[TechAssist] Re: Sanyo DS31590 partial schematic needed
- From: John Mielke <maintv2002@xxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Thu, 19 Sep 2002 15:09:23 -0600
From SMPS transf. pin 15, rectified by D624 to Q627 emmitter (on/off
switch) thru R486 (12 @2w) to Q486 collector (9v reg). Thru R498 (8.2
ohm) and controlled by zener D493 (7.5v zener). That makes +7.5v to
IC101 pin 26 for Vcc. John.
Dave Routson wrote:
> Hi John,
> The 9V source is there but I am having trouble tracing
> where the 7V source originates. B+ is 112V but set
> will not power up since voltages to sweep Ic apparently
> not right yet. I didn't have to replace Q601 or Q604
> but did have to replace the drivers and opto. Before
> replacing the drivers and opto-isolator with a light bulb
> load across HOT and HOT loose, B+ was 289V.
> There is a test point TJ7 that shows on the pcb 7.6V and is located close to
> the tuner and in the vicinity of the sweep IC but it has
> zero voltage and does not read short to ground. Tracing
> back it ends up on Q627 Collector. It may be that this
> voltage is not developed until set is turned on so I will
> check into your instructions with D680. Also my 5V is
> a bit low, only 4.23V so must still have loads.
> Thanks for help.
> Dave Routson
> Dave's TV
> 208 Stroud
> Cleburne, TX 76033-8738
> Ph. 817-641-8465 fax same
> email. davestv@xxxxxxxxxxx
> ----- Original Message -----
> From: "John Mielke" <maintv2002@xxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Thursday, September 19, 2002 11:54 AM
> Subject: [TechAssist] Re: Sanyo DS31590 partial schematic needed
>
>
>
> That exact set is in Sams 4355 or very similar sets are in Sams 4363 and
> 4339 and others. Do you mean the 7 and 9v sources are there but low?
> What is the +130v source? This power supply runs all the time but at
> about 60% (the 130v source is about 75v) when in standby. To force the
> power supply on, short the anode of D680 to ground. To force the entire
> set on short the cathode to ground. With a lightning damaged set we
> have seen the audio output short to load down the power supply. BTW, if
> you need to replace Q601 and Q604 you need to use the exact transistors
> (generic OK) but not NTE or they run very hot and will short again.
> They are 2SC4423 and 2SC3807. John.
>
> John Mielke
> Main TV
> 636 Main St.
> Longmont, Co.
> maintv2002@xxxxxxxxxxxxx
>
> Dave Routson wrote:
>
>>This Sanyo had power surge and every section lost
>>power. I have replaced all regulators, HOT, opto-isolator and still have 9
>>and 7V sources not all there.
>>Thought maybe someone has a scan or partial of
>>SMPS where I can trace out losses. I am just about
>>to zero this one but thought I would ask first.
>>Thanks for any help.
>> Dave Routson
>>Dave's TV
>>208 Stroud
>>Cleburne, TX 76033-8738
>>Ph. 817-641-8465 fax same
>>email. davestv@xxxxxxxxxxx
>>
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>
>
>
> --
> John Mielke
> Main TV
> Longmont,Co
> 303 776 6955
> maintv2002@xxxxxxxxxxxxx
>
>
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--
John Mielke
Main TV
Longmont,Co
303 776 6955
maintv2002@xxxxxxxxxxxxx
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