Dead eMac Fan, USB resurrection?

Question

Hi,
The fan has died on my beloved eMac. The local Apple specialist wants about $700 to fix it. (They claim they need to replace the '61-2850 Display/Analog Assembly, Northern Hemisphere' because, while the fan itself is fine, it's supposed to receive power via this part and that Apple does not supply the specific component on the assembly that powers the fan alone.)
I know the computer is not worth $700 but I would like to keep it for my kids to use as, other than the fan, the thing runs with no problem.
I'm wondering if there might be a relatively easy way to disconnect the fan from the blah, blah assembly and connect it to another power source, possibly even a USB port.
Does this sound doable? (I have experience swapping drives and ram on various macs.) What equipment would I need?
Can anyone think of a better solution? I've seen the assemblies in question on eBay for over $400, so with shipping to Europe this does not seem like a good solution.
Thanks

Answer 1

Hey Mcfugu,
The big problem is finding a power source for the fan as from what I've been told, the fan itself is not the problem. The problem is with the board that powers the fan and the internal speakers. (I had to hook up USB speakers to get sound.)
Some of this doesn't make much sense to me.
So supposedly the speakers are powered from the same board that powers this fan? The Northern Hemisphere?
Here's the procedure for the symptom
"No sound from either internal or external speakers"
From the service manual...
"1. Verify volume setting is correct in system preferences.
2. Verify the computer is not set to “mute”. Press the mute key on the Apple keyboard.
3. Reset parameter RAM. Press Command-Option-P-R during startup.
4. Boot from Apple Hardware Test (hold down the “C” key at startup). Run both quick and extended tests.
Proceed based on any error codes given. See AppleCare Knowledge Base article 112125 - Service
Diagnostics Matrix for Error Code information.
5. Test the computer with known-good headphones. Do you get sound? If yes, go on to step 6. If no,
replace the main logic board.
6. Verify that the speaker cable is connected.
7. Replace the speaker assembly.
8. Replace the logic board.
No sound from the headphones
1. Verify the problem with known-good headphones.
2. Verify the computer is not set to “mute”. Press the mute key on the Apple keyboard.
3. Verify volume setting is correct in Mac OS X system preferences. If the preferences are set correctly,
replace the logic board.
4. In Mac OS 9, check the Sound Control panel, Speakers tab. When headphones are connected, a
headphone icon will be present. If the headphone jack is malfunctioning it may indicate that
headphones are connected when none are connected. In this case, replace the logic board."
Hmm no mention of the PAV eh? either north or south.
Did you check the headphone output? It can be the cause of no sound to either internal or external speakers since there's a cutout circuit in there.
I've only got a 1 GHz taken apart here but the fan plugs into the front of the logic board. It doesn't make sense to me that there is a split power supply in your eMac.
The fan runs off of 12VDC off the logic board and if you have all other functions esp hard drive power (12VDC and 5.5 VDC) then the PAV is got to be OK. The eMac is constructed similar to the early G3 machines in that they have a PAV, Down Converter and Logic Board assemblies. It seems to me the fact that there's a Northern and Southern Hemisphere is due to the room needed for the extended CRT. So in construction they had to split the PAV.
The fan has 3 leads red-+12, black- -12, yellow - control (I think I've got one here and can verify that)
Unfortunately the Repair Extension Program finished a few months ago.
If you take the rear housing off mind the power connector. Only pull the housing back 4 inches before disconnecting the lead to the power button. If you take it off all the way you'll destroy that connector.
If you want to investigate further you can email me.
Richard
Message was edited by: spudnuty