"Baron" wrote in message
...
Arfa Daily wrote:

Booked in by shop as a 'Bingo calling unit'. It has a large 5 digit 7
seg display made from discrete LEDs. Has two 5 digit BCD encoded
switch units to set start and end number. Has jack input to which is
connected a hand-held push button unit. Chip date codes indicate that
this thing is from 1981. It looks 'professionally' hand built, if you
see what I mean. It has stickers on with a company name, but that
could be largely meaningless. Two problems reported. First that it had
a problem with the LEDs, and secondly that it had "lost its memory".

LED problem was straightforward enough. One segment of one digit was
not lighting due to one LED in the series chain of five which made up
the segment, being open circuit. A replacement LED restored that.

Now, the second problem. For playing bingo, the start number would be
set to "1", and the end number to "90". All ok so far, and if this is
done, it does indeed generate random numbers in the range 1 to 90, one
per button push.

The next requirement is that the unit is going to need to know for any
game in progress, which of the numbers between 1 and 90 that it has
already produced so that they are not duplicated, and this is where it
all goes tits up.

After a while, numbers *do* start to duplicate. If you set the start
and end numbers to say "1" and "10", it might take 15 button pushes to
get all ten numbers out, the other five being one or more times dups.

So I have a good look at what's in it. 2 x 4027 dual J-K, 3 x 4011
quad
NAND, 2 x 4081 quad AND,
1 x 4040 12 stage counter, 1 x 4020 14 stage counter, 1 x 555
timer and
last but not least, 1 x MK50395 decoder / driver. Now I don't know if
I'm just being dumb-arsed here, or having a senior moment, but I'm
buggered if I can see any chips in that line up that could form a
memory and comparator for potentially 99999 numbers. Or even for 90
numbers come to that ... If this is what it was meant to do, even back
in '81, I would have expected to
see a couple of CMOS memory chips, and a Z80 or 8080 processor,
maybe.

What am I missing here ? Could it be that they are mistaken in
thinking that it can be used to properly call a game of bingo ? Is it
in fact a raffle ticket drawing machine, where you would set the
serial numbers of the first and last tickets sold out of a batch of
perhaps 1000 and then draw maybe 10 prize ticket numbers with the
chances of it duplicating any when it's only generating ten random
numbers out of a pool of 1000, being at worst, slim ?

Haven't managed to get hold of the owners again yet to check if they
feel that it has ever worked as a bingo calling machine, but at the
moment, my feeling is that it is a 'new acquisition' to some little
club, and that it has been given to them after sitting long forgotten
in an attic somewhere for 20 years.

Any thoughts anyone ?

Arfa

Hi Arfa,

If you have what I think you have it was never intended for Bingo !
They were made in Leeds, I forget the company name, but were intended
for use in Working Mens Clubs for the members pool ! Each member had a
number and the members paid money into a pool each week. The member
who got his number called took the money less a few percent for the
club.


--
Best Regards:
Baron.


Hi Baron. Yes, that's my feeling too. This was actually made in Hemel
Hempstead according to the stickers on it. I'd forgotten about members pool
draws. It's been many years since I graced a WMC with my presence !

Arfa