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PowerBook 520c will not power up


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I recently just got a new cpu and ram for my PowerBook 520c and went to try the new processor and it wouldn’t even spin up. Switching the cpus back does nothing either. It relies on it’s old ac adapter and I don’t know where to start to get it working. Any ideas to start?

 

:(

 

Emmy

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You didn't bend a pin, did you? Check the connector and try to reinsert. The CPU daughter card needs a fairly firm hand to reinsert so maybe check to make sure it's positioned correctly and press harder. Not like HULK SMASH but just a few pounds of even pressure over the connector. Also make sure it's not hung up on the RAM card supports or anything.

 

Check that you didn't dislodge the display cable. Maybe use headphones to check if it's making a startup sound.

 

Did the keyboard cables come undone? Maybe use an external keyboard to try to turn it on.

 

If you have a voltmeter, you may want to check the voltages at the power adapter.

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Ok! I’ve checked the cpu, tried it without ram and tried a spare with no luck. No chime, no boot.

 

I have plugged in speakers in the audio jack and tried an and keyboard to power it on, no dice. 
 

I have not checked the dc power as I don’t know the pin out. I have a multimeter but can anyone tell me the pin out for it? I don’t want to short anything. 
 

Also there is no battery installed on either side as I do not own one.

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2 hours ago, EmmyOcelot said:

Where would a reset button be? 

 

I've recently done some work on these, and found this procedure to revive after the PRAM battery is compromised:

https://discussions.apple.com/thread/479298

 

Quote

With batteries out and AC adapter disconnected, allow the PB to sit for 10min. Hold down the command-option-control-power keys together (the 500s lack the reset/interrupt switches of other PBs and desktops) for 20-odd sec. to reset the Power Manager. Reconnect the AC adapter, start up and immediately hold command-option-p-r to reset the PRAM (and point the PB at its hard drive). If the PB successfully boots from its hard drive, you can insert the batteries, but don't attempt to power the PB from them. Let them take what charge they will as you use the machine and after shutdown.

 

If all you changed was the CPU board and you were careful, I would suspect the PRAM battery is at fault. If you have a memory module installed and the plastic brace bar fits properly under the metal shielding, your connections should be inserted securely. As suggested, if you have any ADB keyboard of the era, you could try it's power button to be sure it's not the keyboard connection or the power button itself causing trouble. 

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Also here's this (mine tested more like 16.5-16.6v) One of the 16v rails is 1A for battery charging and the other is 1.5A for the system. Not sure which is which on the plug...

 

42165286_ScreenShot2021-01-05at7_28_33PM.thumb.png.6789440c782917c9bf4addc5f303cfd8.png

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Ah, that would make sense. If you haven't yet, it may be worth unplugging the power supply from the wall for a few hours- not sure if they have self-resetting fuses like modern supplies do, but that can sometimes revive a supply that acts dead. If you've already done that or it stays dead afterward, it could be worthwhile to try cracking it open...

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7 hours ago, MikeatOSX said:

here are the pin outs, it's seems there are different models...

 

75630299-841F-4EDA-BE65-D52F25718E96.jpeg

Would you double check this is transcribed correctly? I have two adapters, both marked M1893 and tested to have the same pinouts I posted above. They both work for my 520c, 540c, and 550c models, and both are physically missing the contact you have labeled Vbatt.

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I was in my cellar now:

I have 6 PowerBooks 5x0. They all have this missing pin as you call it.

On your picture it looks like that there is no metal in the missing pin. 

All of mine show metal in it. 

Edited by MikeatOSX
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2 hours ago, MikeatOSX said:

I was in my cellar now:

I have 6 PowerBooks 5x0. They all have this missing pin as you call it.

What do you read with a volt meter? I doubt yours would be inverted compared to mine...

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2 hours ago, MikeatOSX said:

On your picture it looks like that there is no metal in the missing pin. 

All of mine show metal in it. 

Yeah, neither one of my adapters seem to have metal in that pin at all. I don't have a working battery to test charging with, but the PowerBooks indicate they briefly try to charge their worn out batteries before reporting fully charged.

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I don't measure it now. I have more important things to do now. I did it in the past to find out if there are more than one  PB 5x0 power supplies with no power on vbatt+

BTW: I did not invent the expression "vbatt+".

I found it on a picture of this power supply in Internet some years ago. 

Edited by MikeatOSX
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They're labeled as such on the adapter brick itself; Vbatt and Vmain, so it makes sense. I suspect your label may be on the wrong pin though, since I see nothing on that pin and still find two separate +16v pins on mine.

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