[vcf-midatlantic] Any trick to discharging ADM-3A

[Ian Primus]

You don't have to, no. It really doesn't matter. You're just
discharging the tube. You can if you want to, provided you are very
sure you are attaching the clip directly to the metal mounting ears,
implosion band, or that spring strap that actually contacts the bell
of the tube, and not to any other metal chassis work in the monitor
that might be connected only to electronic ground and may have become
disconnected.

It's always safe to clip onto that spring strap on the bell of the
tube. You're shorting out the capacitor formed by the picture tube.
The one plate of this capacitor is the inside coating - which is
attached to that connector that's hidden under the suction cup. The
other plate of this capacitor is the conductive gray aquadag coating
on the bell of the tube. The spring strap connects this to the metal
ears/implosion band of the tube, and the ground wire that attaches to
the chassis.

-Ian

On Thu, Feb 8, 2018 at 10:12 AM, Jason Perkins via vcf-midatlantic
<vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> Is it a good idea to unhook the tube from the chassis / electronic ground
> before discharging?
>
> On Thu, Feb 8, 2018 at 10:10 AM, Ian Primus via vcf-midatlantic <
> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>
>> Yeah, of course - you can disconnect the neck without discharging the
>> tube. There's no danger there. You can clip on to any part of the
>> metal mounting ears of the tube, the implosion band, or that spring
>> that stretches across the bell of the tube. That's all connected to
>> dag ground.
>>
>> -Ian
>>
>> On Thu, Feb 8, 2018 at 8:51 AM, corey cohen via vcf-midatlantic
>> <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>> > Ok.  Well then let me ask you and Ian this..
>> >
>> > Can I safely disconnect the plug at the end of the CRT neck without
>> discharging?
>> >
>> > That would make it easier to take the tube out while the anode wire is
>> still connected and then in can discharge the tube with a screwdriver.
>> >
>> > Also is the best place to clip onto the implosion bracket since the ADM
>> doesn’t really have a metal chassis?
>> >
>> > Thanks,
>> > Corey
>> >
>> > corey cohen
>> > uǝɥoɔ ʎǝɹoɔ
>> >
>> >> On Feb 8, 2018, at 12:01 AM, Joseph Oprysko via vcf-midatlantic <
>> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>> >>
>> >> I’ve done the screwdriver trick myself. Because often, even after
>> waiting a
>> >> few weeks, there can still be enough voltage to make your hair stand on
>> >> end. LOL
>> >>
>> >> On Wed, Feb 7, 2018 at 7:05 PM Ian Primus via vcf-midatlantic <
>> >> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>> >>
>> >>> I don't remember any particular trick or real difficulty in doing it.
>> >>> Maybe you needed to get the tube loose to get the screwdriver in
>> >>> there? But I thought it would fit in there without too much problem. I
>> >>> know I've done it a whole bunch of times and nothing sticks out at me
>> >>> as being out of the ordinary about working on the 3A. Remember you
>> >>> don't need to disconnect the anode connection right away, just
>> >>> discharge it.
>> >>>
>> >>> If you're doing a lot of work on one of those monitors, sometimes you
>> >>> do need to get a bit creative though:
>> >>>
>> >>> https://i.imgur.com/k2wPmw3.jpg
>> >>> https://i.imgur.com/UwU3gek.jpg
>> >>>
>> >>> -Ian
>> >>>
>> >>> On Wed, Feb 7, 2018 at 6:29 PM, corey cohen via vcf-midatlantic
>> >>> <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>> >>>> So I was about to swap out my ADM5 for my ADM3a with my ALTAIR and
>> >>> realized while I did replace the electrolytic and tantalum caps on the
>> main
>> >>> board, I didn’t change the electrolytic caps on the analog board
>> behind the
>> >>> tube.
>> >>>>
>> >>>> No big deal except that the rubber cup is on the top where I can’t get
>> >>> to it without removing the tube and you aren’t really supposed to
>> remove
>> >>> the tube till you discharge it under the rubber cup.    So chicken or
>> the
>> >>> egg?
>> >>>>
>> >>>> Or am I just supposed to let the ADM sit unplugged for a few weeks and
>> >>> just assume it self discharged?
>> >>>>
>> >>>> Just when I thought I was finished with this project and was going to
>> >>> move onto my TI silent rebuild.
>> >>>>
>> >>>> Thanks,
>> >>>> Cheers,
>> >>>> Corey
>> >>>>
>> >>>> corey cohen
>> >>>> uǝɥoɔ ʎǝɹoɔ
>> >>>
>> >> --
>> >> Normal Person: Hey, it seems that you know a lot.
>> >> Geek: To be honest, it's due to all the surfing I do.
>> >> Normal Person: So you go surfing?
>> >> Normal Person: But I don't think that has anything to do with knowing a
>> >> lot...
>> >> Geek: I think that's wrong on a fundamental level.
>> >> Normal Person: Huh? Huh? What?
>>
>
>
>
> --
> Jason Perkins
> 313 355 0085