PB 160 sound keeps failing

Shaddam IV

Well-known member
After having experimented with several mother- and daughterboards and screens, I believe the culprit is the 160's motherboard, not the interconnect board. The mobo killls screens. I now have another 160's screen (with a single dead pixel, unfortunately) running - that one is not so good, it needs recapping.
 

demik

Well-known member
Usually that's the jedi/interconnect board or the cable who do this. Sometimes it's indeed the logic board connector.
Theses panels have one top half and one bottom half.

Some lines from the top half aren't connected

Theses connectors / interconnect board are dead or at least unreliable after ± 10 plugs. It's a pain to keep them working.
 

croissantking

Well-known member
Check all the pins on the CPU daughtercard connector (that goes to the interconnect board) are straight. I had one with a bent pin - not so bent that it wouldn’t plug in but bent enough to not make a good connection - and I couldn’t use some of the keys on the keyboard.
 

Shaddam IV

Well-known member
Yes, thanks, a bent pin was a problem on the original daugher card. I‘d straightened it. However, to try the new screen, I‘ve changed it for another PB 160‘s daughter card (the poor machine is turning into a Frankenmac).
So far, all good. I‘m now wondering whether I can re-fit the original (re-capped) screen without danger to the (new) motherboard, given that the original motherboard caused the screen to go first stripy, then entirely dark. (I tried this by fitting the new screen to the old motherboard-and daughtherboard-combo: it also was dark. Using a new mobo and daughter board, the new screen lit up and works - it‘s just not been recapped and is not *that* great).
Another big step will be the battery. I‘ve sourced a 6 V 800 mAh NiCd pack. The original batteries packed 2,800 mH. What will happen when I charge an 800 mAh pack? Does the charging circuit expect a 2,800 mAh pack? In other words, will it overheat? Does anyone know? Thank you so much for all your help and info!
 

luRaichu

Well-known member
Another big step will be the battery. I‘ve sourced a 6 V 800 mAh NiCd pack. The original batteries packed 2,800 mH. What will happen when I charge an 800 mAh pack? Does the charging circuit expect a 2,800 mAh pack? In other words, will it overheat? Does anyone know? Thank you so much for all your help and info!
I haven't actually looked into the PB 1xx charging circuits yet, but I think nothing bad SHOULD happen. You can compare your 6v pack's "standard charge" specs (x mA for y hours) with the PB charging behaviour buried somewhere in a technical note IIRC.
 

Shaddam IV

Well-known member
I charged the replacement battery pack in an external Apple charger. At some point, the charger status lights actually turned from yellow to green. The pack was what in Germany we call "handwarm" at that stage. I put in it in the Powerbook and at least so far, nothing has started to burn. Fingers crossed.
 

Shaddam IV

Well-known member
Now I’ve swapped screens and I have a nice PB 160 with a beautiful recapped screen and a (at 800 mAh very weak) working NiCd battery.
Based on your experience, is it safe to use NiMH? The NiCd pack does get warm (not hot, I’d say 25°C) when the PSU is in.
Oh, and since I‘ve also switched the motherboard, the sound issue seems to have gone. #happycamper
Thanks for all the help and info!
 

3lectr1cPPC

Well-known member
NiMH in these is generally agreed on to be safe, plenty of people like @PB170 have been using NiMH batteries for years now with no issue. I do believe the charging parameters are slightly different between the two but not enough to be a problem (ie, lighting on fire or anything like that).
 

demik

Well-known member
IIRC, there is a thermistor on theses that will stop charging the battery if it's too hot. It's located near the battery slot and connected with a 4 pins or so ribbon cable to the logic board
 

Shaddam IV

Well-known member
I reloaded a battery with a 6V 2.4 Ah NiMH pack and it does get noticeably warm. Not really hot, but I'd say around 35-40°C. I don't feel comfortable with that and am going back to NiCd- just ordered two 1 Ah 6V packs that (hopefully) fit inside the battery case.
 

indigo_k

New member
I killed the machine. After I soldered a new PRAM battery to the interconnect board, half the screen is missing pixels: The upper screen half is showing vertical white stripes every 7 or so pixels. I have another interconnect board which shows the same phenomenon (actually worse: The whole screen is now showing white stripes)(, so I guess that I managed to damage the interconnect board. Hm! Any ideas…?
I'm reviving this old thread because I just encountered the exact same issue, and think I might have figured out the cause:

After removing the old PRAM battery and soldering on a new holder with a removable battery in its place, the top half of my display was also missing every-other vertical line of pixels. At first I thought I must have shorted something or damaged something on the board, but inspecting the board didn't show any obvious problems. Then I thought it was because maybe the removable holder was bulkier than the previous soldered-on battery, and was maybe pressing down on something. I kept the machine open while I restarted it and started pressing on things around the Interconnect board, and discovered that the culprit was the interconnect ribbon itself. Seems while I was struggling to remove the original PRAM battery I was pressing down too hard on the bunched-up ribbon and damaged it.

So, I think anyone attempting this same modification needs to be aware of how delicate that ribbon really is and to make sure to put as little pressure on it as possible. I couldn't figure out if it's possible to disconnect the ribbon from the interconnect board itself, but if so that would be the ideal first step.

I've got a replacement board on its way (I hope), and will see if I can source a replacement for just the ribbon to see if I can repair the one I damaged and have two working interconnect boards again.
 

indigo_k

New member
IIRC, there is a thermistor on theses that will stop charging the battery if it's too hot. It's located near the battery slot and connected with a 4 pins or so ribbon cable to the logic board
If the thermistor fails will it shut the computer down if there's a battery connected?
 

croissantking

Well-known member
I've got a replacement board on its way (I hope), and will see if I can source a replacement for just the ribbon to see if I can repair the one I damaged and have two working interconnect boards again.
I wrote a repair guide:

 

indigo_k

New member
I wrote a repair guide:

Oh wow this is a fantastic guide! This makes it look downright simple, definitely something I'll feel confident in trying at least.

Also good tip on the barrel jack! I have noticed mine is not getting a good grip on the AC cord and was wondering if there was a fix for that. Going to plan to order one of these, too!
 

Shaddam IV

Well-known member
I tried that same screen on several different 160es that I have and it showed the same symptoms in every computer in which I installed it. I guess the issue is with my screen (specifically, its electronics), and not the connector. Good luck!
 

indigo_k

New member
Ah that's a good point - I haven't tried swapping out the screen yet, so it could still be something there that's causing my problem as well. I have another PB160 arriving today, so I'll be able to poke around a bit more and see if I can really isolate and identify the problem here.
 
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