VOGONS


First post, by vvbee

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Have a TI TravelMate 4000M laptop (486) that doesn't work, and am looking to either fix it or strip it for parts. Was sold as non-working, and got lots of cosmetic damage in shipping.

What it does on power-on is it illuminates the power light and the keyboard leds, and spins the hard drive. No image on screen, and no signal to an external monitor. This is also how the seller described it. No indication of hdd activity, except the hdd led blinks once or so right after power-on. Curiously, the keyboard indicator lights don't respond to keyboard input - you can press the numlock or whatever and the light won't change - until you cycle power. For whatever reason, it seems that the caps lock controls the numlock light, and the numlock controls the caps lock light, or something like that. It's possible the lights just come on randomly each bootup, but I'm not immediately sure that's the case. If you keep the laptop running for a minute or two, it starts erratically beeping and blinking the battery light, whether there's a battery or not. The ac adapter (original for this model) is from another source, but measures good and looks ok internally.

I tried a few basic things already. There was an optional ram expansion installed, removing that didn't help. Removing the hard drive and floppy drive did nothing. Removing the battery, nothing, same with unplugging the battery leads off the motherboard. Capacitors seem fine. Can't see leakage onto the board from the motherboard battery, but there is some discoloration at the terminals. Tried blindly triggering some common keyboard shortcuts, but nothing, not even hdd activity. There was a screw missing off the bottom, so someone may've had a go at it already.

Haven't yet tried powering it on without the sound card, which probably won't do much good, haven't tested for any blown fuses, and haven't taken off the motherboard battery. All I can think of right now. Any knowledge on this particular topic?

Reply 1 of 8, by vvbee

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Video of the laptop trying to boot: https://www.youtube.com/watch?v=8hWaYjWiLD4 (one of the capacitors has a smudge on it - that's not leakage)

The red light blinking is the battery indicator. No battery is connected. The manual says an amber light here means the battery is charging, while a red light that the battery is low. Can't tell whether that's amber or red on there, but I guess it's red. The beeps come from the beeper, and don't seem to transmit a code of any kind, sound more like an intermittent connection. It seems that if the laptop is off for a while, it takes a bit of being powered on for the beeping to start, and after that, it starts pretty soon after bootup, though not always immediately after.'

The laptop indicates some life in that if the internal 'screen bezel down' button is pressed while powered on, the beeper gives a steady on-off tone, which the manual indicates is a correct thing. The laptop should then shut down the lcd screen and route the image to an external monitor, but that doesn't happen.

The motherboard hdd connector outputs about 4.9 v, which seems ok.

Reply 2 of 8, by vvbee

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Well, maybe the fact that there are scorch marks on the power input board has something to do with the thing not working, huh?

[images]

Images from the back and front of the board, centered on the same area.

Looking at the side of the oscon capacitor on the left (the red smudge on top of it is marker, or looks like it to me anyway), it seems it's the black component to its right that's been getting hot. Not my expertise - that a resistor of some kind? What would it be doing heating up? There's some black buildup on its leg on the left, too, doesn't look healthy.

Not sure how I missed this at first, but reviewing my pictures from the day I got the laptop, the browning seems to have already been there. As I mentioned in the first post, I'm using an ac adapter that's designed for this model, looked clean inside to an amateur, and with a multimeter, before connecting it to the laptop, at least gave out the rated voltage. So I'm guessing this happened before I got the laptop.

Last edited by vvbee on 2017-05-20, 22:12. Edited 1 time in total.

Reply 3 of 8, by vvbee

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Resistor still within its 5% spec but physically done. Removal of some components in the area shows the pcb is a charred write-off. Unless someone in europe is looking to sell a full working power board, #9792511-0001, this one's for parts.

Reply 4 of 8, by vvbee

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On further inspection, the pcb may be salvageable. Some darkening on the backside, but the surface is good. Whether the pcb is charred underneath I don't know, but given that nothing sparked or appeared to short while I had it running, I assume it's ok. For safety, scraped off pcb charring on the front under the resistor. Went all the way down to a large copper plane. I assume it's fine once the crater is filled with epoxy, and hope that there were no layers between the surface and the plane. Some rough spots on the pcb's surface in that area remain but don't seem to be conductive.

