128K Added Resistor Array

[Mac128]

Larry Pina describes the addition of a resistor-array at location D-15 on the original 128K logicaboard to prevent a random bug where the Mac simply locks up. This is in the section where he is describing the 512K RAM upgrade, so I always thought it was related to the upgrade. I have seen a large number of 512K upgrades to the original board and have seen this resistor, however I've not seen many original 128K boards with this added resistor-array. Of the ones I've seen, they all look extremely professional, but then so do some of the 512K RAM chip upgrades.

When did Apple realize they had a problem, and was this resistor array added at the factory or was it only added by authorized service providers? Was there a recall, or did the Macs just get upgraded when they consistently failed on a customer who finally brought it in for service?

Here's a pic from a current eBay auction, note the yellow resistor-array at D-15 soldered onto the side of the 6522 VIA chip.

 

[Charlieman]

Can you tweak the image enough to read the bar code and get an approximate manufacture date for the logic board?

Note also the massive barrel distortion in an otherwise wonderful photo!

 

[JDW]

Note also the massive barrel distortion in an otherwise wonderful photo!

Not to detract from Mac 128's post or get off topic here, but folks, it's so easy to avoid these nasty barrel distortion photos. So easy! Just stand back farther from the object you are shooting, then zoom in on it. The more you can zoom in, the more distortion you eliminate. And put that camera on a tripod so you can use the lowest ISO and get a fantastic photo. Yes, in most cases, that's all there is to it! (The only times when you can't do this is when you have a call phone camera or other such non-zoomable camera with a tiny lens.)

 

[Megas3300]

Odd... Your ram chips look different from mine.