Well, some obscure online auction sellers are sometimes manipulating old stuff in order to achieve higher rates. Although not very "popular" it might have been possible that this Mac is a physically downgraded Plus with the faceplate from an "out of order" 512k. Plus Macs are much easier to find nowadays...
Either way, the end result is the same. I guess there's no easy way to determine if a 512K was upgraded to or downgraded from a Plus.
European Macs sometimes bear special markings from some non-Apple companies that tested those machines in operating security aspects - but these markings are missing.
This too is something subject only to where the Mac Plus case back was manufactured and how Apple distributed the Plus upgrade kit. It is possible that the Plus case back and upgrades were not subject to the same government regulatory rules that a "whole" Mac was and in this event, "one-size-fits-all".
When you say "held in black", so you mean the metallic RF coating on the inside of the case is "black"? If so, I have seen compacts where the shielding coat is so thick it conceals the signatures, but if you look real closely you can still make out a few."
The RF shielding foil just covers the back up to the top of the connection ports, it doesn't reach the top of the housing, so it doesn't cover the signatures in my Plus which are placed on the plastic housing itself and not on the shielding foil. It's the plastic housing itself which misses the beige color. To me it looks like this housing just got the paint's grounding on the inside but wasn't colored beige afterwards (I know that the beige color wasn't sprayed onto those housing parts, Apple colored the plastic itself - it's just a description to give You an imagination until my photos are made).
I wasn't talking about the foil covering the ports. I was speaking specifically of the metallic paint which served to shield the entire case, which in every compact Mac I have ever seen is a dark gray or silver color. Some models have a much thicker coating than others and sometimes that paint is so thick it covers the signatures so that you don't know they are there. A photo will not improve the situation. I have never seen a compact Mac which was either missing the RF paint or had a beige layer painted over it, so I'm not sure what you are comparing it to – are you saying your other Mac Plus is missing the RF paint or uses a beige-coloured paint instead?
You are better off repairing the Plus board and switching it to the 512K case if you prefer its design.
As long as I don't know --- exactly --- what to fix where (I just heard something about Pin 1 re-soldering) I'm simply not able to fix my Plus
There are two types of Mac collectors. Those that use them and those that store them. Sadly if you intend to actually use your old Mac you are well advised to start learning how to repair it, or find someone locally you can pay to maintain them. They are not hard to maintain yourself once you've done some minimal education. Either way, if you start using the old 512K power supply in any regular way, it won't be long until you experience some kind of failure. Word to the wise ...
