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Search: Posts Made By: jkb242
Forum: Troubleshooting TVs and Video Sources 12-09-2020, 10:32 AM
Replies: 3
Views: 237
Posted By jkb242
Re: Samsung LED TV UN55J6201FA

Thanks for the advice. I wanted to keep the initial thread brief without going into certain steps I took when investigating the no BL issue. Simply to share what I did next in troubleshooting the...
Forum: Troubleshooting TVs and Video Sources 12-08-2020, 06:47 PM
Replies: 3
Views: 237
Posted By jkb242
Samsung LED TV UN55J6201FA

This set has a BL issue for which all BL strips are on order. I need to isolate the BL issue once new LEDs are installed without the screen being connected to the TCON board. I do not want to...
Forum: Troubleshooting TVs and Video Sources 11-19-2020, 04:34 PM
Replies: 13
Views: 680
Posted By jkb242
Re: samsung un60j620dafxza backlight led smd diode

Just to comment on this subject i full agree replacement of all the strips is the fastest and easiest. For those who are familiar with SMD component soldering and choosing to replace the defective...
Forum: Troubleshooting TVs and Video Sources 11-19-2020, 04:26 PM
Replies: 13
Views: 680
Posted By jkb242
Re: samsung un60j620dafxza backlight led smd diode

I donít believe 3v/6v replacement LEDs for any strips being repaired is an option. It depends on the LED driver potential for the strips. You must replace with the same voltage LEDs. 30v?? 770ma?...
Forum: Troubleshooting TVs and Video Sources 11-19-2020, 04:13 PM
Replies: 10
Views: 883
Posted By jkb242
Re: Which LEDs do you buy?

Iím repairing a Samsung UN55J6201 with 5 strips 14 LEDs each strip. I was using a couple of strips as donors for the good LEDs on each to fix one or two LEDs that were bad on the other strips but am...
Forum: Troubleshooting TVs and Video Sources 06-13-2018, 06:47 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Further testing on power MOSFETs show that all four TK4A60DA drivers measure the same using simple power or switching action using diode mode on DVTM. This includes Q701,706,715, 720.

Q801, 802...
Forum: Troubleshooting TVs and Video Sources 06-09-2018, 07:06 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

What frequency were you expecting from your experience within what typical range.

Thanks
Forum: Troubleshooting TVs and Video Sources 06-05-2018, 06:45 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

The replacement. I have a few missing parts on the original board that I am replacing from my last Digikey order that has not yet arrived bringing it back to its original condition. I also have the...
Forum: Troubleshooting TVs and Video Sources 06-04-2018, 09:24 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Sorry I forgot but I confirmed that if PSON is not connected to the 5vstby rail, the 12vdc will disappear along with the signal measured at T703. The supply of the Toshiba power Mosfets has nearly...
Forum: Troubleshooting TVs and Video Sources 06-04-2018, 08:04 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

There isn't a BL on pin, there is a Lamp pin but I thought that was not for turning on/off the BL but used to monitor the lamp? Is that incorrect?
Forum: Troubleshooting TVs and Video Sources 06-04-2018, 07:52 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Panel model is LC420
Forum: Troubleshooting TVs and Video Sources 06-04-2018, 06:10 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Will chech the removal of BL-On feed and advise rests. Will also confirm the 390vdc is being delivered to the power HV switching stage.

Thanks
Forum: Troubleshooting TVs and Video Sources 06-03-2018, 07:23 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Will check. The drive at T703 scope capture suggest things are normal to this part. You agree?
Forum: Troubleshooting TVs and Video Sources 06-03-2018, 01:44 PM
Replies: 106
Views: 5,576
Posted By jkb242
Forum: Troubleshooting TVs and Video Sources 06-03-2018, 12:20 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

DIM, PSON and Ion/off tied to 5v stby through 470 ohm resistors, measuring R760A 10.5V R799 11.4V both sides, virtually no drop reference to secondary ground.

Probing secondary of T7037A&B pins...
Forum: Troubleshooting TVs and Video Sources 06-03-2018, 05:24 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Sounds good will perform that check today.

Thanks
Forum: Troubleshooting TVs and Video Sources 06-02-2018, 08:54 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

To avoid connecting the board to the AC mains I am applying current regulated 12V to the LV secondary at the drain side of the Q910 MOSFET. There is no voltage at R760A or R799. This maybe because it...
Forum: Troubleshooting TVs and Video Sources 06-02-2018, 05:54 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Thanks and please advise when find the pinouts, I’ll continue the search as well. I’ll report back on the voltages measured as suggested. Also have a little info on ringing of T703A/B probing at the...
Forum: Troubleshooting TVs and Video Sources 05-31-2018, 06:47 AM
Replies: 106
Views: 5,576
Posted By jkb242
Smile Re: Need schematic for Visio LC420

IC701 is a DDA007GN after searching all the sites I locating same the Alia Baba affiliates and links therefrom do not provide a datasheet as insicated so I have been unable to get the pin assignments...
Forum: Troubleshooting TVs and Video Sources 05-30-2018, 05:16 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Tested each lamp with ccfl test inverter, all lamps are good??

Please assist, thanks
Forum: Troubleshooting TVs and Video Sources 05-28-2018, 02:57 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

I removed the panel to expose the lamps and their connection to the two HV leads from the power supply HV transformers. All of the lamps on each end are connected in parallel as measured by DC...
Forum: Troubleshooting TVs and Video Sources 05-27-2018, 12:33 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Just wanted to add another bit of info:

In order to isolate any power supply issues from a lamp issue, when testing with CCFL test lamps, would I not have to use two test lamps, one for each phase...
Forum: Troubleshooting TVs and Video Sources 05-26-2018, 09:48 AM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

Wow, you are really very helpful and I thank you for hanging in there with me.

Really, I do and I know that I am going to learn more about this issue than I already have with your help but I do...
Forum: Troubleshooting TVs and Video Sources 05-25-2018, 04:56 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

I’ll confirm R805 and advise.
Forum: Troubleshooting TVs and Video Sources 05-25-2018, 04:56 PM
Replies: 106
Views: 5,576
Posted By jkb242
Re: Need schematic for Visio LC420

I meant to say that it isn’t likely the inverter circuit would be bab on three different boards one of which was a SJ board which tested good. This analysis help me understand the PWM is on the power...
Showing results 1 to 25 of 134

 
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