Macintosh IICi No chime and blackscreen

[croissantking]

This is the board as it sits now

These looks like originals. Are they?

 

[Elv1s]

View attachment 69681
These looks like originals. Are they?

No, all caps are changed from new stock

 

[Elv1s]

The three 74HC logic chips, right? In my case the middle one failed without any visible signs of corrosion. I even desoldered it, cleaned up all the traces and re-soldered it down. I am sure it was killed by cap goo.

The chips looks to be fine, little to none corrsion.

 

[Elv1s]

Can we see hi res photos of the logicboard please

Over

 

[Elv1s]

under

Can we see hi res photos of the logicboard please

 

[JC8080]

If you have a hot air gun, great. Otherwise, I recommend ChipQuick desoldering solder. Yes, it is expensive. So, get the smallest amount you can. It is useful in almost any stubborn electronics situation. It is just solder with a low melting point, so it stays molten long enough to 'float' off the chip with just a soldering iron.

I keep ChipQuik around as a standby, it does work well in many situations, you can buy a small kit from Amazon (link) for $11.95. Personally, I recommend picking up a hot air station, I bought mine from Amazon for $40 (link). I'm sure there are better ones out there, but this one has adjustable temperature and fan speed, as well as swappable nozzles. I end up using it quite often. If you will be removing the type of SMD ICs with the legs that curl underneath, I believe a hot air station is necessary. I tried ChipQuip on that style of chip once with no success, though other people may have different experiences.

 

[Elv1s]

I keep ChipQuik around as a standby, it does work well in many situations, you can buy a small kit from Amazon (link) for $11.95. Personally, I recommend picking up a hot air station, I bought mine from Amazon for $40 (link). I'm sure there are better ones out there, but this one has adjustable temperature and fan speed, as well as swappable nozzles. I end up using it quite often. If you will be removing the type of SMD ICs with the legs that curl underneath, I believe a hot air station is necessary. I tried ChipQuip on that style of chip once with no success, though other people may have different experiences.

I have all the tools (not including an oscilloskope)

 

[Elv1s]

The three 74HC logic chips, right? In my case the middle one failed without any visible signs of corrosion. I even desoldered it, cleaned up all the traces and re-soldered it down. I am sure it was killed by cap goo.


Is it just me or are the caps at C10 and C13 still the originals? Also, you might consider replacing the axial caps as well, although they are less crucial than the SMD parts.

74HC74 and 74HC132 is now changed for new. The chips I got gold of is ”74HC74D and 74HC132D” I hope that does not matter?
But still, I have the same problem as before :/

 

[croissantking]

74HC74 and 74HC132 is now changed for new. The chips I got gold of is ”74HC74D and 74HC132D” I hope that does not matter?
But still, I have the same problem as before :/

It doesn’t matter, the parts are correct.