Hi there.
Meet my Macintosh Classic II.
It has been behaving rather badly lately, displaying a checkerboard pattern on the internal CRT whenever I fire it up. At this rate, the most useful thing from this Liberation might have been the single solitary HyperCard diskette that was in its superdrive!
Here is a picture of the infamy it displayed. :simasimac:
A little internet research revealed that the problem was a well-known fault due to the SMT electrolytic caps deciding they were ready to die spectacularly.
So, what course of action should I take, other than to bust out my labcoat and soldering iron, and attempt a recap of the board!
That's all and very well when you have the knowledge to pull it off - I didn't. This was my first repair job that actually required extensive resoldering, and I was only "fairly sure" my replacement caps were actually still working.
I gathered up a list of capacitors that were needed and found them in my junk box:
Unfortunately, It appears I have made things significantly worse with my attempt. xx( xx( xx( xx( xx(
Here are some photos of the board :
The caps near the sound hardware that tend to leak most obviously, from what I've read, replaced with electrolytics of equal value.
The caps near the RS422 controllers and near the RAM - I don't know what they do exactly but I replaced them anyway, because they were leaking also.
The fully reassembled logic board, after being very carefully cleaned, reseating the ROMs and the RAM SIMMs ...
The problem I now face is that on switching on the Classic II, I hear the fan spin up, and nothing else. No chime, and furthermore, I don't see ANYTHING on the CRT where once there was a nice ready-made chess board
Has anyone here any ideas what this particular failure mode likely means? If higher-res photos of the board are needed, I can do that easily. I'd just like my Classic II working.
I'm going to be getting some new SMT caps at some point, in case my caps are just bad, but i've no idea how to solder SMDs so that might be a bit pointless.
Also, if I screwed something up while soldering I'd like to know before I spend $20 on a set of replacement caps ( yes, they're that expensive here for tants! - I might have to see if trag will ship me some and how much it would cost... )
So, I ask you all, any ideas?
Meet my Macintosh Classic II.
It has been behaving rather badly lately, displaying a checkerboard pattern on the internal CRT whenever I fire it up. At this rate, the most useful thing from this Liberation might have been the single solitary HyperCard diskette that was in its superdrive!
Here is a picture of the infamy it displayed. :simasimac:
A little internet research revealed that the problem was a well-known fault due to the SMT electrolytic caps deciding they were ready to die spectacularly.
So, what course of action should I take, other than to bust out my labcoat and soldering iron, and attempt a recap of the board!
That's all and very well when you have the knowledge to pull it off - I didn't. This was my first repair job that actually required extensive resoldering, and I was only "fairly sure" my replacement caps were actually still working.
I gathered up a list of capacitors that were needed and found them in my junk box:
- C3 47µF, 16V
- C4 47µF, 16V
- C5 10µF, 16V
- C6 10µF, 16V
- C7 10µF, 16V
- C8 10µF, 16V
- C9 1µF, 50V
- C10 10µF, 16V
- C11 10µF, 16V
- C12 10µF, 16V
- C13 47µF, 16V
- C14 10µF, 16V
- C15 1µF, 50V
Unfortunately, It appears I have made things significantly worse with my attempt. xx( xx( xx( xx( xx(
Here are some photos of the board :
The caps near the sound hardware that tend to leak most obviously, from what I've read, replaced with electrolytics of equal value.
The caps near the RS422 controllers and near the RAM - I don't know what they do exactly but I replaced them anyway, because they were leaking also.
The fully reassembled logic board, after being very carefully cleaned, reseating the ROMs and the RAM SIMMs ...
The problem I now face is that on switching on the Classic II, I hear the fan spin up, and nothing else. No chime, and furthermore, I don't see ANYTHING on the CRT where once there was a nice ready-made chess board
Has anyone here any ideas what this particular failure mode likely means? If higher-res photos of the board are needed, I can do that easily. I'd just like my Classic II working.
I'm going to be getting some new SMT caps at some point, in case my caps are just bad, but i've no idea how to solder SMDs so that might be a bit pointless.
Also, if I screwed something up while soldering I'd like to know before I spend $20 on a set of replacement caps ( yes, they're that expensive here for tants! - I might have to see if trag will ship me some and how much it would cost... )So, I ask you all, any ideas?