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Macintosh Portable Sad Mac

at0z

Well-known member
The likelihood of this scenario being correct in the normal sense is remote. But anything is possible. 

If this were to be true, it would likely be due to vias that have already been damaged by the capacitor leakage to begin with, in which case, would have already been a ticking time bomb. I have soaked/washed so many different boards using a couple different methods, and even do it during manufacturing of boards, and never had an issue "except" in areas that were already damaged by leaking caps. 


I thought more about this and as I don't ultrasonic for more than 2 minutes per side and at the recommended 60C I wouldn't have expected the thermal expansion to be that big but I follow the soak up with the warm oven at 170 for 30 minutes after the post IPA wash. That seems a more likely target for thermal expansion but I agree with you, it was likely just triggering a potential land mine. Which bus chips were you referring to ?

 

glay78

Well-known member
It has been a year and half, I still can’t get this up. I’m thinking to try to pull out ram on board but looking at the error code which ram should I try? Or is there a way to test on board ram using multimeter?
 

Johnnya101

Well-known member
If it helps, I think techknight says he usually just replaces all the ram in one shot because it's time consuming to find the bad one.
 

glay78

Well-known member
If it helps, I think techknight says he usually just replaces all the ram in one shot because it's time consuming to find the bad one.
Oh man, there are like many of them and I can’t remember how many. I wonder if I can find them too
 

desertrout

Well-known member
Yep there are a lot... 32. You're looking for 256k CMOS 100ns SRAM... might take some digging to find a direct replacement (check UTSource maybe, '62256' is a good search term). Looks like there's lots of 70ns out there though, which should probably be ok (imo - I'd personally try it)... there's even more 45ns out there (and the cheaper option), but might be too fast? Best case, you're looking at at least $60 or $70 to do a wholesale swap... I guess it depends on what your time and patience is worth.
 

glay78

Well-known member
Yep there are a lot... 32. You're looking for 256k CMOS 100ns SRAM... might take some digging to find a direct replacement (check UTSource maybe, '62256' is a good search term). Looks like there's lots of 70ns out there though, which should probably be ok (imo - I'd personally try it)... there's even more 45ns out there (and the cheaper option), but might be too fast? Best case, you're looking at at least $60 or $70 to do a wholesale swap... I guess it depends on what your time and patience is worth.
Omg that’s a lot to change, not the price but the time and patience, you are right. So there aren’t really ways to rest the rams using multimeter?
 

wymtb

Member
Maybe you should first buzz out the ram. I was able to identify broken traces located under one of the ram chips with a multimeter. Could be fixed
with three wires. If I remember right more or less the pins from one chip should be connected to the same pins on the other chip. Maybe there was some slight difference when reaching row 5. Too long ago I did this.

IMG20220214140327.jpg
 

glay78

Well-known member
Maybe you should first buzz out the ram. I was able to identify broken traces located under one of the ram chips with a multimeter. Could be fixed
with three wires. If I remember right more or less the pins from one chip should be connected to the same pins on the other chip. Maybe there was some slight difference when reaching row 5. Too long ago I did this.

View attachment 38476
Ahh good way to try too. Doesn’t hurt to buzz around connectivity, rather than changing them blind.
 

glay78

Well-known member
Wow thanks mate! This should keep me busy for the coming weekend. If all fails are u keen to buy? Shoot me a PM. It’s recapped but just the sad Mac M5120. I’ve got another M5126 which I’ve recapped and restored working well, I’ll just keep that will do.
 

Johnnya101

Well-known member
Wow thanks mate! This should keep me busy for the coming weekend. If all fails are u keen to buy? Shoot me a PM. It’s recapped but just the sad Mac M5120. I’ve got another M5126 which I’ve recapped and restored working well, I’ll just keep that will do.
Really only looking for a working one. So if you get it working and still want to sell, let me know.
 

glay78

Well-known member
After buzzing all 32 pieces of rams they are no issues. Sadly it’s still shows

0000 0003
0000 FFFF

when starts
 
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