Quadra 950 rebooting and losing video

[CelGen]

I have three hard drives hanging off my Quadra 950. There's two drives internally and a drive that is external. All three of them have been formatted with the patched Drive Setup utility and to me at least they are completely blank. I'm currently running off an MO cartridge.

If I reboot the system, remove the cartridge and zap the PRAM I'm still getting a problem where one of the drives still supposedly has something on it and the system shows a happy mac, screen goes blank and the system reboots (or it hangs at the black screen and you have to press the reset button). It will do this three or four times before finally going to the flashing question mark.

If you have an install on my main drive (first on the bus) it continues to do this weird reboot thing however a quarter of the time you will either lose the internal video or the system crashes with a bus error or no error at all which I suspect is the OS trying to mount or poke at something I cannot see and it should not see.

If I take all three drives and blast the filesystems away with a format on a Windows PC, the problem goes away and when you power up you are greeted with the blinking question mark.

...until you initialize any of the drives, then the problem returns. xx(

I have a Duobook which does this as well but nowhere near as bad as the quadra. I don't remember it doing this before either. It had a few hard power cycles and then it started happening. The fact that it happens between formats is what really puzzles me.

 

[CelGen]

Also, would like to add that this isn't limited to one system. My other quadra 950 does it too when you put the drives in it.

It's also getting worse. Now my MO cartrtidge is doing it too. The only thing immune to this problem is my Mac OS 8 boot floppy because you can write protect that.

 

[volvo242gt]

Caps are good on all three machines? Definitely something odd going on.

-J

 

[CelGen]

They use tantalum tech so unless it's in the PSU the boards should be fine.

 

[uniserver]

Tantalum caps are not gods gift, they do burn up.

Electrolytics are more forgiving in some instances then tantalum caps.

a board wash is still nice thing to do.

 

[CelGen]

What exactly will a wash do in this situation?

 

[mcdermd]

Clean off the dust? Give it some self esteem?

 

[uniserver]

then after that give it a nice massage.

 

[CelGen]

I blasted it out with compressed air whatever dust there was (and there was not much as I cleaned it last year) and no change.

 

[trag]

What exactly will a wash do in this situation?

In the case where electrolytics are present, it will remove the leaked goo. The leaked goo is a double whammy. It is corrosive and can eventually destroy parts of the logic board. The goo is also conductive, and can cause short circuits on the board. This is why washing the boards will sometimes get it working again -- for a while.

In your case, with tantalums, even if the caps have died of old age, there should not be leaked goo on the board, so a wash should not, in theory have any effect. It might be an interesting experiment to try any way. Always good to test our hypotheses with experimentation.

As far as your bizarre hard drive/boot behaviour, beats me. Maybe try a formatter other than the hacked Apple formatter. I was always fond of APS's Alliance Power Tools. Also double check that your SCSI chains are configured properly with no ID conflicts, nor termination errors.

BTW, you don't have any of the internal drives set to the same ID as the external MO drive, do you? If you do, that's likely to be your problem.

The Q950 does not have SCSI Manager 4.3 in ROM, so it treats the two SCSI busses as a single logical bus, and SCSI ID conflicts will happen at boot time if devices share the same ID.

 

[Unknown_K]

Any chance they are HVD drives on a LVD/SE system?

 

[James1095]

There are electrolytic capacitors in the power supply and those are prone to failure. Especially the ones in the output filters.

 

[CelGen]

Drives are SE/LVD SCA drives with 50 pin adapters. Been using them in the system for three years now. Not a hiccup.

I swear that in the system swap I changed PSU's as well. I find it REALLY doubtful that both systems are showing the exact same problems.

 

[IIfx]

Here is something that may work out for you. My Q800 and IIfx became randomly flaky (both of these use tantalum caps). It turns out that the electrical contacts on the motherboard to the RAM and Nubus cards were dirty. I bought a can of Electronic Contact Cleaner at an auto parts store, sprayed all the connections, and boom no more random crashes or glitches. The tin pins on the RAM slots seem to be temperamental.

Ensure that the can you pick is plastic safe.

(The specific can I used was NAPA CRC QD Electronic Cleaner)

Be careful not to spray your hand - it stings. Even if dirt on contacts is not the issue, it doesn't hurt to clean them.

 

[CelGen]

I bought three cans of MG Chemicals contact cleaner before I left Vancouver. The board has already seen a rather generous spraying of it.

Also, it seems the install broke on my MO cartridge. I'll have to reload it.

 

[CelGen]

BuMP.

I'm still slowly advancing on this issue. The first major breakthrough came when I finally uncovered the Applevision service manual. The green power LED but a blank screen is a fault of the monitor. Even LEM says that even for a nice monitor, it's very badly designed. A power cycle rectifies that. I need to reload the OS on my 9600 before I can run the AppleVision utility and try resetting the microcontroller.

The odd happy mac behaviour has gone away now that I've stripped a machine down to one drive, no expansion and four 4mb SIMMs installed. I could of sworn that I have checked all the ram but it appears Snooper will only ever scan the first bank. IS there any better ram testing applications available? Swapping banks around can yield undesired results on flaky sticks. It might also of been the VRAM.....

I'll keep you posted.

 

[CelGen]

Yeah, the best way to deal with the AppleVision is to ignore the auto on/off and ue the manual switch. If you let it do anything erratic it you get the blank screen issue and you will need to reset the monitor.

Both drives have seen a complete nuking. The 36gb spare remains uninitialized and thus invisible to the mac through the following tests.

For this test I started by doing a customized 68K install of 7.6.1. After repeated boot cycles the mysterious happy mac reset had not of shown so I proceeded to load Snooper and tested each bank of 4mb SIMMs one at a time, followed by testing of the onboard and expanded VRAM. No problems reported and no issues gained as memory was added.

I'll now proceed to clear out the system folder, install a Universal 7.6.1 install and fit the PowerPro 601 card.

 

[CelGen]

Weeeird.

So now that everything is installed this time around I'm not running into the issue anymore. Bizarre.

Oh well, I guess this issue has fixed itself.