Agreed. Often with light corrosion like on U46, applying RMA flux and reflowing will carry away the green stuff and leave behind shiny joints.
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How urgent is recapping a Quadra 610 when the logic board looks in pretty good shape.
- Thread starter fergycool
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Agreed. Often with light corrosion like on U46, applying RMA flux and reflowing will carry away the green stuff and leave behind shiny joints.
Great story and a great find. Thanks. I removed (gently by twisting with needle noses pliers) the caps yesterday, then gave the board a clean. I washed with distilled water and detergent, scrubbed lightly, then rinsed twice with isopropanol. I found it quite hard putting the water on the board as it just felt wrong. But the whole board now looks shiny! I also treated myself to a new soldering iron. So now I have all the kit, I just need the skills to do itMy, I do ramble. What I meant to conclude with, was even with a board that has corrosion like mine, the system can be stable - but I still will risk the rework to replace the leaked caps as a priority. The caps were in the design for a reason, and new caps preserve that design. Getting the residues up in the process stops any additional corrosion, too. Just be careful as you work, be patient, and observe polarity
Recap early! I did not and sadly, my good fortunes did not last.
I managed to get the original internal HDD of my dumpster'd Centris spinning and booting again by leaving it powered up all night. I then attached another HDD and an external Jaz 1GB drive, low-level formatted the internal HDD to mask a lot of bad blocks, started planning what to use this Mac to do.. it was all good.
Until I installed two VRAM SIMMs. Now the SCSI bus appears to have gone completely dark.
The NCR 53C96 is adjacent to the VRAM slots, and I can only imagine that pushing the SIMMs into place flexed and opened some of the corroded contacts in that area. Perhaps the system was was tossed for that reason, for having an intermittent SCSI bus. The system still boots from FDD, and I might be able to plow ahead if I can load my TashTwenty with an image of the boot disk. I'll hope to revive this Centris when I recap, probably in early August. I can also check the back of the logic board at that time for any bad joints.
(Actually, I do not know that the Centris ROM will boot from a TashTwenty on the only FDD port. Crossing fingers.)
I managed to get the original internal HDD of my dumpster'd Centris spinning and booting again by leaving it powered up all night. I then attached another HDD and an external Jaz 1GB drive, low-level formatted the internal HDD to mask a lot of bad blocks, started planning what to use this Mac to do.. it was all good.
Until I installed two VRAM SIMMs. Now the SCSI bus appears to have gone completely dark.
The NCR 53C96 is adjacent to the VRAM slots, and I can only imagine that pushing the SIMMs into place flexed and opened some of the corroded contacts in that area. Perhaps the system was was tossed for that reason, for having an intermittent SCSI bus. The system still boots from FDD, and I might be able to plow ahead if I can load my TashTwenty with an image of the boot disk. I'll hope to revive this Centris when I recap, probably in early August. I can also check the back of the logic board at that time for any bad joints.
(Actually, I do not know that the Centris ROM will boot from a TashTwenty on the only FDD port. Crossing fingers.)
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Strong recommend on the Pinecil. It’s a great iron for hobbyists.I'll add some tantalums to my upcoming Mouser order! Now I just need a soldering iron that isn't utter trash(I'm in Norway - finding a decent price/performance compromise isn't so easy)
Thanks for the recommendation! Looks like it can even work with one of my 67W apple laptop chargers. Now to find someone who ships to Norway for less than $50
So little by little I replaced all ten caps. After a thorough washing with isopropanol and checking, again and again, that everything was the correct way around I put the logic board back into the case. On boot I still get the chimes of death. I consider this as a success as whereas I have not fixed the problem I have not gone backwards. Plus I have now got a recapped board that is not going to die on me badly! The board will now come back out and I'll try looking at the corroded bits under the microscope. Also I have not done any soldering for some time and with my new soldering iron (you have to treat yourself every now and again!) I enjoyed it. Fingers crossed.
Well after inspecting, washing, scrubbing, "reflowing" some of the legs and redoing some of the caps I've replaced, I've decided to give it a pause for a few weeks. Since the Quadra was working fine when I bought it, then those annoying Chimes of Death came along, I can sense myself getting frustrated. So best I pause, watch a few more videos then restart in a few weeks (...and it's sunny finally in Cambridge, UK!). To be Continued...! Cheers.
Sometimes the solder under IC legs will corrode from cap goo and be completely eaten away, and you can't tell with the naked eye. I'd recommend using some magnification and a dental pick to gently put some sideways pressure on each leg of any dodgy looking chips and see if they have any movement.
Thanks for that. I dug out the board and moved it back to my workshop. I've gently done as you suggest with all chips near a cap. All look to be solid. Not sure where to go next with it. To recap (I am new to this!) this was a working Quadra 610 that I bought on ebay. On arrival it booted fine and the board looked to be in good condition. I booted it a few times, then bought a BlueSCSI device. After disconnecting the SCSI cable from the logic board (to remove the optical/HDD) I booted it and started hearing the Chimes of Death. I'm guessing I must have used too much force in removing the cable and caused some damage somewhere. So I recapped the board and here we are!
Well I scarely believe it! After spending a few hours washing the board (again!), reflowing some more ICs then redoign some of the caps I'd previously replaced with no success I was about to give up. However. I dug out the meter once again. I'd previously tested near the IC above caps C54 and C53 and to the left of C52. There was corrossion that I'd previously cleaned, then tested continuity between the trace on the reverse of the board. All was good. But this time I noticed that one of the legs/pads was not actually touching the via. In fact two of the legs looked bad. So I added two small drops of solder, and the Chimes of Death were no more! Yah! A quick cleanup, re-assembled the Quadra and I was booted into macOS8.5!
I should add that was macOS71 and not 8.5!
To be clear it's this one. I guess being surrounded by three caps makes it vunerable! That area is also the issue in this YT video by Mac84. Good luck!
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