The working hypothesis is that in the laptop's previous residence, someone hooked up the wrong ac adapter, or something to that effect. The resistor got plenty warm, as did other components near it. That something got too hot on there is clear, but what all got damaged isn't. The latter might well include the caps next to the resistor, though the resistor itself kept functioning. The main board can still run the hdd, and for a brief moment at bootup detect keypresses. The hdd is getting 4.9 v or so, and nothing on the main board appeared to be getting hot. The power board convects fairly warm air when the laptop was on, maybe 40-50 c, but whether that's abnormal or from which component(s) is unclear. That the lcd doesn't come on and the computer freezes once it's on could indicate among other things low voltage.

The plan is to finish cleaning up the pcb and to replace the resistor and all through-hole caps on the power board, with the fairly hopeful assumptions that (a) the problem of the computer not booting is on the power board, (b) some of the power board's capacitors are bad, (c) what caused them to go bad was external and has been removed, and (d) nothing not to be replaced now was fried with the caps.

Reply 5 of 8, by vvbee

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Replaced the resistor and three of the four oscon capacitors. Was hoping to get away with not replacing the fourth capacitor furthest from the burnt resistor, but no. Still no apparent boot besides lights on, still no image on screen, and still no response to keyboard input. On the other hand, the random flickering of the battery light is gone, a seemingly more normal level of heat is emanating from the power board, and the cpu is now getting slightly warm. So maybe an improvement, and maybe not. The most obvious next step would be to replace the fourth capacitor, but this oscon series should generally be high quality and not fail willy nilly, so I'm not sure whether that's going to help really. There's another oscon on the main board, but...

Reply 6 of 8, by vvbee

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Replaced the last cap, but same deal. Given all, can conclude that assumptions b and c were likely correct, c more so, while assumption d was likely not. Good effort, but whoever broke it did a better job.

Reply 7 of 8, by sangokushi

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vvbee wrote on 2017-05-17, 18:00:
Have a TI TravelMate 4000M laptop (486) that doesn't work, and am looking to either fix it or strip it for parts. Was sold as no […]
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Have a TI TravelMate 4000M laptop (486) that doesn't work, and am looking to either fix it or strip it for parts. Was sold as non-working, and got lots of cosmetic damage in shipping.

What it does on power-on is it illuminates the power light and the keyboard leds, and spins the hard drive. No image on screen, and no signal to an external monitor. This is also how the seller described it. No indication of hdd activity, except the hdd led blinks once or so right after power-on. Curiously, the keyboard indicator lights don't respond to keyboard input - you can press the numlock or whatever and the light won't change - until you cycle power. For whatever reason, it seems that the caps lock controls the numlock light, and the numlock controls the caps lock light, or something like that. It's possible the lights just come on randomly each bootup, but I'm not immediately sure that's the case. If you keep the laptop running for a minute or two, it starts erratically beeping and blinking the battery light, whether there's a battery or not. The ac adapter (original for this model) is from another source, but measures good and looks ok internally.

I tried a few basic things already. There was an optional ram expansion installed, removing that didn't help. Removing the hard drive and floppy drive did nothing. Removing the battery, nothing, same with unplugging the battery leads off the motherboard. Capacitors seem fine. Can't see leakage onto the board from the motherboard battery, but there is some discoloration at the terminals. Tried blindly triggering some common keyboard shortcuts, but nothing, not even hdd activity. There was a screw missing off the bottom, so someone may've had a go at it already.

Haven't yet tried powering it on without the sound card, which probably won't do much good, haven't tested for any blown fuses, and haven't taken off the motherboard battery. All I can think of right now. Any knowledge on this particular topic?

Hi vvbee, I recently bought a TravelMate 4000M. How can i remove/replaace the hard drive? Do I need to remove all the screws at the bottom? Thanks!

Reply 8 of 8, by vvbee

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sangokushi wrote on 2021-11-07, 08:44:

Hi vvbee, I recently bought a TravelMate 4000M. How can i remove/replaace the hard drive? Do I need to remove all the screws at the bottom? Thanks!

Can't remember, sorry. Maybe you did need to take off the whole case. I do know the laptop's plastic is brittle and the monitor hinge is especially easy to break if you start removing screws and then opening the lid.