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Step Down Tx


steptoe

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I need a step down  230-110

approx 250vA

anybody got any at a sensible price?

Ive been gifted a US charger, so need to change it over simply/cheaply,

I was going to just change the internal Tx, but, there are some bits and stuf before the internal Tx and from what I can make out some of it is only rated at 200v

I dont want to go mad on money, I could buy a charger for 30£ odd

 

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I remember that we had a US "Biddle Hi Pot tester" that I used to use (in my previous life)..... I used an 110V auto transformer to power it...

Used to use it to test Harriet auto stab sticks ;)

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Haven't you got a site transformer you could use?

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Steps, what bits before the internal Tx?

Pics?

I'll look in the unit, I know I do have a couple of Tx's there kicking around, but, no promises and it won't be for a few days yet.

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Haven't you got a site transformer you could use?

 

not really very handy tho marvo, my site Tx is hardly ever used,

 

Steps, what bits before the internal Tx?

Pics?

I'll look in the unit, I know I do have a couple of Tx's there kicking around, but, no promises and it won't be for a few days yet.

 

Im not sure sidey, I'll take some pix,

a couple of suppressors [i think] , a capacitor, a couple of SMDs, what looks like an isolating Tx, a few more big caps[rated 200v] then the reducing Tx to battery voltage [i assume],

ive got a biggish 240-24 Tx Im going to see if it has any other taps on it, maybe,,,,

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That sounds like a switching power supply, so you wouldn't just be able to swap the internal tx anyway.

 

What is is for?

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just a charger for cordless tools dave, but it charges more than one at a time, and different voltage batteries,

thats why I'd like to get it sorted, one charger does all, rather than 2 or 3 different chargers

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As PD says, if it's an SMPSU then you are goosed as far as changing the TX goes, but, I suppose you could bolt on an external 230-100 Tx in a box?

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As PD says, if it's an SMPSU then you are goosed as far as changing the TX goes, but, I suppose you could bolt on an external 230-100 Tx in a box?

ye, after I opened it up that was what I was thinking, what with all the other stuff going on before the internal Tx,

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I doubt you will find a 250VA auto transformer for less than £30, cant see anything on ebay.

 

I would just go fetch your site tranny. That will keep you fit into the bargain.

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I wouldn't use an auto tx tbh for a supply like this, personally.

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not really very handy tho marvo, my site Tx is hardly ever used,

You said cheap, you didn't mention it had to be handy ;)

 

 

Im not sure sidey, I'll take some pix,

a couple of suppressors [i think] , a capacitor, a couple of SMDs, what looks like an isolating Tx, a few more big caps[rated 200v] then the reducing Tx to battery voltage [i assume],

ive got a biggish 240-24 Tx Im going to see if it has any other taps on it, maybe,,,,

It's probably not as easy as just changing the TX if it's a switched mode supply that's tied to a tight input voltage range, the transformers of SPMS's are very specifically designed items. Chances are it's not going to be worth the effort to make changes to the power supply itself..
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post-7-0-64920000-1432235783_thumb.jpgAll the stuff to the bottom, and right is straight fed from.input, some SMDs under the board, 

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Hold on a mo. I might have something.

 

I've just been and had a look in my "transformers" box.

 

I have an RS 300VA torroidal transformer, Part No 257-5247  this one http://uk.rs-online.com/web/p/toroidal-transformers/2575247/?searchTerm=257-5247&relevancy-data=636F3D3126696E3D4931384E525353746F636B4E756D6265724D504E266C753D656E266D6D3D6D61746368616C6C26706D3D5E5C647B337D5B5C732D2F255C2E2C5D5C647B332C347D2426706F3D313426736E3D592673743D52535F53544F434B5F4E554D4245522677633D4E4F4E45267573743D3235372D3532343726

 

Brand new still in sealed box.

 

That would do it, but would need to be put in a box of some sort.

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