jesterace
Senior Member
Last Activity: 04-28-2025, 03:52 PM
Joined: 08-01-2013
Location: Lincolnshire
-
I'm not an expert but I have a brain and like to learn. You telling me about fail count tells me that the TV is monitoring if the LED's were able to be illuminated within expected current ranges and if it detects a fault then increments a counter, and when the counter is exceeded the output is turned off? If thats the case then all that i'm trying to say is that wouldn't it be sensible to expect to see some voltage on the led output while it is checking the LED's and incrementing the fail count? or am I to expect that (on this model) I would not see any voltage until good LED's are connected?... -
Thanks, I know you've told me that its bad led's and I value you're advice. I'm not trying to upset anyone who has more knowledge than me. I'm only trying to clarify some things because usually when i've probed the output in the past on other TV's there is usually voltage output on the LED connector whether there are LED's connected or not. Even if it's just a brief spike. On this TV I see nothing even when the LED's are disconnected. Maybe that's normal for this TV but this is why i'm asking these questions.
Take for example this video.
[url]https://www.youtube.com/watch?v=uIrlbsbiltY[/url]...Leave a comment:
-
Ok thanks, I did find a PSU for about 8 quid so i grabbed one anyway that should be here next week to experiment. It just seemed odd that there is no voltage at all on the led output even when they are not connected. So i gather that is normal for this kind of set?Leave a comment:
-
Samsung UE49MU6400 acts dead until disconnecting backlights, then works.
Hi everyone I have this TV which was dead one day when I tried to turn it on. I've had the cover off and there was just a pulsating/electrical clicking/ticking noise from the PSU. I disconnected the mainboard as sometimes this works to just fire it up with backlights on? That didn't help. Same noise. Then I disconnected the backlight cable from the PSU and the TV came alive. It appeared to respond to the remote and i'm pretty sure it's fully operational when there is no backlight connected.
However, I am in a dilemma.
I tested the backlight outputs with the lights disconnected... -
Good news i put the board in the TV and screen lights up I am just going to see if it all works!
Tv is currently fully working at the moment. After doing some reading online it seems that devices with active pfc can sometimes cause high current draw using the light bulb idea (so it always lights brightly in my case), but it was certainly helpful in protecting everything. So for anyone new like me, be aware that the light bulb may not always mean there's a short remaining that you've missed - at least in my case.
I did try higher wattage bulbs but it always lit brightly....Leave a comment:
-
Some more updates. When i went to replace the DS809 diode i found that actually it wasnt shorted after I removed it. There seems to be a 0ohm resistor in parallel so that must be ok but I replaced it anyway. I replaced the ICS801S and the 1KV cap. Now when I turn on with lamp, for the first time I hear the relay click! The lamp flicker a bit and then stays on. The output of 5V standby and 5V is present on multimeter and stable. Is it possible that the light bulb is staying bright but nothing is actually wrong now?
I have also put thermal camera over the board while its on and there...Leave a comment:
-
Ok i will hopefully have the diodes/cap/IC this week and will install all of them together.
I'm using a 60w light bulb at the moment. If everything is ok when they are installed, should I be able to measure output voltages on the board with the light bulb still in series?Leave a comment:
-
Thanks for the heads up. I have found DS809 to be short on underside. The Zeners on the back under the ICS801S are not short at the moment. Drain to Source on the ICS801S not short but I have ordered replacement IC.
I have also ordered replacement CS809. CS809 is very high voltage, is this for some kind of surge/transient suppression?...Leave a comment:
-
I powered up the board with light bulb today after replacing those 3 diodes. Bulb lit fairly brightly and then i slowly saw smoke, turning the board off and scanning it quickly with a thermal camera found that CS809 was burning hot. Nothing else on the board was warm at all. In diode mode in circuit it measured about 400 one way and 600 the other. I am going to take it out to see if its bad. Is it safe to power on the board without this cap to see what happens next? I will check the IC while im at it.
