Power Macintosh 8500 Display + Sounds Issues

[thinkdifferent]

Mr Power Macintosh 8500 has stopped functioning properly. While I was using Photoshop 6, the screen froze, and I was forced to press the shut down button to turn off the computer. When I turned the computer on again, the monitor no longer functioned. I tried plugging my Power Macintosh into a different monitor, and that didn't work either. After several shut downs and start ups using the power button, the sound failed to work as well. When I asked this question before, someone, I believe it was LCGuy, suggested I check to make sure the processor was not damaged or knocked off its mount. However, I cannot find a way to the motherboard, and the screws preventing me from accessing it are very tight. Can anyone help me on this issue? Any support would be much appreciated.

 

[superpantoufle]

Did you first try to reset the PRAM?

I don't have a 8500, but it has the same case than the 8200 and 9500, both of which I own. What screws are you talking about? The six securing the back panel to the case? There's no way you can open the machine without unscrewing them…

 

[thinkdifferent]

Did you first try to reset the PRAM?
I don't have a 8500, but it has the same case than the 8200 and 9500, both of which I own. What screws are you talking about? The six securing the back panel to the case? There's no way you can open the machine without unscrewing them…

I did not... I found this guide on apple.com, which should apply to my Power Macintosh as well. http://support.apple.com/kb/HT1379 I unscrewed the six back screws without a problem, but had some trouble accessing the motherboard. I saw the expansion slots, but everything beyond that was unreachable. Thanks for all the help, I will try resetting the PRAM.

 

[Unknown_K]

If the processor was not inserted correctly the machine would not do anything. Video going might be a VRAM problem (there are 4 1MB VRAM slots on an 8500, installed in pairs). If sound is going then you probably have a problem somewhere on the motherboard (leaking capacitors, something shorting out) unless you took the speaker cable off the motherboard while tinkering and forgot to put it back on.

Have you tried a mac PCI video card to see if it works?

 

[mac2geezer]

If the 8500 is the same as the 9500 disassembly is as follows:

1. Unscrew the 6 large screws on the back of the case, then slide the main case forward an inch or so then lift it off.

2. Remove all PCI cards and the processor card

3. On the right side of the machine as you face the front there should be a screw in the center of the motherboard; remove it and the plastic molding covering the MB (if there is one).

4. Disconnect all cables on the MB edge, the pop the front on/off switch assembly forward a little.

5. The MB should then slide forward about 1/2 inch and come right out; don't forget the cables for the fan and front switch.

Assembly is obviously the reverse steps.

 

[jimjamyahauk]

Hi,

I would try pressing the CUDA reset button on the 8500 (small grey button in a silver square mount just above the top PCI slot, see image below) and re-seating the processor card (You will have to remove the processor card in order to access the CUDA button).

If you're using a PCI video card, disconnect this and only use the onboard video. Also, if you have any other PCI cards installed remove these and try to boot.

If you make any progress on this let us know.

James.

 

[thinkdifferent]

Thanks for all the help, guys. I will try to the reset button, and examine the motherboard for any problems.

 

[thinkdifferent]

I finally removed the motherboard... it took awhile, due to a VERY annoying daughter card that prevented it from moving (I hear that the daughtercard contains the processor.) I am examining the motherboard for any issues.

 

[equill]

... (I hear that the daughtercard contains the processor.) ...

It sure do. Be assured, for all future occasions, that the ... ah ... interesting 8500/9500/Quadra 800 case style has a charm of its own. Replacing battery or RAM is an exercise in almost complete demolition, sometimes literally as the models suffered from a strangely rapid embrittlement of the internal plastics. In the 8500/9500, the plastic PCI-card-retaining tangs—and the main power-switch tangs—snap off as you look at them. The chiefest requirement for removal of the MLB is to remove the daughter-card first, and to be sure that it is completely bottomed in its slot when you reassemble the Mac. Failing to bottom the card, which can take considerable force when the slot is in good condition, is equivalent to having no processor installed.

Despite the layout, it is also necessary to work around the installed daughter-card to do anything useful with the CUDA switch. It needs a long, thin, nonconducting rod and a good light. The whole point of pressing the CUDA switch, and holding it in for 40-odd seconds (assuming that your battery shows 3.4V or more when measured in-circut), is to signal to the system that the present hardware is what has to be taken account of. That cannot be done if the daughter-card is not yet installed.

de

 

[thinkdifferent]

... (I hear that the daughtercard contains the processor.) ...

