PowerPC 5200/75LC wants to come back and be used again

[FoaRyan]

Hello! This is my first post here but I've browsed, read, and learned for a few months with a renewed interest in 90s Macintosh computers. I have a PowerPC 5200/75LC that has been mine since my high school dumped their fleet in a stairwell back in like 2000... I wanted to get them all then, but you know the parents might ask too many questions!

It worked when I first got it, I can remember playing Sim Tower. In any case, despite not even plugging this in for 10 or 15 years, it does power on. It just won't boot or get to the bootloader as far as I can tell. It may be that the monitor is not turning on, although I hear it "click" like I expect a CRT to do.

Startup goes like this: flick the 0/1 off/on switch on the back to the ON position, then press the power button on the kb. I hear the fan and HDD, or at least I think that's what I'm hearing. The speakers pop (they turn on) then an initial booting sound plays. One second later, the dramatic notes of doom (a.k.a. death chime) play and nothing further happens. It's still on making what I assume is fan or hard drive noise, and the CD tray will eject.

Can anyone help me narrow down the problem? Here's what I've looked at/done so far:

• Physically cleaned the logic board
• Re-seated the RAM, of which there are 2 cards
• Replaced the PRAM battery and pressed the red button for 10s
• Quickly turning the back power switch off/on "to see if that did it"

When I inspected the board I do not see any broken traces, bad solders at least visibly, or obviously blown capacitors. I know a lot of people say to replace them proactively and I may do that, but it seems like something else is the issue. Could it be bad elements on the built-in monitor not allowing the system to completely boot? If so would connecting an external one help?



Edit: there is also a Power Mac & Performa subforum, I'm not sure which group mine belongs in so if it's the other someone can feel free to move this thread over.

 

[LaPorta]

First, let me welcome you! Someone here will definitely be able to point you in the right direction. Now, for sure, you have a working ROM and things are decently working to get you a startup chime. Each machine does something different and will play a different sound depending on what happens after (your “doom” sound). I’d check the PM 5200 repair guide and see what it says, as well as any PDF you can find for MacSecrets or the like talking about the sounds and what they need to check.

Here is the repair guide:

https://www.applerepairmanuals.com/the_manuals_are_in_here/PM_Perf5200_5300.pdf

 

[FoaRyan]

Thanks for the welcome & the link! I have looked over a bit of the repair manual, and generally it says things like "replace the logic board" or "replace the CRT" which is not quite as specific as I'm hoping to get. Lots of good reference for further troubleshooting once this can be figured out though.

Good to know, and it makes sense that it would require a working ROM to generate the chime.

I'd like to test the video theory with an external monitor, but I'm on the hunt for a VGA-ADB cable or converter for a few dollars so until I do find one that would have to wait.

 

[robin-fo]

My 5200 and the spare Logic Board I have are still working without recap, but I wouldn‘t really be surprised if a recap is already necessary on certain boards.

My guess is that a logic board failure is more likely than an analog board defect according to your description. (Can you see anything on the screen after a few seconds?) It is also not unlikely that the internal HD failed (or boot blocks are corrupted). This can sometimes also result in a death chime. Did you try to boot from a CD? Another issue might be oxidised contacts on the logic board connector.

Could you post photos of the logic board and make a video of your Mac when it attempts to boot?

 

[FoaRyan]

My 5200 and the spare Logic Board I have are still working without recap, but I wouldn‘t really be surprised if a recap is already necessary on certain boards.

My guess is that a logic board failure is more likely than an analog board defect according to your description. (Can you see anything on the screen after a few seconds?) It is also not unlikely that the internal HD failed (or boot blocks are corrupted). This can sometimes also result in a death chime. Did you try to boot from a CD? Another issue might be oxidised contacts on the logic board connector.

Could you post photos of the logic board and make a video of your Mac when it attempts to boot?

Have thought about the HDD being dead. From the sounds I hear at startup - which overlap so it's difficult for me to discern what's what - it could be the HDD trying to spin up then failing. Since the screen never illuminates I don't know if it would be trying to display anything. I've left it on for several minutes once or twice, incase it was really slow to warm up.

I do have some images & bootup videos, will take me a min to transfer them but I can post some closeups of the logic board. If I get a chance to make a boot CD I'll give that a try also. Good thing I keep my old MacBooks with disc drives!