820-00281-A turn on no chime

[kingskie]

Hi all,

I have a problem with 820-00281-A board..
fan spin, can turn on but no chime. vibrate when click touch pad. no keyboard backlight on caps lock.
usb amp meter: 19.2V 2.85A
PPBUS_G3H = 12.58V
PM_SLP_S4_L = 3.252V
PP3V3_G3H = 3.3V
PP3V3_S5 = 3.3V
PP5V_S4 = 5V

any suggestion? thanks before

[macattack600]

Re: 820-00281-A turn on no chime

If you plug in USB mouse does it light up on the bottom?, (confirms CPU activity)

[mon2]

Re: 820-00281-A turn on no chime

PP3V3_G3H = 3.3V

This is too low for this model. It should be 3v42 on a normal board.

Remove all power. Meter in resistance mode (2k scale).

Check the resistance to ground for the PP3V3_G3H rail.

Also check the resistance to ground for the input of the buck regulator that creates this power rail.

Post all readings.

[kingskie]

Re: 820-00281-A turn on no chime

If you plug in USB mouse does it light up on the bottom?, (confirms CPU activity)

no light came up bro

[kingskie]

Re: 820-00281-A turn on no chime

This is too low for this model. It should be 3v42 on a normal board.

Remove all power. Meter in resistance mode (2k scale).

Check the resistance to ground for the PP3V3_G3H rail.

Also check the resistance to ground for the input of the buck regulator that creates this power rail.

Post all readings.

today i disassemble the board and plug the usb amp meter again and only shows 5V...and found that one of the usb ic controller is very hot..if i take out this hot one, can this machine turn on without one of the usb ic?

[macattack600]

Re: 820-00281-A turn on no chime

Post schematic part number of the usb_ic
Too hot to keep finger on for more than 10 seconds?

[kingskie]

Re: 820-00281-A turn on no chime

Post schematic part number of the usb_ic
Too hot to keep finger on for more than 10 seconds?

it is CD3215A for schematic or CD3215C00 and yes to hot to touch with finger more than 5 second

[macattack600]

Re: 820-00281-A turn on no chime

That is the ACE controller both are needed to make the board power up .

Mon2 should be able to help you on this one.
Search the forum for CD3215 and you can see a few similar posts.

[kingskie]

Re: 820-00281-A turn on no chime

That is the ACE controller both are needed to make the board power up .

Mon2 should be able to help you on this one.
Search the forum for CD3215 and you can see a few similar posts.

this machine have 4 usb controller ic. Mon2 havent replied maybe he is still sleeping

[mon2]

Re: 820-00281-A turn on no chime

Hi. Missed this post.

Yes, as noted, all ACE controllers need to be functional to allow for the 20V power delivery contract.

If you have a 'hot' ACE controller, guessing that it is already toast and needs to be replaced.

Confirm and replace the ACE controller with the same. At this time, personally do not know about the differences in the part markings so best to source the same product from Aliexpress (a vendor with a good rating) or remove from a donor board. If you remove from a donor board (not a bad idea), you will need to also have the BGA stencil for this device so it can be reballed.

There are good vendors on Aliexpress like

SUHMS
https://www.aliexpress.com/item/3291...rch-mainSearch

VISEN
https://www.aliexpress.com/item/3297...rch-mainSearch

Here is one stencil vendor for this component:
https://www.aliexpress.com/item/1005...rch-mainSearch

and this one for a DIRECT HEAT STENCIL:
https://www.aliexpress.com/item/4000...rch-mainSearch

On this subject, the direct heat stencil apparently will not flex when the hot air is applied to the surface of the solder paste. Still recommend a fixture to secure the IC and the stencil - makes it easier to align the solder paste or solder balls to the pads.

You can buy miniature solder balls to apply onto a donor BGA. Just check with the vendor on the recommended solder balls for this stencil & BGA you wish to deploy.

You will need to also source a fixture to keep this part down without flexing. The vendor can probably supply it or recommend one. This along with solder past and an applicator to squeeze down the solder paste.

You can start to remove this part because based on the very hot temp, the part is likely defective already. After removing the part, confirm there are no shorts on the solder balls on the PCB pads where this part was soldered. Clean it up with flux and desoldering braid. Be very patient and if the soldering braid gets stuck on the pad - STOP STOP STOP else the pad can be torn off the board - game over and logic board is garbage.

Use higher heat + flux to gently remove the solder braid. A flat tip (blade) soldering iron tip is very helpful for this process. There should be some good videos on youtube on this topic.

With this part OFF the board AND no solder short on the PCB pad site, power up again using a different USB connector port.

Do you now see 3v42 for PP3V3_G3H ? If not, that needs to be fixed before moving forward. Of course the ACE controller needs to be replaced.