Quadra 840AV battery desaster...

[gvollmann]

Opened my Quadra 840AV and what I found was horrible, see pictures...

Repairable? New CPU?!

thx

 

[Compgeke]

Absolutely repairable. New CPU for sure but the logic board looks pretty good. I don't see any eaten traces or corrosion around other ic pins.

It will need a recap though but that's typical of any 68k Mac with the SMD electrolytic caps.

 

[gvollmann]

Absolutely repairable. New CPU for sure but the logic board looks pretty good. I don't see any eaten traces or corrosion around other ic pins.

It will need a recap though but that's typical of any 68k Mac with the SMD electrolytic caps.

Thx!

Do you know a good source for a new CPU?

 

[gvollmann]

Absolutely repairable. New CPU for sure but the logic board looks pretty good. I don't see any eaten traces or corrosion around other ic pins.

It will need a recap though but that's typical of any 68k Mac with the SMD electrolytic caps.

Ad recapping: Can I also use caps with a 10% tolerance or only 20%? The 47uf 16V in size C are hard to find with 20%?!

 

[techknight]

youll need to change the socket as well if rotten CPU pins got stuck inside. 

 

[gvollmann]

youll need to change the socket as well if rotten CPU pins got stuck inside. 

eight pins are broken and I have all these pins!

 

[techknight]

whew. saved a huge headache with the socket

 

[Compgeke]

Ad recapping: Can I also use caps with a 10% tolerance or only 20%? The 47uf 16V in size C are hard to find with 20%?!

I'd personally recommend replacing with ceramic or tantulum if possible. The electeolyrics are very prone to leaking again hence so few people use them in recaps. If you look through the forums you'll find many threads on doing so.

As far as tolerance though, as long as it's an equal or higher tolerance you'll be good. The tolerance percentage just means it's acceptable for the cap to be +/- n% of the rated capacitance. A 10% would therefore be better than a 20%.

 

[gvollmann]

I have recapped it + new CPU!

I get a part of the start-gong and that’s it!? What else could it be?

 

[gvollmann]

... that's all I get?!

View attachment Quadra840-Start.m4a

 

[Macdrone]

without battery i found my 840av needs the same kind of double tap as the 6100 to start up.  

 

[firebottle]

without battery i found my 840av needs the same kind of double tap as the 6100 to start up.  

Ok... what's this "double tap" you speak of?

 

[Macdrone]

power on. power off fast then on again.  Its the same thing you do with the 6100 series with no battery.  Not technically sure why it works but it does, either that or put a good batery in, but with danger of leakage and cost I do not put batteries in them.