Toshiba c855 - Hannstar E89382

[botero]

I've a Toshiba c855 with Hannstar E89382 J MV-4 94-0. Due a jack repair the polarity has been inverted so the lapotop, when there's no battery plugged, doesn't turn on, dead, no led blinks, no fan. With battery plugged the charge circuit works and charge led is on, the laptop starts but the screen doesn't turn on and the cpu fan doesn't work. I've find this service manual It's right? Someone have some suggestions? Thank you very much for attention and excuse me for my bad English.

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

I've a Toshiba c855 with Hannstar E89382 J MV-4 94-0. Due a jack repair the polarity has been inverted so the lapotop, when there's no battery plugged, doesn't turn on, dead, no led blinks, no fan. With battery plugged the charge circuit works and charge led is on, the laptop starts but the screen doesn't turn on and the cpu fan doesn't work. I've find this service manual It's right? Someone have some suggestions? Thank you very much for attention and excuse me for my bad English.

Hi, I don't think problem is due to reverse polarity, in page 38 we can see that this circuit is protected for this kind of issues.
Check voltage at both sides of diode PD14, you should obtain 19 volts, if not, there are two coils that could be open. (PL2 and PL3)
Why are you asking if the schematic is the right one?. In the photos seems to be that it is right.
Regards.

[botero]

Re: Toshiba c855 - Hannstar E89382

When i've remounted the laptop, it started and worked for 2-3 hours without recharge the battery even if on windows status bar the plug-in icon was in ac mode. When i've pulled in and out the ac power cable few times the laptop stops. I've checked voltage up to the charge controller and the 19v its ok.

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

When i've remounted the laptop, it started and worked for 2-3 hours without recharge the battery even if on windows status bar the plug-in icon was in ac mode. When i've pulled in and out the ac power cable few times the laptop stops. I've checked voltage up to the charge controller and the 19v its ok.

Didn't you check diode PD14?. Check also PR198, there will be 19 volts to reach VA2.
D/C# signal must be zero volts, in order to make PQ34 conduct, and let VIN=VA2 (19v.)

[sparker1]

Re: Toshiba c855 - Hannstar E89382

Lol, I had the oppposite issue - would only work with AC and would not run with a battery inserted. Ended up being a BIOS issue. Could this be a possibility for you?

[botero]

Re: Toshiba c855 - Hannstar E89382

Hi sparker1, i've read your thread and i've upgraded the bios to 6.60 version but nothing. When i insert the battery all the leds are on and the icon on windows bar shows the charge state on. I've found another laptop similar to my model and i've charged the battery. When i'm remounted the battery on own laptop i've seen that it works fine but not charge.
So i can say it's an issue on charger circuit. I've a doubt about the schematics because i don't found the same name and type of device on motherboard. Maybe i'm not so practise!

In the evening i would reopen the laptop to follow Francisco's suggestions.

[sparker1]

Re: Toshiba c855 - Hannstar E89382

Hi sparker1, i've read your thread and i've upgraded the bios to 6.60 version but nothing. When i insert the battery all the leds are on and the icon on windows bar shows the charge state on. I've found another laptop similar to my model and i've charged the battery. When i'm remounted the battery on own laptop i've seen that it works fine but not charge.
So i can say it's an issue on charger circuit. I've a doubt about the schematics because i don't found the same name and type of device on motherboard. Maybe i'm not so practise!

In the evening i would reopen the laptop to follow Francisco's suggestions.

There are at least two schematics. Here is the one I used. I have another one of these with a similar problem. Windows says "Plugged in and charging" but it isn't.

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

Sorry, I have being busy lately.

Due a jack repair the polarity has been inverted

I think, I misunderstood you. If laptop runs with charger, it's obvious that it has 19 volts in all circuits, then probably the problem is in the chip that controls the charger circuit. (ISL88731, PU1)
Could be also, that data bus coming from battery to pin 9 and 10, (SDA and SCL) doesn't work properly. (there have to be communication pulses in those pins)

I had the oppposite issue - would only work with AC and would not run with a battery inserted.

You have to check the same circuit, and PQ38,PQ39 also. When PQ39 conducts, current flowing trough it, feeds the laptop from battery.

[botero]

Re: Toshiba c855 - Hannstar E89382

I not sure for the schematic. I've searched the ISL88731 but i haven't found it. This component has 28 pins, on motherboard there's not nothing to similar. If i try to follow the circuit the components don't match the schematic. I've a doubt about one component but could be the hard disk controller, it hasn't 28 pins and any label on top, i've signed in red on pitcure. Could be an another model of smbus controller? I've attached pictures from front side and back side, too.

