Hi, my Pegasos II G4 CPU card is no longer working, I think the CPU card got slightly warped from the weight of the heatsink/fan over time, and perhaps now the CPU would need to be re-flowed.

I've seen lots of videos of re-flowing using a heat gun on Youtube, do you think this could potentially work?

Failing that, does anyone know a place that could repair the CPU card?

Thanks,

Darren

[ Edited by HammerD 06.12.2022 - 13:53 ]

Hi, first check if none of 4420 chips are burnt 8wfyHoR.jpg

Quote:

ok, will do, and if they are not? Anyway I will post some photos of the board.

Darren

[ Edited by HammerD 06.12.2022 - 15:26 ]

Changing it (SI4420DY N-FET 30V 10A 3W) should help (if it is burnt) and it is a lot easier than reballing cpu, also reballing cpu won't help if this IC is broken :)

I know 3 cards with this component burnt (one is laying next to me).

[ Edited by zukow 06.12.2022 - 21:34 ]

Quote:

I think you may be right. I took a photo and there was a white blob on it. I used isopropyl alcohol to swab it and it looks like the plastic of the chip is melted.

Link to photo here before I cleaned the area. After I cleaned it, it was just black melted circular plastic.

https://photos.app.goo.gl/p4Pzq5tjzKqBM87p9

So I am screwed I guess? Is this possibly a design problem? Normally you would think this should not happen. I did not even use it that much!

[ Edited by HammerD 06.12.2022 - 16:59 ]

Yep, seems to be burnt. Probably some design issue. Change it and hopefully your Peg2 will be ok.

Quote:

Thanks, would this be the correct chip?

https://www.digikey.ca/en/products/detail/rohm-semiconductor/RSS100N03FRATB/8026642?utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax:%20Smart%20Shopping_Product_Zombie%20SKUS&utm_term=&productid=8026642&gclid=Cj0KCQiA7bucBhCeARIsAIOwr--tyD8Tc-dheHIkFICO2OT1t5dWYGAeQKDlsYcZ1eJveyjFb3CyENQaArC2EALw_wcB

this one: https://www.digikey.ca/en/products/detail/infineon-technologies/SI4420DY/358252

Quote:

Crap, it says that one is no longer manufactured.... :(

Does the G3 card have the same chip? I have a working G3 CPU card.

[ Edited by HammerD 06.12.2022 - 17:31 ]

Quote:

I think you can still find these chips on eBay. Just look for SI4420DY.

Quote:

Uhm well, it would also be wise to check the components around it to make sure it was the culprit and not the victim. Mosfets and caps are usually the culprits when you get a burned chip.

Edit: Never mind, the 4420 *is* a mosfet.

[ Edited by KennyR 07.12.2022 - 19:51 ]

If you do manage to fix it, a little heat transfer pad and a heatsink may help to stop it happening again.

Quote:

Yes I'm not sure what I will do yet. I can probably get the chip itself pretty cheap, but replacing it is beyond my skills. Yeah I could try to do it myself but would probably screw it up...so for me to get it done by an electronics shop or some other place may not be worth the cost.

Still thinking about it.

I have ordered the chip from eBay...will take awhile to arrive. I will keep this post updated.

Darren

I'd suggest contacting Acill since he's well known in the Amiga communtity and his work is highly regarded.

https://acillclassics.wordpress.com/contact/

Quote:

Thanks Rob. Acill is quite far from me but there are local electronics shops or perhaps mobile phone repair shops that could do the swap (if I get cold feet trying to attempt it myself :)

Darren

I replaced the chip and the CPU card came back to life, but no OS would fully load. I could get to the Openfirmware prompt and select an OS to load (eg. OS4.1 or MorphOS) and it would start to load and then just hang.

I think there were other issues with the BGA solder connections to the G4 due to stresses overtime of heavy heatsinks "warping" the circuit board and BGA solder connections of the G4. I tried to fix that by heating the board up in my oven but that appears to have totally killed it. Now it won't even POST to openfirmware.

I may try it again to see if it comes again back to life, but as of this point it's dead after my oven baking experience.

"...heating the board up in my oven" who told you that?!

Quote:

Unfortunatelly youtube is full of such baking examples
Even if it is sometimes works ( corrupted tin joints ), it causes more harm than it improves.
Hands off this.

I have two g3 cpu cards that are broken.

I wonder if there is still someone who is able to make a check and perhaps fix them.

You can reply on this topic or send pm.

I also got two broken mobos. One Peg1 and one Peg2.

And yeah this oven thing never seemed like a good idea for me.


[ Edited by CountRaven 27.03.2023 - 03:15 ]