[Premium-Rx] Update on RF-590 display problem

[Mac]

no heat problems at all.. I got three in the same cabinet and one in an
original close fitting desk cabinet  and no problems at all..  light emm
up...  run emm ...  mac/mc  and thanx for the follow on about getting the
display up and o/r
----- Original Message -----
From: "Gary Mitchelson" <n3jpu at speakeasy.net>
To: <premium-rx at ml.skirrow.org>
Sent: Monday, November 25, 2002 6:50 PM
Subject: [Premium-Rx] Update on RF-590 display problem


> OK, I'm happy to report that the replacing the zener has indeed fixed my
> display to be nice and clear. So far so good and am not sure what caused
> the problem to start with.
>
> How sensitive is the RF-590 to heat? Pictures in the manuals show no
> clearnance between the 590 and other units in a rack, does the 590 need
> clearance for proper cooling?
>
> -----Original Message-----
> From: Barry Hauser [mailto:barry at hausernet.com]
> Sent: Sunday, November 24, 2002 22:27
> To: Gary Mitchelson; premium-rx at ml.skirrow.org
> Subject: Re: [Premium-Rx] RF-590 display **Found the problem**
>
>
> Gary wrote:
>
>
> > Well I found the problem on why the unused segments had a slight glow,
>
> > there was no 6.2 V Bias to the Display Converter (the sealed box). VR1
>
> > (provides the 6.2 VDC from the 35VDC supply) was toasted causing a
> > short (really about 20 ohms) to ground. Luckily Radio Shack has 6.2 V
> > Zeners in stock so I'll pick one up tomorrow. Everything else in the
> > converter ohms out OK.
>
> Hi Gary & list:
>
> Yup, that's one of the things I mentioned when you first posted.  Yet
> another case where it wasn't the display itself, but a supply or ground
> problem.  The vacuum luminescent displays don't seem to fail at the same
> rate that the LCD's do which largely replaced them.
>
> However, I had suspected it to be more likely a drifted resistor or
> failed cap.  Question is now -- what caused VR1 to fail?  It's possible
> that it failed on its own, but could be due another component in that
> circuit.  Was this heat-sunk to anything?
>
>
>
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