Repairing Toshiba 29″ 2927DE CRT Television
This Toshiba 29″ 2927DE 29″ CRT TV was collected from a friend’s house. The complain of this TV was no signal-only the blue raster and no sound even with the TV’s antenna connected. For your information i don’t repair television but i do analyze Television circuit, and read TV troubleshooting magazine and book especially the TV Repair book by Homer L Davidson. Since this TV is belong to my friend so I’m doing a favor for my friend to repair the set.
If a TV set have raster, no picture and no sound chances are high the tuner, IF section or the AGC circuit have problem. Since TV tuner is the easiest to see i started off with the tuner first. As usual in any electronic repair, i would use the handle of my screw driver to knock on the suspected section which is the tuner. Surprisingly i got back the picture and sound the moment i hit the tuner casing. Turning back to see the circuit board, i found a slight dry joint in one of the tuner pins. After resoldering it i thought it would be fine and after hitting the tuner again the same problem arise again. I concluded that it was the tuner internal section that might have dry joints.
I soldered the tuner out again removed both metal covers and began to see with the help of magnifying glass. Ha! got it, found two pins that had very obvious dry joints. After applying fresh solder on all of the internal joints, the bright, nice picture and sound came back again. I just love electronic repair!
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yanyoo
May 22, 2012 at 3:45 am
hi sir justine i had a tv LG wen i replace the flyback the tv ok but after one week it back again the power led is blenking
Jestine Yong
May 27, 2012 at 4:07 am
HI Yanyoo,
Back again? Do you mean the flyback spoil again?
Jestine
yanyoo
June 14, 2012 at 1:49 am
no just her case before blinking her power led but the flyback looking gud
Jestine Yong
June 15, 2012 at 8:48 am
Hi Yanyoo,
Try use the below link to isolate the problem:
http://www.scribd.com/doc/2957819/TT204-Identifying-television-SMPS-problems
Jestine
cedrick
June 26, 2012 at 6:56 am
sir my samsung tv has white lines and grey background all over the screen whats seems to be the problem????/
Jestine Yong
June 26, 2012 at 8:02 am
Hi Cedrick,
Check if the G2 voltage is too high or if the G1 voltage is zero volt. It should not be zero volt.
Jestine
yanyoo
July 19, 2012 at 7:52 am
hello sir i have a amlifier sakura the resistor easily burn 220 ohms have power but no sound wat should be the cause?thxz
Jestine Yong
July 19, 2012 at 8:36 am
Hi Yanyoo,
Check along the burnt resistor line to see if there is any other component bad. Resistor rarely burn by itself unless if there is something shorted.
Jestine
yanyoo
July 19, 2012 at 8:11 pm
thank you sir
yanyoo
July 25, 2012 at 2:16 am
hi sir i had a jvc component dvd 5 disc theunit is on but sumthing went wrong the system going crazy the botton ol not function
Jestine Yong
July 25, 2012 at 6:46 am
Hi Yanyoo,
Have you check if all the output voltages from the power supply are good and stable?
Jestine
yanyoo
July 27, 2012 at 7:46 am
sir halow im olwz read ur blog im electronics student how can i get a book from u?
Jestine Yong
July 27, 2012 at 10:10 pm
Hi Yanyoo,
I have sent an email to you. Please check your inbox.
Thanks.
Jestine
yanyoo
July 27, 2012 at 7:55 am
helow sir i had lcd monitor the dsplay had distrupting color up and down horizontaly i cant see the dsplay properly
Jestine Yong
July 27, 2012 at 10:08 pm
Hi Yanyoo,
Is all the output voltages from the power supply good?
Jestine
yanyoo
July 28, 2012 at 12:15 am
the lcd monitor was wet after typhoon sendong her n philpns it cud b the cause?
Jestine Yong
July 28, 2012 at 8:36 pm
Hi Yanyoo,
Yes this could be the cause. Make sure inside is dry up using hair dryer and start checking on the components.
Jestine
yanyoo
August 26, 2012 at 12:06 am
hi sir justin i had a sakura amplifier av-5023 have power but no sound only the sorround speakr having sound,the fuse after the positive terminal of filter capacitor blown....the audio ic is good pls help me to solve this problem....more power..
Jestine Yong
August 27, 2012 at 10:38 pm
Hi Yanyoo,
If the fuse blown that you need to check on the component especially semiconductor for short circuit.
Jestine
yanyoo
August 26, 2012 at 12:53 am
sir justin the two capacitor stalled in board positive-negative-positive-negative is this correct
Jestine Yong
August 27, 2012 at 10:40 pm
Hi Yanyoo,
if the primary section is using the two main filter caps then yes it is correct.
Jestine
Jhee baraquiel
July 13, 2017 at 12:26 pm
Hi sir..i have toshiba crt but she burn of fuse..what the problem of this?my h.out & regulator its ok
Jestine Yong
July 14, 2017 at 10:06 am
Hi Jhee,
May I know what have you checked? Usually burnt fuse is due to shorted semiconductor such as shorted bridge rectifier.
