The eMac was an all-in-one G4-based mac designed for the education market. It was the last mac to use a CRT display, and was sold at a low price to schools, and other institutions.

53 Questions View all

Not booting at all; bad power supply?

I bought an eMac at a yard sale, and found that it won't turn on at all. No chime, no lights, no fans or anything. It has no RAM (I think I have some RAM that it'll accept) and no PRAM battery (which I can go buy), but I was told the power supply may be dead. Any other possibilities? How can I fix it?

Answered! View the answer I have this problem too

Is this a good question?

Score 0

Comments:

How handy are you? also, remember you are dealing with a CRT monitor and a lot of current Do you have a multimeter and can you use it to check the power supply?

by

Thanks for the answers. I'm gonna have a friend look at it, he has proper tools and such (grounding cable, etc.) and experience from messing around with stuff. Definitely not anything I'll pursue on my own. Worst case scenario, I'm out $5, which is all I paid for it. Again, thanks very much.

by

Sounds like a steal for $5, may just be the power fuse ;-) Just be careful. Good Luck.

by

Add a comment

3 Answers

Chosen Solution

Do the PRAM battery first. Here's are three guides I've put together on this machine:

Installing eMac PRAM BatteryeMac PRAM Battery Replacement

Installing eMac RAM

eMac RAM Replacement

\Installing eMac AirPort Card

eMac AirPort Card Replacement

eMac RAM Image

Guide

eMac RAM Replacement

Difficulty: Very easy10 minutes

eMac PRAM Battery Image

Guide

eMac PRAM Battery Replacement

Difficulty: Very easy10 minutes

Was this answer helpful?

Score 3
Add a comment
Most Helpful Answer

Eion Woods, this should be taken as academics only and should only be done if you have any experience with AC current and multimeters at all. this is what the manual says:"

The computer will not power on.

1. Verify the power outlet is good. Plug a different device into the socket to ensure there is power, or plug computer into another outlet.

2. Check the power cord. Use a known good power cord.

3. Check connection of the power cord on both ends. Verify that the plug is securely plugged into both the A/C outlet and back of the computer.

4. Remove keyboard, mouse, and other peripherals such as speakers.

5. Position the computer so it rests on the CRT face.

6. Remove the user access door.

7 Touch a metal surface inside the computer.

8 Unplug the unit.

9 Verify the battery is good before replacing modules. A drained battery may be indicative of a crashed Power Management Unit. Does the battery measure at least +3.5v? If not, replace the battery and reset the PMU.

10. Reset PMU.

11. Remove the rear housing

'''Warning: This product contains high voltage and a high-vacuum picture tube. To prevent serious injury:

• Review the CRT safety information on Service Source online.

• Discharge the CRT

• Never use a grounding wriststrap until after discharging the CRT and setting up an ongoing ground connection.'''

12. Check the power button. Attach a known good power button to the unit. Do you have power now? If yes, replace the power button. If no, go to the next step.

13. Unplug the unit. Warning: Make sure the ground screw is attached to the frame when testing power.

14. Check the AC connector. Make sure it’s connected. Do you have power now? If yes, test the unit and return it to the customer. If no, go to the next step.

15. Warning: Make sure the computer is unplugged. Check the fuse.You will need an ohm meter to do a continuity test on the fuse. Using an ohm meter, touch the red and black probes to the two metal points at location F901 and check for continuity (reading of “0”). If the ohm meter registers “0”, the fuse is good. If the meter registers “infinite”, the display/analog assembly should be replaced.

16. Plug the unit in. Check for AC voltage. Warning: Do not force the probes into the connector. Doing so could break the connector. Do you measure 120V (line voltage)? If yes, go on to the next step. If no, replace the display/analog assembly.

17. Make sure the computer is plugged in. Check for 5V trickle on capacitor C3202 (located near the modem board) on the logic board. Do you get 5V? If yes, go to the next step. If no, replace the display/analog assembly.

18. Check the down converter connector. Verify that it is properly connected.

19. Plug the unit in, but don’t press the power button. Check the down converter. Be extremely careful when checking voltages. It is easy to short between the pins. Ground to the frame with the black probe and check pin 1 on P801 with the red probe. A reading of 10.5V up to 17.5V is acceptable. If you get a reading in that range, replace the display/analog assembly. If not, replace the logic board.

Again, this is for your education only. CRT's can zap you pretty darn good. Hope this helps, good luck.

Was this answer helpful?

Score 3
Add a comment

Sound like the diagnosis is correct. CRT machines are How dangerous is it to work on a CRT display? for DIYers! You must know what you're doing opening and working on a CRT machine. You can find power supplies through Google.

If this Answer is helpful please remember to return and mark it Accepted.

Was this answer helpful?

Score 1
Add a comment

Add your answer

Eion Woods will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 1

Past 30 Days: 17

All Time: 2,195