RE: Need Star Castle Help

OK - for those who may have read my previous post.

I began suspecting my problem may actually be in the power supply. When
I plug the Molex connector to the board - I'm only getting about .6v.
When I unplug the Molex connector, I'm reading +6v from the pins. So my
roommate suggested I connect a 5 ohm resistor to the pins which are
supossed to be putting out +5v. If the voltage drops to 0v - then it's
most likely to be the power supply. So I did - sure enough, the voltage
dropped to 0v.

So... when looking at the schematics for the power supply - my roomate
suggested that the most likely candidate for a problem would be the
large transistor (Q1). So I gave it the diode test. With positive lead
on emiter and negative lead on base, I get a reading of 1.6v. With the
leads switched I get .6v. I'm not exactly sure If this transistor is
*the* problem. I guess I'll have to do some more probing around. If
any Cinematronics experts out there have any further suggestions let me
know....

Thanks....

Matt

BTW - This is the first time I've tried posting on the vectorlist. If
it's more "appropriate" to post tech help questions on rgvac - let me
know.

****** <Previous Post> ******

Perhaps someone can give me some direction with this Star Castle that
I'm working on.

The original problem was - The LED on the CPU board was staying lit.
Which, I assume, is an indication that the game is stuck in reset mode.
I was getting +5v across the board. Distorted sound was coming out of
the speaker - and the CRT was glowing. No picture of course.

So - I took a logic probe and tested all of the chips within the reset
circuitry. Everything seemed good, except the reset pins were reading
low instead of high. So - on the chip at A2 on the board - I tried a
little experiment. I forced the reset pin to be high instead of low.
This did indeed cause the LED to go out - but the game still didn't
work. To make matters worse - somehow the circuitry shorted out. Now I
only get .6v across the board. - Yup, I'm a greenie.

So.... I need some expert advice on the following.

1) I have a logic probe, an Eprom Burner, a DMM. I probably should
start becoming more familiar with a scope. Does anyone have
recommendations as far as getting a nice scope to work with? - And more
importatnly, does anyone have recommendations for any other tools that
might be helpful? I would love to get the Cinematronics exorsizor - but
I'd only be dreaming I suppose.

2) As far as the problem I mentioned above. Any suggestions as to
where to go from here? I have the manual/schematics and can get any
parts I need.
Received on Wed Oct 7 01:33:23 1998