PSU MOD - Chip KA7500 wicj leg is sense?

[sn34ky]

Hi, i got a Levicom X-Alien 500W PSU.

The +5V is a too low under high load. I need to mod it.

I found that it has the KA7500B chip. After a google search i found out this chip regulates 5V.

Here's the documentation: http://www.spelektroniikka.fi/kuvat/ka7500b.pdf

I can't figure out wich leg to solder a resistor on and how many ohm to use.

Anyone got an idea??

[rubberenrobbie]

Hey there,
I've got the same problem with my Levicom X-Alien. I was searching for this info also but I haven't found anything yet.

I do know another way of modding the 5volt line without opening your PSU though.

Try this:
http://www.ocforums.com/showthread.php?threadid=58333&perpage=30&pagenumber=1

I havent't tried it yet cause I'm unable to get my SMD grabbers (I really can't solder), but a lot of people did and succeeded...

Good luck!

Lekker suf, zag dat je Nederlands bent... Irritant he, die 5v lijn!!
Hoe is jou 12v lijn dan? Die van mij is 12.80 load!!

[sn34ky]

My +12v is 11.60 under load:(

But i do have a Vapo attached to the PSU.

I have some spare SMD grabbers... PM me if you need any.

[sn34ky]

K, i looked at an old Vcore mod an a mobo wich used the same KA7500B chip.

Connect a 50K trimmer/potmeter to pin 1 and 7. These are faced towards the inside of the PSU.

44K resistanse brought my +12v from 11.60 to 12.50 and my +5v from 4.85 to 5.11 under load:toast:

I fitted some SMD grabbers but they come loose from a few bumbs because the legs of the ic are too wide.

If you want i can solder on a trimmer for you...

[rubberenrobbie]

Hi,
Sorry for the wait, but I couldn't post?!? Yes i'm very interested in those spare grabbers... They aren't easy to get here.
I won't be modding my 5v in my PSU though, that will also raise my 12v and that one is already 12.60v idle on the molex!!! I'd rather lower it...

Good that you managed to succeed with your mod!
Congrats...

[sn34ky]

Thanx m8!

You say 12.60 on the molex...
The voltages on the mobo are more accurate. If you check your voltages on your mobo or vidcard they will be a lot lower than on the molex.

12.50 on the molex means 12.05 on my mobo. So your 12.60 should be about 12.10 or 12.15.

On these X-aliens this mod is worth doing. I OC higher now with this mod.

PM me for the grabbers...