I Do Not Think There Are Enough Caps On This 7200 Board...

[macoslove]

Looking at this it makes me wonder what Macintosh board has the largest amount of capacitors upon it. An abundance makes my heart happy!

And what does it mean when you get a chime but no video output from one of these? I performed a recapping and that was the result. Before the caps I had no chime so its a step in the right direction it seems.

Thanks to everyone who gives their time to others on here! It's awesome! Love ya!

 

[macoslove]

I picked the wrong job! I should have been soldering all these years. May not be good at it but it sure it enjoyable.

 

[macoslove]

Another 7200 board was found! Good golly, these things seem to be replicating somewhere in my shop...

This one is backed up by my man 'Tyrone' as pictured. I thought those only came in size 'D'

Are there Scotty or Billy branded batteries out there? There ought to be.

 

[DavidUrban]

I just picked up a 7200 and the caps seem fine. i could not see any signs of leakage. Is this an issue similar to the compact Macs?

 

[macoslove]

I get some that all look good but incident to age I replace them.

Often times I find leakage underneath that was unseen.

My personal use 7200 is running original caps still so it is possible.

 

[DavidUrban]

What is that short brown connector by the video connector?

 

[macoslove]

I believe that is for a modem but I cannot remember for sure. It is not something I have ever used these days.

 

[trag]

Looking at this it makes me wonder what Macintosh board has the largest amount of capacitors upon it. An abundance makes my heart happy!

And what does it mean when you get a chime but no video output from one of these? I performed a recapping and that was the result. Before the caps I had no chime so its a step in the right direction it seems.

Thanks to everyone who gives their time to others on here! It's awesome! Love ya!

Can you tell if it is booting (hard drive or floppy drive sounds) even if t here is no video?

If it is not booting, or you can't tell, and even if it is booting, but it won't solve your issue in that latter case, replace the heat sink compound between teh PPC601 and the heat sink if you have not already done so.

On these old machines, teh heat sink grease Apple used under that old fence post heat sink has long since turned to chalk. The machine could be overheating right after the bong.

If you do replace the grease, be very careful/gentle removing and replacing the heat sink. Those old PPC601 packages are very prone to physically cracking. No downward pressure in the center. Well, a tiny bit, because you do need to swab the old heat sink grease off.

 

[macoslove]

I cant tell if it is booting or not (though I am certain I had a working drive connected and it spun up but no seek/work sounds past the initial) but I have carefully replaced the thermal compound. That is part of my process as you are right, the original resembles solidified toothpaste and came off nearly in one piece.

I have two boards in the same state and though I adore them, I would rather they not be wall art.

 

[trag]

Ah, well, beyond the obvious of inspecting the board, that's all I've got. Hmmm. Let's see...

Ah, here we go. If you do not have this, it should keep you busy a while. Here's the 7200 schematic. You can check your connections if you have lots of patience and a continuity meter.

I haven't examined it closely, but I wonder about that schematic, because the 7200/120 has some electrical differences. It adds an ICS9178 chip to handle the clock tripling, IIRC. Perhaps this is just for the 75/90 and there's another out there or a revised page for the 120.