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View Full Version : B&W G3 chimes, but no video



normyzo
04-08-2003, 10:03 PM
I came into a B&W G3/300, and it doesn't boot. I knew that when I got it, and am trying to figure out if I have to buy a new logic board for it. Here's the deal: it powers on, chimes, then nothing. No video at all. There is no hard drive in the unit so I can't hear if it actually _does_ boot anything.

I tried:
1) Moving a 64MB stick of Crucial PC100, known good, around the slots, no difference. No ram produces the single beep error tone.
2) Matrox Mac PCI video card in 33Mhz slot, take out ATI card, no difference, no video
3) Swap out processor for known _good_ Beige G3/300 one, powers on, chimes, no video, same
4) CUDA reset, 20s, no difference
5) Voltage tested power supply and battery, both good
6) Resetting PRAM with USB keyboard, does NOT reset (no additional chimes)

Any ideas, help? If I do need a new board, where's a good place to get one?

Thanks,
Dan

kaye
04-09-2003, 12:14 AM
I would still get a new battery to get started with this. A voltage check under no-load conditions can be very deceiving. If it tests low, you know it is low. If it tests normal, you still don't know if the voltage will drop off significantly under a load.

Maybe someone else with knowledge of the B&W sees something else in your list. k

normyzo
04-09-2003, 12:53 AM
How much would the battery contribute to the non-video issue though? I would understand if the box didn't boot at all, but it at least chimes.

On a side note, Apple's technote about the BW G3 talked about the POST code in ROM, and the fact that it includes a small debug nub. Does anyone know how to connect to that debugger?

Thanks,
Dan

TZ
04-09-2003, 06:05 AM
I had that happen with one stick of 10 ns RAM in B&W and all the other sticks were 10 ns. but I would definitely put a new battery in, and yes, you could get a chime but no further.
And then you can you get the Open Firmware screen to show, so that you can reset and clear nvram and set defaults. So you can output or enable the debugger... I can point to Apple's Open Firmware Docs but not how to program Forth.

- G.

[This message has been edited by Gregory (edited 09 April 2003).]

normyzo
04-10-2003, 01:43 PM
Well, the RAM is PC100, I forget if that's 10ns but isn't it faster? Like 8ns? I will have to try other RAM just to be sure. Will have to try new battery too.

TZ
04-10-2003, 02:22 PM
Check in the Memory section, Memory FAQ.

PC100 can be 10 ns or 8 ns. Why I don't know but B&W should have 8 ns. RAM has to be faster than the front side bus to work. 10 ns isn't. In fact, it should be 125 MHz RAM (8 ns) to work properly. You can also use PC133 in B&W and it will work in PC100 mode. PC133 is 7.5 ns, much closer as you can see, in performance spec. PC100 10 ns can be used in 300 MHz cpu system probably, but if you upgrade to 350MHz or faster or use a G4 zif, no. And OS X is much more sensitive to such problems.

It was hard to find 125 MHz PC100 back in July '99 when Apple published the Memory Guide pdf and listed that as a requirement. In fact, some or most of the 64MB SDRAM that B&W's shipped with were using memory that didn't even meet Apple's own specs, the industry was having trouble even meeting SDRAM requirements - DRAM is not easy.

Those occasional crashes (once a day, couple a week) went away with proper DRAM. OS X Public Beta crashed with kernel panics with low quality RAM. Apple issued a firmware update - but only for G4's - to check the DRAM CAS/RAS timing information on the chips (some lacked any code whatsoever which was one of the problems). Having all the RAM of the same make, speed, vendor, tends to work better by eliminating timing issues totally.

I just bought what OWC said was "PC100 8ns" only it turned out to be PC133 7.5 ns which would not work in a Beige, does work fine in B&W. I wanted RAM I could use in either.

normyzo
04-14-2003, 10:55 AM
I did try a different battery, that from my working G4, but that didn't make a difference. So I'll have to try other RAM.

Bailey
04-14-2003, 02:34 PM
I had a similar problem recently. The computer would chime then nothing but gray screen. After the ram was removed and reseated, the problem went away. Some other wires and things may have been moved in the process, but essentially I just reseated the ram.

Is 64 meg big enough for the B&W? My system 9.2.2 requires almost 80 megs. I use a mimimum of 256 megs of ram.

normyzo
04-14-2003, 04:43 PM
I've reseated the RAM countless times, tried different modules (both 64 and 128MB), and tried all the slots available and nothing... http://macgurus.com/infopop/emoticons/icon_frown.gif

ricks
04-14-2003, 06:27 PM
Dan,

?Here's a link to the Servece Manual for the B&W. It's on my iDisk and is 10MB so be prepared for a download.

?G3.pdf (http://homepage.mac.com/rstephens/.Public/powermac_g3_blue.white.pdf)

?It has descriptions of what all the leds on the motherboard are indicating, how to reset the motherboard and what parts to try in event of differing failures.

?Hope that helps out some, easier than posting seemingly endless answers to all of our questions as we narrow it down. If there is a hardware problem this may help you tell.

Rick

normyzo
04-16-2003, 11:32 AM
Hi,

Tried the reset procedure listed in the manual. I also tried a stick of 32MB RAM _known_ to work in another B&W G3. Neither worked. I think its just got a bum logic board...

Dan

TZ
04-16-2003, 03:48 PM
Most of the 32 and 64MB SDRAM included and sold 4 yrs ago was not really compatible with 100 MHz bus, safer on 300 MHz cpu but was 10 nanosecond rather than the req'd 8 ns.

you're probably right anyway and would be beating a dead horse at this point. (though those 1GHz G4's do sound tempting!)

jlipitz
05-14-2004, 07:22 AM
I am in the middle of the same issue with our BW G3 350, although I do not get any start-up chime.

All was working well, until I installed Sonnet firmware update. Now the original processor won't work in the machine. I am having same/similar symptoms to the problem machine being discussed in this thread.

Any help would be great!

J

ricks
05-14-2004, 08:36 AM
This link For the Service Manual (http://homepage.mac.com/rstephens/.Public/powermac_g3_blue.white.pdf) is still good. The manual lists all the LEDs and test procedures.

Rick

virtualav
05-14-2004, 04:10 PM
I am in the middle of the same issue with our BW G3 350, although I do not get any start-up chime.

All was working well, until I installed Sonnet firmware update. Now the original processor won't work in the machine. I am having same/similar symptoms to the problem machine being discussed in this thread.

Any help would be great!

J

Same problem here shortly after performing the firmware update for our Tempo133 card. This machine (originally a B&W G3/400UltraSCSI) also has a Sonnet G4/500 processor upgrade. I've tried some suggestions & will try more. If I have success, I'll share it, of course!

Charlie