Old Toshiba Satellite Pro 440CDT Has Odd Issues?

Discussion in 'Computer Hardware, Devices and Accessories' started by Friendsxix, Jul 9, 2017.

  1. Friendsxix
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    Friendsxix Introspective Potato

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    I recently acquired a fairly old laptop from a Goodwill for $10 -- a Toshiba Satellite Pro 440CDT. The machine shipped with Windows 95, and I managed to upgrade it to 98SE. The machine seems to function almost perfectly, except for two really bizarre issues.

    First, the right speaker seems to be out, despite the good condition of the machine. Perhaps coincidentally, the right channel is also out when you plug in a pair of headphones, but it comes back if you push on the jack. Considering the laptop was owned by a law firm (as evidenced by a sticker on it), I doubt the jack is damaged. After some light disassembly, it seems the sound card (a Yamaha OPL3-SA3) is situated immediately behind the jack. Perhaps the pressure on the card fixes it?

    Secondly, and perhaps more annoyingly, a few keys on the keyboard seem to not work. Specifically, the Windows key, Caps Lock, and the Left Control keys. Normally I'd assume the keyboard just failed, as it's a membrane keyboard. However, the keys will work if you also press an adjacent key simultaneously. For example, if you hold Tab and then press Caps Lock, the key will work. If you hold Alt, the Left Control key will work. And lastly, if you hold Pause/Break, the Windows key will work. Whatever failure the keyboard has does not appear to be straight forward...

    Any tips people could give me would be greatly appreciated. Amazingly, the original battery still holds a charge, powering the laptop for a little over an hour. :P
     
  2. FAST6191

    FAST6191 Techromancer

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    If the laptop was a presentation laptop then it could have had the audio jack rammed in and out a lot. First thing I would look at is if the little tabs inside the thing have bent (if you have had a phone think it is in headphone mode then same thing).
    After that then yeah a cold joint somewhere would be what I look for, step one being the jack itself (mechanically speaking you can have a lot of force applied to it and only resisted by a couple of solder joints -- if you have ever had a USB charge port fail on a device then probably the same deal).


    No windows key is usually considered a bonus. Anyway keyboards tend to be in a matrix (why when you spill things it can end up as clusters of keys which go out, or start pressing repeatedly, if you have never seen a circuit then http://blog.damnsoft.org/wp-content/uploads/2015/07/K40-1-Matrix-Keyboard-Schematic.png ) and an adjacent key could provide a path. Alternatively it could be something more mechanical. If you can take the keyboard off and check the connector (if it is a ribbon then clean it carefully, if it is a connector block then take it in and out a few times) then do that as it is it easy and you will have to take it off anyway.
    After that you are pulling it apart to clean and check traces. I don't know what it will be like for this one but there is a reason I tend to just buy a replacement keyboard, or chuck an external one on there, when it comes to dodgy keyboards. The former is probably not going to be as doable here though.

    On the battery it is probably a NiCad one and while they are perhaps not as high power as Lithium they don't suffer deep discharge type issues quite as much, and if they are stored at sane temperatures it can take years and years for it to happen.

    P.S. There is a port replicator ( PA2717U ) going for less than $10 buy it now on ebay, it might even be incorrectly listed as a II when it is a III (the PA2717U number in the manual I link in a second says III but the listing says II so who knows). If you can get a docking station/port replicator for a laptop you own I highly suggest it.

    Specs sheet
    http://support.toshiba.com/support/staticContentDetail?contentId=638341&isFromTOCLink=false
     
  3. Friendsxix
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    Friendsxix Introspective Potato

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    I just tried taking the sound card in and out, and magically the right speaker started to work again! :)
    However, the audio that comes out sounds horribly tinny, and low in volume. In fact, I had to push the balance all the way to the right, and raise the volume to the max, for it to be close to usable. The audio I get from the headphones by pushing down on the plug does not sound tinny like this. I'm not sure what the issue could be, as the speaker doesn't appear damaged. :unsure:

    Sadly, the right channel from the headphone jack still refuses to work. :(

    So, I looked inside the audio jacks, but all three (Line-in, Mic, and Headphone) looked to be in identical condition, making me doubt a mechanical failure. I have a multimeter on hand (Fluke 115), though am not well versed in its operation. If you could provide any tips on checking for cold solder joints, I'd appreciate it. :P

    I tried cleaning the keyboard's ribbon cable with an eraser, but it still has the same problem. I found a cheap-ish replacement keyboard on eBay for $10 shipped, so I'll give that a whirl.

    I also added a 48MB RAM card to the laptop (part KTT500-48), as I noticed that even Windows 98 started to page with the paltry stock 16MB. With the now combined 64MB, things seem to run better. :)

    Lastly, I purchased the port replicator that you suggested, so it won't matter as much if I can't get the front audio jack working (though I'd still like to for portable retro gaming). It'll also be awesome for its joystick port, so I can use my IBM joystick with a few games. :D
     
    Last edited by Friendsxix, Jul 10, 2017
  4. FAST6191

    FAST6191 Techromancer

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    That sounds like a dodgy connection somewhere along the line (if it is high resistance you get that). The connector itself could be a thing, alternatively manhandling it might have helped a bit.
    The headphone might well use a separate path.

    Cold joints I usually go for a combination of visual (if they are dull, obviously if there is a crack, if it looks like the lead is poking out of something rather than all around it then it could be cold) and brute force (most things I fix have maybe 20 joints in the path, easy enough just to reflow them with an iron in that case). You can try resistance tests but they are not so reliable at times, not to mention you will have to figure out what is the good value/range (probably using the left speaker path).
     
  5. Friendsxix
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    Friendsxix Introspective Potato

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    Okay, I just found the weirdest thing. While toying with my malfunctioning keyboard, I have discovered that if I remove the keyboard from the chassis, and do the aforementioned trick to make one of the problem keys work, the problem key will keep working until the keyboard is placed back in the chassis. I suspected the ribbon cable, but then I found that the issue only came back when the keyboard touched the metal part of the chassis. To confirm my suspicions, I took a screwdriver and touched the back of the keyboard. Nothing. I then touched one end to the metal of the chassis, and the other end to the back of the keyboard. Magically, the keys stopped working. This is extremely puzzling. Perhaps even more odd is that the fix is persistent across power cycles. If I leave the keyboard out of the chassis in a working state, shut down, and then start up again, the keys still work until the metal of the keyboard touches the chassis. :unsure:
     
  6. FAST6191

    FAST6191 Techromancer

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    In that case either the chassis is live and causing fun there, probably not as there would be other effects.
    Or the chassis is providing a path to ground that does not want to be there.

    A solution would be to put an insulator between the keyboard and chassis. Depending upon how it is put together that might be easier said than done.
    The next would be to figure out what is causing it. The classic one is someone put it back in but left a screw in there and pushed in part of the case (if you have ever seen someone shut a laptop on a pen and break then screen then same idea) into contact. Another is all those are usually in the same location; someone might have not put it back in properly and twisted the case to much the same effect. Either way you are going to want to take out the dents/bends and that is not an easy task for any sheet metal really, never mind the tissue thin thing on most keyboards. Part of the reason I replace keyboards rather than clean them to fix when they have things spilled in them is because disassembling them is a nightmare.
     
  7. tedmg091309131

    tedmg091309131 GBAtemp Regular

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