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Home▸ Forums▸ 68kMLA▸ Macintosh 512+ Oddities... Any ideas? — #13
Post #13 by iMac600
Source Forum68kMLA
CategoryTroubleshooting
Post DateSun, 6 Sep 2009 - 18:34
Original URLhttps://68kmla.org/bb/threads/macintosh-512-oddities-any-ideas.18431/
Post
Followed the guide to the word, it failed, and I yanked the power and ditched the fan.
So the fan "melted" or merely "failed" now? If truly melted, I for one would love to see a photo.
I just say "failed" as to not overdramatize it... although I think in saying "melted" i've already given everyone the wrong impression. The spark show was fantastic. The internals of the fan burned and heated, warping the outer case from heat... to say it melted, in hindsight, gives everyone this impression it turned into a puddle of black goo. No such dice, i'm afraid. ;) Spectacular, but not that spectacular.

As to the need for a fan, it all depends on your usage. I for one baby my old Macs. I never have run my 512k for more than 2 hours at a time (obviously, as its not my only computer), and anytime I walk away from the machine for even 30 seconds I dim the screen to zero brightness manually to prevent burn in. I habitually touch the analog board side of the Mac to see how hot it is, and if it becomes extremely hot to the touch, I shut down the machine. So unless you are running the machine more than 4 hours straight a day every single day, you will do just fine without a fan. Eliminating the fan also means you will reduce noise and save anywhere between 60 to 200mA in the process too. :)
Yes well, I somehow doubt i'll be running it for more than an hour a day on certain days, so it's probably not so much of a concern. I think I have all the same habits as yourself, dimming the screen before leaving it and so on... I tend to look after my machines pretty well, if they even get so much as a speck of dirt on them, they get cleaned, and i'd never dare letting the cases get chipped or damaged... would be devastating. Needless to say i'm a real fan of the compact. (fan, compact... yeah, bad pun).

In the days when these Macs were our main computer at home, there was a great need for internal cooling. But that doesn't necessarily hold true anymore. Again, it all depends on your usage of the Mac.
I think my intention was to try and improve its lifespan, and make general operation of it just a little bit easier on the hardware inside. All about longevity. After trying to fit the fan though, I think it's safe to say that I realized trying to install it would probably reduce the lifespan of the hardware anyway... especially if it was blowing fuses. :lol:

Ah well, it doesn't need a fan. All brand new fuses in there, tested and it's running beautifully again. No big deal. I still can't work out what the go is with the CRT though. Keep in mind that it exhibited this issue before the fan accident. Although it does look as though i've improved the situation a lot by swapping in a spare CRT assembly I had here (just for the hell of it, I had some free time), it still appears lower on the top left as opposed to the top right, even though the raster is perfectly flat along the bottom edge and sides. It's the corner closest to the top of the analog board, for reference. It may be one of those large capacitors near the top, so i'll look into those when I have some free time.

C1 and its surrounding caps are original, that is I never swapped them out on the initial run... perhaps that one or two is worth looking at. Anyone have the ratings for that or the two capacitors surrounding the width adjustment coil? This is a 240v international board, not sure if that makes a shred of difference. Any tips for replacing C1 are also appreciated.

mp.ls