Re: Trouble with Space Wars Monitor

On Thu, 12 Aug 1999 22:14:37 -0700, John Robertson <jrr@flippers.com> wrote:

>Great Zonn! (like Great Scott only friendlier ;-)
>
>True enough that you can't run the monitor with BOTH the yoke and output
>transistors unplugged, however for testing purposes you creak a no-load
>situation if you run the monitor with the yoke alone unplugged. If you have
>no input signal to the monitor then there is no damage done to the
>outputs. Consider that a vector monitor is just a rather overbuilt audio
>amp, with surprisingly similar characteristics, and you will better
>understand that !@#$%!@#$% things.
>
>John :-#)#
>
>At 06:54 PM 8/12/99 +0000, you wrote:
>>On Wed, 11 Aug 1999 10:38:52 -0400, you wrote:
>>
>> >I'll try to sum up my problem as clearly as possible, this is my first X-Y
>> >monitor game, so I'm new at this:
>> >
>> >Currently, the monitor only displays the upper left quadrant on the screen.
>> >All of the power transistors (Q110, Q111, Q210, Q211) check out OK when
>> >tested with a diode tester. If I run the monitor with the power transistors
>> >disconnected, I get a nice little rectangle in the middle of the screen.
>>
>>For a little while, then you will start noticing smoke coming from
>>R118, R119, R218, R219 and possibly Q108, Q109, Q208, Q209, as these
>>parts try their best to drive the yoke alone.
>>
>>Running the monitor without the yoke plugged in, and the power
>>transistors NOT plugged will eventually lead to monitor damage.

Oops I blew it here, what I *meant* to say was:

"Running the monitor WITH the yoke plugged in, and the power
transistors NOT plugged will eventually lead to monitor damage."

This is the condition that will cause the pre-drivers to try and drive the yoke
without help from the final output transistors, leading to the frying of parts.

Sorry about that!

-Zonn
Received on Fri Aug 13 19:33:39 1999