Mac 128k error 048010

[Mac128]

The Rom Hi chip is missing the two pins closest to the 68k processor.

I really can't see how I am going to find another ROM Hi chip.

I wish to give my personal thanks to JDW, Mac128, Charlieman, and tomlee59. You all have provided the best of support.

Do NOT despair. This really isn't as big a problem as you think it is. In fact it makes your job easier ... first, with minimal soldering skills you can likely replace the missing pins. I asked a similar question not long ago about replacing a broken pin off a ROM mount SCSI card. It can be easily replaced with a copper wire or even a paperclip.

In addition, since the 512K used the same ROMs as the 128K, replacement ROMs are MUCH easier to find than the 128K RAM chips from a donor board, again quite commonly found on eBay for very little (compared to functional boards and units). You can even replace them with Mac Plus ROMs with no noticeable difference. WIth any luck, this will be the ONLY problem. FYI to remove the ROMs, use a flat head screwdriver to slightly pry each end, alternating, little by little to avoid bending the pins, until it pops out. Putting it back in is a matter of simply aligning the pins over the holes and firmly pressing it down while maintaining the pin alignment.

You are quite welcome for the support. That's what we are all here for.

 

[Megas3300]

It fixes half of my ram problem by jumping the pin to the socket with the broken off end of a tack, I need now to figure out the other chip. Code went from 048010 to 040010 the G12 chip is back online somewhere in my tinkering.

 

[mfortuna]

A clean way of doing the repair is first go to radioshack and buy the cheapest DIP logic chip you can find. Carefully bend off or cut off two of the pins. Give the pins a slight bend just were they get narrow. Plug the pins in the socket so the tops line up with the pin remants on the ROM. You should plug the pins in so they bend towards the ROM. Now carefully solder the top of the pin to the ROM. You should get a good but fragile connection.

Mike