[TechAssist] Re: Sanyo DS27590 Intermittent/No start
- From: John Mielke <maintv2002@xxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Wed, 18 Dec 2002 14:02:21 -0700
Hello. If the power supply runs but the output is too high, check Q604
(2SC4423) for short base to emitter. The power supply should run in
standby when off, the collector of the HOT should be about 80 volts. If
you need to replace Q601 you must use the original transistor type or it
will overheat and fail in a few days (you can use a NTE2308 to test the
set). BTW, IC681 (upc78L05J) is a common failure causing a lot of
strange problems when the output is too high (more than 5 volts). I
have also had bad POI D612 (TLP621 or NTE3098). You can short Q693 base
to ground to force the power on and I use a light bulb to load the +130v
line (the set will not come on even tho PS at full unless you push the
power button. John.
John Mielke
Main TV
Longmont, Co
maintv2002@xxxxxxxxxxxxx
Larry E. wrote:
> Hi guys, This Sanyo DS27590 will start up everytime on a variac at 105
> volts, most of the time at 110 volts but never at 117/120, I don`t
> have the print for it, I tried to monitor what I ASSume is the regulator
> transistor, Q601`s collector but it reads 153 volts with 105 volts AC
> applied and goes to over 200v with 120 volts AC applied, strange thing
> is the collector voltage on the HOT (Q402) at 105 volts is only 85
> volts, at 120 it decays very rapidly, ANY HELP APPRECIATED, Larry E
>
> Larry Eastman
> American TV & Electronics
> Crystal River, Fl.
> http://www.tvjunkyard.com
>
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--
John Mielke
Main TV
Longmont,Co
303 776 6955
maintv2002@xxxxxxxxxxxxx
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