Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!claris!sts!sts!galvey
From: galvey@sts.sts.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: problems with an amiga 500
Message-ID: <67100001@sts>
Date: 1 Sep 89 00:40:27 GMT
Lines: 45
Nf-ID: #R:<8908311544.AA28591@jade.berkele:-38:sts:67100001:000:2211
Nf-From: sts.sts.UUCP!galvey    Aug 31 16:53:00 1989



Rick,

I have had the same "jump" occur on my system for some time now. I also 
have a friend with a 2000 (and a 1084 monitor) that has similar things happen.
He has informed me that, after talking to a "Amiga Service Guru" at the local
dealer, the "jump" & "POP" you experienced was propably caused by HI-VOLTAGE
DISCHARGE in your monitor (1084?). It was explained that the hi voltage line
going to the CRT (picture tube) runs very close to some other metal components
inside the monitor.

I have not taken my monitor apart yet to check this out, but having some 
previous experience working with Television Repair, I can understand why the
screen jumps & you hear a "POP". This all happens when too much static builds
up INSIDE THE MONITOR between the hi voltage line (anode, wire, etc) and some
other metal (usually the chassis) surface. Since color monitors use hi voltage
anywhere between 20 to 30 THOUSAND VOLTS, you will HEAR when a discharge takes
place! 

I also heard that, in some cases, this spark can get back TO THE COMPUTER and
cause all kinds of NASTIES!!! (such as the blown chips your friend experienced).
It is well known in the electronics industry that ESD (Electro Static 
Discharge) of just a FEW thousand volts can cause component failures or 
DEGRADING of components, which may be the cause of the continued problems with
the computer.

The service guru suggested getting inside the monitor and use ELECTRICAL TAPE
to wrap around the hi voltage line. When I was still working in TV repair,
we used this trick all the time when hi voltage lines would get bent and 
get close to the chassis. One note: the tape should say something on it's 
label about insulation value (1kVolts per layer ?). I would also suggest 
that the hi voltage cable be moved as far away from all metal (including
circuits) inside the monitor. 

CAUTION: CRTs can hold a charge for quit a while (they are BIG capacitors) so
if you are not experienced with this type of thing, take it into the shop and
have the service tech do it for you. 

I hope this helps you guys out. Send me something back to let me know what
happens, maybe I will finally tear my monitor appart and do it myself!

				Later,

				Greg A.