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

You should find PL4 (also mosfet PQ35, PQ36) equivalent in your MB. (near the battery connector) . From there, try to locate the chip than control the charge circuit , and look for its data-sheet over the Internet, then study it and try to find out all the information you can.
I know it's very difficult, but you can post your results, and ask for help.
Regards.

[botero]

Re: Toshiba c855 - Hannstar E89382

I've identified the charger section and i've found my component, it's a BQ25A. I've read datasheet, it's a 1-4 Cell Li+ Battery SMBus Charge Controller with N-Channel Power MOSFET Selector and Advanced Circuit Protection. Moreover, i've test all components in the section, there is only one zener that i'm not sure. Whit diode test i've continuity in bias and in reverse bias (value readed more higher).

Someone has to suggest some test before i change the BQ25A?

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

Check pin 8 and 9 (SDA,SCL) voltage, as I said before, this signals communicates with internal battery smart chip.
There is some protection diodes connected to this signals, near the battery connector, and could be in bad state.

[botero]

Re: Toshiba c855 - Hannstar E89382

I've found 1v without battery and 3,25v with battery half charged. I've checked continuity between battery connection and SDA and SCL pin, it's ok but there's not diodes and i've continuity in all tester tips position, bias and reverse bias. I've checked PQ35 and PQ36 without battery and there is 1v, too. I think there is some bad component on line that supplies power directly the motherboard because when i put the battery status led is on, when i put off and insert only the cable all leds are off and the all circuits look dead.

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

I've found 1v without battery and 3,25v with battery half charged. I've checked continuity between battery connection and SDA and SCL pin, it's ok but there's not diodes and i've continuity in all tester tips position, bias and reverse bias. I've checked PQ35 and PQ36 without battery and there is 1v, too. I think there is some bad component on line that supplies power directly the motherboard because when i put the battery status led is on, when i put off and insert only the cable all leds are off and the all circuits look dead.

The diodes I've mentioned, are PD4 and PD5, but if you have 3,25v, then I think it's OK.
SDA and SCL signals, are the same as MBDATA-MBCLK and goes to EC chip, U21 (WPCE775).

I think U21, is the one that controls the circuit for charging the battery, but if BQ25A is bad, the battery won't charge, and won't report battery status.

[botero]

Re: Toshiba c855 - Hannstar E89382

I'll change the BQ25A chip. If i had an oscilloscope i could see the MBDATA-MBCLK signal and determinate if they are the rights signals. I've read they are in the order of khz.

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

I'll change the BQ25A chip. If i had an oscilloscope i could see the MBDATA-MBCLK signal and determinate if they are the rights signals. I've read they are in the order of khz.

Yes they are pulses that you can hear with an audio signal-tracer.
Perhaps you can make a signal-tracer with a PC amplified speaker, or an old portable radio.
You can get ideas from Internet.
It is not an oscilloscope, but you know that DC voltage is good, and only needs to know if there are pulses.
Regards
PD: did you tried to update the bios?

[botero]

Re: Toshiba c855 - Hannstar E89382

In the features i've read "SMBus Host-Controlled NMOS-NMOS Synchronous Buck Converter with Programmable 615kHz, 750kHz, and 885kHz Switching Frequencies". I'm not sure i can ear something with this frequencies.
I tried update bios, from 6.10ver to the last 6.60 ver and nothing is changed!

[Francisco.s]

Re: Toshiba c855 - Hannstar E89382

In the features i've read "SMBus Host-Controlled NMOS-NMOS Synchronous Buck Converter with Programmable 615kHz, 750kHz, and 885kHz Switching Frequencies". I'm not sure i can ear something with this frequencies.
I tried update bios, from 6.10ver to the last 6.60 ver and nothing is changed!

The frequencies you mention, refers to the Buck Converter, not to the communication bus.
SMBus as I2C bus, are low frequency buses, not like SPI bus that can reach 100 Mhz. (good for bios flash)

http://en.wikipedia.org/wiki/Buck_converter

[sparker1]

Re: Toshiba c855 - Hannstar E89382

Botero, how did you go? Also thanks go to Franciso.s for helping.

[botero]

Re: Toshiba c855 - Hannstar E89382

I've read this topic https://www.badcaps.net/forum/showthread.php?t=21949 and i was inspired.
In the datasheet is written:

"System Power Selection:
The ACDRV drives a pair of common-source (CMSRC) n-channel power MOSFETs (ACFET and RBFET) between adapter and ACP (see Figure 1 for details). The ACFET separates adapter from battery or system, and provides a limited di/dt when plugging in adapter by controlling the ACFET turn-on time. Meanwhile it protects adapter when system or battery is shorted. The RBFET provides negative input voltage protection and battery discharge protection when adapter is shorted to ground, and minimizes system power dissipation with its low RDS(on) compared to a Schottky diode."

so i'll change ACFET and RBFET, too. Now i must know and try which of these are equivalents.