HELP WITH MACINTOSH PERFORMA 200 BOOT UP

[Elfen]

See the link attached.. These are the ROM/SIMMS CHIPS i am talking about which i am sure are the problem..

http://www.downtowndougbrown.com/wp-content/uploads/2011/08/OriginalROMs.jpg

Those are not SIMMs, those are the actual chips; called DIPs for Dual Inline Package. A SIMM is a Single Inline Memory Module, and goes onto a clip-socket on the mother board.

The problems is not (usually) the ROMs but the circuits that access them. Its more than likely that it's a bad or broken trace on it. You can check the connection of the ROMs themselves with a multi-meter. All but 10 - 12 pins on each ROM should be connected to the others. These 10 are 8 data lines and 2 - 4 Read/Write and Chip Select lines. These 10 - 12 lines you need to check to the connected VIA or the CPU. The ROM Address Lines should also connect to a VIA.

Edit Add: I have the same freaking issue with a SE/30 and I know that the issue is with rotted traces to a couple 74LS series chips on the board (the 74LS chips are replaced by the VIA on your board). I just have to sit down and actually trace the lines and replace the broken traces with thin wires. Just been too busy to get it done.

 

[Alex]

I don't know if this helps or not, probably not but this video 

does show an SE30 with very similar symptoms. If the logic board on the performa 200 is similiar to the SE30 in particular the video chips perhaps this video can help.

 

[Elfen]

The Performa 200 is a Classic II. That is a BIG difference between a SE30 and a Classic II. The Classic II's board is 1/2 the size of the SE30 board; from the ports of the SE/30 to the first set of SIMMs and with a lot fewer chips. It is more like an LC II than a SE/30.

Because of this, the problems might be similar, its cure won't be. Where all those tiny chips on the SE30 board, there is only 1 chip on the Classic II board that replaces them all. So chances are that chip is either dead (highly doubtful) or you got rotten and broken traces around the chip.