Powerbook 170 repeated chime

[joeyjojonesjr]

TL;DR: Powerbook 170 boots to checkerboard and repeated chime, about 1s apart, doesn't stop.

Backstory: Got this powerbook 170 off of ebay for "untested/as-is" for cheap, no power supply.  (For reasons, I thought it might work.)  Got a power supply.  Plugged in - nothing, no . . no nothing.  Removed battery (only very mild beginnings of corrosion, easily wiped off, was a replacement NiCad).  Then it powered on!  Sort of.

I get the powerbook "checkerboard" and the familiar Apple chime (not the chimes of death, the standard "we're good" one), but the chime repeats over and over.  The screen never progresses, and the chime never stops until I pull the plug.  Sometimes the chime doesn't finish fading out before it chimes again, that's how close they are together.

I opened it up, and was somewhat surprised it looked pretty clean - removed the memory, the daughterboard, and inspected the motherboard but didn't find any evidence of chips being blown (no black/brown stains, no bad solder joints, everything looked - pretty good really).  The only thing I found that was sort of suspicious was the power jack itself had a slight bit of corrosion on the "lip" that seats the plug in.  Not bad, just a little, shouldn't cause what I'm seeing, but that was the only thing I saw.  I air-dusted everything, put it back together and -  same thing.

Any thoughts?  Thank you.

 

[Byrd]

The checkerboard image displayed on powering on a PB170 is normal, next up I'd check your power supply is known good (check under load, presume if original Apple the caps are weak).  Another weak point is the CPU daughtercard, try apply firm pressure to it when powering on.  Remove the additional RAM module as installed.

 

[joeyjojonesjr]

Thank you for the points to try.  I have unfortunately been unable to find my multimeter yet (It's either here or there but when I checked it was neither).

I did remove the memory and try booting holding down the daughterboard near the connector; then as it kept chiming I tried pressing on different areas, but alas no joy.

 I did attach this piciture which shows a black "holder" of something, just below the SCSI  port where I would normally expect to see CMOS or a battery for something.  Does it mean anything if this "holder" is empty?  

I'll report on power once I locate the multimeter.  Thank you!

 

[Papichulo]

Your logic board has the yellow chips. Idk why but i had a 170 with yellow chips and was having the same issues until i just replaced the whole logic board.also it could be the power supply 

 

[joeyjojonesjr]

Well two things happened: 1) I found the multimeter, and 2) a replacement AC adapter arrived, as I hadn't found the multimeter yet.  Go figure.

Anyway, the short version is - same thing.  There's a staticky click before the chime as the speaker is engaged that makes it sound like a record skipping: click-bong-pause; click-bong-pause; click-bong-pause, etc.

I'd mentioned before that it chimed again before the first one faded out, but that isn't the case,  it "cycles" all together as a pattern.  Also, I was able to stop the cycle with a very quick re-press of the power button.  Before I could only unplug it to stop it.

I checked the voltage on the new and old adapters; new adapter: 7.5v spot-on; 2.5ma; old adapter: 7.85v (forget the amps but it was the original apple ac adapter.)

Seeing no change, I put the memory board back on, tried the battery in/out (0.0v btw, obvs), and also took a reading off of the power button here:



Which read at 4.5v - a bit low for the power button, isn't it?  Maybe not, I don't know.  Anyway - any other suggestions welcome, I'm kind of stuck as-is.

Thank you!

 

[PB145B]

Unplug that Quantum GoDrive (the hard drive). I've seen the PCB on those short out and cause power troubles.

 

[Papichulo]

I still think you should replace the whole logic board. Mabie something shorted a chip out. These 100 series powerbooks have the weirdest problems. Im done buying those. I did that with my 170 and it fixed everything. 

 

[joeyjojonesjr]

Well I tried it again with the HDD unplugged (and the memory board out) but same thing.

If I get a logic board replacement I'll update the thread    Meanwhile if anyone has other thoughts please let me know.  Thank you!

 

[joeyjojonesjr]

Okay you're going to love this - so I bought a second 170 to use for parts; specifically to swap out the daughterboard on the theory that it has some defect causing the repeated chime.  It arrives, I swap them out and - same thing.  No memory card, no HDD, just by itself.

Given that, any suggestions?

 

[Papichulo]

Did you swap both the logic board and daughter board? If u did then the gray cable that connect the screen and board together is probably bad. The board were the speaker is located is bad then 

 

[joeyjojonesjr]

I didn't swap the logic board as well - It's worth a try though.  Will report back.

 

[techknight]

And youve tried various power adapters? if its the original Apple power adapter, its likely puked its guts out all over the place from capacitors already. 

 

[joeyjojonesjr]

Yeah I have two different power adapters, an original Apple and a modern replacement.  Same on both.  :/

 

[Papichulo]

Well when you swap the logic board it may fix it