Curious if reducing a couple of caps could down-rate a power board to US-voltage only

[ja1870]

This total noob is re-posting here (from General Capacitor Questions & Issues), as it was noted that it's a kind of power board design question (although probably trivially obvious to those here).

Could a manufacturer actually "down-rate" a power board to US-voltage input only (and reduce cost?), simply by reducing the voltage rating of a couple of caps?

Detail: I was checking out power boards for a 40in Samsung LED TV (UN40H5003AFXZA ver IF02) model which sold in the US a couple of years back. Looks like the current preferred replacement part number is BN44-00769C.

In photos of the part, saw printed on the board "110V Only" - and wondered if they stopped making universal power supplies, or did Samsung print it to discourage people from moving electronics around.

Then I noticed pics of a different listed-as-compatible board, BN44-00769A, show no 110V warning, and the two biggest caps appear doubled in physical size (420V/100uF). I couldn't read the voltage rating of those same-position (smaller) caps in any of the 110V "C" board pics I've located so far, but presume they may be, say, 200V or 250V.

So could Samsung actually "down-rate" the board to US-voltage only, simply by reducing these two caps? (Keeping everything else the same - as it looks.)

Thanks.

See the capacitors in question upper right, and "110V-Only" lower left

110V "C" board

Universal? "A" board
https://www.badcaps.net/forum/showpo...21&postcount=3

Image source: http://www.shopjimmy.com/samsung-bn4...-led-board.htm

[stj]

Re: Curious if reducing a couple of caps could down-rate a power board to US-voltage

yes, they could.
i'v seen it done years ago with crt monitors.

[ja1870]

Re: Curious if reducing a couple of caps could down-rate a power board to US-voltage

Thanks for the information. I learn a lot at badcaps.net.

By the way, looks like the wrong picture got uploaded above. I can't edit the first post, so for completeness here is the correct Bigger-Higher-Voltage Cap (Universal?) "A" board picture:


Image source: http://www.shopjimmy.com/samsung-bn4...-led-board.htm

[budm]

Re: Curious if reducing a couple of caps could down-rate a power board to US-voltage

One thing is the the MOV used in the 120V US will not have the same rating for the 230V version, and there may be some resistors changed if there is circuit to detect the incoming AC, etc.
So unless you have the diagram of the board then you will not really know.

[stj]

Re: Curious if reducing a couple of caps could down-rate a power board to US-voltage

they could also downrate the voltage of the diodes / rectifier.
picture? i couldnt see one??

[Per Hansson]

Re: Curious if reducing a couple of caps could down-rate a power board to US-voltage

picture? i couldnt see one??

It's because he hotlinked ShopJimmy which is blocked for non US visitors.
I uploaded the pictures above and provided credit links.

[ja1870]

Re: Curious if reducing a couple of caps could down-rate a power board to US-voltage

Most interesting. Appreciate the additional comments. (And thanks, Mod. Sorry, didn't realize the blocks on the photos.)

Unsuccessfully poked around for a schematic, but did find more pics of the "US" board.

this one, clearly depicted 100uF 250V Samwha caps in this image from Amazon ASIN B01G7KC1A8:

https://images-na.ssl-images-amazon....L._SL1500_.jpg

rather than the 420V/100uF on the "universal" board, shown above.