Urgent help needed for my Powerbook 170!!!

Cyclone740

Tinkerer
Oct 29, 2023
105
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There will be leakage under the caps most likely, it's probably just fresh enough not to have corroded anything yet. If it's in that good of shape, then yes, it will likely be good again after a recap.
Post photos of both sides of the PSU board too, that will be helpful.
Ok I will do that as soon as I get home.
 

Cyclone740

Tinkerer
Oct 29, 2023
105
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There will be leakage under the caps most likely, it's probably just fresh enough not to have corroded anything yet. If it's in that good of shape, then yes, it will likely be good again after a recap.
Post photos of both sides of the PSU board too, that will be helpful.
Here are the photos.
 

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Androda

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Try whatever you’ve got.
With what you’ve said now though, you’re not gonna get a chime. Your PSU is bad. It shouldn’t ever drop from 7.5V or thereabouts.
I'm pretty sure it should drop the output voltage when the current limit is reached.

If it's dropping to 1.1v then either the adapter is bad or there's actually a short and it's protecting the system.
 

Cyclone740

Tinkerer
Oct 29, 2023
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I'm pretty sure it should drop the output voltage when the current limit is reached.

If it's dropping to 1.1v then either the adapter is bad or there's actually a short and it's protecting the system.
Ok so if it is shorting where abouts would it be most likely to be shorting?
 

Cyclone740

Tinkerer
Oct 29, 2023
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Also does the bottom of this capacitor look like it has started leaking? And also do you think that this reflow job for all of the solder point on the underside of the psu board is good? (Ingore the holes they are just where I have removed to two biggest caps.)
 

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Cyclone740

Tinkerer
Oct 29, 2023
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Hey ok so this is what I am getting now. I think you were right with is being a bad cap.

Now all I need it to see if there is still something wrong with it or if this is normal?

Because no sad mac or anything on the screen.
 

Cyclone740

Tinkerer
Oct 29, 2023
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And I also have power button functionality back.

I don't care about the tunnel vision at this stage I just want the thing to work some what.
You can recap it, yes. Thing is that they're a royal pain to crack open, the ELNA caps' leakage inside is a huge pain to clean up, and when you're done there's a well under 100% chance it will work right. I've had a stone-dead OEM supply for almost 2 years now that I still haven't gotten around to recapping yet just because my aftermarket ones work just fine.
By all means, go ahead, but it will be a lot more work.
 

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Cyclone740

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Oct 29, 2023
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And I also have power button functionality back.

I don't care about the tunnel vision at this stage I just want the thing to work some what.
Any advice or insight into both what is going on and how to fix it would be greatly appreciated.
 

Androda

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Ok so if it is shorting where abouts would it be most likely to be shorting?
I'm not an expert on the 170. But a short should be causing a lot of heat to be generated by the component which failed.

Could be a chip, a capacitor, a mosfet, a resistor, tons of possibilities.
 

3lectr1c

Active Tinkerer
May 15, 2022
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You have a later revision power supply without ELNA caps, the ones that fail most frequently. Still, seems they were bad based on the bad voltages.
Start the system with the hard drive disconnected now that you have power and then see if you get a question mark.
Bad SCSI drives can hold up the bus. You probably have a cursor but can't see it because of the tunnel vision.

Also, make sure you're getting a chime out of the headphone jack.

Double check that you now have stable voltages.

And to answer your question - 1 or 2 volts won't be enough to get any activity out of one of these.
 
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Cyclone740

Tinkerer
Oct 29, 2023
105
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You have a later revision power supply without ELNA caps, the ones that fail most frequently. Still, seems they were bad based on the bad voltages.
Start the system with the hard drive disconnected now that you have power and then see if you get a question mark.
Bad SCSI drives can hold up the bus. You probably have a cursor but can't see it because of the tunnel vision.

Also, make sure you're getting a chime out of the headphone jack.

Double check that you now have stable voltages.

And to answer your question - 1 or 2 volts won't be enough to get any activity out of one of these.
I will have to show you what seems to be coming up when I don't have the HDD connected. Plus can I ask if it is normal for the screen bezel to not sit quite right after reassembling the display construction? I am feeling as though I am having to modify the shell slightly to allow me to put it back together properly.
 

Cyclone740

Tinkerer
Oct 29, 2023
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It should sit correctly under normal circumstances. Sounds like the alignment is off on your plastic fixes.
I figured as much, but I done know where the fault would be though. I will have to keep you all posted. But just as a form of extra information, the bezel is just simply not setting properly around the right hand side hinge, and when I look at it, it looks as though the item that is most likely causing the issue is the screw well on the right hand side of the screen bezel where it sits against the hinge. If I have done something wrong please let me know I will be sending some photos this afternoon when I am back at home.
 

Cyclone740

Tinkerer
Oct 29, 2023
105
8
18
Sounds like an alignment issue there with your repair. Yes, send photos when you can.
Ok, firstly I just want to start off by saying sorry for the late reply, life has gotten busy lately, but I should be able to work on the powerbook 170 some more in the foreseeable future.
Secondly, I would to say that yes one of the posts that is used to hold the screw in place, was out of alignment. I had ago at fixing it and I managed to sort it out...
only to then over correct and make it slightly misaligned in the other direction. I am going to have a go at fixing it one final time and then I will be done with it.

