LC 475 Beeping noise

[onemoremac]

Dear people,

Two years ago i've bought a clean and nice second hand LC 475.

Since a year i just tried to boot it up and it made a terrifiying ticking noise.

To me it sounded like a somehow wrong electricity flow.

Last time I booted it up every thing was just working fine. I stored the computer under my desk (climated controlled room) in a box. I have never changed someting on the inside.

Thanks for reading and please help.

Cheers from the Netherlands,

Levi

 

[Macdrone]

Motherboard capacitors have aged and gone bad and need replacement.  That and pram battery maybe leaking also causing damage to motherboard.

 

[bibilit]

A ticking noise will be more a PSU trouble, have you checked outputs ?

Black wires are 0 Volt, orange must be 5 v, yellow 12 Volt and blue - 5 Volt.

 

[Elfen]

A ticking noise will be more a PSU trouble, have you checked outputs ?

Black wires are 0 Volt, orange must be 5 v, yellow 12 Volt and blue - 5 Volt.

I agree. This symptom is usually the PSU needing to be recapped. The question is, what PSU do you have? The most popular is TDK PSU that is used since the LC (1); the 475 needs a bit more amperage so it should be different. But there are at least 3 other PSUs. Recapping the PSU is simple - there are 6 main caps that in replacing them usually fixes the PSU but eventually they all need to be replaced.

The Black wire is ground. And Blue is Negative 5V. To read this on a non-digital multimeter, put the red (+) wire on the black wire or the PSU Casing and the black (-) on the blue wire and it should come up with 5V. ONLY on a digital meter can you have the red wire on the blue wire and it will (or should) give -5V reading. If the multimeter does not give a negative reading, switch the red and black wires to get a 5V reading.

So see what PSU you have, then see (PM) Uniserver as to what information he has on a non-TDK LC-type PSU. If it is a TKD you can see (PM) CompuNerd about buying a basic LC-Type PSU. It's about 6 caps that fixes most LC-Type PSU problems - and cheap too. If you do not know how to recap or have basic soldering/desoldering skills, you can see (PM) Uniserver to recap the PSU for you. He does a great job. I would also ask him about recapping the logic board as well. If they have not gone bad yet, they soon will.

 

[bibilit]

I agree with Elfen, if you have some basic knowledge and some PC parts, you can also manage to do a quick test with a PC PSU.

Most modern PSUs can output all those voltages.

You will probably have a working Logic board in the end, but needing also fresh caps (as the PSU will)

 

[Macdrone]

if the power supply is gone i bet that motherboard wont boot if its fixed. 

 

[onemoremac]

Thanks for all the comments and advice, i was busy at school so i couldn't check the forum.

There are no signs of battery leakage and since the previous owner was also a apple fan he probably replaced the battery, this is the current battery: http://www.amazon.com/SAFT-Lithium-Battery-LS14250-Mac/dp/B000GED9NA

I can check the psu outputs at the school workshop, i can also replace and solder the caps over there.

Does any one know where i can buy the caps, i've googled and can't find them...

It think i am also going to replace the caps on my macintosh se/30 as well..

 

[bibilit]

Caps are 47µf 16v and 100µf 6.3 v so pretty standard, probably any electronic shop will be able to supply those.