Same board - different coating?

[ObeyDaleks]

Does anybody know why Apple used different solder mask coating variations for the same boards? I've seen that on multiple boards. For example, I have 2 identical LC II boards, one is glossy "bright green", the other is matte "muted yellowish green". I saw the same with other boards such as PM 8500. So this practice spanned many years. In all cases, the board numbers are the same, and they are made in the same year. Why?

 

[Nixontheknight]

Does anybody know why Apple used different solder mask coating variations for the same boards? I've seen that on multiple boards. For example, I have 2 identical LC II boards, one is glossy "bright green", the other is matte "muted yellowish green". I saw the same with other boards such as PM 8500. So this practice spanned many years. In all cases, the board numbers are the same, and they are made in the same year. Why?

maybe apple was using separate circuit board providers for their machines, maybe to save costs

 

[unity]

There were numerous fab plants that proceeds the boards for Apple. And they were located all over the world. Most have a branding for the factory that made them in the copper etch.

 

[ObeyDaleks]

Ok that makes sense. I just didn't know different plants were free to use different types of solder mask coating. I guess it wouldn't matter in terms of functionality. Thanks.

 

[Forrest]

i’ve worked in the PCB Fabrication for years. There are probably half a dozen manufacturers making green solder mask, but they are all not the same shade of green. Unless Apple specified the exact mask to use (which is unusual), the PCB manufacturer is allowed to use whatever they want as long as it’s green and the correct type of mask.