New theory on the cause of the infamous Tunnel Vision problem - Testers needed!

[3lectr1cPPC]

One thing I'm curious about is how you figure out where the fuses need to go and that sort of thing. I know right about nothing about battery design so I'd just be going off of where everything was located in the original pack, but I'm worried this lack of understanding would lead to me screwing something up eventually, which you don't want to do with batteries. I've got my 500 series packs open already, and I've clipped out the singular fuse and internal ribbon cables (it's a weird battery) to protect them from damage from the leaking original cells, just have to buy tabbed cells and wire it up.

 

[Powerbook27364]

It had 2 fuses in it, so I just marked own where they were, I'm pretty clueless to this type of thing. I triple checked all the wiring so it should be good to go once I get the parts. I heard that the 500s are less tolerant of re-celling and may not properly accept higher capacity cells, so be wary of that. I'm basically brand new to this type of thing, but I have wired several 2 cell batteries out of 18650s previously, so I'm hoping that experience is all I need.

 

[3lectr1cPPC]

The 500 series packs used a very early attempt at a "smart" battery, using a custom-designed BMS that they called the "EMM" (Energy Management Module I believe). I have indeed heard that they may not be able to take advantage of the higher capacity of high capacity cells, but like many things in this hobby, most of the info is inconsistent and a whole lot of it is out of date. Most people who recelled these batteries did it back in the late 1990s/early 2000s when some people were still trying to get daily use out of these. A lot of that info may be out of date now, or they may have missed something. There are a total of three utilities used to calibrate the EMM.
1. Apple's own tool, forget what it's called.
2. EMMpathy
3. Another one by Lind
The combination of all three will usually get the EMM running again, but I don't know if they'll calibrate it for a higher than expected capacity. I'll have to see that.

 

[Powerbook27364]

Oh cool, thats neat. The info I heard was probably old then. Good to hear it can be worked around. Hopefully the duos work with high capacity cells because the ones I ordered are quite a bit higher than the originals. I ordered 2100mah cells. I wonder if they will be fine in the 145B/170 as well..

 

[3lectr1cPPC]

We'll see... No idea if the EMM will calibrate to the higher capacity cells, they may just give me the same capacity as the original. Will be a while before I recell it though, I'm going to do that after I recap my AC adapter as running the separated power/charge lines at once will stress the original caps way more.

 

[okto]

Additional data point, my 170 lives in Houston, a humid swamp, and as far as I know has spent its whole life here, and has nary a trace of tunnel vision.
If it was exclusively moisture, I think it's spectacularly unlikely that mine would remain unaffected, so there seems to be some variability--perhaps spotty QC is at play.

Haven't read the whole thread because it's huge at this point...has anyone tried baking a screen in a vacuum oven? If we're trying to remove water, that would be the ultimate cure, and may take fewer hours to accomplish.

Yeah, it's a typical patterned plastic diffuser, if I'm not mistaken. The best way to measure the thickness of something that thin is a micrometer gauge.

Caliper would be fine. A mic is really only necessary for measuring diameter or for measuring down to ten thousandths of inches/hundredths of millimeters, which is super overkill for figuring out the thickness of a plastic plate that just has to fit. I'd be surprised if the thickness was held to even ±.002"

 

[Powerbook27364]

Well, 3lectr1cPPC, my friends duo just arrived. (He lives in the USA so shipping super fast) I will try to get the photos from him tonight for the logic board and screen. He should be able to test the tunnel vision as well, so if it has tunnel vision, he can also document the process of dealing with that.

He doesn't have a charger... We thought the g4 charger would be compatible but I guess that was wrong. He is trying to wire a charger to fit now (temporarily until he can get something more permanent)

 

[3lectr1cPPC]

Haven't read the whole thread because it's huge at this point...has anyone tried baking a screen in a vacuum oven? If we're trying to remove water, that would be the ultimate cure, and may take fewer hours to accomplish.

Believe that was suggested in the old thread. Don’t know if anyone tried it though.

@Powerbook27364 thanks a bunch! Yeah G4 charger has a narrow plug that won’t fit the older ones. It will functionally work if you bend the ring around to fit to my knowledge though. Make sure your friend has given permission for the images to be used on my site.

 

[Powerbook27364]

Believe that was suggested in the old thread. Don’t know if anyone tried it though.

@Powerbook27364 thanks a bunch! Yeah G4 charger has a narrow plug that won’t fit the older ones. It will functionally work if you bend the ring around to fit to my knowledge though. Make sure your friend has given permission for the images to be used on my site.

He has! He's working on the power supply still since bending the ring didn't work. He hasn't yet gotten the laptop apart, so I will send those photos when he opens it.

 

[3lectr1cPPC]

Great! Tell him to be careful getting the display apart - and if he doesn't need to due to tunnel vision, I'd recommend against it, because it involves removing two fragile screw covers that are easily damaged. The cosmetic condition of his Duo matters more to me than knowing the LCD model number. If he's got TV though, best way I know of to get the screw covers off is a thin plastic tool of some kind, like a filed down spudger.

 

[Powerbook27364]

Ah, completely forgot about those. They suck. I'll warn him against removing those unless necessary for now. He should be good to take apart the rest though.

 

[3lectr1cPPC]

Sounds good. Thanks again!

 

[Powerbook27364]

Sounds good. Thanks again!

He may not be able to get to disassemble it tonight, but it doesn't seem to be showing any signs of power when plugged in. Any ideas on what the cause may be?

 

[3lectr1cPPC]

There's absolutely no rush to get any images, no worries at all about that. Well, best guess as to a no power situation would be bad caps. Those caps are part of the voltage regulation circuit, so it would make perfect sense.

 

[Powerbook27364]

I let him know, hopefully that's all the problem is. He is quite resilient on making the charger lol. Caps should not take too long to arrive so hopefully he can get it working within the next week or two and start diagnosing the display.

 

[3lectr1cPPC]

Alrighty then. Wishing him the best! If he's got further trouble, he's always invited to join up here. There are some other folks here that know a lot more about board-level troubleshooting then I do. If it goes beyond caps or corrosion (or some other already known failure point) I wouldn't know where to go next.

 

[Powerbook27364]

Alright, here are the photos.

 

[3lectr1cPPC]

Well, those caps look pretty good overall. Surely failing, but I can't see any leaks. They're probably what's behind the startup issue though, it's the first thing to rule out at the very least. And thanks for the images! #8 will go into use on the site.

 

[Powerbook27364]

Good that they are of use! They don't show any signs of leaking at all, but you never know if they have failed or not. Only way to rule the out fully is to replace, which he will be doing. Though he is worried that they may not be the cause since there is no signs of power at all and there is no leakage yet.

 

[3lectr1cPPC]

I've heard plenty of accounts of 190 and 5300 series systems acting dead or presenting the green light of death symptom, and replacing the non-leaking but clearly out of spec caps brought them back. There's also a fair chance the area under the caps will show leakage signs, it takes a bit before the leakage becomes fully visible.