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Mac classic almost starts - bong, screen... that's it, no cursor pointer

Juror22

Well-known member
I picked up a Mac Classic (2MB, 40MB HD) and it was immediately subjected to a recap.  As part of that process, I cleaned around the old cap areas with alcohol and re-tinnned the pads, before soldering in the new caps.

When I started it after that, it showed a sad mac / checkerboard, so I figured there was more cleaning to be done.  I washed the board, dryed it out well and then waited a day.

Now it starts with a correct bong, followed by what appears to be a normal startup until the point where the cursor pointer would appear on the screen - it never appears and although I can hear the HD spin up and seek occasionally, since it doesn't make it to the cursor, it also doesn't get to mounting the hard drive.

Any suggestions?  I will try it without the 1MB expansion card, and I suppose I can give it another cleaning, but if anyone knows what could specifically cause this, I would appreciate the help.

Thanks fr any suggestions.

 

Elfen

Well-known member
As long as you got the flashing '?' inside a floppy disk icon, the Classic is or should be working. You got a Bong an you got video - that's 2 out of 3, which the third is booting.

I too suspect the drive. Disconnect the power from the drive when booting from a floppy.

Since it is a Classic you should be able to boot the ROM Disk by holding the Apple-Option-X-O keys when you turn it on. If the ROM Disk works, you have a near (95%) working Mac.

If you have no boot floppy, you can make one through the ROM Disk. Once you get the floppy working, try the hard drive and plug it in. With either floppy or ROM Disk Boot, see if a hard drive icon comes on. Maybe it was formatted or the system folder deleted. But if no Hard Drive icon comes up, suspect that it is a dead or corrupted drive.

The ROM Disk might have a disk fix utility. But it is only for System 6. If the hard drive had/has System 7, using this System 6 tool will scramble it good. Ever tried to unscramble an egg? Its not possible!

Note: If this is a Classic II, it does not have a ROM Disk. Only the Classic has this ROM Disk. System 6.0.8 is the system on it.

 
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Juror22

Well-known member
Thanks for the suggestion, I don't get a flashing ?, yet.  I removed the RAM card and it did not help, in a separate attempt, I removed the HD cable and the startup remains unchanged.  Elfen - I tried to boot from the ROM disk and also from a boot floppy, but I don't think it is making it that far along, thanks for those suggestions as well.

Then I went through and re-checked my solder connections and re-cleaned the board with 99% alcohol and did a visual checkout, with magnifying glasses - I didn't see any broken or corroded vias.  I will let it dry overnight and see if either of those helps. 

 
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techknight

Well-known member
This happens if the ROM cant see the SWIM. grab the classic schematics and go throught it.

Your not gonna see via corrosion AFTER you already washed it. You needed to take note of those beforehand.

 
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Elfen

Well-known member
Your not gonna see via corrosion AFTER you already washed it. You needed to take note of those beforehand.
That's why I'm having trouble finding the corroded traces on my Classic II, LCIII, LC 475 and SE\30 boards! Thanks, now I know.

 

Paralel

Well-known member
If you can get your hands on a polarized light source and the right optics, under polarized light conditions, a corroded trace should look different than a normal trace, even if they both appear normal in typical light.

 

Juror22

Well-known member
I think the jury is out.
Nice one! :)  It is... I have gotten the schematics though, and I will start sorting through them.

I have some PB1xx's that I am recapping right now, so I am working on those as well.

 
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