17 Oct
2001
17 Oct
'01
4:49 p.m.
This is the one I am not sure about.
'Philippines' suggests Texas
Instruments to me. And many TMS1000s did have 28 pins... I am going to go
with that guess for the moment
Oh, I'm sorry, I might have forgotten to mention, ALL 3 chips are Texas
Instuments (unless someone else used the TI logo back in the early
eightys :-) )
75494 'Hex MOS to LED digit drivers'
Basically 6 inverting open-collector drivers with a common enable input.
This chip is another one that turns up in electronic games as an LED
driver, etc.
Makes sense, since there is an LED 2 digit counter/display in it. It is
also the chip closest to the LED display
Another standard part
TL496C '9V Power Supply Controller' (the TMS1000 runs at 9V, BTW).
Basically a switching regulator normally used to get 9V from a couple of
primary cells.
I guess it can step up the power. The game uses 2 D cell batteries
connected in series, so it gets 3 volts input power. Humm... thinking
about that, the choke coil could actually be a light weight transformer
then (maybe? I'm not an EE, so I am guessing since a trans and a choke
both have lots of wire wrapped around a magnetic core)
I will have to see if I can get a chance to draw up those schematics,
that will help tell more about it I am sure. Heck, I have to take it back
apart anyway, I need to either oil the motor, or replace it. The game
seems to still be working (thank god no perm damage from the battery
leak), but the motor starts to slow and stress at certain points.
-chris
<http://www.mythtech.net>