PB 160 sound keeps failing

[Shaddam IV]

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]

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]

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]

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]

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]

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]

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]

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]

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]

OK. Thanks!

 

[Shaddam IV]

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.