Startup problem with my 7500

[protocol7]

My 7500 originally came with a G3 card. I swapped it out with a 604 so I could play about with some old systems that didn't like the G3, but now I'm done with those and I've put the G3 back in.

Since doing this, often the 7500 won't start up from a cold boot. It'll chime, the fans power up and the hard disk grinds but doesn't boot into the OS. If I hit ctrl-cmd-power it will boot fine but the reported RAM is wrong. There's 96MB in this (2x8, 1x16, 1x64) but it will only show 80 in the ATM screen and system profiler is missing the 16mb stick. If I restart then it shows all 96MB.

I've reset the pram and cuda but still no improvement. Anything else I'm missing?

 

[phreakout]

Regarding the startup issue, sometimes the vram can cause some fits, especially after swapping out RAM or the processor card. What I do is I remove the vram, the RAM, leave the processor card in and remove all PCI cards. Power the 7500 up until you hear the sound of glass breaking from the front speaker, then add everything back in. If the vram is bad, replace with a new set.

Regarding the RAM, keep in mind that the 7500 uses an interleaving scheme on the RAM sockets, that is, it's best to have like pairs in the matching banks. So, for example, Bank A1 and Bank B1 should have the 8MB sticks installed, instead of just throwing whatever RAM sticks regardless of capacity into any socket at random. Think of it almost like how some DDR RAM works best when installed as "like pairs".

Give that a try and report back.

73s de Phreakout. :rambo:

PS: If you'd like more RAM, send me a PM reply back. I've got a few 8MB sticks laying around.

 

[protocol7]

Yup, I have the RAM interleaved correctly. I tried what you suggested but it didn't change anything.

I put the 604 back in and ran a set of tests with MacTest Pro. It passed all of them and I'm now redoing the RAM/VRAM tests on the long settings so that's going to take a while. So assuming they pass then I can rule out any failing hardware in the system as-is. I don't think there's anything wrong with the G3 card either as it worked perfectly fine when I got the 7500 last year.

When the tests are done I'll shut it down for a half hour or so and then try a cold boot with the 604 installed. It should power up fine. Then I'll swap in the G3 and try again. Is it enough to just swap cards and hit the CUDA switch?

Update: The tests all passed (I just ran the extended RAM test as it told me the long one would take 20-40mins per MB). I left it sitting for 30 mins or so and fired it up. Booted up just fine with the 604. So I'm leaving it for a little while and then I'll put the G3 card back, hit the CUDA reset switch and see what happens.

 

[protocol7]

Nah, it still won't boot from cold with the G3 card installed.

 

[phreakout]

Protocol7,

I, too, have a 7500 and ran into the same issue. It has a Sonnet Crescendo G3 500 Mhz instead of a 601 or 604. It happened more frequently whenever the PRAM battery was dead or old. So that has one contributing factor.

The trick that works for me is shutdown the 7500, remove ALL PCI, RAM, VRAM, Processor card and battery from the logic board, then power it on and briefly push the CUDA button once. What this does is "shock" the logic board and reset it; kind of like using a heart defibrillator on a patient when needed. Next, unplug the power cord, reconnect the battery and processor card. Then, reattach the power plug and add VRAM. Finally, add back in the RAM and PCI card(s). Then try turning on the 7500 again and reset the PRAM (CMD + Option + P + R). If the normal startup tone plays while resetting the PRAM, you're good to go. Let it boot up and restore your control panel preferences.

So to recap, basically you'll be removing each piece of hardware and then adding them in until it boots normal. You will want to shock it before you add parts back in or even try shocking it after you put in the VRAM. Any combination should work. If not, keep at it until it boots.

Keep me posted as to success or not.

73s de Phreakout. :rambo:

 

[protocol7]

Hmm, y'know I think it might be just the battery. I put in another one that I thought was good. The chime was louder than usual but it fired right up. Then I got the date/time is wrong error. I left it a while with no battery installed, tried again and it fired right on up too. Both times the screen kicked in faster than when I had the old battery installed.

I really need to get myself a multimeter so I can check things like this out. I'm just hoping it won't give me any grief once I put in a good battery.

 

[24bit]

How is the G3 upgrade installed physically? I recall I removed my stock 601 card from the 7500 to exchange it for a 604 upgrade.

So my 7500 only had one cpu to boot from. For the Centris650 I had a 601 cpu upgrade to be installed in addition to the 68040.

Therefore it came with a init/control panel to select the cpu at cold start.

Could it be you are missing some kind of software to select the cpu, as you seem to have installed 601 and G3?

Otherwise it may be the PRAM battery beeing weak, so your Mac will default to the stock 601 at cold boot.

 

[protocol7]

It's a straight swap (the CPU is on it's own board). I didn't get the original 601, it came with the G3. I just swapped it out for a 604 to play about with Copland and old BeOS stuff. I want to use it for my occasional printing needs (I've only got a CSW1500) as the 5400 is a bit tight with 32MB RAM, especially when I need to use 8.6 for Acrobat Reader 5.

I thought the battery was OK because the clock was keeping time, but perhaps it was a bit weak. Enough to keep the clock but not enough to keep the G3 happy. So now I have no battery in it. I'm using Network Time to fix the time on boot and PRAM Auto-Restore to set stuff like Appletalk on ethernet rather than printer port. Seems to work fine.

 

[24bit]

Good to know you made it.

I seem to have misunderstood the issue a bit.

Cant say the 7500 was a favourite of mine.

My System used to crash several times a day, even after swapping some hardware: RAM, SCSI, CPU daughterboard.

One of those dreadful "Monday logicboards" ,I presume.

 

[ClassicHasClass]

I like the 7500 the least of the outrigger Macs. Maybe it's the 601, maybe it's the bugs they hadn't worked out of the motherboard yet, but the 7300 and 7600 were clearly better machines. Heck, if I wanted an outrigger 601, I'd probably get a 7200. (I had a 7200 for awhile before the first of my many warhorse 7300s, and I loved it.)

 

[beachycove]

Classichasclass:

Are these logic board differences documented?

 

[ClassicHasClass]

I have an acquaintance who worked at Apple during that time who says there are differences. I have never seen them documented, but it seems logical given the time progression.

 

[mac57]

I wonder if the power supply is at the outer edge of its ability with that G3 card in? I had a similar problem, and if I just restarted the machine for a second time in a row, while the hard drive was still spinning, it would come right up. I concluded that the extra power that the hard drive takes as it spins up from a cold stop was likely pushing the power supply past its limits. The second time, with the drive already spinning. all was well. Eventually, I replaced the two drives I had in the machine with one larger and more modern one (much less power usage) and I haven't had the problem since.

 

[protocol7]

I don't think so. It came with the G3 and I guess had been running fine with it for years. I don't have any other cards installed that would be putting any strain on the PSU. Without the battery it's worked fine, so I'm assuming the battery had enough juice to keep the time, but not enough to keep everything else right. I should get my hands on a multimeter some day and go through all these PRAM batteries and see what state they're in.

 

[applefreak]

try to startup once with the extensions off (startup with shift key down) with the G3 card built in

then restart normaly

any improvement ?

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first without G3 card

if it's run fine with the extensions off

you have to check the loaded extensions for incompatibilities

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then with G3 card