CUSTOMER SENT ME A POWER SUPPLY BOARD TO TEST 

Clever use of the incandescent bulbs for a load. I might have come up with the same option.

Im glad you are back...you are by far the best tv repair man on RU-vid...i have learned alot from you....considering that i am almost 50 years old ...keep them videos coming...you are the champ :)

I can tell you without all of that testing what's wrong with that TV: ITS A HISENSE! 🤦‍♂️😂

i have a clicker press with an end of life pcb..I got it fixed for about $80US.They changed a cap and a relay.I was very relieved they got it fixed .Its really a very old Italian made machine Atom G999..You Electronic guys are the greatest..sorry for my english im not a native speaker.Have an awesome day!

Great work as usual. I had the cap problem in that power supply, took me three days of back and fourth on the chassis, I saw your video and bingo, it was fixed. Of course, that was a few years ago .

Good video as usual. I'll be leaving it on for a while and looking for dry joints before sending it back though. Mounting in the chassis might also cause the issues that the customer has mentioned. I like your smoke machine with the bulbs and pad! Last supply I got in was from a Sami 46A650 (old but nice image) where the owner tried to fix the fuses that kept blowing by wrapping a dead one in aluminium foil. There was a short in the power fets, you wouldn't believe the damage that board suffered when he turned it back on.

I have never needed to deal with a base load for the standby. However, it has been a common issue that the MAIN output ( 5 V because it provides the feedback ) has needed a minimum load. That has been listed in the data sheet. But generally that covers all worst case situations regarding line voltages and ambient temperatures. The data sheet specified value has been more than the necessary minimum load. Our experience has been that 50 to 60% of the specified minimum load has always worked. But definitely only occasionally does some power supply start without at least some load on the main output.

Hey Norcal great video, its been a while since I seen a new video. Miss your very informative and professional skill trade videos.

Mate! A Variac does NOT isolate you!!! Only an isolation transformer isolates you and ONLY if it is explicitly made for the purpose. A Variac is connected to Active and Neutral, all that is happening is that you have a variable voltage out from the Variac. You are NOT isolated from the mains. Also, that alligator clip connection on to the mains pins is NOT secure. I fixed switch modes and you are NOT doing it the save way. Also, that switch mode is old. First thing to do is check all capacitors with power off. Switch modes can BLOW UP if you are not careful.

All switchers need a minimum load to operate. Sometimes an active load is built on the supply to ensure startup. Obviously that is not the case here. However, you can probably get away with a small load on one of the rails because it looks like they are all generated by the same switcher. What I'm saying is that you probably could have put two lamps in series on the 24V rail and the entire supply would have come up. Just a suggestion, not in any way a criticism. Good video, thanks.

I am in NorCal/Shingletown near Redding...My son has 1000W switching supply sodium lamp driver that delivers between 300 and 400V to the lamp for variable output. the unit runs on 220VAC supply but it was wired incorrectly, where ground got 1 of the 110V lines, and 1 of the line inputs got ground with the other getting 110V line as it's supposed to. the unit no longer works. As expected the case (ground) has only 2 references to the circuit board. Each of the 2 only go from the ground plane/case through flat capacitors to each Line connection after induction coils but before bridge rectification, I know this to be for surge protection. This should not have caused a failure. . I was thinking that maybe driving the 220V lines with 110V (ground is referenced to neutral back at the electrical panel) may have cause the mosfet switcher to lock "on" instead of oscillating which would send solid current through the mosfet via one of the primary windings of the main transformer and burning it. I call it the "exciter" winding because the other primary winding gets constant filtered DC from the line input via a bridge rectifier. (actually they parallel two of them and heatsink.) What else could be wrong? P.S. they poured a black goop all over the board and components that melts at about 200F, how nice of them :-) If you have any ideas, you can PM me because I don't get notifications to replies.

thank you sir

Just a safety issue. If all you're using is a plain variac, then you're NOT isolated. Variacs are autotransformers, there is only one winding. If any part of it connected to mains, the output is too. Not trying to get on anyone's case about it, just don't want folks to think a variac protects them. An actual isolation transformer is needed.

Thanks! I saw some smoke there at the end...

Helpful, fixing my TV now.

NorCal715, You might wish to save some time and effort by recapping the supply. It's a cheap fix and prevents problems later.

Sometime the 4.7volt need to be exactly 5.0 are something you may have intimated starting on the TV

Thank you..

OMG your back with new videos!!!

I was going to get a HiSense , low cost , but CHEAPED-OUT ON ELECTRONICS ? I mean It isn't going to have Nichicon caps in it.🤣

It's my understanding that a variac does not provide isolation. Do you have some special power input arrangement?

Smoke at the end of the video.

Is it true that if display panel is bad it’s useless to repair as cost of available is as much as a replacement tv

I had the same power supply and the 2 caps on the top corner 10uf 25v was dead

so smart

How did you have the power supply connected to get past the in-rush current needed by the bulbs?

hello sir what soldering iron do you use and what temperature thank you

I love ur watch.. 😁😁😁

i see failed cap with out needs measure?how did did video maker miss it??

No ESR cap testing or ripple test with a oscilloscope when under load?

great video. The resistor from STBY to PSON ...is that to limit current?

Yes i remember u had 2 tvs with the same problem in your shop

replace parts from www.boardss.com

You say a variac provides mains isolation. Well they don't. What on earth, no pun intended, are you telling us it does for? You sound to be a dangerous person.

Z

Great Video. Lets Fight against obsulation and the crap the big Players produce so that you wont have to buy a new Set because of parts for 50cents. More of these repair Stuff.