• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

How urgent is recapping a Quadra 610 when the logic board looks in pretty good shape.

fergycool

Well-known member
Hi all, after getting rid of my old macs a few years back I appear to have caught the bug again. Got myself a G4 Mac Mini running Mac OS 9, then a server with Netatalk, then tashrouter and a few minivMac images. I will join #Globaltalk2025! Now I just bought my first M68k Mac (well the first for a few decades). It's a Quadra 610 and looks in pretty good condition.
I know I must recap at a certain point, but if there is absolutely no sign of corrosion how urgently should I do this? I'm not that practised with a soldering iron. So I find the prospect a little daunting. If I work myself up to doing it in a few months would that be so risky? Thanks!
 

saybur

Well-known member
Yup, recap is needed. You're better off doing it now before electrolyte leaks and corrosion sets in.
 

fergycool

Well-known member
Thanks. I knew I have to recap, but I guess you are saying I should do it now rather than wait a few weeks/months.
 

Byrd

Well-known member
Evidence of this would be to wipe a cotton bud around the caps, you’ll find it’ll pick up cap goo readily. Of course you can wait a little while it’s survived this long, practice recapping on scrap electronics in the mean time.
 

lmartu

Well-known member
I agree with Byrd. That’s exactly how I check for potential cap leakage. I have some newer power Macintosh boards (8500, 6200 beige g3) whose motherboards are so clean they are mirror shiny.
That does not mean I won’t recap them.
I’m just not in a hurry to do it , and until
Then I will monitor the situation.
 

fergycool

Well-known member
Evidence of this would be to wipe a cotton bud around the caps, you’ll find it’ll pick up cap goo readily. Of course you can wait a little while it’s survived this long, practice recapping on scrap electronics in the mean time.
Thank you for that. Great ideas. I wiped some cotton wool around each cap and I only picked up dust. See the photos attached. I must have a few boards around I can practise on.
 

Attachments

  • EB6495EE-6AC7-42E0-8501-CCFB283053F5_1_105_c.jpeg
    EB6495EE-6AC7-42E0-8501-CCFB283053F5_1_105_c.jpeg
    343.8 KB · Views: 33
  • 2297A5F8-6162-427B-9074-0CA8146441B1_1_105_c.jpeg
    2297A5F8-6162-427B-9074-0CA8146441B1_1_105_c.jpeg
    258.3 KB · Views: 29
  • 630C09D6-14F9-41EC-BAA8-AF65DAB6866C_1_105_c.jpeg
    630C09D6-14F9-41EC-BAA8-AF65DAB6866C_1_105_c.jpeg
    270.4 KB · Views: 42

fergycool

Well-known member
Well it looks like the board was not in as good shape as I thought. I went to fit a BlueSCSI device yesterday. Upon boot I get no video and then the eight tone Chime of death! I removed the BlueSCSI device and I still get the same. I guess that, even though I was careful, I must have disturbed something when I tried to rearrance the SCSI cable. From googling this eight tone chime means a RAM issue. I removed the two SIMMS but I still see the same. The board has 4MB soldered onto it so I guess this is bad. Not sure what to do now.
 

fergycool

Well-known member
I removed the board to get a closer look. There's a pair of chips (RP2 and RP3) and one of them looks to have some corrosion. By their proximity to the on board RAM I would make a naive guess they are involved with memory. Which would make sense with the chime? Is that plausible?
 

Attachments

  • D2B971B4-1EC8-4E79-994B-77F55E2D383C_1_201_a.jpeg
    D2B971B4-1EC8-4E79-994B-77F55E2D383C_1_201_a.jpeg
    1.8 MB · Views: 36

joshc

Well-known member
With how dull the solder is on those caps, they are definitely bad. Recap it before you do any more troubleshooting.
 

fergycool

Well-known member
I had a go at removing a cap with needle nose pliers and slightly twisting back and forth. It came off really easily, although I think I need some smaller pliers! Thanks all for pushing me.
 

Attachments

  • 01B4F532-5612-4E51-B738-0301C772CA72_1_102_o.jpeg
    01B4F532-5612-4E51-B738-0301C772CA72_1_102_o.jpeg
    848 KB · Views: 34

joshc

Well-known member
Get some flux, and good quality solder. Cleaning up those pads is really important before you put the new capacitors on. The leads are still attached there so you're not ready for a new cap just yet. Sorry if you already know this, but sometimes people jump into these projects before they've spent some time to learn the techniques.

