Testing a TV Power Supply

[matlob]

Hi
I have a Sony TV with the below power supply block (sony version though). Is there a way I can test if the block is powering the tv with a multimeter easily?

I want to know if I can just buy a new supply or if the tv is toast

Thanks in advance for any help

 

[Wayners]

Start with LAP Non-Contact Voltage Detector Pen 1000V AC - Screwfix https://share.google/YgvYxERRwcSYlltkF

Only proves it's not dead. If it shows power then you need a multimeter.

Some would say just buy a multimeter but a wand is very useful and safer

 

[Jurassicspark]

Black probe on the metal casing of the DC jack.

Red probe inside the dc jack.

If the meter reads 19.5v DC approx (based on the picture although do check the output voltage on the power supply to be certain) then the adapter is good.

If it fluctuates badly or doesn’t give any power then it’s faulty. Check fuse in the plug. If it’s blown chances are you still would need a new power supply but you can check with a same rated fuse.

 

[matlob]

Thanks all

Managed to test and it showed 0 v

Swapped the fuse and it then read 15v (power pack as 19.5v printed on it)

Plugged the tv in and it wouldn't work and then the probes read 0.5v on the pack and it seems to fuse has blown again

Would this be the tv causing the issue or the power brick do you think.

 

[Jurassicspark]

Thanks all

Managed to test and it showed 0 v

Swapped the fuse and it then read 15v (power pack as 19.5v printed on it)

Plugged the tv in and it wouldn't work and then the probes read 0.5v on the pack and it seems to fuse has blown again

Would this be the tv causing the issue or the power brick do you think.

If you’re implying that the power supply did output voltage after changing the fuse, and after plugging it in, the fuse has blown again then that suggests the TV is at fault and something is drawing too much current.

Just asking, what is the output voltage stated on the power brick? 15V or 19.5V?

 

[matlob]

Thanks 19.5 printed on the brick

It was hard to get a good reading with the probes but was definitely reading 15v with the new fuse before I plugged in the tv.

Noting went bang it just wouldn't work and fuse went

 

[flameport]

I have a Sony TV with the below power supply block (sony version though).

Which model of Sony TV, and what exact power supply as the image is some generic affair intended for laptops.

Plugged the tv in and it wouldn't work and then the probes read 0.5v on the pack and it seems to fuse has blown again

If the mains side fuse to the power supply is blowing, then the power supply has a severe defect.
All of these supplies, even the cheapo no-name types have output current limiting where the output will switch off if shorted or too much current is drawn. They generally auto reset once the fault is removed, or some might need to have the power removed and then reconnected.

 

[matlob]

Thanks

This is the actual supply. The one in the original post was the replacement I was going to buy/ to show what I needed to test

The fuse is blowing in the plug to this

Tv is a Sony Bravia 55 from about 2015. No great loss if it's dead but wanted to try and get it going for a spare room. It's been in a box for 5 or 6 years but worked when it went in

 

[Harry Bloomfield]

Which model of Sony TV, and what exact power supply as the image is some generic affair intended for laptops.

He did say it was the Sony PSU, I assumed it was a generic photo he posted?

If it is blowing the plug fuse, then for certain the PSU is faulty, and needs to be replaced. The TV itself, might also be faulty, but the only way to be sure, is by testing it, with a working PSU.

 

[Harry Bloomfield]

The one in the original post was the replacement I was going to buy/ to show what I needed to test

The potential replacement is a slightly lower current rating, 4.7 v 5.2amps, but it also suggests the output is protected by a 3.15amp fuse, suggesting it might, or might not work.

 

[matlob]

Thanks Harry

Yep a generic pack image first as I originally just wanted to know how to test it

I think I'll just buy a new supply and hope it's that rather than a fault with the tv. As the fuse blew only when the tv was powered up I assume it may be the tv as jurassic mentioned but worth a try

The fuse in the plug was 3A if that makes any difference

I've found one that I can select the model number on as below so hopefully compatible and worth a punt for a tenner

Thanks again all!

Power Supply AC Adapter Cable Lead for Sony Bravia LED LCD TV | eBay UK

Specifications: Output Voltage: 19.5V Output Amperage: 3.05A / 3.08A / 3.3A / 4.35A / 4.36A / 4.74A Every Sony Bravia TV model takes a different size power adapter so the appropriate one will be dispatched according to your selection from the drop down menu. Please do no hesitate to contact us...

ebay.us

 

[Harry Bloomfield]

I think I'll just buy a new supply and hope it's that rather than a fault with the tv. As the fuse blew only when the tv was powered up I assume it may be the tv as jurassic mentioned but worth a try

As said, the fuse in the plug, should never blow, unless the PSU is faulty - in normal working order, the PSU is designed to protect itself without blowing fuses.

The fuse in the plug was 3A if that makes any difference

The 3.15amp fuse, is an internal fuse, on the DC output - a sort of last resort, if all else fails. The current output, will be much higher, than the current input, because the voltage is only a fraction of the mains voltage. amps x volts = watts.

 

[matlob]

Thanks Harry

Will try the new pack and see what happens

 

[Scally-Ho]

Thanks

This is the actual supply. The one in the original post was the replacement I was going to buy/ to show what I needed to test

The fuse is blowing in the plug to this

Tv is a Sony Bravia 55 from about 2015. No great loss if it's dead but wanted to try and get it going for a spare room. It's been in a box for 5 or 6 years but worked when it went in

Six or so yrs without power could have knackered some electrolytics and that might be the set's problem. Capacitors do tend to 'dry-out' if left without power after working for a number of years.

 

[matlob]

Thanks, would that be within the tv or powerpack?