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which macs need recap


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Hi,

i have lots of old Macs. I think most of 68k will need recap ASAP. But should i also start with PPC Macs (601-604)?

Also which caps are in Performa 630 Power Suppy?

List of some of my Macs

Mac LC II - Recap ASASP

Mac LC III - Recap ASAP

Mac LC 475 - Recap ASAP

Quadra 650 - ???

PowerMac 7200 - ???

PowerMac 7300 - ???

PowerCenter 120 - ???

PowerMac 9600 - ???

PowerMac G3 Beige - ???

PowerBook 160 - Recap ASAP

I think i dont need to worry about color Macs

 

Edited by TheMrKocour
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Not what @TheMrKocour was asking, but what about the early macs (128k, 512k, Plus)?  I've seen conflicting information - both that they need recaps and that they don't (the analogue board does but not the logic board maybe).  Does anyone have a definitive say on that?  I fail to see why they'd be different from the other, later macs.

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Generally speaking, the axial and radial electrolytics don’t leak with anywhere near the frequency of the surface mounts. There is immediate danger to boards from leaking electrolytic. The 128k-Plus logic boards aren’t prone to this with their axial caps. They almost never go bad, though at some

point they will likely go out of spec, after which they should be replaced. They are so cheap, I usually do it anyway. The AB caps take much more abuse over life (especially with a passive cooling system) they fail much sooner. Replacing at this 35 year old age is prudent for any electronic.

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Some are more prone than others. You might want to consider the more advanced  high-end 68k machines first.

 

That said there are so many factors that come into cap leakage from what caps they used from the factory at the time it was assembled, to the ammount it has been used (and possibly even the condition of the power supply). 

 

Rule of thumb, if you want to keep things simple, oldest to newest is a good plan.

But IMHO, I think it would pay to take some time and research the machines most prone. Look at the condition of your machine's boards, look for tell-tale signs when powering on and running (from audio issues to non-booting garbage on the screen) and decide then what to recap.

 

One thing you should do, if you only have limited time and/or funds, wash the problematic and iffy looking boards to avoid any further corrosion while they are queued up for recapoing in the future.

Edited by tokyoracer
Added paragraph.
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  • 8 months later...

Every electrolityc capacitor will leak, due to quality or defects in the original design. I have two oscilloscopes from the nineties by Tektronix, who are famous for the quality (and the prices) of their products....they are a caps leaks party. The rule is : if the machine has more than 15 years, just check and eventually change them.

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For the machines that I can't get to re-capping right away, I make a diagram of what caps (mf, V and type - size if I know it) went where (I don't usually include orientation, since it is marked on the board) then I un-cap the board, wash it and set it aside (usually reassembled back into the computer is the safest place), with the documentation attached.  That way it can't get any worse, until I get to it.

 

I currently have only about 3 in queue right now (un-capped, waiting for me to get around to it), but I'm thinking that I should get around to re-capping my cube.  I've never had it open and its in perfect shape, being boxed up for years, but I have read that others had to re-cap theirs.  I also have other computers, like my Tandy and other brand laptops that need it as well.

 

I too have mostly re-capped oldest to newer; I've never yet had to re-cap an SE. 

 

Edited by Juror22
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  • 2 weeks later...

Even when caps physically look OK and there's no visible leakage, they may still require replacement. Often the leakage is just directly underneath the cap and hasn't spread yet. I've recapped numerous boards that were like this.

 

Caps are so cheap, that I would really think it makes more sense to recap than not, regardless of what model it is (assuming it uses electrolytic capacitors).

 

I haven't heard of capacitor problems in PowerMac G4s yet, but I have heard of trouble with the eMac and iMac G5s because they used lower quality capacitors than other models.

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@joshc The eMac and iMac G5, I believe, were affected by the industry-wide capacitor plague of 2001-2008 (Dell is well known as being among the hardest hit, especially from 2004-2007, but Apple got hit too).