I learnt most of my technique from Branchus Creations videos:

SMD rework takes time and patience. Practice on something you don't value if you're not confident yet.
 

fergycool

Well-known member
Please do not apologise for offering advice! I'm fairly new to this and welcome as much as possible. Thanks for the video. Will watch.
 

killvore

Well-known member
I also have a Quadra 610 with issues (powers on, but no bong or video out), and some of the components have some leg corrosion (the caps look fine, though). Is there any accepted procedure for fixing corroded legs?
IMG_1068.jpeg
 

joshc

Well-known member
I also have a Quadra 610 with issues (powers on, but no bong or video out), and some of the components have some leg corrosion (the caps look fine, though). Is there any accepted procedure for fixing corroded legs?
View attachment 76212
Unfortunately I would say the caps are not good - you can see the dull solder on the cap right there, and its clearly leaked into the chip that you have circled. Ideally that chip would be removed with hot air and you may be able to remove the corrosion with vinegar & a good soap scrub before isopropyl alcohol. But your board definitely needs to be recapped.

At the end of the day, the 610 came out in 1993 and were made until 1994, so even the 'newest' of these is 30 years old. These capacitors need to be replaced by this point.
 

killvore

Well-known member
Ah you're right, I just don't have the skills to do it or the space to learn at the moment so hoping for a temp fix 😅
 

LaPorta

Well-known member
The only reason those legs on that chip are like that is because of cap goo leaching over there from that cap next door. Usually it isn’t a huge issue, but you can use some IPA and interdental brushes to scrub the stuff off.
 

Addicted

Well-known member
Well, I did a virtual dumpster dive today. I was out for a walk. It was trash collection day on the block. There was a Centris 610 just lying out on the curb for collection. It looked like it had been exposed to a lot of soot or some other black dust, but was only missing the cosmetic panel for the CD-ROM. I checked it out as discreetly as possible.. no rust on the video/SCSI connectors.. no shattered cover.. I am trying to finish off my Mac restoration habit, but this was too tempting. I went back and got it.

Once home, I opened it. Hmm, it was fully stocked, odd. Looked like it had not been pillaged at all. I broke it down, and brushed and air-dusted away the black stuff and dust balls. All dry cleaning. No solvents, yet. The logic board looked only borderline salvageable. Photos attached.

Every single 47uF can-cap has leaked, and the nearby chips have been affected. Note in particular the ROM leads, the IOSB small-numbers leads, the Zilog too. My rework skills are certainly not up to lifting the IOSB or the 8530 and putting them back down.

killvore - I've got damage like you have on U46, too (see IMG_5240) .

There was just a hint of white ghosting around the clock battery mount, no orange rot, so perhaps the nearest cap was to blame for that. The old battery looked fine, but had no measureable voltage remaining.

But voila, it boots. Someone dumped a bootable Mac. 68LC040 at 20MHz. 12MB RAM total. Two empty VRAM SIMM slots. Internal audio plays the happy chord. Video works. But, the internal HDD (230MB) has issues. So that's why it was being trashed.

Tested the internal SCSI with a known good HDD. Haven't tested the serial ports, sound in, CDROM, or Ethernet yet

I will most certainly recap. Ten 47uF tantalums are cheap. I have already replaced the clock/PRAM battery. I will overhaul the FDD, as it is very slow in ejecting discs, and it is always good to clean the heads on a dusty FDD. I'm now eager to find an FPU expansion, a CD caddy, and an AAUI-to-10BaseT solution. VRAM SIMMs are still available. I'll search for any 3d-printable CDROM faceplates, too. The black dust mostly came off of the cover, and the cover clips are broken but still get a grip. Perhaps some clear epoxy will adhere to the cover clips.. I doubt cyanoacrylate (super glue) will.

Not sure I should go overboard in cleaning up the corrosion. But U46 and the resistor packs, maybe.
 

Attachments

  • IMG_5240.jpeg
    IMG_5240.jpeg
    1.9 MB · Views: 19
  • IMG_5241.jpeg
    IMG_5241.jpeg
    2 MB · Views: 18
  • IMG_5242.jpeg
    IMG_5242.jpeg
    2.3 MB · Views: 17
  • IMG_5243.jpeg
    IMG_5243.jpeg
    2.8 MB · Views: 17
  • IMG_5244.jpeg
    IMG_5244.jpeg
    2.8 MB · Views: 16
  • IMG_5246.jpeg
    IMG_5246.jpeg
    2.6 MB · Views: 17

Addicted

Well-known member
My, 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 :)
 
Last edited:
Top