Color Classic is Dead?

Question

Level 1

105 points

Color Classic is Dead?

I just bought a cheap color classic that, according to the last owner, simply stopped working one day. I figured it must be the PRAM battery, but that wasn't the case (replaced with a working battery). I've used the power switch and key to turn it on, nothing. I tried to short the ADB plug to force it on, still nothing. When I pull out the motherboard and flip the power switch in the back nothing happens. I thought I heard the speaker pop when I flipped it on once, but it might have been my imagination. Please help! Any suggestions would be greatly appreciated.

Powermac G5 (dual 2ghz), Mac OS X (10.4.6), 1Gig, 2x 160GB

Posted on Jul 14, 2006 11:02 PM

Reply

Answer 1

Top-ranking reply

Denis Eddy

Level 4

3,571 points

Jul 21, 2006 9:29 AM in response to nosoupforyou

nosoupforyou
Given your last response, you are faced with failure of your CC's power/analogue board. You didn't mention whether you hear/feel the HDD spin up. Rule out the mains cable, as James suggests. Then take a DVM to the HDD's supply cable to see whether you have the 12V and 5V rails present when the Mac is connected to the mains, switched on at the rear and the keyboard pseudo-soft power switch is depressed. YEL = +12V. RED = +5V. BLK = 0V. Additionally, pin 25 of the DB-25 SCSI port is TERM PWR = +5V relative to pin 24 = 0V. Unfortunately, finding the correct DC voltages from the power supply does not clear the video section of the power/analogue board.

As an 'encouragement', Apple's Service Source manual has a larger than usual number of troubleshooting entries under Video. Fifteen of the sixteen symptom sets include 'Replace the analog(ue) board'. Regrettably, the number of CC's ready to continue, these days, is fewer than the number of available power/analogue boards. That board was, and remains even more so today, one of the prime causes of retirement for CCs.

Apple IIe; 68K: 11DT + 4PB; PPC: 5DT + 3PB; G3: 6DT System 6.0.8 to OS 10.4.x

Reply

Answer 2

Denis Eddy

Level 4

3,571 points

Jul 15, 2006 12:13 AM in response to nosoupforyou

nosoupforyou
The CC is one of a small number of Macs with pseudo-soft power. Perhaps yours had not been powered from the mains for some time before your acquisition of it. If you don't already, leave the Mac permanently attached to mains power and switched on at the rear rocker switch. Give it up to a day of just soaking. I have rescued two CCs from oblivion thus. At the end of the soak, use the keyboard power switch to start up. You may have to reset PRAM at startup with the usual four-fingered salute.

Apple IIe; 68K: 11DT + 4PB; PPC: 5DT + 3PB; G3: 6DT System 6.0.8 to OS 10.4.x

Reply

Answer 3

Denis Eddy

Level 4

3,571 points

Jul 17, 2006 3:17 AM in response to nosoupforyou

nosoupforyou
You've already gone part of the way into the next stage. Take out, unless you still have them out, the FDD, HDD and RAM, and also remove the logic board. Clean along the accessible contacts (RAM and logic board) with a pencil eraser, and then blow off the junk with canned air. Blow out the SIMM slots and cable connectors (including those for the analogue board to logic board) with air. If your CC has a CUDA switch at the rear (not all of them do), press and hold that for 20sec after leaving the board without battery for 10min. Restore the battery, reconnect the cables and reassemble the CC. Break and remake the cable-to-drive connectors a couple of times during reassembly.

Reattach the CC to the live mains, switch on at the rear rocker switch, attach the keyboard and mouse, and again let the CC soak for 24hr. When you start up again, take careful note of HDD spin-up (whether it does), whether video tries to start (during the four-fingered salute). Do you have a Disk Tools diskette (System 7.1 to 7.6.1), or an external SCSI CD-ROM drive?

Apple IIe; 68K: 11DT + 4PB; PPC: 5DT + 3PB; G3: 6DT System 6.0.8 to OS 10.4.x

Reply

Answer 4

Jul 20, 2006 11:18 PM in response to nosoupforyou

Two question. Could the power cord be the problem? Could the power supply be the problem?

If the computer per the previous owner "simply stopped working", I would suspect the power supply.

Reply

Answer 5

Denis Eddy

Level 4

3,571 points

Jul 18, 2006 12:27 PM in response to nosoupforyou

nosoupforyou

Ok, I blew out the innards with a vacuum ...

The reason for advising the use of canned air to clean electronics is that the blades of a vacuum-cleaner's fan so thrash the air during its throughput as to load it with static charge, and especially so if the air is dry. The same is true of air compressors, but those often have grounded metal reservoirs for the compressed air. Suffice it to say that outlet (compressed) air from a vacuum cleaner is a no-no.

If you followed the rest as written you have reset the logic board. Did you hear/feel spinup of the HDD? If the soak achieves nothing it will be time to begin isolating the drives in turn to make sure that they are not overloading (power or signal) the logic board.

Apple IIe; 68K: 11DT + 4PB; PPC: 5DT + 3PB; G3: 6DT System 6.0.8 to OS 10.4.x

Reply

Answer 6

nosoupforyou Author

Level 1

105 points

Jul 21, 2006 9:38 AM in response to James Whittaker

I replaced the power cord with one that I know works, but that didn't help. I think you're right about the power supply. Hopefully I will have time to pull the entire machine apart this weekend to double check that this isn't an internal connection issue.

Reply

Answer 7

nosoupforyou Author

Level 1

105 points

Jul 16, 2006 9:15 PM in response to Denis Eddy

I let it soak up some power for a day, still nothing. I cracked open the case to unplug the floppy and hard drives to see if that would make a difference (also removed the RAM). I'll let it soak for another day or two to see what happens. Thanks for the help.

Reply

Answer 8

nosoupforyou Author

Level 1

105 points

Jul 18, 2006 8:53 AM in response to Denis Eddy

Ok, I blew out the innards with a vacuum, cleaned the logic board contacts with an eraser, disconnected the RAM, HD, and floppy, and hit the CUDA switch. Still nothing. No video or anything. I wasn't able to check the contacts and cables at the front of the computer. Not sure how to discharge the CRT, but the technical manual I downloaded seems to help understand what's going on. I'll let it sit for another 24 hours. I might have a startup disk, but unfortunately, I got rid of most of my floppies a year ago and the only mac with a floppy is my Plus. And anyways the boot disk would have been for a Classic II, which I don't think uses the same system enabler.
I was under the impression that the fans/HD would spin up if I switched the main power on while the logic board is out. Is this true? Nothing happened when I tried it.

Reply

Answer 9

nosoupforyou Author

Level 1

105 points

Jul 19, 2006 5:05 PM in response to Denis Eddy

Well I'll try canned air once I get out to the store. I've vacuumed many computers before without repercussions, but that's good to know.

I did a day of soaking, nothing. Then a day of no power, nothing. Neither of the drives were connected at the time. No speaker pop, no sparks when I inserted the power cord, no lights, no fan, no video.

Reply

Answer 10

nosoupforyou Author

Level 1

105 points

Jul 22, 2006 8:48 AM in response to Denis Eddy

Yeah that's too bad. I guess I'll just have to use this machine for parts, but thanks for the help.

Reply