need help: mac 7500 no display

[oblivion]

picked up a mac 7500/100 but on powering it up I get no display. i know the monitor is fine since it works with my other G3 mac. the thing powers up but i get no display and no sound. I assume even with no hard drive i should get a white display and/or a sad mac face or some kind of chime. any ideas on steps i should try?

it was pretty dusty inside when I opened it and had no hard drive.

 

[oblivion]

ok, now oddly I do get a chime from it when i power up but the first few times it was silent. also noticed it has a G3 cpu upgrade card, not sure if this has anything to do with no display

oh, I think i figured it out. no ROM simm

 

[njroadfan]

Not all the PCI PowerMac machines use a ROM SIMM. Some boards have the ROM soldered on and an empty slot. If you are getting the startup chime, you have a working ROM on-board. These machines are picky when the PRAM battery dies. Zapping the PRAM multiple times usually gets video. Hold down Command+Option+P+R when booting until you hear the startup chime, this is confirmation that its "zapped".

http://support.apple.com/kb/ht1379

 

[oblivion]

no luck, holding down those buttons does repeatedly give me the chime sound as its zapping but still nothing gets displayed to the monitor. tried this several times. I tried reseating the VRAM as well but nothing. I know this mac was previously connected to a big NEC multisync 5fgp monitor that i got with it. unfortunately that monitor is dead but maybe it was set to some weird frequency my current monitor cant do but then again i assume resetting the pram would set it all back to default.

 

[oblivion]

ok, appreently it was the monitor. i was using a viewsonic ps775 and i went and tried it one a newer gateway CRT and it worked. the viewsonic works fine with my G3 minitower though

 

[njroadfan]

What kind of Mac to VGA adapter do you have? Some Macs may default to LCD unfriendly refresh rates depending on how their dip switches are set. Apple commonly used oddball rates like 67Hz instead of the common 60 or 70Hz.

 

[oblivion]

the viewsonic i was using is a CRT. the adaptor is a viewsonic adaptor set to "multi-res" up to 1600x1200. the same adaptor worked fine on the gateway crt. maybe the viewsonic doesnt support that res? as a size question do you happen to know if the 7500 can accept non mac rom hard drives? without using special partitioning software?

it works now, just lowered the res max on the adaptor. apperently the viewsonic just isnt capable of extremely high reselutions

 

[njroadfan]

Apple's "Drive Setup" included with MacOS 8 or 9 should have no such restrictions. That limitation was imposed by the older "Apple HD SC Setup" program included in System 6 and 7. According to Apple, Drive Setup 1.7.3 is compatible with System 7.5. With a G3 CPU card and ample RAM, the machine can run MacOS 9.1 without a problem. 9.2.2 can be installed with OS9Helper. OS X 10.4 with help from XPostFacto is possible if you have the RAM and HD space, don't expect it to be blazing fast though.

 

[oblivion]

Apple's "Drive Setup" included with MacOS 8 or 9 should have no such restrictions. That limitation was imposed by the older "Apple HD SC Setup" program included in System 6 and 7. According to Apple, Drive Setup 1.7.3 is compatible with System 7.5. With a G3 CPU card and ample RAM, the machine can run MacOS 9.1 without a problem. 9.2.2 can be installed with OS9Helper. OS X 10.4 with help from XPostFacto is possible if you have the RAM and HD space, don't expect it to be blazing fast though.

awsome, thanks. this is basicly for mid to late 90's games so OS 8 is probibly what im going to go with. now all i need is a 50 pin to 68 pin scsi adaptor and I can use one of those 4 gig ibm scsi drives i have here.