It sure do. Be assured, for all future occasions, that the ... ah ... interesting 8500/9500/Quadra 800 case style has a charm of its own. Replacing battery or RAM is an exercise in almost complete demolition, sometimes literally as the models suffered from a strangely rapid embrittlement of the internal plastics. In the 8500/9500, the plastic PCI-card-retaining tangs—and the main power-switch tangs—snap off as you look at them. The chiefest requirement for removal of the MLB is to remove the daughter-card first, and to be sure that it is completely bottomed in its slot when you reassemble the Mac. Failing to bottom the card, which can take considerable force when the slot is in good condition, is equivalent to having no processor installed.

Despite the layout, it is also necessary to work around the installed daughter-card to do anything useful with the CUDA switch. It needs a long, thin, nonconducting rod and a good light. The whole point of pressing the CUDA switch, and holding it in for 40-odd seconds (assuming that your battery shows 3.4V or more when measured in-circut), is to signal to the system that the present hardware is what has to be taken account of. That cannot be done if the daughter-card is not yet installed.

de

Hmm... I successfully removed the motherboard and hit the reset button (not sure if the computer needs to be on while I do that...) After putting the motherboard and daughter card back, and re-connecting all those messy wires, I turned the computer on again and it hummed to life (minus the start-up chimes... I removed the speaker since it was getting in the way.) Eager to test it with my monitor, I brought it downstairs and re-connected it to the power supply. Oddly, as soon as I started it up again, the computer clicked twice and failed. I removed the daughter card, and strangely, the computer started up as normal again. :?: :?: :?: I have no idea how a computer can start up without its processor... unless the processor wasn't in the daughter card, which isn't the case here. I hit the reset button again and the machine shut down. Then I started it up, and just like before, it started up without the processor. It failed to connect to the monitor though. After putting the daughter card back in, the computer once more failed to start up. It seems to be doing EXACTLY the opposite of what should happen. I have no idea what I'm going to do... perhaps I should pay the money to have it fixed by a professional computer repairmen, or ask our school's IT very nicely to help me. Thanks for the support, I really appreciate it. :b&w:

 

[thinkdifferent]

... (I hear that the daughtercard contains the processor.) ...

It sure do. Be assured, for all future occasions, that the ... ah ... interesting 8500/9500/Quadra 800 case style has a charm of its own. Replacing battery or RAM is an exercise in almost complete demolition, sometimes literally as the models suffered from a strangely rapid embrittlement of the internal plastics. In the 8500/9500, the plastic PCI-card-retaining tangs—and the main power-switch tangs—snap off as you look at them. The chiefest requirement for removal of the MLB is to remove the daughter-card first, and to be sure that it is completely bottomed in its slot when you reassemble the Mac. Failing to bottom the card, which can take considerable force when the slot is in good condition, is equivalent to having no processor installed.

Despite the layout, it is also necessary to work around the installed daughter-card to do anything useful with the CUDA switch. It needs a long, thin, nonconducting rod and a good light. The whole point of pressing the CUDA switch, and holding it in for 40-odd seconds (assuming that your battery shows 3.4V or more when measured in-circut), is to signal to the system that the present hardware is what has to be taken account of. That cannot be done if the daughter-card is not yet installed.

de

Hmm... I successfully removed the motherboard and hit the reset button (not sure if the computer needs to be on while I do that...) After putting the motherboard and daughter card back, and re-connecting all those messy wires, I turned the computer on again and it hummed to life (minus the start-up chimes... I removed the speaker since it was getting in the way.) Eager to test it with my monitor, I brought it downstairs and re-connected it to the power supply. Oddly, as soon as I started it up again, the computer clicked twice and failed. I removed the daughter card, and strangely, the computer started up as normal again. :?: :?: :?: I have no idea how a computer can start up without its processor... unless the processor wasn't in the daughter card, which isn't the case here. I hit the reset button again and the machine shut down. Then I started it up, and just like before, it started up without the processor. It failed to connect to the monitor though. After putting the daughter card back in, the computer once more failed to start up. It seems to be doing EXACTLY the opposite of what should happen. I have no idea what I'm going to do... perhaps I should pay the money to have it fixed by a professional computer repairmen, or ask our school's IT very nicely to help me. Thanks for the support, I really appreciate it. :b&w:

I put the processor back in and now the computer has started up. Monitor still isn't working at all... So it looks like I may be exactly where I started. A Power Macintosh 8500 that will not run the monitor.

