On 21 Nov 2004, at 17:30, Richard Bennet wrote:
Hi all - Would someone please point me to the proper and safe way to discharge a crt, in order to work on the unit? We all know there is danger, but part of learning includes handling - or in this case, discharging, the danger. This is knowledge that should be as widely circulated as the warnings of same.
Before we start yet another 'dangers of CRT discharging' thread, here is what for me is the definitive statement on the subject. Remember that from half way through SE production, bleed resistors were fitted to allow all charge to dissipate. All SE/30s should have them.
Tom Lee's statement: (Tom is a prof at Stanford)
1) Don't discharge the crt unless you really have to disconnect the HV lead for some reason (like swapping out the crt or analog board). For a detailed description of why you have little to fear from a compact mac's crt, see
http://www.applefritter.com/thefritter/13/drwebster.html.
2) If you do have to discharge the crt, don't go to the trouble of building the resistor/alligator clip device. Unless
your resistor is rated for HV operation, the HV will simply jump across it. This so-called "arc-over voltage" is only a few hundred volts for most resistors, so going to the trouble of including it makes no sense. To do it right, you'd need to string dozens of them in series, and carefully arrange them, say, in a helix around an insulator (this is in fact how high voltage resistors are constructed). It's more trouble than it's worth. Just make sure that the discharge is dumped well away from the logic board, or else you risk frying something there (another reason for not routinely discharging the crt just for the heck of it). My favorite method is to just to let it sit unplugged overnight. What little charge might remain will truly be inconsequential.
(TL's statement ends)
Unless you have some first-hand evidence of injury from the CRTs of Compact Macs, please do not contribute to CRT danger frenzy hysteria mania.
Stuart
-- Compact Macs is sponsored by <http://lowendmac.com/>.
Support Low End Mac <http://lowendmac.com/lists/support.html>
Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/>
---------------------------------------------------------------
The Think Different Store
http://www.ThinkDifferentStore.com ---------------------------------------------------------------
