Has anyone here got experience recapping/repairing a Performa 5X00?

Hi all,

My Performa 5400 is starting to show its age and is exhibiting unstable video at times (normal colours, wavy geometry on the Y-axis). I believe failing electrolytic capacitors on the analogue boards to be the likely culprits as the machine's problem gets worse as it warms up. It is, of course, possible that there's a dodgy transistor or IC at play. A visual inspection has yielded nothing but a capacitor doesn't necessarily have to fail to lose its capacity.

I plan to start pulling caps and checking their values with a 'meter tomorrow - hopefully just one or two are at fault. Sadly there are no schematics, references, or previous repairs recorded online anywhere I can find so this is very much a job that will require me to write down every little thing about every little component as I go. There are some very awkwardly-designed sections on these boards and I will have to desolder large RF shields in order to access every capacitor. Naturally, I will post any discoveries here for posterity. 

Has anyone on this forum ever replaced the caps on this particular family of Macs, or even just experienced similar issues? Is there some record of a previous repair out there that has eluded me? If so, please do chime in. Given that this machine has been rock-solid for the entirety of its life until now I suspect that there could simply have been no need for anyone to repair one yet!

Thanks in advance everyone.

Did LG do the monitor part on these?

If so, I'm not surprised to hear that the boards have awkward layouts and oddly-placed shields.  That was my experience doing a full teardown and recap of a trayloader iMac too, where the monitor and power supply are LG.  I was able to complete a full recap in the end, though — it just ended up being one of the more frustrating and tedious recap jobs I've done.

If you don't mind, share pictures of internals as you go along!  I've always wondered what the guts of a 5X00 monitor look like, but, like you, haven't found a whole lot of info online.

68krazy said:

Did LG do the monitor part on these?

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They sure did. The PSU is LG too. 

I will be sure to document everything with photos and notes as I go. The 5X00s have a great design – one of Apple's most refined and well thought-out, IMO. It's by far the most straightforward to take apart of any Apple AIO. Being able to remove the entirety of the casing without taking the chassis off its base is lovely and a breath of fresh air compared to a G3 iMac. 

One oddity: there is a lot of hot glue on these boards, possibly too much. Both the PSU and video board had a web of hot-glue-stringy-mess all over them. Why do OEMs cover caps with gobs of hot glue? Is it for protection when shipping? I wouldn't be surprised if some of the caps had simply cooked under all the mess. It's going to be a challenge to remove the glue without jeopardising the capacitors themselves. 

I'm debating whether I should just commit to doing a full recap. It'll potentially make things more complicated down the road if I only replace the caps that are failing but it will also be significantly cheaper... 

Usually I find glue when boards are going to be mounted vertically. Large, heavy caps can, over time, pull and work their way free of mounts, causing premature failure. The glue, I would surmise, is there to hold it in place so it is not held by its solder points alone.

LaPorta said:

Usually I find glue when boards are going to be mounted vertically. Large, heavy caps can, over time, pull and work their way free of mounts, causing premature failure. The glue, I would surmise, is there to hold it in place so it is not held by its solder points alone.

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That's a very logical explanation - I like it!