trying to fix or replace a bad power adapter - please help

[mariushm]

Re: trying to fix or replace a bad power adapter - please help

Attaching some pictures on the decoder with labels on the back and whats on the inside and everything.

Hey, so you have a picture there in that set :



See that rectangular thing that says KBP01 ?


That's a bridge rectifier, four diodes in a single package. AC voltage comes in through the jack, goes through that fuse and then goes to the center pins of that rectangular thing, right where it says AC.
On the corners, you have + and - marked on the bridge rectifier.

You can desolder this bridge rectifier from the board and solder two wires to + and - then connect those wires directly to the Toshiba's DC adapter + and -.

However, this might not work, because when the bridge rectifier receives 16v AC, the conversion produces 16 x 1.41 = ~ 22.5v DC which is quite more than the 15v the Toshiba adapter outputs.

You might be able to source a cheap 18-19v DC adapter for a laptop (dell, hp etc) and that should be close enough in voltage. Such adapters can be found on Amazon or eBay and probably local shops for 10-20$ (though I'm not sure of their quality).

If you want to replace the transformer, you can get a cheap one from element14, it's not 50$ ... well, it shouldn't be.

You need to pick one that does around 16v ac at 600 mA .. that's 16x0.6 = 10VA .. if you pick one that has a bigger VA rating you'll be fine.

Most of the transformers are 2 x 115v - 1x230v on the primary side. If you can only get 2x115, you can link them together to behave like a 1x230v.

That's fine if you can only get 230v/2x115v, they'll work with 240v but the secondary will be slightly more voltage, let's say instead of 16v AC you'll get 16.5v AC

Here's for example some transformers that will work for you:

exact match:

http://au.element14.com/block/fl-14-...-8v/dp/1711390

2x8v = 1x 16 AC , 14VA (more than original), 230v primary, so you'll get slightly more than 16v AC on secondary

cheaper, you have :

http://au.element14.com/myrra/44268/...15v/dp/1689089

1x230v in , 1x15v ac out, 667mA (10VA) .,.. on 240v, you'll get very close to 16v AC.

http://au.element14.com/myrra/44304/...15v/dp/1689096

Same story, just a bit higher VA rating.

So you can just remove the old transformer from the Creative box and replace it with one of these and you're done.

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

Okay Guys So I went the easy way, I removed the thermal fuse, then re soldered 2 red wires to the enamel coated copper wires. then connected the 2 red wires to a larger wire to connect to the mains, heatshrinks everything uses some contact cement epoxy to attach the old transformer tape and then placed some electrical tape over it and a cable tie. done. connected it and there is power

briefly connected my computer fan and it spins up and I did notice a short in there / spark but I think its okay?

But I am not going to use with my decoder until I check it with a multimeter for the current its delivering. Any idea what I need to set the multimeter to check that? and what values I need to be sure it wont damage the decoder?

Also you guys mention its a fire hazard now? I really dont see if this will melt the casing and catch on fire? any suggestions and feedback would be appreciated.

The thermal fuse thing helped the most since I went the route to eliminate it completly. thank you mariushm, josh, budm and everyone that helped, great information,.


oh forgot to add some pictures of the finished product..

[mariushm]

Re: trying to fix or replace a bad power adapter - please help

If for some reason, there's a short in the device your transformer is connected to, the short makes the transformer give more current than its rated for, therefore it will overheat.

If this continues, the fuse is supposed to cut the primary side, so the circuit is interrupted.

Without fuse, the transformer may continue to heat up until the insulation on the wires breaks down and now you may have a short on your mains side, which can get the mains cable super hot and burn the plastic insulation, burn the case of the adapter etc...

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

If for some reason, there's a short in the device your transformer is connected to, the short makes the transformer give more current than its rated for, therefore it will overheat.

If this continues, the fuse is supposed to cut the primary side, so the circuit is interrupted.

Without fuse, the transformer may continue to heat up until the insulation on the wires breaks down and now you may have a short on your mains side, which can get the mains cable super hot and burn the plastic insulation, burn the case of the adapter etc...

What are my chances? I mean its a 10W device and finely built a decoder actually so not sure if there will be any shorts, but then again.. Do you think this can damage my device any way in the long run? should I spend the $50 and get the adapter Josh showed. I mean it has the same specs right? only more Amps which is no big deal, the device will draw as much as it needs, in my case only 600mA.

But I don't want to start a fire but I hear its pretty okay? and thermal fuses aren't a big deal? added some pictures to my above post by the way... and thanks

[joshnz]

Re: trying to fix or replace a bad power adapter - please help

briefly connected my computer fan and it spins up and I did notice a short in there / spark but I think its okay?

What do you mean when you connect the fan?
or when you plug in the power supply?
If when you connect the fan that is because the fan is designed for dc not ac (your power supply outputs ac)

to measure secondary current it depends on your meter the same apply for primary side current (also dangerous to your safety).

