XBox PSU Repair Help - Replacing an MOV....

[bsodmike]

Hello guys!

I'm posting here hoping some XBox guru out there will know the answer to my question:

**broken link removed**

**broken link removed**

In the first image you can see that I have desoldered the 200V cap and near the top you can see signs of burning. The item marked VA2 which I believe is a MOV (metallic Oxide Varistor) is pictured below in pieces. This was removed from the heatshrinking ....all I can see in the number 10....

Best guess is that it is a 100-110V, 4-5A MOV.

You can also see in the first image that I have replaced the fuse with a fuse holder

Ohh yea - a buddy brought this over for repair, as someone in his house plugged the 110V XBox into 240V mains :blink:

Edit: Click **broken link removed** to see step by step images of what I did....

Any help will be appreciated!

 

[ChrisP]

Generally, these MOV's are used in like pairs -- one on each leg of the AC input. See if there isn't another one there somewhere (VA1, maybe?), and if so, remove the HST from it to get the info printed on the MOV.

Be sure to check the FWBR before returning the unit to service...

 

[ChrisP]

BTW -- you can often ID MOV's by diameter and thickness, as well...

 

[bsodmike]

FWBR? Can you get on MSN messenger by any chance? I'm bsodmike@hotmail.com - thanks!

 

[udi_hakim]

NM

 

[bsodmike]

Why nevermind?

FWBR: full wave bridge rectifier? OK.

Chris: Found VA1 - it is Yellow color - on the front:

TVR
104.31

So this means VA2 is 104.31 and I could only see the '10'.....

Regards,

Mike

 

[ChrisP]

Only assume that the MOV is the same if it is in fact used in the same relative location on the opposite AC leg...

FWBR = Full Wave Bridge Rectifier...

I looked on MSN Messenger -- says you're not online...

 

[Sebi]

Check the solder side: if this part connected serial with bridge rectifier, must be an NTC. (need for switching-on peak supressing.)

 

[ante]

Sometimes they put a PTC in series with the input as a safety circuit breaker (fuse) to protect the circuit from inrush current.

Ante :roll:

 

[bsodmike]

Thank you- Chris here helped me find a matching NTC Thyristor and I'll be replacing this if the PSU fails after I've replaced both varistors and the 200v cap (which has suffered a bit of overvoltage - 617uF on my fluke). I tried to test the thyristor and it's reading was about 2.5ohm and the colder I made it, I noticed a large swing...

 

[mvs sarma]

I am sure the 110V xbox psu can me rewired inside for working on 230V dc
i am doing one on my table as of now

 

[blueroomelectronics]

Why on Earth did you bump a 9 year old thread?

 

[mvs sarma]

extremely sorry, Bill, Thanks for the hint.
i was in fact searching for some clues of xbox psu, like a service manual etc
i did a mistake in not watching the date of the previous post.
extremely sorry ....