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@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@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@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@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@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@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