Jestine
Liz
September 20, 2012 at 7:11 am
Hi Jestline
I am looking for someone to help me repair an old CRT tv (I guess more than 10 years easily). While watching tv, the screen was blackout but we can still hear the audio. Few seconds later, we heard a small explosion inside the TV, audio gone and burnt smell everywhere. Do you possibly know what is wrong and whether this can be repaired?
Thank you.
Jestine Yong
September 20, 2012 at 8:05 pm
Hi LIZ,
It could be flyback transformer problem or the main filter cap already exploded. I suggest that you send to any nearby electronics repair shop for them to check it out.
Jestine
Liz
September 20, 2012 at 11:03 pm
Thanks for your reply. If it is really the problems you mentioned, is it repairable?
Jestine Yong
September 21, 2012 at 12:12 am
Hi Liz,
It is repairable if there is no components burnt beyond recognition. This means the repairer have to open and check it first.
Jestine
Liz
September 24, 2012 at 2:39 am
Okay, I will send it to a shop then. Thank you, Jestine
nasrul
November 26, 2012 at 11:03 pm
hi bos...
my crt (panasonis 29") problem like the picture is moving (shrinkage and expand all time) than yesterday cannot on... blinking led (red to green to red........) what the problem?
thanks...
Jestine Yong
November 27, 2012 at 6:32 am
Hi Nasrul,
Is the output voltages from the power supply good and stable?
Jestine
nasrul
November 29, 2012 at 9:17 pm
hi...
tv can on now (just luck after i try to trobleshoot it) but the picture remain moving.. is it about power?
thanks
Jestine Yong
December 3, 2012 at 11:21 pm
Hi nasrul,
If the power supply output voltages are good and the display still moving then you may need to check on the jungle chip area. Moving can be cause by vertical/horizontal section.
Jestine
Eric Lam
December 23, 2012 at 10:10 am
Hi,
My Toshiba Bomba 20" TV couldn't turn on and only can see a red dot LED when power on, where was gone wrong?
Thank you.
Regards,
Eric Lam
Jestine Yong
December 25, 2012 at 6:47 am
HI Eric,
It could be the fault of TV CPU or eeprom ic. Make sure the both IC are getting the right supply voltage.
Jestine
yanyoo
January 3, 2013 at 10:10 pm
hi! sir justin, its me again, i had a CRT tv ahm! standby mode only but the B+ supply is ok. could you help this problem... thank you sir and god bless!!!
Jestine Yong
January 4, 2013 at 8:53 pm
Hi Yanyoo,
Standby in crt could be caused by bad tv cpu, eeprom data corrupted and improper supply voltage
Jestine
yanyoo
January 11, 2013 at 7:25 pm
HOW CAN I REPAIR THIS PROBLEM SIR
Jestine Yong
January 12, 2013 at 12:37 am
Hi Yanyoo,
You just have to test the supply voltage and if it is good then replace the cpu or the eeprom ic.
Jestine
yanyoo
October 29, 2013 at 12:18 pm
hi sir i had a tv sharp 21 inchs the picture so blurd even i adjust the focus and screen of flyback nothing happens,its still blurrd what should i do?
Jestine Yong
October 29, 2013 at 12:51 pm
HI Yanyoo,
If it still blur then the picture tube could have problem. Sometimes the flyaback itself also have problem because it can't produce the 5 to 10kvdc that is required by the tube.
Jestine
yanyoo
October 31, 2013 at 7:26 am
thnk you sir
yanyoo
December 13, 2013 at 10:19 am
hello sir jestine i had a crt tv wen i turn on the tv only red light appear standby mode only,,,, the b+ supply ok but the G2 Into the crt board have no supply voltage,,it could be the flyback defect sir?
Jestine Yong
December 14, 2013 at 5:59 pm
Hi Yanyoo,
Standby means either:
1) CPU IC got 5 volt but cannot send out the "On" signal due to the ic itself have problem or the EEPROM IC have corrupted
2) CPU IC could send out "On" signal but it can reach the main power supply section due to bad components in the optoisolator ic and surrounding components problem
3) On signal can reach the main power supply but main power supply it self have bad components like shorted secondary diodes, bad power ic and etc.
Jestine
yanyoo
December 28, 2013 at 11:31 pm
hello sir id lost the component of my tv along wth the tuner small round metal plate with 3 legs,,i cant fix my tv no signal...KONKA 19 INCH..
Jestine Yong
December 30, 2013 at 11:01 am
HI Yanyoo,
You need the find the right schematic because I do not have the info for this.
Jetsine
yanyoo
February 2, 2014 at 9:43 am
hi sir the resistor 10w2RK has open could i use a jumper wire as a relplacement of this component.....
Jestine Yong
February 3, 2014 at 11:24 am
HI Yanyoo,
No, you have to use back the same value.
