68kMLA Classic Interface
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| Click here to select a new forum. | | Color Classic strange booting behavior | Posted by: Daniël on 2020-08-12 05:39:41
Check if all of the pads and traces to the sound chip are still OK, I believe it handles the soft power on the Color Classics. The connections of the traces to the pads of it are a bad recessed, allowing for cap goop and corrosion to more easily settle there and break the connections, from what I understand.
| Posted by: MDMacGuy on 2020-08-12 07:25:57
Check if all of the pads and traces to the sound chip are still OK, I believe it handles the soft power on the Color Classics. The connections of the traces to the pads of it are a bad recessed, allowing for cap goop and corrosion to more easily settle there and break the connections, from what I understand. Thanks! I’ll take a look at that tonight as well now that I have a bit of newfound confidence in this stuff.
I wish Apple had published a technical guide to the Macintosh that covers the CC like they did with the earlier machines!
| Posted by: bibilit on 2020-08-12 14:58:50
soft power is still not working
There is another chip to be removed and soldered back.
On your above picture U8 (just by the Egret chip)
| Posted by: MDMacGuy on 2020-08-18 22:25:27
There is another chip to be removed and soldered back.
On your above picture U8 (just by the Egret chip) Unfortunately no dice. I've done this twice now. I am also getting odd feedback through the speaker when it is accessing the "hard drive" (I have a scsi2sd in this machine), so I have baked or cooked something else.
I'm going to take up Fizzbinn's offer and purchase a good known board and put this one aside to tinker with as time allows.
| Posted by: Fizzbinn on 2020-08-22 09:59:04
I’m going to take up Fizzbinn's offer and purchase a good known board and put this one aside to tinker with as time allows. So not good news, I recapped the spare board I have and it’s not working :-( . The cuda chip and U8 do look to have some crud on the chip legs, I’m going to try to remove them tomorrow, clean up and resolder. I think I have a method down (using chip quick & drag soldering) after doing a couple IIsi power supply soft-power card chips successfully a couple weeks ago. Fingers crossed!
| Posted by: Fizzbinn on 2020-08-23 08:15:55
Success! I decide to try a more aggressive cleaning approach before removing the chips and that got the CC board working, passed the Apple Personal Diagnostics tests (for what’s that worth).
I had pretty much surface cleaned, using isopropyl alcohol, before. Today, I switched to using flux remover, tooth brush and dental pick brushes to clean between the chip legs and under the chip in the case of the sound chip, U5, which also looked gunky. The little dental pick brushes worked great, I keep spraying to flush the crud out that I dislodged, mopped it up with cotton swabs, soaked up a lot yellow stuff from under the sound chip, and green from the cuda...
4140A Flux Remover for PC Boards (Improved Formulation) 945 mL Liquid https://www.amazon.com/dp/B07XDCRLR6/ref=cm_sw_r_cp_tai_pEVqFb78KCW9F
DenTek Slim Brush Interdental Cleaners | Brushes Between Teeth | Extra Tight Teeth | Mouthwash Blast Flavor | 32 Count (packaging may vary) https://www.amazon.com/dp/B009MHV3VW/ref=cm_sw_r_cp_tai_AGVqFbMX3FD0G
| Posted by: MDMacGuy on 2020-08-23 10:19:32
Success! I decide to try a more aggressive cleaning approach before removing the chips and that got the CC board working, passed the Apple Personal Diagnostics tests (for what’s that worth).
I had pretty much surface cleaned, using isopropyl alcohol, before. Today, I switched to using flux remover, tooth brush and dental pick brushes to clean between the chip legs and under the chip in the case of the sound chip, U5, which also looked gunky. The little dental pick brushes worked great, I keep spraying to flush the crud out that I dislodged, mopped it up with cotton swabs, soaked up a lot yellow stuff from under the sound chip, and green from the cuda...
4140A Flux Remover for PC Boards (Improved Formulation) 945 mL Liquid https://www.amazon.com/dp/B07XDCRLR6/ref=cm_sw_r_cp_tai_pEVqFb78KCW9F
DenTek Slim Brush Interdental Cleaners | Brushes Between Teeth | Extra Tight Teeth | Mouthwash Blast Flavor | 32 Count (packaging may vary) https://www.amazon.com/dp/B009MHV3VW/ref=cm_sw_r_cp_tai_AGVqFbMX3FD0G Oh awesome! I’ve just about thrown in the towel on the one I have. Soft power is just no bueno on it.
Are you still considering letting it go to a good home?
| Posted by: Fizzbinn on 2020-08-23 10:47:19
Are you still considering letting it go to a good home? Yeah, PM me we’ll work something out. :cc:
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