Dell 1564 does not charge battery

[pippo_one]

Hi, All
i replaced the mainb of my Dell 1564 DA0UM3MB8E0 REV E REV A00 PWB 5X2FJ for video card problems.
once installed OS I see that despite power supply connected and battery inserted it does not charge the battery tray icon and battery led off.
I tried to update the Bios from version A01 to the latest A13
but it does not allow me to update and shows the error "AC is missing"
but the power supply is on
I found the wiring diagram and I started to check the PQ14 and PQ15 line
and FL5
FL5: 19 volts
I insert battery
and I find myself 0 volts, but there are no short circuits
to get back 19 volts I have to remove the battery and power ac
Can anyone help me ?
Thank you

[emestee]

Re: Dell 1564 does not charge battery

First off, where did you get the replacement board? Are there traces of repair on it?

Here's the full schematics https://cdn.badcaps-static.com/pdfs/...e44d155765.pdf

I'm incredibly sick of Dell's smart adapter detection bullshit. Go to dell BIOS and see how it identifies the AC adapter.

Here are some conditions for battery charging:

1) The EC must believe the connected adapter is powerful enough to sustain both run power and battery charging power. Does the battery charge when the machine is off?
2) The battery must be detected (PBAT_PRES# pulled down to 0v)
3) The battery controller must communicate (oscilloscope on SMbus pins)
4) The battery controller must agree to charge according to its internal state

You said you were going to check PQ28 and PQ29. You didn't say what was the result. Do their gates get the pulse? There is a silly circuit to override the adapter identification - is PQ11 open? That circuit is a hack meant to disable adapter ID for a dock. If the circuit is misbehaving and no dock is present, the board will think there's no adapter attached.

[mcplslg123]

Re: Dell 1564 does not charge battery

I agrre with @emsestee. Fisrt thing to check whether bios shows the adapter as identified or not. If not, then search PSID section and fix it or you can even bypass it if you understand the circuit.

[pippo_one]

Re: Dell 1564 does not charge battery

Hi,
first of all thanks for your support, I have attached 3 photos 1- bios ... 2- without battery ... 3- with battery (see icon on the O.S. try).
unfortunately I'm a beginner so I don't have an oscilloscope, I'm armed only with a voltmeter. I will try to check Pq11 and Pq12 as suggested and I will update you, if please in these three photos they suggest other tips that you can give me is appreciated

Thank you

[emestee]

Re: Dell 1564 does not charge battery

BIOS doesn't detect the adapter, but the machine powers on. This is classic dell nonsense.

In this condition the battery will not charge.

Before you do anything else try to find another original Dell adapter that you know works and try doing the same thing with it. Alternatively, put your adapter into another Dell machine. This is to eliminate a fault in the adapter (these things have a whole serial protocol between the adapter and the motherboard and if the circuits in the adapter that are responsible for it die, this is exactly what you would see). After that you can start dealing with the board problem. See sheet 53 of the schematics.

You did not tell us where you got the board. The point here is, it was probably sold because it had this exact problem.

[mcplslg123]

Re: Dell 1564 does not charge battery

Check whether PR80 is 33 Ohms. This is very minor issue and certainly can be resolved.

[pippo_one]

Re: Dell 1564 does not charge battery

Hi, I bought the mainb on Aliexpress, however I wanted to update you on the tests performed
with the old mainb and a monitor connected to the Hdmi everything works fine the battery is charged and the icon on the w10 tray responds if the power supply is connected or not (I'll have to see how the old mainb bios sees the "ac adapter", I will inform) however I assure you that the power supply is ok !!
tomorrow I will make all the checks suggested or that you will recommend to me during this discussion

Thanks

[emestee]

Re: Dell 1564 does not charge battery

You can now use the working board as a reference, by comparing resistances and voltages and following the differences back to their origins you can find the culprit much quicker.

If the old board works with an external display, there's non-zero chance the matrix video output circuit/connector has problems that do not require the replacement of its host chip, hence if you repair that you'll end up with two working boards.

[pippo_one]

Re: Dell 1564 does not charge battery

Hi @emestee, pls explain to me more info about the vga problem from the old mainb
Thank you

[emestee]

Re: Dell 1564 does not charge battery

Please be more specific about the old boards problem? Does it output to the matrix? The VGA output?