 

[~Coxy]

I'd never actually seen a 8500 board before; that does look like a very unique layout.

What does the daughterboard plug into, that dark grey slot above the PCI? What are the large empty PLCC solder pads for?

 

[equill]

When you reply to an immediately-preceding post, you will save a lot of forum real-estate if you quote only the relevant portion of its text, or even none of it if you are replying to its overall content.

Use of the CUDA switch has been dealt with here. As briefly as possible, it is used after you have changed some part of the logic or the peripheral hardware, or reset the MLB. As with all work inside the computer, it is done while mains power is not connected to the Mac, even if you use the mains cable as a ground-return to remove static charge from the Mac and yourself. You can do this only if the mains outlet (wall or power-board) is switched off, and if the outlet is definitely grounded.

What are you considering as 'startup'? If the internal speaker was not connected at the time, you could not have heard the chime that follows a successful POST (Power-On Self-Test). Were you using fan noise and HDD spin-up as your cues? The chime is the first of a defined sequence of audible/visible signs that Startup Manager has begun the process, and that 'mileposts' in the startup sequence have been successfully attained: POST, video raster (grey screen), mouse-tracking (pointer movement), Happy Mac, splash screen and desktop. If you are not yet able to see life (raster) in your display, startup is far from being a detectable happening. Further, you can be certain that with no processor installed, nothing else is going to process the startup code in ROM that gets the ball rolling.

Before you hand off resuscitation of the Mac, your own knowledge of what the Mac lacks at the moment will be greater if you have made sure of such basics as battery voltage, RAM DIMM quality, condition and insertion, cable connections, drive condition, peripheral functionality (by replacement with a known-good example, or checking with another Mac), and so forth. If the Mac's configuration has not changed since before the failure, you have both software and hardware to check, and the former can be checked only after the latter has been verified, unless the HDD can be checked in another Mac. Good hunting.

de

 

[thinkdifferent]

What does the daughterboard plug into, that dark grey slot above the PCI? What are the large empty PLCC solder pads for?

Yes, although I would say it's more of a dark brown :b&w:

 

[Bolle]

those large solder pads are only used on 7x00 PowerMacs that have composite and S-Video in/out. They used the same motherboard as the 8500.

 

[thinkdifferent]

I have now ruled that it is a problem with the video card. I plugged the Power Mac into my TV using the three RCA connectors, and the sound was great. The screen only showed a white box though.

 

[System7]

... (I hear that the daughtercard contains the processor.) ...

It sure do. Be assured, for all future occasions, that the ... ah ... interesting 8500/9500/Quadra 800 case style has a charm of its own. Replacing battery or RAM is an exercise in almost complete demolition, sometimes literally as the models suffered from a strangely rapid embrittlement of the internal plastics. In the 8500/9500, the plastic PCI-card-retaining tangs—and the main power-switch tangs—snap off as you look at them. The chiefest requirement for removal of the MLB is to remove the daughter-card first, and to be sure that it is completely bottomed in its slot when you reassemble the Mac. Failing to bottom the card, which can take considerable force when the slot is in good condition, is equivalent to having no processor installed.

Despite the layout, it is also necessary to work around the installed daughter-card to do anything useful with the CUDA switch. It needs a long, thin, nonconducting rod and a good light. The whole point of pressing the CUDA switch, and holding it in for 40-odd seconds (assuming that your battery shows 3.4V or more when measured in-circut), is to signal to the system that the present hardware is what has to be taken account of. That cannot be done if the daughter-card is not yet installed.

de

Equill, Did YOU make a typo???? "It Sure Do". Its the end of the world!!!!!! :O

 

[alk]

those large solder pads are only used on 7x00 PowerMacs that have composite and S-Video in/out. They used the same motherboard as the 8500.

I thought it was the other way around: the 8500 had the extra ICs to drive the composite video out. C- and S-video out was only available on the 8[56]00 and not available on the 7[56]00. The 7x00 and 8x00 both allowed video input, however.

This could also be a 7300 motherboard (which didn't support AV at all), and it is conspicuously missing the header for the AV module's ribbon cable. I vote 7300.

Peace,

Drew

 

[Temetka]

I am pretty sure the mobo pictured is not 2 things:

1. The OP's mobo

2. An 8500 mobo for reasons pointed out by the poster above me.

@OP: Can you take a pic of your mobo for us? It's not required as the case is hard to work in glares at my 8500 under the desk>.