Re: Atari B&W: no HV

On Fri, 07 Dec 2001 03:43:10 -0600, Rodger Boots <rlboots@cedar-rapids.net>
wrote:

>Alrighty, you all knew I couldn't resist to nitpick this!
>
>The cathode end of the diode is connected to the CRT, which IS the
>filter capacitor.

Oops! Got my anode/cathodes reversed! I was talking about a filter capacitor
(or a cap used as part of a doubler) on the "anode" side of the diode.

Here was my concern (warning ASCII art ahead -- set your phasers to fixed font):

        C1 D1 C2
Vin ----||--+--->|---- Vout --<(CRT))-+
            | |
            - D2 |
            ^ |
            | |
            +-------------------------+
                                      |
                                     GND

This was taken from the G05-146 pdf file available on spies.

The voltage doubler is C1,D1,D2 and C2 where the CRT is used as C2.

What happens with the 'Vout' connection (which is connected to the CRT cap) is
shorted to ground? My concern was that C1 is discharged very quickly through
D1.

Not as familiar with D1 as Rodger is, I'd forgotten that there are no 15kv
diodes, but instead a string of diodes. Does having a string of diodes limit the
amount of current that can be discharged from C1 to ground?

I don't know, but Rodger seems to have a good understanding of this and his
concerns seem different from mine (if I understand his description), which is
another reason not to discharge with a direct short.

-Zonn

>I don't personally see a problem with directly discharging the CRT, but
>John seems to think there is a link, so let's assume this somehow DOES
>damage the diode. How could that happen?
>
>The diode is actually quite a few diodes in series.

<snip>

---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to neil@synthcom.com.
Received on Fri Dec 7 10:43:26 2001