I'm servicing a Daewoo DTQ-27S2FCV television. The HOT and switching
regulator transistor were shorted. I replaced the HOT with an RCA sub but
still stamped with the original part number, 2SD1880. I replaced the
regulator with an NTE 379 which is a sub for an E13009-2. The set powered up
fine with a great picture. A half hour later, same parts shorted out again.
I decided to order the original parts from Daewoo and have now received and
installed them. I monitored the collector of the HOT and it appears to be a
nice clean pulse. The temperature of the HOT is another story. After about
10 minutes, it climbed to 150º F (66º C) and I turned off the set to post
this message. A blurb in Sam's FAQ
http://www.repairfaq.org/REPAIR/F_monfaqi.html, section 14.12) says that a
temperature of over 130º F (54ºC) is cause for concern. The datasheet for
the 2SD1880 says the operating junction temperature, Tj is 302ºF (150º C).

I fondly remember monitoring those STRS6301 switching regulators in the
older Sony sets and making sure those would stay under 160º F (71º C) but I
really haven't considered using the temperature of a HOT as a
troubleshooting technique until now.

Thanks for your reply.

--
David Farber
David Farber's Service Center
L.A., CA

The NTE is not a good sub in that set.
Follow the service bulletin, required, for the overheating and blowing
HOT problem in that model. Plus there likely will be a bad cap on the
HOT driver circuit.

I no longer have a copy of the service bulletin, but if Daewoo is still
in business they can email it to you.

As I recall, the bulletin made some changes to a couple of parts and
added a 39 ohm resistor across the B-E of the HOT as well.

wrote in message
oups.com...
The NTE is not a good sub in that set.
Follow the service bulletin, required, for the overheating and blowing
HOT problem in that model. Plus there likely will be a bad cap on the
HOT driver circuit.

I no longer have a copy of the service bulletin, but if Daewoo is still
in business they can email it to you.

As I recall, the bulletin made some changes to a couple of parts and
added a 39 ohm resistor across the B-E of the HOT as well.


Daewoo is still in business. Along with my parts order, they sent me an
unsolicited application to be an authorized service center. When I called
and asked if the HOT failure was a common problem, the technician told me
no, and suggested that replacing the parts with the originals would fix it
properly. I'll call them back and definitely ask them about the service
bulletin.

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

Replace 1.0 uf electrolytic capacitor in horizontal drive...there maybe
two in this area. This is what kills the set, if it's shutting down, &
you keep using it.

http://www.globalsemi.com/ Just search this kit. DAE-SPKIT

For a free service manual download:
http://schematicsforfree.mattsoft.net/

then click on: "click here to see the files" "video" "products"
Daewoo
CN200I-chass.zip"

Q805: 2SC3203, Q803: 2SC2500, C418: 1.0 Uf,160V (horizontal driver
section)
R818=0.33 ohm,1W, Q402: 2SD1880 horizontal output, Q804: E130090, R818
0.33 OHM 2 WATT, 100 uf @ 25 volt electrolytic capacitor in thePWM
power
supply, resolder the degaussing thermistor. This fixes these T.V.'s
most times.
Hope this helps you. Dani.

Lest everybody forgets any and all solder bad/cold connections in the
HOT drive circuit will also cause the HOT to heat up and blow. The cold
joints cause noise in the base circuit and this high switching
speed(noise) causes the HOT to over heat. If you take a 50X magnifier
and look at the joints, that are bad, you can see the cracks in the
solder. Learned that from a SONY service flash but my in experience it
applies to any HOT circuit.

Later
KC8OJU
Raymond Borowiak

"Dani" wrote in message
oups.com...
Replace 1.0 uf electrolytic capacitor in horizontal drive...there maybe
two in this area. This is what kills the set, if it's shutting down, &
you keep using it.

http://www.globalsemi.com/ Just search this kit. DAE-SPKIT

For a free service manual download:
http://schematicsforfree.mattsoft.net/

then click on: "click here to see the files" "video" "products"
Daewoo
CN200I-chass.zip"

Q805: 2SC3203, Q803: 2SC2500, C418: 1.0 Uf,160V (horizontal driver
section)
R818=0.33 ohm,1W, Q402: 2SD1880 horizontal output, Q804: E130090, R818
0.33 OHM 2 WATT, 100 uf @ 25 volt electrolytic capacitor in thePWM
power
supply, resolder the degaussing thermistor. This fixes these T.V.'s
most times.
Hope this helps you. Dani.


