Performa 6400 only boots every second time

[netbeui]

Hi everyone, I have a strange problem that I can't figure out, I'm hoping someone can help!

Every second time I turn on my Performa 6400 it doesn't boot. I hear the chime but the screen stays black, I then press the button on the back to turn it off and then press the keyboard power button to turn it on and it boots up successfully. But then the next time I shutdown and then try to start it again it doesn't boot and just sits on a blank screen until I power down and power up again.

Does anyone know why this pattern occurs and more importantly how to fix it so it'll boot every time instead of every other time?

Thanks in advance for your help!

 

[Macdrone]

Pram battery may need replaced.  the 6100 series does this, i would start there.  If not may be cleaning and cap time.

 

[mariik]

Well, i got both Performa 6400/200 and a Powermac 6500/250 with empty pram batteries for years. Both boot and run just fine. Maybe it´s something else..

 

[Macdrone]

thats why i mentioned claning and caps.

 

[rsolberg]

Does it power on normally if you use the power button on the back of the computer rather than the keyboard button? If so, try a different keyboard and/or ADB cable.

You could also try removing the dead PRAM battery entirely (if it's still installed.) I remember that fixing more than one 6360 that wouldn't boot on the first try. (6360 is a very similar logic board in a different chassis)

 

[techknight]

how long are you "waiting" at the black screen before getting impatient and switching it off? if its maxed in ram, it takes forever.

 

[rsolberg]

Good point, techknight.

I misread the OP- I didn't notice that it was chiming on each boot attempt. IIRC, there was no chime when I encountered the 6360 PRAM issue I mentioned. Still, I'd remove the dead PRAM battery if still installed. Since we're talking a chime with black screen, I wonder about a video issue. Check the monitor connection. If you're using a PCI video card, check to make sure it's fully seated in the PCI slot. You could also try using the logic board video port. If you have a compatible monitor on the 6500, try it in case it's a monitor or cable issue. If your 6500 has a PCI video card, you could swap that into the 6400.

 

[netbeui]

Thanks everyone for the excellent suggestions. Turns out techknight was correct. My machine has the RAM maxed out, and I guess every other boot it goes through a RAM check? I decided to wait and sure enough, almost a full 3 minutes later, the display lit up and continued the boot process.

Still not sure why it sometimes does the RAM check and other times it just boots right away. I'm starting to wonder if maybe the RAM is flakey. Anyway I'm just glad I know what's going on now, and from now on whenever it decides to check the RAM I'll just wait patiently. 

 

[techknight]

it skips the RAM check if you power off and back on or do a forced-reset. 

 

[olePigeon]

My IIci does that.  It used to take a full 5 minutes or so to do the RAM check (128MBs of RAM.)  I zapped the PRAM, and now it doesn't do the RAM check.  Go figure.