My son-in-law just gave me a Viewsonic M70 - VCDTS21503 sound and video
monitor. MFD in 1999. He said the person who gave it to him said it was
working, then suddenly there was a puff of heavy smoke and it died.

I have opened the case and examined both sides of the PWB and as many
of the componenets as I can see, No sign of discoloration anywhere,
not even on the inside of the light-colored case. When the power
switch is turned on, you can hear the degaussing coil hum briefly.
There is no high voltage. I checked and there is about 155 volts on
the one main capacitor in the vicinity of the power supply components.
But, I don't have a schematic and don't want to start investing in a
lot of $$$ if there is a major problem, as I don't really need the
monitor, but would fix it and give it away. I have a scope and many
years repairing older TV sets so am willing to tear into this.
Suggestions gladly accepted.

H. R.(Bob) Hofmann

wrote in message
ups.com...
My son-in-law just gave me a Viewsonic M70 - VCDTS21503 sound and video
monitor. MFD in 1999. He said the person who gave it to him said it was
working, then suddenly there was a puff of heavy smoke and it died.

I have opened the case and examined both sides of the PWB and as many
of the componenets as I can see, No sign of discoloration anywhere,
not even on the inside of the light-colored case. When the power
switch is turned on, you can hear the degaussing coil hum briefly.
There is no high voltage. I checked and there is about 155 volts on
the one main capacitor in the vicinity of the power supply components.
But, I don't have a schematic and don't want to start investing in a
lot of $$$ if there is a major problem, as I don't really need the
monitor, but would fix it and give it away. I have a scope and many
years repairing older TV sets so am willing to tear into this.
Suggestions gladly accepted.

H. R.(Bob) Hofmann


Check for B+ voltage at the HOT, if you have no voltage there, work your way
back, there could be an open fusible resistor. HOT may have shorted and
burned dust off the resistor hence the smoke, if you have TV experience you
should be able to track this down with some effort for not much money.

Thanks, that's what I was planning on lookling at next after I gert
some other chores done.

Bob Hofmann
James Sweet wrote:
wrote in message
ups.com...
My son-in-law just gave me a Viewsonic M70 - VCDTS21503 sound and
video
monitor. MFD in 1999. He said the person who gave it to him said it
was
working, then suddenly there was a puff of heavy smoke and it died.

I have opened the case and examined both sides of the PWB and as
many
of the componenets as I can see, No sign of discoloration
anywhere,
not even on the inside of the light-colored case. When the power
switch is turned on, you can hear the degaussing coil hum briefly.
There is no high voltage. I checked and there is about 155 volts
on
the one main capacitor in the vicinity of the power supply
components.
But, I don't have a schematic and don't want to start investing in
a
lot of $$$ if there is a major problem, as I don't really need the
monitor, but would fix it and give it away. I have a scope and
many
years repairing older TV sets so am willing to tear into this.
Suggestions gladly accepted.

H. R.(Bob) Hofmann


Check for B+ voltage at the HOT, if you have no voltage there, work
your way
back, there could be an open fusible resistor. HOT may have shorted
and
burned dust off the resistor hence the smoke, if you have TV
experience you
should be able to track this down with some effort for not much
money.

wrote in message
ups.com...

But, I don't have a schematic and don't want to start investing in a
lot of $$$ if there is a major problem, as I don't really need the
monitor, but would fix it and give it away.

If you haven't already checked, this may help in locating the schematic:
https://gullfoss2.fcc.gov/prod/oet/c...ericSearch.cfm

Thanks - I will use the FCC if I can't google and get some info.
Bob Hofmann