As for the fire safety thing if the cord shorts the transformer will overload and turn that into heat once enough heat builds some of the winding's will short causing more heat if it catches fire by this point you have fire and as you seen by the wire size the wire will melt well before the fuse for the power point will trip.

[joshnz]

Re: trying to fix or replace a bad power adapter - please help

to avoid fire you can replace with
http://newzealand.rs-online.com/web/...fuses/1769508/
will cost $10.0625 in total

element14 may have the cheaper but
have $10 minimum order

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

I f ed up.

I was putting it all together in the case and the enamel coated wire on one of them broke right off the beginning. needless to say there is no more enamel exposed wire left for me to solder on. unless you guys have any more ideas.


looks like I will be buying the adapter josh showed me

http://newzealand.rs-online.com/web/...upply/2304073/

this is the one right? I realize I may have to solder the wiring but other then that it will plug right in, no hassle right?

[joshnz]

Re: trying to fix or replace a bad power adapter - please help

You could also measure the size of the old one we might be able to find something
that fits

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

You could also measure the size of the old one we might be able to find something
that fits

its around 4Cm into 3.3cm x 4.5cm give or take, I am sure something close to it I could try fitting in the box. You know if I can get that for a few bucks instead of having to spend $50...that'd be great.. heck if its really that important I could build a small box from particle board maybe?

[mariushm]

Re: trying to fix or replace a bad power adapter - please help

This one i linked to a few posts above is 50 x 42 x 35 mm :

http://au.element14.com/myrra/44268/...15v/dp/1689089

https://cdn.badcaps-static.com/pdfs/...c3b346606c.pdf

and it's about 10$ plus about 5-10$ shipping.

If you take off the insulating cover maybe its even smaller.

[joshnz]

Re: trying to fix or replace a bad power adapter - please help

mariushm these sites for New Zealand dollar.
http://nz.element14.com/
Goods Subtotal: $14.23
Shipping Charge: $14.95
GST: $4.38
Total: $33.56

This one is free shipping
http://newzealand.rs-online.com/web/
i'll post back if i can find link

[mariushm]

Re: trying to fix or replace a bad power adapter - please help

Yeah, I wasn't aware they have a nz version, that's why I pointed to the one with AU in front.

Just replace AU with NZ then and you should get the nz prices.

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

ah screw it fellas...I think I am just going to get that one josh pointed out..newzealand.rs-online.com/web/p/plug-in-power-supply/2304073/ - this will work just to confirm, I wont have any worry of damaging my decoder right?

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

Oh guys, I emailed the friend, he said he knew the adapter was bad so he said there was a second adapter he used for it in the box.. this is the one.. I plugged it in and it did work. I dont know, he said it worked for him....should I use this?

[joshnz]

Re: trying to fix or replace a bad power adapter - please help

http://newzealand.rs-online.com/web/...rmers/7320433/

$18.17 may have to make it fit as mariushm suggested for the other one.

[joshnz]

Re: trying to fix or replace a bad power adapter - please help

Oh guys, I emailed the friend, he said he knew the adapter was bad so he said there was a second adapter he used for it in the box.. this is the one.. I plugged it in and it did work. I dont know, he said it worked for him....should I use this?

I'm suprised it works with low voltage, as for it running off dc i expected that due to the bridge rectifier, I would say it will be happy with it if it works normally.

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

he said this is how he ran it for a few years? I dont know but should I use his +12 adapter or my 15V one. I mean if I had to chose between he two.. would you pick this one or the one I showed in the first picture? I would guess 15 is more close then 12 so..hey if these two would work, why not..

[joshnz]

Re: trying to fix or replace a bad power adapter - please help

I'm cheap I would use the 12v dc one.

[newtoCaps101]

Re: trying to fix or replace a bad power adapter - please help

The laptop one plugs in too.. just saying

stuck between the 15v dc and 12v dc now..heck saves me $50..


anybody here know how to open a laptop power brick? then maybe I could rewire it nicely with the cord from the original adapter.

[mariushm]

Re: trying to fix or replace a bad power adapter - please help

Look man, this decoder would normally run even on 3.3v or 5v, the decoding stuff doesn't use more than 5v.
But the decoder also has an audio amplifier for the headphones output and for the 5.1-7.1, whatever it has there as connectivity.

The electronics that decodes the dolby signal and makes 5.1 or whatever the decoder does powers itself from an internal converter somewhere, which takes power the box receives and generates 3.3v or 5v or whatever low voltage is used. So that doesn't care about what you use at input.

The audio amplifier used for headphones output and so on does however care how big the voltage is. Depending on what type of amplifier it is, the higher the voltage at input, the more watts the amplfier can produce and the louder the volume.

So you can probably safely use even a 12v DC, but don't be surprised if you turn the volume up a bit and it sounds bad.