dell latitude e5470 not charging

[dqtech]

this laptop no have 12v on pbatt1, but it should right?...i have another dell laptop different model and it has 12v on pbatt...i found this schematic and boardview is not for e5470 but the marking is same...ive try bypass PSID but no luck, still not charging

LINK to schematic & boardview --> https://www.badcaps.net/forum/troubl...bv#post1671359

[mon2]

Attached.

[dqtech]

Attached.

thank you sir...i see that the problem is from pbat_pres#_c is not pulled down to 0v and he change the charging ic right....but mine it does pulled down to 0v when i inserting the battery...or i should try to replace the charging ic also?...because if so,i have to order the ic first since i dont have bq24777 ic right now

[mon2]

No. Do not replace the charger IC..yet.

Does the laptop power up with the power adapter? If yes, what does the BIOS report for the power rating of the adapter? If not a match then the PSID needs to be reviewed.

[dqtech]

No. Do not replace the charger IC..yet.

Does the laptop power up with the power adapter? If yes, what does the BIOS report for the power rating of the adapter? If not a match then the PSID needs to be reviewed.

yes laptop does power on with adapter...even im using dell adapter it saying adapter Unknown...perhaps adapter is not original maybe?

[mon2]

Issue is with the PSID since the adapter details cannot be properly detected.

Attach the power adapter, what is the voltage to ground on PL4 (either side is ok). This voltage must be ~3 volts. Respectively, this same contact must be able to mate with the center needle like pin of the adapter connector. Confirm that this center pin is not bent on the power adapter. Confirm this pin is able to mate with the motherboard's power connector.

Is the power adapter a known good model that functions with another Dell ok? If not, source a known good adapter for testing. When the PSID is not functioning as it should, the motherboard speed will be throttled and the battery charging function will halt.

[mcplslg123]

Check the 33 oms resistor on psid line. It often fails.

[dqtech]

Check the 33 oms resistor on psid line. It often fails.

psid line got 39ohm sir

[dqtech]

Issue is with the PSID since the adapter details cannot be properly detected.

Attach the power adapter, what is the voltage to ground on PL4 (either side is ok). This voltage must be ~3 volts. Respectively, this same contact must be able to mate with the center needle like pin of the adapter connector. Confirm that this center pin is not bent on the power adapter. Confirm this pin is able to mate with the motherboard's power connector.

Is the power adapter a known good model that functions with another Dell ok? If not, source a known good adapter for testing. When the PSID is not functioning as it should, the motherboard speed will be throttled and the battery charging function will halt.

0v on PL4 sir...im using dc power supply and also this adapter...seem like original...i try this adapter on other dell laptop its charging normally

[mon2]

Measure the voltage to ground of the 33 ohm resistor. Post the voltage.

[dqtech]

Measure the voltage to ground of the 33 ohm resistor. Post the voltage.

do you mean psid line voltage?...if so, its 0v sir

[mon2]

Confirm the voltage on resistor PR6. Test both pins to ground.

Also test the resistance across PR6. No power during resistance checking.

[dqtech]

this is PR6...resistance test got 33ohm....and 0 voltage on both side sir

[mon2]

No. PR6 is 33 ohms. PR7 should be 2k2 ohms. You must also have the +3v3_ALW rail present.

[dqtech]

No. PR6 is 33 ohms. PR7 should be 2k2 ohms. You must also have the +3v3_ALW rail present.

yes sir...its PR6...33 ohm ...0 voltage on both side

[dqtech]

like this sir

[mon2]

Someone is pulling this line low.

Remove all power. Measure the resistance to ground on PL4. If there is a low resistance, then most likely, the ESD transient device @ PD6 = PESD5V0U2BT has triggered and is shunting this signal line. Then you must flux and remove PD6 and test again.

If the resistance is ok on this line, continue..

With the power adapter connected, measure the voltage to ground on each pin of PQ3.

Carefully, also measure the voltage on each pin of PU1 switch. We need to confirm that this switch is being powered on pin # 5 with +5V_ALW. Confirm the voltage to ground on pin # 4 = PS_ID from the EC.

The EC is the bus master that is driving this 1-wire interface.

[dqtech]

Someone is pulling this line low.

Remove all power. Measure the resistance to ground on PL4. If there is a low resistance, then most likely, the ESD transient device @ PD6 = PESD5V0U2BT has triggered and is shunting this signal line. Then you must flux and remove PD6 and test again.

If the resistance is ok on this line, continue..

With the power adapter connected, measure the voltage to ground on each pin of PQ3.

Carefully, also measure the voltage on each pin of PU1 switch. We need to confirm that this switch is being powered on pin # 5 with +5V_ALW. Confirm the voltage to ground on pin # 4 = PS_ID from the EC.

The EC is the bus master that is driving this 1-wire interface.

"Remove all power. Measure the resistance to ground on PL4. If there is a low resistance, then most likely, the ESD transient device @ PD6 = PESD5V0U2BT has triggered and is shunting this signal line. Then you must flux and remove PD6 and test again."

with PD6, resistance to ground on PL4 is = 41 Ohm
without PD6 = 110K ohm

[dqtech]

thank you so much sir mon2 ....everything working fine after PD6 replacement

[mon2]

Well done!

While the product will work ok without PD6, it is a good idea to install another PD6 onto the board. This part is used to suppress higher than 5 volt signals to ground. This is a safety crowbar part that will enable only if the signal voltage is too high to protect other parts from damage. The part is passive (out of circuit) unless the voltage is higher than the trigger voltage of this TVS diode.

Good case closure!