For VGA, look at sheet 25 of the schematics.

A basic VGA display can be driven through 6 signals: R, G, B, H-sync, V-sync, and ground.

Between the VGA connector and the GPU, there's a circuit that stabilizes and controls the signals. The DAC in the GPU (sheet 17) outputs the necessary signals to drive the VGA (R, G, B, h-sync and v-sync). The color channels go directly to the output, each through their individual inductor. The sync signals go through buffers U2/U3 and additional inductors. On top of that there are smoothing capacitors everywhere and a pull-up circuit.

Additionally, there are two signals G_DAT_DDC2_C and G_DAT_CLK2_C, which carry the DDC exchange that allows the connected display to inform the host chip about its capabilities, same as EDID in the native matrix of the machine.

There are several important conclusions:

1) A fault in this circuit (more so in the sync and DDC group) will manifest itself as absence of VGA output
2) There are three groups of signals, and each group has identical layout for every signal, which means each signal should have the same resistance to ground as the other signals in the group
3) If any of the voltages are missing, or any of the elements are shorted (esp. the smoothing caps) it will be observable with multimeter.

You have another board to compare the resistances against. If you have an oscilloscope, you can probe every signal and see if things are happening on it.

If this circuit tests fine, and the connector itself is fine too, then unfortunately the DAC part of the GPU is dead. It's possible that the analog plane voltage for the GPU is missing but it is probably used for other stuff and the GPU won't be able to drive other outputs if it is. Worth a check, but not much hope there.

[pippo_one]

Re: Dell 1564 does not charge battery

Excuse me, let's take a step back to the mainb that doesn't charge the battery:
i checked all the pr80 resistors included between the two mainb (sheet 53 schematic) and the values are the same also. when "PS_ID" is turned on there are about 3.25 volts in both.
furthermore, when switched on with the old mainb for a fraction of a second the charge led lights up ... while in the new one it does not.

other suggestions?

[pippo_one]

Re: Dell 1564 does not charge battery

Another check performed in the old Bios mainb the "AC ADAPTER" detects 90 W
in the bios of the new detects NONE

[pippo_one]

Re: Dell 1564 does not charge battery

I update you on other tests performed:
I checked the continuity of the signal from the power jack (pins 3) to pins 3 PQ11..from pin1 of PQ11 to pins 87 ITE everything ok.
I tried the voltages PQ 11 pin3 3,3volt, pins 2 5v., pin 1 3,27v.
towards the ground.
PQ11 pins 3 5v., Pins 2 0.45v., Pin1 0v.

the only difference between the two mainb that from OFF in the old one (which charges the battery) the 3.3 volts in pins 3 of the Pw-Jack is already available immediately when I insert the power supply. while in the other I have 0.volt

[emestee]

Re: Dell 1564 does not charge battery

Note the PS_ID_DISABLE# signal which you should compare on both boards.

Generally speaking on Dell machines the PSID signal is not voltage level; it is one wire protocol and the adapter communicates with the KBC by shorting PSID to ground. Properly observing the behaviour of the PSID signal can not be done with voltage measurements and requires an oscilloscope. Identical voltage measurements on both boards mean nothing.

I don't understand the meaning of the second measurement you posted - is this from the good board?

Just to make sure, you can pull out PR80, PD5 and PR70 and test the resistance of PS_ID (i.e. the KBC pin) to the ground to make sure it isn't too low.

[pippo_one]

Re: Dell 1564 does not charge battery

Hi @emestee, only tonight I read your message, during the day I indulged in checking a lot of signals, I found the following: in the mainb old from off and inserted power pw-jack to pin1 of Pr70 I find myself 3, 25 volts while in the "mainb 2" -0 volts, I went up all the net "+ 3.3V_ALW"
in fact in the "Pq21" I enter with 19v, but I don't go out with anything, and the pin 4 of the Pq21 is not driven by the pin26 output of the "PU7"
input in pin 25 does not reach 3.3Volt "+ 3.3V_EN2 follows 3.3V_ALW_ON3.3V_ALW_ON
in the end I got to sheet 37 where one of the Q1 Q2 Q3 I presume is corrupt.
In your opinion @emestee this reasoning is possible

[emestee]

Re: Dell 1564 does not charge battery

It's not just possible; it's correct. What you're observing is 3.3VALW rail not coming up. Because the PSID signal needs to be pulled up by 3.3VALW, the adapter will not be identified. I think it's extremely strange that this rail doesn't come up and the board starts anyway. Maybe I missed something obvious. However, weirder things have been known to happen.

