Toshiba T1000SE - Anyone know how the charging works?

[alank2]

I've got a battery pack, but its cells are long dead. I'd like to figure out how to open it without destroying it, but with contacts on multiple sides I'm not sure how to do that.

I did make up a NiMH 6 cell pack to just connect to the battery terminals which seemed to work, although sometimes it wouldn't come on without the AC also plugged in. The batteries were fully charged so that surprised me, but I wonder if some of the capacitors in the power/charging circuits are just maybe too old.

Anyway, I turned it off and the battery light comes on - which I took to mean it is charging. It didn't take long and the batteries warmed up because they were already fully charged. Does anyone know how the charging system works? Does it operate for a fixed period of time and they just assume the cells can take the heat? I don't see any details about this in the hardware manual.

 

[alank2]

I fashioned a new RTC/CMOS backup battery for it and one thing this changes is that it can power up now on a 7.2V battery connected to the battery terminals. Before it would take much more like 8V+ to power up.

I still don't have a sub battery built, but it is next.

Now that it will startup on the 7.2V AA NIMH cells, I can measure what some currents.

It uses about 650mA running off of battery.

If I connect a 12V power source to the DC IN, and it is off, it will charge the battery around 650mA (battery light lit). Last time I let it do this for awhile, the AA cells got pretty hot. They were fully charged and this is 1/3C being forced into them.

If I turn it on, battery charging will slow to half that or around 300mA (battery light not lit).

Oddly, if I try to unplug the DC and replug it WHILE THE UNIT IS ON, it won't transition from battery back to AC mode. It repeats a sequence where it uses more of less of the battery, but it never charges it at the 300mA mode light it should. Something is definitely not right. If I power it off, then back on with 12V DC present, it will then charge the battery at 300mA.

Any ideas of what to look at? I suppose it is possible it might be different with a sub battery installed.

Also, my RTC/CMOS battery which is two 1.2V NiMH cells never seems to fluctuate. The voltage is about the same off, on battery, on wall, etc. I wonder how/when it charges.

 

[bola_dor]

I've just started to resuscitate a T1000SE too, so I'll keep watching. And let know If I discover something..
What are the sub battery specs?

this was posted on the 386/486 forum perhaps some mod can fix that..

 

[alank2]

Sub battery = AAAA NiCD cells, 5 of them inline.

I don't remember posting it in 386/486 forum, so maybe it was moved here?

 

[bola_dor]

Hi Alan, I'vechanged all the awfully bad Nichicon electrolytic capacitors, in the PSU main board and two from the display PSU board. A lot of work as the solder in this boards is really difficult to take off..
Thing is it still doesn't work. Red led is blinking. I,ve connected a lab PSU to the battery terminals at 7.2, 7.3 and 8v.. perhaps more.. nothing. I places a diode at one of the terminals and connected the external 12v PSU to the socket.. and still nothing.. I have 5.5v at the battery terminals if only the 12v PSU is connected.. RTC bat terminals have 1.5v and Sub bat 5v..
Something is wrong but I don't have a clue now.. I'll try to fit a 3v lithium bat to RTC and 5 AAAA to the sub battery, both with diodes to avoid any recharge to them...

Now Display blinks shortly when I pres start button. Allnorange with some thin horizontal lines.

 

[GiGaBiTe]

Hi Alan, I'vechanged all the awfully bad Nichicon electrolytic capacitors, in the PSU main board and two from the display PSU board. A lot of work as the solder in this boards is really difficult to take off..

If you don't have a suitably powerful iron with a large enough tip as a head reservoir, then the PCB can suck all of the heat out of the tip before it can melt anything. I'd recommend a 60-80W iron and using plenty of flux.

Thing is it still doesn't work. Red led is blinking. I,ve connected a lab PSU to the battery terminals at 7.2, 7.3 and 8v.. perhaps more.. nothing.

Don't start slapping random voltages across the battery terminals if you aren't sure what they're supposed to be, or you'll end up frying something.

I places a diode at one of the terminals and connected the external 12v PSU to the socket.. and still nothing.. I have 5.5v at the battery terminals if only the 12v PSU is connected.. RTC bat terminals have 1.5v and Sub bat 5v..
Something is wrong but I don't have a clue now.. I'll try to fit a 3v lithium bat to RTC and 5 AAAA to the sub battery, both with diodes to avoid any recharge to them...

Now Display blinks shortly when I pres start button. Allnorange with some thin horizontal lines.

Many Toshiba laptops of that vintage used 18v for the DC barrel jack, but I can't find a definitive answer for that laptop.

 

[alank2]

I think it is labeled on the DC IN that it is 12V. Verify this as my unit is put away at the moment and I can't check it.

The red LED per the service manual:

This indicator lights red if power is supplied from AC
adapter when you connect the AC adapter to T1000SE and a
wall outlet. If the AC adapter's output voltage is abnormal,
the indicator labeled "DC IN" flashes red.

It might be affected by whether both things are present. Is a 4x NICD battery pack (C cells) present on the battery connector? Is the right DC voltage coming in on the external power input? I suspect there is something controlling the charging, but without a schematic or diagram I have no real idea. It says it has an "intelligent power supply" in one diagram, but I'm not sure how intelligent it is.

 

[bola_dor]

Yes I have the original PSU and is 12v and I think it's switching or at least ragulated..
I guess that with "inteligent power supply " it refers to the internal PSU circuitry that it's not working in mine. It should be feeding something higher than 7.3v to the main battery to recharge it and it's only giving 5.5v
I will replace the RTC and sub battery and give it another chance.

 

[alank2]

It does seem more functional when all the batteries are present. I tried to substitute some AA NiMH and it was charging them too fast and they were getting hot. I think it really needs NiCD C or larger.

 

[bola_dor]

Good to know, thanks you!!
Yes NiMh are less tolerant to charge and load than NiCd. Usually the reverse exchange is easier. In the mean time I will use a lab PSU to the battery conectors with a diode to avoid any recharge attempts..

 

[T-R-A]

It does seem more functional when all the batteries are present. I tried to substitute some AA NiMH and it was charging them too fast and they were getting hot. I think it really needs NiCD C or larger.

NiMH batteries often get pretty warm, especially if they're nearing an end-of-life state. But you're correct in replacing with Ni-CADs, if that's what the machine came with.