After that I want to look at sorting out the screen maybe, or even work on troubleshooting the motherboard side of things, or even both.

I was hoping that someone could please give me a detailed description of what they did to get their screen fixed?
Currently all I know is that I need to bake it in the oven for 5hrs at 100⁰C.
The things is I don't quite know if I am to preheat the oven to that temperature? Put the screen in while the oven is off and let it heat up to the 100⁰C at the same rate as the oven? Put the screen on a tray or just place it onto the oven grate? And do I use so.ething like chopsticks to raise it slightly if I do put it on the tray? Also is it better to use an air fryer? Or a convection oven? Also if I am to use the convection oven, do I have the fan turned on? Or do I leave it turned off? Also should I have something on top of the screen to apply pressure to it while I let it bake? Or is it not necessary? Lastly, when taking it out after the cooking, do I first leave it in the oven too cool down with the oven, or would it be better to work with the screen while it is still hot?

I am hoping to have the screen done today or this week, so I was hoping that I could maybe get a responce quickly to these questions. Thank you.

Thank you all again for all your help so far with this project, this has helped me out so much.
 

Paolo B

Tinkerer
Nov 27, 2021
258
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There’s no real fix. At best, you can get some temporary improvement. Those screens were technically flawed, in the sense that they were not built to survive the long term environmental aging. Chemicals such as glues irreversibility deteriorates. I got some kind of improvement with my unit by keeping it constantly in a dried up environment (a sealed bag with silica inside). So, instead of darkening after 3 minutes, it now lasts - say - half an hour. Enough for a nostalgic rendezvous, but surely not a machine I can use for any real purpose.
 

Daniel Hansen

Tinkerer
Oct 29, 2021
175
130
43
Ok, firstly I just want to start off by saying sorry for the late reply, life has gotten busy lately, but I should be able to work on the powerbook 170 some more in the foreseeable future.
Secondly, I would to say that yes one of the posts that is used to hold the screw in place, was out of alignment. I had ago at fixing it and I managed to sort it out...
only to then over correct and make it slightly misaligned in the other direction. I am going to have a go at fixing it one final time and then I will be done with it.

After that I want to look at sorting out the screen maybe, or even work on troubleshooting the motherboard side of things, or even both.

I was hoping that someone could please give me a detailed description of what they did to get their screen fixed?
Currently all I know is that I need to bake it in the oven for 5hrs at 100⁰C.
The things is I don't quite know if I am to preheat the oven to that temperature? Put the screen in while the oven is off and let it heat up to the 100⁰C at the same rate as the oven? Put the screen on a tray or just place it onto the oven grate? And do I use so.ething like chopsticks to raise it slightly if I do put it on the tray? Also is it better to use an air fryer? Or a convection oven? Also if I am to use the convection oven, do I have the fan turned on? Or do I leave it turned off? Also should I have something on top of the screen to apply pressure to it while I let it bake? Or is it not necessary? Lastly, when taking it out after the cooking, do I first leave it in the oven too cool down with the oven, or would it be better to work with the screen while it is still hot?

I am hoping to have the screen done today or this week, so I was hoping that I could maybe get a responce quickly to these questions. Thank you.

Thank you all again for all your help so far with this project, this has helped me out so much.
@TheBasement does a great job walking through the process:
 
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Cyclone740

Tinkerer
Oct 29, 2023
105
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There’s no real fix. At best, you can get some temporary improvement. Those screens were technically flawed, in the sense that they were not built to survive the long term environmental aging. Chemicals such as glues irreversibility deteriorates. I got some kind of improvement with my unit by keeping it constantly in a dried up environment (a sealed bag with silica inside). So, instead of darkening after 3 minutes, it now lasts - say - half an hour. Enough for a nostalgic rendezvous, but surely not a machine I can use for any real purpose.
Ok but I would like to direct your attention to this thread, on pages 6 and 7, the first reply on page 6 is the one I am mainly referencing.

 

Cyclone740

Tinkerer
Oct 29, 2023
105
8
18
@TheBasement does a great job walking through the process:
I will have to give it another watch, but I am not sure if he covers all the things that I was wanting to know, but I will definitely give it a watch again.

Thank you.

I will post an update on the situation with the laptop itself once I have fixed the misaligned screw post. :)
 

TheBasement

Tinkerer
Mar 2, 2022
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13
Launceston, Tasmania
youtube.com
I will have to give it another watch, but I am not sure if he covers all the things that I was wanting to know, but I will definitely give it a watch again.

Thank you.

I will post an update on the situation with the laptop itself once I have fixed the misaligned screw post. :)
I think you’re over thinking it a bit.
Just chuck the panel in the oven, on a tray or on a rack it doesn’t matter. Preheat or non preheat it doesn’t matter. Keep it below 100°C and bake for as long as you have patience for. Longer the better. Take care with reassembly getting everything realigned correctly, this is probably the trickiest part.
Good luck and let us know how you get on.