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Thread: Dead Toshiba T4500C

  1. #1

    Default Dead Toshiba T4500C

    So,
    I picked up another dead Toshiba from local auction site (for eur 19,- shipping included).
    It's a T4500C with a dead battery and it won't start with the power charger either with battery unplugged.
    Instead, the display shows a P30 error. Quick googling reveals, it is a "overvoltage" error. But the charger
    seems to be ok, giving 15,16V with on load on it.

    Cause might be dead caps at the power supply board. I listed all electrolytic caps there is (I already took the unit apart):
    6,5V/1500uF (x2 units)
    6,3V/1000uF (x1)
    25V/470uF (x2)
    16V/56uF (x2)
    25V/33uF (x1)

    I'm hunting cheap caps from ebay, since it'll take most likely 6 weeks to get all,
    in the mean time I'm thinking if I could try to get some life by giving power to the board
    from battery leads.

    1.jpg
    2.jpg

    The battery is 9,6V, but there are 4 leads ? Does someone know the pinout for these ?
    I'm not sure I have 9,6V psu, but maybe 9V / 10V I could find.

    I tried the motherboard leads with multimeter after plugging the power supply on.
    Let's read the contacts as A, B, C and D on the motherboard (A being negative, D being + on the motherboard).

    When the power connector is plugged in, I'm getting zero voltage between A and D.
    Since the battery is 9,6V, shouldn't this be also be 9,6V or slightly higher as the battery should be charged
    from these pins ?

    I'm getting 1,26V between A and B. And 4,86V between A and C contacts on the motherboard.
    But, since I have no pinout, I can't imagine, what voltage these pins, B and C should have.

  2. #2
    Join Date
    Feb 2006
    Location
    in the basement
    Posts
    913

    Default

    Quote Originally Posted by VintageVic View Post
    .....the display shows a P30 error. ....
    I have a dead Toshiba too that probably has the same issue. Would you please
    explain what the display is .....and how you notice a P30 error? My laptop is
    dead as a door nail and I get nothing on the screen...


    ziloo

  3. #3

    Default

    P30.jpg

    Sure thing, Ziloo. The picture above is self explanatory, I hope ?
    Older Toshiba models, like the T1900C (that I also have in pieces...) do not have that
    little display there. Instead, it only has LED indicators for battery and so on.

    The T4500C has that little display. It has charging icon there, when the power supply is plugged in.
    When start button is pushed, the P30 error appears and nothing else happens.

    At least, this one is not dead as a nail, eh ? =).

  4. #4

    Default

    I have a T4600C which had the same problem. Replacing the single 6.3V/1000uF capacitor fixed the P30 problem, but it still had problems. Being stupid, I replaced most capacitors with ones which were as close as I could find in my box of caps, and I did not record the original values.

    Now, the system spuriously turns on when connected to power (even if connected to the DeskStation). Very creepy when it starts booting in the middle of the night...

    Anyway, I assume that the whole T4500/T4600 series share the power circuitry. Could you please take a picture of the power supply of your device and label the capacitors? It seems that I should replace all caps with new and correct ones now...

    Regarding the battery, I just replaced the NiMH cells in the past. That made the system work, but the shown percentage was completely off and the device would simply turn off after a few hours with 80% on the display. At that point, I stopped using the battery and a year later, stashed the system away completely.

  5. #5

    Default

    Thanks for your input, Svenska!

    I will be changing the 6.3V/1000uF cap first. I have already ordered the caps (from China), but it will take weeks before
    they arrive to me. On the positive side, they cost next to nothing.

    I have already ordered ESR meter a month ago. I'm hoping for it to arrive as well soon, it would help me document
    capacitor esr values after removing them.

    Just to be exact, did you have exactly the P30 error - and not P31 or anything else ? If it was P30 and you got it fixed,
    this gives me hope that this unit might be salvageable as well.

    I believe, that the 1000uF cap was at the very corner of the pcb. I will take a picture of the layout and check the locations
    of each cap and their values for you. Might help someone else too later. However, currently I'm not with the parts, since I'm still
    between two jobs (and two locations) for another couple of weeks.

    Did you notice, that there was a small block between the capacitor pins? I believe that they are surface mount resistors.
    Just wondering, if you accidentally removed them at the same time you removed the old caps ? They are very small in
    size and even difficult to see, at least for me. If some got missing, perhaps that might cause some of the symptoms you mention on your device.


    Edit:
    Oh, by the way, I found PSU, that gave 9,23V (at 1 amp). I tried to connect it to bettery connectors (+ and -) leaving the two center
    connectors empty. I could see some symbols on the little display. Trying to power on the laptop however did not have any effect.
    No P30 error, nothing. Absolutely no change. Either that little PSU is not sufficient for the task or, maybe something is required
    to be connected to the two center contacts as well. I'm not going to risk attempting to try that any further, just waiting to get the spare caps.
    Last edited by VintageVic; November 23rd, 2020 at 07:31 AM.

