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Sell me your broken computer

NO Audio - MacBook 1181 2.16GHz

edited February 2012 in MacBook
I am new here and this is my first post. I have tried many ways to fix the audio of my Macbook and nothing made it start working..No sound at all during startup etc. From authorized apple service center here, they squeeze cash to repair and their only solution is to replace the logic board for this!! All I can tell is that the problem is in the logic board and where I could find the Audio area?? And if there is a problem in a resistor etc, is it possible to get one.. I have the Macbook 1181 schematic that details everything..It says there are 4 parts under AUDIO and they are CODEC, SPEAKER AMP, JACK and JACK TRANSLATORS. From where I could find these and the connectors on the logic board. All I see are the connectors are labelled as "J7302" (For left hand speaker connector) and "J7303" (For R/H speaker)...I can send the pictures of the logic board so if there is any Avionic or and Engineer/Tech that knows, please guide me out and let people like us know to familiarize the logic board and there unit,parts, connectors etc..

Answers

  • edited February 2012
    Hi! Thanks for the post. First off, does your logic board see the audio hardware, as in, do you see the volume control icon in the upper-right, or is everything to do with audio greyed-out and/or missing? Also, by chance, when you look in the headphone jack, is there a bright red light (which would indicate the board is stuck in "digital audio" mode)? If there is a red light, you can generally reset it by inserting a q-tip and turning it, and then powering on the computer.

    First I would reset the PMU/SMC. Do this by powering off the computer, and then holding the power button in for about 20 seconds -- it should make a loud tone, and the sleep light should flicker. If it doesn't make a tone but the sleep light flickers, that's a good sign that you really do have a board issue, because it should always make that tone. Not seeing the sound hardware in the OS could conceivably be an OS issue, but resetting the PMU/SMC and failing to hear the tone clears up that question nicely. If you DO hear a tone, but you don't get sound in the OS, you might try wiping/reinstalling the OS, or booting to another volume to rule out your OS as the issue. Resetting the PRAM also couldn't hurt, although I don't think it will tell you anything as conclusively as resetting the PMU/SMC.

    Have you opened up the computer? I'd take off the topcase, and examine the board carefully with a flashlight to see if you can spot corrosion due to liquid damage. If you find any, clean it off with 90% rubbing alcohol and q-tips, or a soft toothbrush. Also, make sure the speaker cables are fully seated, although it would be odd for both of them to be disconnected, etc.

    Unfortunately I am not an expert at logic board repair, so if it comes down to a board issue and there is no corrosion to clean up, my abilities stop at that point. However, AB Cellars is on the site occasionally, and he has become quite an expert at this sort of thing...he may be able to advise you further, or even repair your board for a fee, if you send him a note. But keep in mind there is not necessarily a fix -- there are as many ways a board can be damaged as there are boards, and very often it's just not realistic to bring them back from the dead...especially an A1181 board that only goes for $150 these days.

    Good luck!

    John
  • Thanks John. Unfortunately, tried your suggestions too but failed. I am 100% sure it is a logic board error..As for the corrosion, I don't think the board has got one. Anyway, AB Cellars where are you? :-)
  • A1181 T7400 Logic Board 2.16GHz Black Energy Star Apple MacBook 13" C2D (Mid 2007) 661-4484 ...That's the logic board I have. If I need to upgrade to 2.4GHz one, is it possible?
  • You can e-mail him by clicking on "Inbox" at the top, then click "Start a New Conversation", and then enter "AB Cellars" as the recipient. As for the board compatibility question, please start a "New Discussion" and I'll respond there (the site gets cluttered when different questions are asked in the same thread). Thanks
  • edited February 2012
    The vast majority of the audio circuitry is on the bottom of the board. Some of the discreet components are within the RAM slot located right behind the Airport slot. The Codec chip is located right under that area, it will be labeled with a U and some numbers ( I saw both U6200 and U6800 on different A1181 boards, so could be others.) The chips is square, 6mm per side. On one board the chip was made by Realtek on another it was made by Sigmatel. Both chips were a QFP (quad flat package - have no true pins coming off of them) with 12 leads per side for a total of 48 connections. The amplifiers on one board were labeled U6610,U6620 & U6630 on one board. On the other they were labeled U7210, U7220 & U7230. If you are holding the board with the RAM slots toward you and looking at the Codec chip, they are to the left of the Codec chip and also sit under that same RAM slot. When you find the Codec chip any other component with the same first 2 numbers will be in that circuit (example: Codec = U6200 - L6248, C6212, R6235, etc...) The same holds true for the amplifier circuit. Once you find how they are marked any component with the same fist 2 numbers is in that circuit. Not all components are labeled on these boards so you have to watch where traces go on unmarked components. All circuits on this board have components on both sides of the board, as mentioned earlier - some components for the audio circuit are ware within the RAM slot. Once you find the Codec chip and amplifier chips I suggest you take the letters and numbers off of them and use Google to find their datasheets. The datasheets will contain a schematic of what is required to be in a circuit for them to operate properly, along with pin assignment, etc.. The fore mentioned information may or may not be complete in the schematics you have.

    You are going to need special probes for your test equipment so you are certain that you are only touching 1 "pin"/connection at a time. I soldered sewing pin to each of a set of probes. You are going to need an LCR meter that tests in circuit or you are going to need to remove components off the board to test them. You will need something to test impedance, some LCR meters do that, the datasheets will contain the measurements you should see. I suggest you use a stereo microscope. You might get by with a 10x magnifier on a stand.

    Personal opinion: You are better off replacing the board and selling this one to recoupe some of the money. Another option would be getting a USB audio card to get sound.
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