The original message:
>two of our monochrome 19" hitachi monitors have flaked out. our
>diagnosis seems to indicate the flyback transformer as the culprit.
>does anyone know of places that would repair these monitors, or a source
>for replacement flyback transformers? names / addresses / phone numbers /
>experiences welcome. please email and i'll summarize.
As some of the folks suspected, it wasn't a hitachi monitor but a
philips one. Also, after reading the responses, it seems that our
problem might be something other than the flyback transformer. The
symptoms are that the screen intensity flickers at a random rate. If
any one has ideas of what might be the problem, please let me know.
I have not contacted any vendor yet, so none of this information has
been verified by me.
'dorab
======= summary of responses ==========
A lot of people pointed me to:
An article on page 80 of the July 1990 issue of SunExpert dealing with
flyback transformers and Philips monitors.
and
Pinnacle Data Systems
1350 West 5th Ave. Suite 131
Columbus, Ohio 43212
Phone: 614-487-1150
Fax: 614-487-8568
Philips model number M19P114A/6102
flyback part#: 60-101
cost: $99.00
Also mentioned were:
Ed Andrea, Apex Computers (206) 867-1900 $350.
Computer Component Source which has 350 flyback transformers in their
catalog at approx $35 each. tel: (800) 356-1227 fax: (800) 926-2062.
C.R.C. Components Inc. (800) 366-1272.
Brian Bartholomew included some "how to" hints....
The typical symptom of this kind of failure is a loud high-pitched
whine when you turn the monitor on, independent of whether it is
getting a signal.
Prevailing wisdom at our site is to replace the horizontal output
transistor at the same time, as who knows what kind of stress it got
when the flyback went. Prevailing wisdom also suggests to use the
true RCA part instead of a third-party copy, as this is obviously a
weak point in the monitor design, and the original RCA part probably
has more headroom in it than a third-party part that only just meets
the published specs. Note that the appropriate manufacturing division
of RCA has been sold to Harris Semiconductor. You may purchase parts
through Newark (number available but not immediately at hand), who has
proven to be cheaper, faster, and all-around more professional than
the three local electronics stores in town. Remember to have your
tech use fresh heat-sink compound, because if the transistor isn't
thermally well connected to the heatsink, it's a goner.
I still don't have an ohmmeter that goes over 20 Meg, so I have been
ignoring the part of the instructions where they tell you to verify
that the 30 Meg resistor on the new flyback is not open.
Be sure and short down the CRT so that you don't kill yourself. All
of this type monitor I've worked on have had resistors to drain
themselves down automatically - so don't be surprised if you don't get
a reaction out of it. A good healthy clip lead and a screwdriver you
don't care about the tip of will serve as an impromptu shorting stick.
thanks to:
yih%atom@cs.utah.edu (Benny Yih)
"Anthony A. Datri" <datri@concave.convex.com>
jipping@frodo.cs.hope.edu (Mike Jipping)
mdisea!edm@uunet.UU.NET (Ed Morin)
AMPT0659@s2901b.amp.com (John Kelly)
bzs@world.std.com (Barry Shein)
bb@math.ufl.edu (Brian Bartholomew)
glascock@hsr.mayo.EDU (Don Glascock)
curt@ecn.purdue.edu (Curt Freeland)
rhm@mayo.EDU (Russ Moritz)
Dan Butzer <butzer@pinnacle.com>
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