 

Otherwise, it seems that most Macs from the beige G3 onward are still in fairly good shape cap wise, though models built before 2000 (basically all G3s and early G4s) should be monitored somewhat closely, because any caps in those are likely reaching the end of their normal lifespans soon. 

 

c

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7 hours ago, Oberlehrer said:

I seem to recall that the power supplies in the MDD G4 failed quite often; and I think this was also a cap issue.

 

Sorry, I was referring to logic boards. Yes, power supplies are more prone to capacitor failure generally because of exposure to high temperatures.

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Just to add some from personal experience

 

Mac LC : Recap ASAP

IIcx : Recap ASAP

Quadra 650/800 : This one is on a per case basis. Some motherboard only have solid caps, others got electrolytics.

G3 Beige

Do not need recap. Got one runing 24/24 since years and never saw one bad.

PB 1xx : 

Might need a recap, but usually everything is dead before at that point (screen, HDD, power adapter, interconnect board...). Got 5 Logic boards ok (145/145b/165c x2, 180x2) still running strong but and everything else is dead. Never got one bad PowerBook 1xx. However, half of the power adapters needs recap. If the machine is "unstable", ususally it's the power adapter and not the logic board.

PB 1xx with passive grayscale screens need a screen recap though.

PowerMac 6100 : Might need recap, depend of the Motherboard revision

PowerMac G5 SP 1.8 : Need recap (no leakage beaacause Axial caps, but stability issues). Only the 2004 SP got Axial caps

IMHO the worst are the LC series. All of mine had leakage and corroded motherboard (had to redo traces, ripped pads, etc...)

 

Dead logic bopards by caps counter : 1x LCII, 1x LC475, 1x 6100 

 

Edited by demik
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2 hours ago, demik said:

PowerMac 6100 : Might need recap, depend of the Motherboard revision

 

I also find that 6100, 7100 and 8100 boards from Japan need recapping, way more than those kept in most Western countries. The boards I see on Yahoo Auctions and such are often pooled with capacitor leakage, as did both an 8100 board and 6100 AV card that I got from YA through Buyee as well. I'm guessing climate differences might affect the severity of capacitor leakage as well.

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On 12/8/2020 at 11:42 AM, Daniël Oosterhuis said:

 

I also find that 6100, 7100 and 8100 boards from Japan need recapping, way more than those kept in most Western countries. The boards I see on Yahoo Auctions and such are often pooled with capacitor leakage, as did both an 8100 board and 6100 AV card that I got from YA through Buyee as well. I'm guessing climate differences might affect the severity of capacitor leakage as well.

 

Probably true. I got a few (dead) 68k from UK and they were rusted everywhere. Never saw a rusted CDROM drive before.

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11 minutes ago, demik said:

Probably true. I got a few (dead) 68k from UK and they were rusted everywhere. Never saw a rusted CDROM drive before.

 

A number of my machines were stored in a village by the sea (in the UK) for a number of years and before that had spent their life nearby along the coast.  Those machines certainly *seemed* to rust (though not cap leak) more than my inland machines; it may have been the salt in the air.  Certainly cars and so forth rapidly corroded around there...

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On 12/18/2020 at 5:07 PM, toples50 said:

How about Mac II series and compact Macs?

My Mac IIfx needed a recap back in 2014.

The advice that I have been given since is to use the machine until a cap goes and then get it fully recapped. Be sure to replace the 30 year old batteries, however, with either none (if possible) or new ones.

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  • 3 weeks later...
On 12/21/2020 at 2:37 PM, ArmorAlley said:

The advice that I have been given since is to use the machine until a cap goes and then get it fully recapped.


Capacitors can start leaking but still work for some time, and this capacitor leakage can start to damage the board. I've had several boards which visually look great, and even work, but when I removed the capacitors they had started to leak. I would say it's best to take preventative measures at this point, with any pre-1997 machines. Capacitors are cheap enough if you're just doing a couple of boards, and could prevent  substantial logic board repairs.

Edited by joshc
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