[Coco] Magnavox monitor
peak at mail.polarcomm.com
peak at mail.polarcomm.com
Mon Mar 1 15:47:14 EST 2004
Sounds like a Power supply shutdown problem to me. If B+
voltage is a little high the HEW ckt will prevent high
voltage. Another victim of polititians (Health Education
Welfare) getting their hands into our circuitry!
---- Original message ----
>Date: Sun, 29 Feb 2004 20:44:08 -0600
>From: "Boisy G. Pitre" <boisy at boisypitre.com>
>Subject: Re: [Coco] Magnavox monitor
>To: CoCoList for Color Computer Enthusiasts
<coco at maltedmedia.com>
>Marty (and all the others who bothered to reply),
>Thanks for taking time to help with this problem.
>I was incorrect about something, and have to revise the
>the problem slightly. It has been some months since I tried
it to turn
>the monitor on, and I actually hooked it up a while ago.
>When I press the power switch on the back of the monitor, I
>high pitch wine, but as soon as I let the switch go, the
>However, the front panel green LED (which indicates power
>If I press the power switch again, it does the same thing.
As long as
>I hold the power switch down with my finger, I hear the high
>squeal, but the LED does not come on. Releasing the switch
>causes the noise to go away.
>If I recall correctly, this switch should keep the monitor
on once it
>has been pressed. This does not seem to be happening.
>I've checked the fuse and it isn't burnt. It may be that
>has somehow been rendered ineffective.
>I'll put a little more time in diagnosing the problem. If I
>it to work, then I'll junk it, or send it to someone who
>can fix it (and it will be theirs).
>On Feb 29, 2004, at 6:06 PM, Marty Goodman wrote:
>> Hi there, Boisy!
>> You PROBABLY are well acquainted with this, and it
PROBABLY isn't the
>> problem with the monitor you have, but...
>> OLD Magnavox moniotor (8CM series) tended to have cold
solder joints on
>> their boards, especially those connecting the flyback
>> circuit board. If you meticulously solder-reflowed the
>> flyback (and perahaps other large parts connected with the
>> voltage and
>> medium voltage circuits) it often would fix problems with
>> characterized by sudden onset of no picture.
>> It's pretty quick and easy to reflow those contacts, so it
>> worth a
>> Pity it's so hard to ship a monitor... I've a spare Sony
>> would like to get rid of!
>> But your description of your problem... with the high
>> suggests you MAY have a dead component. Perhpas a
>> transistor, and/or something driving it.
>> Sadly, I have no tech data on the 1CM series. I do have a
>> for the 8CM series, tho.
>> Coco mailing list
>> Coco at maltedmedia.com
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