I made a big mistake!!!

[Sea Side]

Oh boy, I think I just killed my iMac while upgrading my internal HD to 160 GB and super drive to a dual layer burner for my iMac G4 800 mhz.

Initially everything was going well. First I used carbon copy to back up my original HD to an external HD, then took apart my iMac and placed the external as my internal. Put everything back together and pressed the power button, everything booted up fine.

OK, now for my dual layer dvd burner. Disassembled my iMac as I did before and took out the existing Pioneer burner and replaced it with a NEC dual layer burner. Put everything back, turned on the computer downloaded and installed patchburn so that my new optical drive would be recognized. So far so good, everything is working just fine but then noticed that I missed a few screws. Damn, tore it apart again, looked around and found a home for each missing screw. Bandaged it up again and when I press the power button nothing happens. OH CRAP!

Ripped it apart once again, made sure all connectors are tightly secured, all screws in place, and made sure there were no damages to wires. Nothing wrong that I could see, put it back together, pressed the power button and still nothing!!! Not even a screen blip, no BONGGG, can't hear the HD, just plain silence.

What went wrong?? I spent about two hours trying to trouble shoot and right about now I'm at a loss. HELP!!!

 

[rugonnaeatthat]

I can't help... but I can offer my condolences. I upgraded my emac a while back and everything worked out - so its not as if Macs cannot be upgraded.

Firstly - I'd check it's plugged in... (don't hate me for saying this as sometimes in a panic we all forget the basics.)

Second - think about how the machine works. If nothing happens when the power is switched on then hopefully it is something simple to do with the power button... nothing is indicating it is going further than that - so your mac may not yet be a ride off.

Of course I don't really know anything... just thought someone should reply in your hour of need

 

[Sun Baked]

Hopefully you stopped at Radio Shack and got a 99 cent tube of themal paste, so you don't risk burning up the CPU.

 

[Cloudgazer]

I think you should take out the extra screws!

A similar thing happened to me a few times when replacing things in my PC.
I would open the case, replace parts, add RAM, etc, but I always power the PC up before putting the cover back on.
It would power up perfectly.
i'd then replace the cover o nthe box, and try power up again.
nix, nada, nothing.

Take off the cover - works like a charm.
Happened a couple of times actually.

I would be way too scared to open my imac and replace anything

 

[macOSX-tastic]

in your hastiness of taking the imac apart, did you remember to touch a metal part of the case? this dissipates any potentially damaging static.



i thought you might have overlooked this since you were taking it apart and putting it back together quite a few times. but im not 100% on this, so try other things too!

does your warranty void when you take bits out/put things in?

i dont know much, but i can lift heavy weights

tastic

 

[Sun Baked]

If a PMU reset doesn't work, don't know what to tell you.

 

[belvdr]

The big thing to note about the iMac G4 is that the connectors on the base align and seat well with the appropriate connectors in the dome.

Make absolutely sure they are all connected. The LCD connector, for one, is very delicate.

EDIT: Also, if you put a long screw in a hole where a short one may have been, you may have driven the screw through something.

 

[Sea Side]

Just woke up, taking a day off work to fix my iMac.

I'm hoping I didn't fry my computer, will recheck the connectors, wires, etc. you know the basic things, maybe I might have missed something due to utter fustration.

If, just if I did fry it what would my options be? Is it over for my iMac? or can it be salvagable??

 

[Sea Side]

what would be the best way to determine is it's my logic board or power supply that's bad?

 

[Sea Side]

need some input please.

i get no power at all, no fan noise, no noise from HD, absolutely no juice running into the system when i press the power button. sounds like a power supply/cord issue don't you think?

if i had a logic board problem shouldn't i get some indication that at least the computer is trying to power up when i press the power button, but not actually boot up because it's fried???

any input or suggestions?? Please!

 

[tech4all]

Had similar symptoms with our PC a while back. I would press the power button but the computer would not respond at all. Turned out to be a blown power supply. Put in a new one (with more watts) and it booted right up.

Not sure if it could be the power supply on the iMac that got blown, but just thought I mention it.

Hope you get the problem fixed ASAP

 

[Sea Side]

tech,

thank's for the reply, that's what i'm hoping for a blown power supply rather than a fried logic board, easier fix.

but i'm still curious if i had fried my logic board wouldn't i get some response when i power up???

 

[madmax_2069]

have you tryed to take every thing back apart and clean the power connectors ane every connection in the mac take out all the screws and look to see if any are to long and look to see if any are to loose and make shure every thing is seated back properly make shure the power button is clean

 

[Sun Baked]

what would be the best way to determine is it's my logic board or power supply that's bad?

Do you have a voltage meter, there are some test pads on the machine to see if the power supply is working or you have a dead battery.

Dowload the Service Manual for your specific machine, you'll find something like this. Your machine may vary in pad number or wire color.

No Power
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. Disconnect the power cord, place the computer in the service stand, and remove the user access plate.
6. Reset PMU. Refer to “Resetting the PMU on the Logic Board” mentioned earlier in this chapter or Kbase article 95165 .
7. 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. If the battery does measure over +3.5v, reinstall the battery and reset the PMU.
8. Connect the diagnostic cables (part 076-0897) between the upper housing components and the logic board. Refer to “Service Cables” mentioned earlier in this chapter.
9. Check the AC line filter. To measure power at the AC line filter cable, disconnect the AC line filter cable from the power supply cable. Switch your multimeter to read AC voltage. Touch the black probe to the pin of the brown wire, and touch the red probe to the pin of the blue wire (see graphic below). Do you measure 120v (line voltage)? If yes, go on to step 10. If no, replace the AC Line Filter.
10. Check power supply output. Disconnect the diagnostic power cable from the power supply connector, and measure power at the power supply connector by touching the black probe to the ground pin, and using the red probe to measure power at the pins indicated in thegraphic below. Did you measure +12v at each point? If yes, continue with the next step. If no, replace the power supply.
11. Check the main logic board voltages. Measure for +12v DC at capacitors C187 and C197 (identified in graphic below). Ground the black probe to the logic board screw next to the battery, and touch the red probe to the positive node at capacitor C187, and then at capacitor C197. Do you measure +12v? If yes, go on to the next step. If no, replace the logic board.
12. Replace power supply.
13. Replace the logic board.
14. Replace the inverter board.
15. Replace neck assembly.

 

[Sea Side]

Sun Baked,

Yeah baby, that's what i'm looking for

where can i find that link?

Thanks soooo much!!!!

 

[bokdol]

also check the ram slots... there are 2.. one internal and one upgrade slot. if the ram is not seated properly you computer wont start correctly.

 

[Sea Side]

You guys are GREAT.

Solution to my problem: Had to reset the PMU on the Logic Board

Here's how:

Resetting the PMU on the Logic Board
Resetting the PMU (Power Management Unit) on the logic board can resolve many system
problems. Whenever you have a unit that fails to power up, you should follow this procedure
before replacing any modules.
1. Disconnect the power cord.
2 Remove the user access panel from the bottom of the computer.
3 Press the PMU reset switch (shown below) once on the bottom side of the logic board and then
proceed to step 3. Do NOT press the PMU reset switch a second time because it could crash the
PMU chip.
4 WAIT ten seconds before connecting the power cord and powering the computer on. If the
computer powers on, go to the next step. If the computer does not power on, there is
something else wrong with the computer, refer to the symptom/cure, “No Power” in this
chapter.

Once again thanks a million, saved me from ditching my iMac!!

 

[tech4all]

Glad to hear you got it all sorted out!