its a 22pf 1KV cap between source and ground on the pwm IC ICS801S.Leave a comment:
-
I've found that DS814 and DS815 are also shorted, thankfully i have a pack of diodes on the way and they are the same model as DS806 so can replace them all. It seems like the standby power has two feeds, one that comes from rectification of the bridge rectifier and DP804 and another that is rectified by DS814/DS815 but i'm not quite clever enough to understand why it has two paths right now. Unless its because the main bridge only gets activated when the relay closes. I'm learning.Leave a comment:
-
They seem to be ok. DP804 measures open one way and about 430 in diode mode the other way. Both Mosfets have no shorts between any pins, and i can measure the built in diode between source/drain on both of them. I've ordered a replacement for DS806 to then try the light bulb....Leave a comment:
-
More info. Varistor tested out of circuit and completely open. Diode DS806 found to be short circuit (and confirmed still short out of circuit). I think the diode might be in line going to transformer to generate 5V STB.Leave a comment:
-
varistor reads approx 600k ohms so i assume that is ok. i will try light bulb tomorrow and report back.Leave a comment:
-
Leave a comment:
-
Samsung UE46ES8000 Blown fuse but no other signs of short
Hi I wonder if anyone might be able to steer me in the right direction. I have this Samsung UE46ES8000 TV and it went bang during use. The main fuse on the PSU board is open. I've checked every diode/mosfet/transistor I can see and nothing appears to be short to cause the fuse to go. The DC output of the bridge rectifier is not short either. I've seen online that some of these models are known for having their PFC mosfet or other mosfets shorting and blowing the fuse but i'm not seeing that here. If anyone aware of these models having any issues to cause this? I'm reluctant to just replace the... -
Re: Samsung B2030HD IR Remote Receiver Dead, shorted micom?
Ok that's fine, I am aware that the micom logic/software and the system fw are completely separate and I appreciate the explanation your giving to us all but how does this help? Yes i did update the FW right at the beginning because it's quite a normal thing to try when you get a fault and there are no obvious hardware issues found (for me anyway). It may have not been the most clever or logical thing for me to do first bearing in mind that bad IR points more to the micom, but how many times have we had a device that didn't...Leave a comment:
-
Re: Samsung B2030HD IR Remote Receiver Dead, shorted micom?
I love it when someone knowledgeable comes along just to observe and laugh. Fear not, I wouldn't lower myself to ask you for any help in case I get more Diah-rhea back.
For the record, I didn't need to do a micom dump earlier than I have done because I had another board on hand that had a working micom to transplant over, albeit from a version of this TV that has a slightly bigger panel - and I'm not as clever as Diah-rhea in knowing if the micom from a bigger TV (but same mainboard) would have...Last edited by jesterace; 11-14-2022, 02:25 AM.Leave a comment:
-
Re: Samsung B2030HD IR Remote Receiver Dead, shorted micom?
more updates, the plot thickens!
I decided to grab the original old (supposedly bad) micom ic and put it onto the other mainboard I have (that i bought from a tv that was dead but was 2 inches different size). Before i fired it up i did a hex compare of the IC with the downloaded DUMP off the internet...they match! so this can't be a micom corruption fault after all. My micom must be fine.
I put the cannibal mainboard in my tv with original micom from my tv and the remote worked straight away....Leave a comment:
-
Re: Samsung B2030HD IR Remote Receiver Dead, shorted micom?
I came to try and get a dump of the micom this morning with rt809h but the tv would not respond to remote at all. Only the front panel again. Oh no!
I managed to get a dump anyway, then checked the PSU and all caps test good with ESR meter and no bloating.
I tried flashing the dump back just to test the writing but after that the TV DEAD. So, I took out mainboard and powered it from 5v bench supply (incase the TV standby isn't stable) and flash again but with a correct dump i found online (finally!)....Last edited by jesterace; 11-13-2022, 05:17 AM.Leave a comment:
-
Re: Samsung B2030HD IR Remote Receiver Dead, shorted micom?
UPDATE: I managed to locate a dead TV with similar board, same model number of main board but size of tv 2 inches different. Swapping the whole main didn't work as it gave me a black image, I guess because of the size difference. So...I swapped over the MICOM ic to mine and the TV started to respond to the remote again! However, when the TV cools down it stops. responding (like when the TV has been off for a while). Only way I can get the TV to respond from a cold turn on is to leave it on for 5mins or so and then try the...Leave a comment:
No activity results to display
Leave a comment: