[TechAssist] Re: CTC 187 power supply update
- From: "Bill S" <billans@xxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Tue, 26 Feb 2002 17:12:47 -0800
Hi again;
getting weirder, Pin 11 and 12 of U4101 is running at 156 volts like it
calls for. However the voltage is not on the collector of the Horizontal
output and because of not the usual symptons that occur when the HOT is
shorted, I did not check it. *BIG MISTAKE* It is shorted.
What actually was happening that inside the U4101 regulator is a overcurrent
sensor and when the current that is needed to keep the 156 volt line on pin
11&12 exceeds a *over current* value then the bottom half of the regulator
will not run which will not produce the standby voltages that are needed to
'start' the set.
I then replaced the Horizontal output and ran the set for a little bit and
then started putting the set back together when it went out. The HOT
shorted again.
Any ideas on this??
Bill Sorensen
New Life Video & Audio
billans@xxxxxxxxxxxx
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----- Original Message -----
From: "Bill S" <billans@xxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, February 26, 2002 2:59 PM
Subject: CTC 187 power supply
> Hi all
> This unit came in a couple of days ago dead. I checked the U4101
> (STK730-150) and on pin 1 & 2 were -1.4 volts, pin 4 had a +1.5 volts on
it.
> I assumed that the regulator was bad and ordered a new one. I put the new
> regulator in and still the set will not start up. There is the raw 160
> volts B +. The schematic shows that this supply should start running when
> plugged in and that the standby voltages should be up at least. Nothing
is
> going on.
> This is going to be one of those dumb things I have overlooked. Right?
> What did I miss?
> Bill Sorensen
> New Life Video & Audio
> billans@xxxxxxxxxxxx
> - - - - - - - - - - - - - - - - - - -
>
>
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