Powerbook G3 Wallstreet PRAM and Cap Notes

[aplmak]

Hey so I had a chance to pull apart 3 Wallstreets. I removed the PRAM batts in them before storing them. I was neglecting this and before I forget just had to do it. At any rate I did a recap job on the total of 5 caps in the main unit (not the screen). I did notice a few beginning to very lightly leak. I saw some white dried up electrolyte. It was not bad but just saying. There was 1 - 220 @ 35 volt which I used a radial and bent it to fit in between perfectly on the power board between the bays, as well as 1 - 33 @ 25v which I used a smd tantalum. Then there was 3 - 33uf 35v on the charging board I believe it's called. I actually was able to get 3 - SMD "D" cases on with no issue (from Mouser). Next to do is the screens which I have no clue when I'll tackle that. I hate prying up the delicate front housing. But it's best to do this stuff now. I figured also while the plastics aren't too brittle.

Just giving everyone the heads up!

 

[3lectr1cPPC]

Thanks for the cap info! I’ll put those notes into use when I recap my PDQ, and I can also add the values to my website’s capacitor reference library.

Did the apparent cap leakage look anything like this?

The photo is a 5300 power board, and I suspect that this stuff isn’t actually leakage, rather dried flux or some sort of glue. I suspect this because whatever it was:

1. Was only on the board and the bottom of the plastic cap bottom, not on the top of the plastic or coming out of the cap itself.
2. Cleaned off very easily
3. Didn’t leave any sign of corrosion whatsoever.

If yours looked similar to that, that’s my guess as to what it was. I don’t doubt that the caps inside Wallstreets will start to fail in the coming years (after all, it’s now as old as the SE/30 was when they started to die), but I do doubt they will leak like the early ones do, as SE/30s 15 years ago were already having liquid electrolyte leak. At the very least mid-late 90s caps are more robust, but I’ll guess we’ll have to see.

 

[aplmak]

Yes it looks similar. So I guess it may be dried flux then. I did finally pull open the display. I only found a 2.2 @ 50v cap on the interconnect board. In fact I only tilted the plastic cover so much so I could remove the interconnect board and recap it, so I didn’t pull the whole display apart. It will be sometime before the Wallstreets cap’s fail but I like to get ahead of it. I side more on prevention then having to deal with leakage damage down the road.

 

[3lectr1cPPC]

There might be another cap or two on the LCD board itself. My 3400 had 2, and it took some disassembly to get to them, and some very careful work to replace them.

 

[joshc]

Looks like leakage to me. Crusty crap and sometimes it does clean off easily if its recent or dried up. It doesn't have to leave corrosion either, if it's not been there that long.

 

[3lectr1cPPC]

I'd think so too, but the bottom of the caps themselves (not the plastic bases) looked pristine, with intact rubber seals and absolutely no sign of any leakage whatsoever, same with the inside of the plastic base. It was only the bottom of the plastic base and the board that had the stuff on it.