Comments on: Electronic Repair Questions/Answers and Testimonials – Part 26

By: Jestine Yong

Jestine Yong — Thu, 27 Dec 2012 19:58:38 +0000

In reply to Biswarup.

Hi Biswarup,

Have not seen such problem before. It could be the charging section or any surrounding components problem. You just need to open the Laptop and begin to check on each of the input/output pins of charger ic and see if there is any abnormal signal within this area.

Jestine

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By: Biswarup

Biswarup — Wed, 26 Dec 2012 04:37:42 +0000

Hi Jestine,
Merry Christmas to you and your family. I hope you are enjoying christmas evening.
I have got a funny problem with a Lenovo G530 Laptop. Details are as below :
1. Power on from battery power only, no problems occured.
2. Plug in power adaptor to the laptop while laptop is on / off without any AC supply, no problems occured.
3. If the laptop once receive the power supply through the adaptor, it shows charging, which is also quiet normal.
4. Now, Switch off the AC line, the charging indicator on laptop, power indicator on adaptor is glowing continiously. At this time the charging indicator on the taskbar shows that the laptop is plugged in, but it is discharging.
5. Now, I have disconnect the DC power jack from the laptop, same behaviour occurs as above (4), except the indicator on the charger, which goes off as usual.
At this time i have connected a multimeter to the laptop DC power jack, and receive 14.6 return voltage !!!
After shutting down the laptop, the charging indicator lits continuously, and needs to disengage the battery to stop all abnormal activity.
Do you have any idea about which area / component of charging section on motherboard or any other section creates this kind of funny problem.
Waiting for your reply.
Thanking you in advance.
Biswarup

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By: Jestine Yong

Jestine Yong — Sat, 12 May 2012 14:20:44 +0000

In reply to jeff.

Hi Jeff,

Try SG6841. The best is to use original. You can try order online at logictoyz.com or utsource.net

Jestine

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By: jeff

jeff — Fri, 11 May 2012 20:03:52 +0000

hi jestine
i need substitute for sg5841 any suggestion? can u email me dinodinero18@yahoo.com thanx

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By: admin

admin — Mon, 24 Oct 2011 04:30:03 +0000

HI Chandrashekar,

Try this link to isolate the problem:

http://www.scribd.com/doc/2957819/TT204-Identifying-television-SMPS-problems

Sony set usually use blinking LED to indicate where the problem section is. I suggest that you look for the service manual to locate the exact faulty section.

Jestine

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By: chandrashekar

chandrashekar — Mon, 24 Oct 2011 00:25:55 +0000

Sir,

In sony klv 32t 400a lcd tv, 8 times Tick sound coming and Red lED lighting up but NO disply,No sound pls. help me
thanks

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By: admin

admin — Tue, 11 Oct 2011 22:02:25 +0000

Hi Pravin,

From my databook, the equivalent number for c4834 is BU306F, BUT12 AF, 2sc4130 and 2SC4161.

Jestine

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By: Pravin Jariwala

Pravin Jariwala — Tue, 11 Oct 2011 21:39:47 +0000

Dear Sir,

What is the solution for two transistors 2SC4834 for Sony KV S29MN1 in SMPS? Any equivalent that is available in INDIA ?

--With Regards
Pravin Jariwala

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By: admin

admin — Wed, 21 Apr 2010 01:01:59 +0000

HI Rm,

If you could see the sinewave then generally the crystal and surrounding components are good. If you have the frequency meter which is much better because you can test the exact value in Megahertz. Yes, it is good to get more meters and this can cut short your troubleshooting time.

Have a good day!

Jestine

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By: RM

RM — Tue, 20 Apr 2010 12:52:32 +0000

Thanks for the quick reply. I have observed this "sine wave" before. It was simple. I hooked both of leads of the scope to the crystal, then hit "auto adjust". Then I saw a sine wave. I didn't have to know anything else about the operation of the scope. Does simply seeing this sine wave mean that the crystal is good? Could a faulty crystal still show a sine wave? I plan to do a lot of additional reading on oscilloscopes and waveforms. I'm currently devoting most of my time to identifying and replacing bad SMD components. I ordered a new wave of meters to add to my arsenal. I just ordered the Blue ESR meter. I already have the Leakseeker 82b, but it's going to continue to collect dust until I have time to sit down and tinker with it. I also ordered a new meter - the Fluke 117. I also ordered a kill-a-watt. I'm hoping to use that to, at least grossly, observe the current draw of a circuit (I work on laptop motherboards).

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