RE: Need Star Castle Help

Matt-

For testing purposes use a switcher. Get that old
monstrosity out of the picture... IMHO.

Mit

>> -----Original Message-----
>> From: Matt Rossiter [SMTP:matt@rossiters.com]
>> Sent: Wednesday, October 07, 1998 2:35 AM
>> To: Vectorlist
>> Subject: 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 12:25:04 1998