  6. #6

    Default

    Quote Originally Posted by VintageVic View Post
    I will be changing the 6.3V/1000uF cap first. I have already ordered the caps (from China), but it will take weeks before
    they arrive to me. On the positive side, they cost next to nothing.
    Well, this is why I replaced them with "mostly-fitting" parts. I guess my current problem is caused by some voltage leaking across the power switch - when the system has been turned on spuriously, I cannot turn it off by using the power switch. Therefore I'd like to replace all caps with their correct ones.

    But I have time. The original replacement was done before I converted my second desk into a home office... so a few months more or less don't hurt. It's just very exhausting taking the unit apart.

    Quote Originally Posted by VintageVic View Post
    Just to be exact, did you have exactly the P30 error - and not P31 or anything else ? If it was P30 and you got it fixed,
    this gives me hope that this unit might be salvageable as well.
    Yes, it was the P30 error specifically.

    Quote Originally Posted by VintageVic View Post
    Did you notice, that there was a small block between the capacitor pins?
    No, I didn't notice anything special when I had the unit open. I'm reasonably sure I wouldn't have removed resistors... but one never knows about one's past stupidities...

    Quote Originally Posted by VintageVic View Post
    Oh, by the way, I found PSU, that gave 9,23V (at 1 amp). I tried to connect it to bettery connectors (+ and -) leaving the two center connectors empty. I could see some symbols on the little display. Trying to power on the laptop however did not have any effect.
    I never attempted this. My battery has seen far better days, partially due to me messing around it incompetently years ago, and I am contemplating just removing the insides completely to make the unit lighter.

    Back in spring, I also learned that the sound card inside the docking station had died (although the Panasonic CR-562 CD-ROM drive connected to it still worked fine). I never succeeded installing an IDE drive inside this unit, which is why I chose this specific drive.

  7. #7

    Default

    Alright, I'm back at the drawing board.

    PSU_caps.jpg

    I took picture of the power supply and marked the capacitor values. I'm making some progress myself here as well!
    I was able to remove the 1000 uF cap (relatively) nicely without dropping the surface mount resistor away.

    I noticed while I was in city that there was electric component shop not too far away. I became impatient and didn't want to wait
    for 6 weeks any longer, since a few caps does not cost many euros in any way. I got all the needed caps for 6 euros - the ones that
    are coming from china I might use on other projects later. Hey - maybe I need to buy dozen of these Toshibas for repair, since there are bunch of caps coming =).

    And so, did I get rid of the P30 error by just replacing that one cap? Hell yeah ! But. I soon found out, I'm not out of the woods just yet:

    1.jpg
    2.jpg
    3.jpg

    No longer P30 error, but the little display shows "ON" symbol. And some strange 'faucet' symbol, what ever that means ?
    I think also, the floppy symbol comes on and goes away, probably it is trying to see if anything is at the floppy drive.

    But the screen. There are definitely some gray pixels there. The back light comes on. I noticed that I had left a couple of
    ground wires unattached. I closed the power, attached the ground wires and the hard drive and tried again. Now a big blog of gray
    instead of horizontal gray lines. On a third attempt, again, horizontal gray lines.

    The hard drive is starting to spin. But I do not hear it starting to move the heads, like what I should expect if the unit was booting
    from there.

    Now I have to think a bit, what to try next. I'm assuming that it is pointless to start changing the rest of the caps, since the computer
    is clearly now getting power. This issue most likely is not the power supply any more, but something else.

    In any case, I'm grateful that there is at least back light and that the hard drive is spinning. I made a step to the right direction here =).

    Thanks Svenska for your insight!!

  8. #8

    Default

    I figured out, I might put the keyboard in.

    Tried to press enter, but nothing happened. By pressing F1, I seemed to got into bios:
    4.jpg

    I escaped without saving from there. Of course, the bios battery is dead and the unit has forgotten what hard drive it
    is attached into. That is why it will not boot.

    It is real pity, that the up part has that gray block in it. after escaping bios, it goes like this:
    5.jpg

    I see the cursor is there, but not what is above it. Most likely and error like 'non system disk or disk error, insert boot disk'.

    I need to look into the manual, but I'm starting to suspect that the unit has got wet, because it shows faucet logo.
    damn, so close and so far...

    I checked already that the busted T1900C I have has different type of screen connectors so it is at least not directly able to be replaced
    here.

  9. #9

    Default

    I opened the cover from the screen. There is definitely something going on there in the upper corner:
    6.jpg

    Perhaps this screen has at some point of it's life been warranty repaired? Looks like it has been tampered with.

    Problem area matches to screen issue:
    7.jpg

    And I got whole new (warning?) icon:
    8.jpg

    Book? Toaster ? Yeah, maybe it knows it is toast .

  10. #10
    Join Date
    May 2011
    Location
    San Antonio, TX
    Posts
    377

    Default

    That's a bookmark in a book. If I had to guess, that's for when the computer puts your info on the hard disk, goes to sleep, and turns off. (i.e. marking your place in your work to come back to it.)

    I don't think it's impossible to fix a display like that. It looks like some of the screen cable's pads were not attached properly. It just needs to be pressed down while melting the solder. I've practiced on a similar screen.

    Also, I think the faucet is meant for power-saving indication. Laptop computers at this time would change how much power went into the computer, like a faucet, to save power in the battery.
    Last edited by T-Squared; November 25th, 2020 at 10:22 PM.

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