This might help you.....
Run iPod diagnostics
By Scott Knaster
August 25, 2004
To enter the diagnostic mode on the iPod, first of all reset it. When you see the Apple logo, hold down Next, Previous, and Select. When the Apple logo goes away, release the buttons. You'll see the coolest thing ever: a backwards Apple logo, as if you were inside the iPod looking out. If it's a 3G, you'll hear the iPod emit a little squeal, like you were pinching it. Diagnostic mode contains stuff used by engineers, technicians, and factory folks to test out the iPod.
The iPod mini is slightly different. For this model, again reset the iPod. When you see the Apple logo, hold down Select and Back. When the Apple logo goes away, release the buttons to see the famous backward Apple and get into diagnostic mode.
When you enter diagnostic mode, you get an ugly, non-iPod-looking screen with a list of eight diagnostic tests. Each test is marked with a letter, A through H. You might expect to use the wheel to select the tests, but it doesn't work. Instead, use the Next and Previous buttons to move up and down the list. Press Select to run the highlighted test. While a test is running, press Play to return to the menu. If you scroll down past test H (or up past test A), you'll see a second screen, items I through P.
Test letter and name
A. 5 IN 1
This runs several tests in a row: LCM, RTC, SDRAM, FLASH/CHECKSUM, and FIREWIRE/FW ID. (See below to find out what they do. Note that you have to press Play twice to get through LCM.) But the real cool stuff comes after the tests finish. On a 3G iPod, you can press buttons to make noises come out of the built-in speaker. Press Previous to hear the wheel's clicking sound, Menu and Select to get two different long beeps, and Next for an effect that sounds a little like a Star Wars blaster. You can have a lot of fun walking around with your iPod, pressing buttons and staring intently at the screen as if you were doing something serious. The clicking sound makes a great fake radiation detector. Press Play to return to the Diagnostics menu.
This resets the iPod, just like pressing Menu and Play together, but slightly easier on your fingers.
This test is actually sort of a video game. You have to press all 5 buttons on the iPod within about 5 seconds. As you press each one, its name appears on the screen. If you get them all in time, you see KEY PASS. If you're too slow, you're humiliated with KEY FAIL.
When you run this test on a 3G iPod, you'll hear a Pac Man-like drumming noise if you have an external speaker connected. On an older iPod, the screen will display AUDIO 0X00000001 DONE.
This one tests the iPod remote. It's another game: you get a few seconds to press all the buttons on the remote. As you press each button, a rectangle appears on the screen in a position that corresponds to the location of the button you pressed. If you don't press them all in time, or you don't have a remote connected, you'll see RMT FAIL.
F. FIREWIRE/FW ID
This test checks out the iPod's FireWire port to make sure it's working OK. If it is, you get the comforting FW PASS message.
When you run this test, your iPod drops off to sleep. When you try to wake it, you might see the low battery icon, and the iPod might refuse to come back to life. If this happens, try resetting the iPod or connecting it to power. That should jolt it awake.
This one checks out the iPod's analog to digital components. The test lists sometimes-cryptic names and results for several parts, which vary depending on the particular iPod model.
I. OTPO CNT
Run this test to play with the scroll wheel. "OTPO" is engineering-ese for the wheel – it was supposed to be "opto", but the misspelling is charming, so why fix it now? When you run this test, move the wheel and you'll see the iPod react by changing the big hexadecimal number on the screen.
This tests the iPod's display. LCM probably stands for "liquid crystal monitor". Run the test, then press Select to see a gradient pattern on the screen. Press Select again to see a giant plus sign. This plus sign refers to the positive effect the iPod has had on Apple's bottom line.
K. RTC/CHG STUS
On older iPods, RTC tests something related to the iPod's real-time clock, the one that knows the time of day. The value sometimes changes a little, but is always small. Is it related to the clock "drift", as described in "Scary Time" in this chapter? I don't know. It's one of those iPod mysteries.
This test is replaced by CHG STUS (charge status) on 3G iPods. CHG STUS displays values indicating whether there's anything connected via USB, FireWire, or the headphone port. It also appears to show if charging power is available.
L. SDRAM/USB DISK
SDRAM tests the iPod's synchronous dynamic RAM. That's the magic ingredient that fights skip protection and prolongs battery life: music is pre-loaded into RAM and the disk drive spins down.
USB DISK tests something unknown and reboots the iPod into disk mode.
M. FLASH/CHK SUM
The FLASH test, called CHK SUM (checksum) on 3G iPods, examines the iPod's flash ROM. The test finishes by displaying a hexadecimal number, probably a checksum to verify the ROM.
The OPTO test, on older iPods only, doesn't seem to do anything at all. CONTRAST lets you fine-tune the screen contrast with the wheel, but any changes you make go away when you leave diagnostic mode.
O. HDD SCAN
This item runs the hard drive test, without the cool animation you get for a disk scan, as described in the section "Use Button Combinations". Scanning the disk takes many minutes. When the scan is done, you'll see either HDD PASS or HDD FAIL. HDD means "hard disk drive". "FAIL" means "Go get it fixed".
P. RUN IN
This last item runs a series of tests over and over, until you press and hold Play. It seems designed to make sure the iPod is ready to go after it's manufactured or repaired.