The next question is why. I couldn't understand from your post what happens to the enable signal on the 3.3 side. Without it, the IC will not start. If it's present, we need to begin investigating this circuit.

According to sheet 2 power state chart(thank you Quanta for not being nincompoops like Asus usually is), 5VALW needs to come up first (sheet 59), then the power button is pressed and 3VALW needs to come up. Let's read the schematic for the control circuit on sheet 37:

If 5V_ALW is present and Q2 is closed, 3.3V_ALW_ON will be enabled. By default, Q2 is open from 5V_ALW pullup, but Q1 will close it if ALW_ON signal comes, and so will Q3 is ACAV_IN is high. In other words, if ALW_ON or ACAV_IN are on, 3.3V_ALW_ON goes up and 3.3V standby voltage generation starts.

This leaves us with two options: a) both signals are missing b) circuitry problem.

If we really are looking at the missing enable signal, we're getting very close to the solution.

Side note: should I write a "how to read schematics" tutorial? Most of what I've seen online is basically "this is what this symbol means" not "systemic method and patterns of schematic drawings"

[pippo_one]

Re: Dell 1564 does not charge battery

after all the checks carried out I finished on page 45 and I analyzed the source of the "ACAV_IN" signal
in fact in the working mainb I have 19 volts on "PQ1"
out 19V and on pin 4 about 1.7 V
in this condition on pin 2 of "PQ3" I find 3.3 volts

in the mainb that does not charge the battery I am IN and OUT 19volt but also the pin 4 I am 19V in this condition I have 0 v. on pin 2 of "PQ3".
I measured the resistance "PR4" and it is 100K I feel ok with the tester, so I don't know why I have 19 Volt before and after "PR4".

What do you think @emestee
I just have to change the "PR4" resistor
to restore the signal

[emestee]

Re: Dell 1564 does not charge battery

ACAV_IN on this board is produced from charger's ACOK, which is a key signal indicating that the external power is functioning. If this signal comes out of the charger intact (3.3 v) but shows up as some other voltage in the ALW power switching circuit, then it is clearly a problem that needs to be fixed.

PQ1 is a P-channel mosfet. It is open only if the voltage on the gate is lower than the voltage on the input. If you're seeing same voltage on all three pins, the chances are the mosfet is blown. Measure gate to drain and source to drain resistance with the board powered off, after having shorted the gate and the source with a tweezer or so to discharge the gate.

PQ1 is controlled by PQ3, which needs to be open to pull down the voltage on PQ1's gate, which will in turn open it as well. The gate of PQ3 is the ACOK signal. Note that ACOK in PU15 is an open drain output; that is, it is pulled up to high by PR84, the IC itself does not produce 3.3v on this output. If the charger IC wants this output to be low, it connects this pin to the ground internally, creating 0v on the output. Otherwise, this pin will reject current and so the pull-up voltage will be the value of the signal. This means that if PR84 is blown, there will never be a high level on ACOK output. Another thing of note is that ACOK will only be high if the ACIN voltage (pin 2) is greater than half of the reference voltage (pin 3) - this is from the charger's datasheet.

The good news is you're very close to a solution.

[pippo_one]

Re: Dell 1564 does not charge battery

Hi Emestee, I've checked Pq1 and it looks good to me.
I'm analyzing the pin2 line of the Pq3
these are the measured values:
pin2 to ground
0.736
pr84 (old) 10k
pr88 (old) 15k
pr92 (old) 0
pr12 (old) 33
while in the card that does not charge the battery I have these values:
pin2 to ground
1,630
pr84 = 6k
pr88 = 6k
pr92 = 0
pr12 = 33
what do you think about it ?

[pippo_one]

Re: Dell 1564 does not charge battery

another consideration
pc97 always appears to be massed to its heads is it possible that it is short?
what is the value of this capacitor?