I also found this list of components to check and/or modify.

Thanks for your reply.

http://hardware.mcse.ms/archive144-2005-7-216959.html

Daewoo tv chassis:CN200A & CN200I repair tips:

White Westinghouse model:WTV-12505
Curtis Mathes model:CM27101S
Portlant model: PT2501
Sams 4086

For a free service manual download:

manual.daewoodigital.com/Service_Manual/DTQ27S3FC_Service_Manual.pdf


C404=1 Uf,160v=replace with 3.3 or 4.7 Uf,250v=Daewoo # CAP3.3MFDA250V

Q402=2SD1880=NTE2353 (you can use 2SD1879)
Sanyo # 410 149 0420
Daewoo # T2SD1880
2SD1881=S2055AF
Samsung # 0502-000209
Sanyo # 405 112 7600
RCA SK # 2SD1880=2SD2539

Q804=NPN SMPS switching driver IC
KSC5021F-R
KSC5021FR
KSC5021
2SC5021
SEC13009-2
Daewoo # KSE5021FR
Daewoo # TKSC5021FR
Daewoo # TKSE130090
Daewoo # KSE13009-H2
Daewoo # KSE13009
Daewoo # KSE 13009Y=NTE # NTE379
Daewoo # KSW13009
E13009-2=NTE # NTE379
Motorola # MJE13009=NTE # NTE379=2SC3890

You can sub with 2SC4834=NTE # NTE2582=SK # 2SC4834=Sony #'s:

SK10000
8-729-019-49
8-729-019-50
8-729-019-51
8-729-039-30

You can also sub with 2SC4164=NTE # NTE379

You can also sub with 2SC3750

You can also sub with NTE2337

http://www.globalsemi.com power supply repair kit part # DAE-SPKIT=$4
CDN

Q805=
KTC3203
KSC3203
KTC3203Y=RCA # 212671
KTC3203O=RCA # 248516
C3203Y
2SC3203
SK # 2SC320
Hitachi # NQSY0KTC3203
2SC2235
2SC3371
NTE # NTE382

Q803=
C2500
2SC2500
TKSC2500B
KSC2500B
KSC2509B
2SC2355
2SC2655
NTE # NTE2363

Q801=TMPA92=NTE # NTE 288
C412=10 Uf,250V
C304= 100 Uf,35V
C411=33 Uf,160V
C418=1 Uf,160V (horizontal driver section)
R818=0.33 ohm,1W
R806=390 K khm,1/2W
R812=100 ohm,1/4 w=Daewoo # RD-4Z101J
C826=2200 Uf,25V

Remove R807=47 ohm,2W and scrape leads & re-install,add a 33 ohm,1/4W
resistor on Q402 between B & E also add 470 Pf,500V cap to Q401 C to E
Horizontal repair kit # DECAKIT011,Global # KTV00198H=$7.50 CDN (Daewoo
service bulletin # 99CTV1):
R526=Trim pot=10 K ohm
D504=1N4148
R420=240 ohm,1 w replace with 1.8 k ohm,1W
C505=2200 pf,50V Mylar replace with 1000 pf,50v Mylar

For black bar change R516=10 K pot

Other tips:
C808=100 Uf,160V
C412=10 Uf,250V
C413=470 Uf,35V
C414=47 Uf,50V
C505=1000 Pf,100V
R420=1.8 K ohm,1W
C410=100 Uf,160V
C401=4.7 Uf,50V
Flyback # FFA93012 or FFA94047L or Daewoo OEM # 50H0000187=HR8783


--
David Farber
David Farber's Service Center
L.A., CA