Jestine
yanyoo
February 2, 2014 at 9:45 am
hello sir i had a tv cant reach any channel the supply to the tuner is stable ive replace a tuner but nothing happen sir..what im gonna suppose to do
Jestine Yong
February 3, 2014 at 11:30 am
HI Yanyoo,
If other input could work like running on a dvd player then you may need to get the schematic to troubleshoot the fault since you have mentioned that you have checked the supply voltage and replaced the tuner.
Jestine
yanyoo
February 22, 2014 at 7:54 pm
sir can i have a favor pls help me to become your student to met you in personal
Jestine Yong
February 22, 2014 at 9:22 pm
I suggest that you get Humphrey's ebook from the link below as he could guide you to become good in CRT TV Repair. We need to invest in order to make our life better:
http://www.electronicrepairguide.com/crt-tv-repair-ebook.html
Jestine
Terrence
April 28, 2014 at 6:57 am
Hi Jestine,
I got a samsung crt tv which has got 320v dc present on the main boosting cap, this voltage also present on the ic collector pin. But there is no voltage on other pins. totally zero.
I check the 2.2 ohm K bleeder resistor but got 0.7 ohm. What you suggest bro.
TL
Jestine Yong
April 28, 2014 at 11:52 am
Hi terrence,
I suggest that you check all the components in the primary side. If all checked to be good then direct replace the power ic and retest. Make sure no shorted diodes in the secondary side.
Jestine
yanyoo
June 11, 2014 at 4:44 am
hello sir i had a sharp tv when i turn on the tv, the b+ shutdown rapidly
Jestine Yong
June 13, 2014 at 12:02 pm
Hi Yanyoo,
What is the B+ supply voltage? How high it goes before shutdown? What about other output dc voltages from the power supply are they high too?
Jestine
yanyoo
June 11, 2014 at 4:47 am
sir i had also a tv unit no display, audio only but after 10 seconds the unit off itself
Jestine Yong
June 13, 2014 at 12:01 pm
Have you checked if the power supply output voltages good or not? What about the B+ supply voltage to the flyback?
Jestine
yanyoo
June 15, 2014 at 10:50 pm
the b+ supply is 125v no its stable before shutdown,
Jestine Yong
June 16, 2014 at 10:34 am
Hi Yanyoo,
125 volts seems to be too high. What are the other output voltages from the power supply?
Jestine
yanyoo
August 19, 2014 at 4:52 pm
sir i had a tv sharp model 21V-FK200M the unit will auto shutdown i olredy resolder all the dry joints isnt the flyback?or the system?
Jestine Yong
August 20, 2014 at 8:08 pm
it can be the flyback or the system or even high voltage circuit. Make sure the B+ voltage is within range.
Jestine
dondu
December 25, 2014 at 8:34 am
hi sir,
i have crt tv with la76931k ic , it has best picture but bad sound even i adjust 4.5 sound system & and forwards fine tune then picture goes b/w ( not clearly) but sound good. please sir help , what should i do?
admin
December 27, 2014 at 9:34 am
HI Dondu,
I have not came across such problem. Have you replaced the IC and retest?
Jestine
leonard williams
April 13, 2015 at 4:42 am
hello sir i have a hcd 10000 sony power on for a wile then turn off what could be the problem
Jestine Yong
April 13, 2015 at 3:42 pm
Hi Leonard,
It can be dry joints, bad e-caps and other components, bad memory ics and etc.
Jestine
john khayanje,kenya
March 20, 2018 at 3:32 pm
hello mr.Jestine?I luck words to express how greatful i am for your work.me reading your posts m crt repair has really helped me.to the point i have opened asmall repair shop.thank you sir.i also need help.am working on toshiba model 198x7m japan made crt which has no picture but turn on perfect.I found D1427 ic just beside the fly back short,one diode which i replace and replaced the ic with D1555 which got to hot when switched on i tested it again and the war continuity on the two outer pins kindly help.am thinking of trying 2499 ic help
Jestine Yong
March 21, 2018 at 10:20 am
Hi John,
You are welcome. Just to check are you referring to the horizontal output transistor instead of IC?
Jestine
fernando
December 8, 2018 at 5:56 am
tengo una tv a colores toshiba modelo 29BS90 todo esta en chino no puedo programarlo bien porfavor si tendras el manuel o donde lo descargo o videos de instrucciones otro problesa es que no capta todos los canales abiertos solo capta 3 si podrias ayudarme gracias
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I have a Toshiba color TV model 29BS90 everything is in Chinese I can not program it well if you have the manuel or where I download it or other instructions videos is that it does not capture all the open channels only get 3 if you could help me thanks
Jestine Yong
December 10, 2018 at 11:45 am
Hi Fernando,
Sorry I do not have the manual but you can try search from www.eserviceinfo.com
Jestine
Kennedy Kaonga
September 4, 2022 at 9:25 am
Hi Justine,
My 29 inch Flat Toshiba CRT color Tv has developed vertical stripes that are prominent on the left side and gradually fade towards the right side of the screen.
I'm not a TV repair technician, but I have vested interests in TV repair works and given a chance, I would take up the challenge of learning the trade.
What could be the problem with my TV? Your response will be highly appreciated in this regard.