Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!mips!bridge2!3comvax!tymix!tardis!jms From: jms@tardis.Tymnet.COM (Joe Smith) Newsgroups: comp.sys.amiga.hardware Subject: Re: WHICH 1084 Fix? (Re: 2002 popping) Summary: Ground the heat sink. Message-ID: <1195@tardis.Tymnet.COM> Date: 26 Aug 90 09:26:30 GMT References: <8015@jarthur.Claremont.EDU> <1179@tardis.Tymnet.COM> <1990Aug13.111924.563@zorch.SF-Bay.ORG> Reply-To: jms@tardis.Tymnet.COM (Joe Smith) Organization: BT Tymnet, San Jose, CA Lines: 74 In article <1990Aug13.111924.563@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes: >In article <1179@tardis.Tymnet.COM> jms@tardis.Tymnet.COM (Joe Smith) writes: >>My A2002 turned itself off once after snapping. After about the 20th "snap!", >>I went in and applied the 1084 fix to it. No more popping. > >WHICH 1084 fix? I've seen one fix discription that attributes >the problem to a metal tab (under part of the hardware) >allowing arcing between components, and suggesting cutting >off/grinding off the tab and cleaning arc sputter residue from >the area That attacks the symptom, but not the cause of the problem. > and another description that attributes the problem to lack of a ground >path to discharge accumulated ambient static charge where the arcing is >occurring, and suggesting as a fix installing a ground strap to short >the two modules together and to ground. The heat sink needs to be grounded. A simple ohm-meter check shows that it is not electrically connected to anything, but it should be. >And I still think Commodore should issue a recall for _all_ >the monitors subject to these problems and fix them at their own expense. You mean, RCA should issue a recall. The A2002 monitor appears to be an off-the-shelf component with a custom logo. >I am dumbfounded that CBM managed to release the 2002 series >of monitors without fixing the problem at the design level. You should blame the manufacturer, not CBM. [Items about jokes and stupidity deleted.] Newsgroups: comp.sys.amiga.hardware Subject: Re: Monitor popping Summary: Connect the heat sink to ground Keywords: 2002, popping, snapping, etc Message-ID: <1105@tardis.Tymnet.COM> Date: 19 May 90 03:29:02 GMT References: <10630@sdcc6.ucsd.edu> Reply-To: jms@tardis.Tymnet.COM (Joe Smith) Organization: BT Tymnet, San Jose, CA Lines: 29 Take off the cover of the 2002 and look at it from the back. Examine the printed-circuit (PC) board. To the left you should find the power connector, the audio connector, and the chroma/luma video connectors. That corner of the PC board is grounded and shielded by a piece of metal that is soldered on. To the right you should find an "L" shaped aluminum heat sink with a power transistor bolted to the right-hand side. (The planes of the heat sink are vertical and surround the flyback transformer. A thick red wire comes out of the flyback transformer and connects to the upper side of the picture tube.) If you look under the printed circuit board, you should see two screws holding the heat sink to the PC board, and a bent metal tang that goes through a hole and also holds the heat sink down. I saw evidence of an electrostatic discharge that jumped from the metal tang to one of the copper traces on the PC board. This is the cause of the "snap" and "pop". The heat sink is not electrically connected to anything, and accumulated an electrostatic charge until it arced over. I simply ran a wire from one of the screws that holds the heat sink to the PC board over to a screw by the input connectors. Make sure the wire is insulated so as to not short out anything else on the PC board. I used an ohm-meter and verified that it showed zero ohms between the heat sink and the grounding shield. "Poof", no more pops! -- Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms PO Box 49019, MS-C51 | BIX: smithjoe | 12 PDP-10s still running! "POPJ P," San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga speaks for me."