Found an eMac 1GHz, but she's DOA

[Huxley]

Hi again everyone! It's been years since I posted here, but I'm still chugging along with my retro Macs...

I recently pulled a 1GHz eMac CTO from a recycle bin at work. It is super (*super*) dusty, and when I plugged it in last night, it basically did nothing. A close inspection found that when I tap the power button, the fan blades twitch slightly (though they never turn), and there's a very brief (less than a second) hum from inside - that's it. No chimes, no front LED, no nuttin.

I do recall that some eMac machines were plagued with the "bad caps" issue that struck ~10 years ago - would the symptoms I'm describing be in-line with bad caps? If this is the case, would I be looking at both a PSU and analog board swap to get this beast running again (assuming no other internal problems)?

Thanks for any tips or suggestions you can provide!

Huxley

 

[Schmoburger]

Fairly certain flyback transformers were also a continuing problem with the eMac too... but from what I can work out, yes most of the issues that plague those wretched things are to do with faulty analogue circuitry, not so much logic-board issues.

So yes, it'd stand to reason if this is the case, that if you were able to find a servicable analogue board and PSU then it'd probably work again. That said, actually finding secondhand items that are functional is a different story... eMacs get binned by the dozen all with similar issues. Even if you were to find working components or event a working machine, there is little to say they wont flake out too fairly shortly... If it's anything to go by, I have 4 or 5 1Ghz eMacs here that are all paperweights and all came from the same place. :-/

Short of determining the specific faulty components and replacing them with brand new ones, eMacs are basically all doomed to fail, and are one of those few machines I'll happily write off as a lost cause. It's a shame about the poor build and crap styling, as in concept they were a good idea.

 

[Schmoburger]

Dunno if this helps you any, but out of interest I decided to take a look at the logic board from one of these eMacs that ive already pulled apart, and found this board which attaches via a socket...

With this buttload of bad caps...

At least 7 of them have popped up ends and leakage/corrosion... a 2200u 16V, a couple of 3300u 10Vs, a 1000u 16V, and 3 1200u 10Vs. thats at a cursory glance... No other visibly damaged components but ya never know.

 

[techknight]

replace them all... then try again.

 

[RickNel]

That twitch-and-die syndrome is almost always due to bad cap(s) in the power supply. The stand-by trickle current is enough for the power switch to activate the start-up circuit, but the main switchmode circuitry of the PSU is not kicking in. The most likely culprit will be a high voltage cap in the circuit before the main switching transistor(s), but if you are going to the trouble of changing one, you might has well change the lot.

The eMacs that are dying in large numbers are most likely the ones that were left switched on 24/7 in school computer labs and suchlike - the capacitors seem to have a certain life in hours x heat stress. I have a couple of older eMacs, ex office and home use, that are running perfectly. It's a bit of an ugly duckling but the display's are still pretty good by any standard.

Rick

 

[Schmoburger]

Agreed... they are one of the nicest looking CRT's Ive seen in a computer.