I have an AOUYIE 701A++ soldering/desoldering station.
https://www.amazon.com/Aoyue-Function-Soldering-Desoldering-Absorber/dp/B009Q5ZH58
Recently, the iron went into ERR mode (displaying ERR on the display after about 10 seconds of showing 064 on the display).
A quick Google search revealed this to be a problem with the heating element in the iron itself. Not a problem with the entire station, which is awesome because I didn't feel like shelling out another $150 for a new station.
Another quick Google search revealed plenty of replacement irons for the 701A+, but none for the 701A++.
I bit the bullet and bought the 701A+ replacement iron and said some prayers every night until it arrived in hopes that iron would be compatible.
I received the iron in about 4 days, plugged it in, and was very surprised when I found that the plugs have a different pin configuration.
Not only that, but there were 5 pins on the new iron, 6 pins on the old.
Being the industrious problem solver that I am, I took apart both irons to compare the differences.
I immediately noticed that the old iron didn't actually use the 6th pin, and that the remaining 5 pins all lead to the same place within the iron's tip and heating element (however the colors were different).
I quickly made a note of wire placement from old vs. new, and a note of where they connected on the plug end.
This is where I ran into a problem. Because my iron was not working, I had no way to remove the wires from the new iron's plug to put onto the old iron's plug.
A quick call to the wife (who works in a place that builds gas detection instruments) with a plea for help, she was able to borrow an iron for the night.
I desoldered the wires from the new iron off the new iron's plug.
I desoldered the wires from the old iron off the old irons' plug.
I then soldered the wires from the new iron onto the old iron's plug.
Doublecheck my work, and plugged it in.
Turned on the power, and wouldn't you know! Fired right up, and quickly went to 400°.
BINGO BANGO, all repaired!
So...... if you ever need a replacement iron for your 701A++ but all you can find is a 701A+, buy it and just switch the wires over to the new plug.
I assume this would work vice versa as well if need-be.