drushel.cwru.edu/schematics/
> >
> > but don't see any immediate matches to the chips whose
> names I can
> > read in the disassembly photos.
> >
> > (4)  I count 19 wires in the top ribbon cable and
> 15 in the bottom  
> > cable
> > (composite of both disassembly photos).  That
> would leave 3 unused  
> > pins
> > on the DB-37 connector.  Very likely the signals
> are 16 address lines,
> > 8 data lines, 2 ADAMnet lines (data and reset), and
> presumably other  
> > Z80
> > control signals of interest that get run out the
> sideport connector.
> >
> > (5)  The circuit board appears to have been
> designed to fit into the
> > Expansion Module #1 case, even though the board is
> clearly *NOT* a
> > reworked Expansion Module #1 board.
> >
> > **** WILD GUESS ****
> >
> >     The circuit board was
> originally for prototype tape drives,
> > either as a prototype of the (apparently planned,
> since there are
> > ADAMnet device numbers reserved for them) tape 3/4
> expansion unit,
> > or else for original development of tape drives in
> general.  Given
> > how fragile the existing connectors are for the tape
> drives (plus
> > the pain of installing them in the first place), I can
> imagine a
> > sideport-based unit being easier to plug/unplug during
> development
> > cycles.  The "TAPE SIM" 68701 just runs a dummy
> tape drive device
> > (or devices).  At the ADAMnet level, all the user
> cares about is
> > reading and writing data, and if the 68701 does what
> is expected,
> > then it doesn't matter that there is no real tape
> drive attached.
> >
> > ***** END WILD GUESS *****
> >
> >     I personally would like to
> have one of these devices.  But
> > as stated before, I have never used eBay, so I am the
> wrong person
> > to ask about bidding.  But I am willing to
> contribute $$$ to someone
> > who knows how to win eBay auctions :-S
> >
> >     *Rich*
> >
> > -- 
> > Richard F. Drushel, Ph.D.       
>     | "They fell:  for Heaven to  
> > them no hope
> > Department of Biology       
>         |  imparts / Who hear not
> for  
> > the beating
> > Case Western Reserve University     
> |  of their hearts."
> > Cleveland, Ohio  44106-7080  U.S.A. 
> |         -- Edgar Allan
> Poe,  
> > "Al-Aaraaf"
> >
> >
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> > http://adamcon.org/cgi-bin/mailman/listinfo/coladam
> 
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