DECmate III and Rainbow 100+

From: Randy McLaughlin <cctalk_at_randy482.com>
Date: Thu Feb 24 12:01:25 2005

From: "Geoff Reed" <geoffr_at_zipcon.net>
Sent: Thursday, February 24, 2005 11:38 AM
> At 07:39 AM 2/24/2005, you wrote:
> >Geoff Reed wrote:
> >
> >>
> >>> > And yes, the whole thing is powered, rather poorly, from 12 volts.
> >>> > (Poorly: if you flip significant quantities of white pixels on and
> >>>
> >>>I've never had this problem. Are you sure you've not got some dried-up
> >>>capacitors somewhere?
> >>>
> >>> > off, the scan area expands and shrinks very noticeably. So clearly
> >>> > the supply regulation is seriously inadequate.)
> >>
> >>
> >>the VR 201 monitors have a couple of points of failure, the most common
> >>is a coil (IIRC) in the vertical that is potted in wax, they potted this
> >>-before- soldering, and wax tended to get down into the solder joint
> >>making a bad joint that fails after a while, there is a resistor right
by
> >>it that also burns up at about the same time.
> >Are you talking about the flyback transformer, and the 0-ohm resistor?
>
> nope, not the flyback, I can't remember the part exactly. it is about 1/2
> inch wide, 1 1/4 inch long and potted in wax :(
<snip>

Basically you are referring to cold solder joints, the bane of classic
hardware.

I tell people that it is usually caused by vibration, invariably they say
"what vibration it just sits there".

Randy
Received on Thu Feb 24 2005 - 12:01:25 GMT