Re: 1982 was also a good year for Acorn
When my kids were at school, I was pressed into upgrading from my beloved Spectrum to a BBC Model B, because that was what was installed at school. I purchased one second hand, but it came with an inbuilt problem, it would crash after about ten minutes use, and refuse to reboot for about half an hour afterwards.
I took it out of the case and used a coolant spray on the memory chips, which would keep it up and running continuously, so long as the chips were kept frozen. I also noticed that all of the memory chips were plugged into chip carriers, although all of the other devices were soldered directly onto the board.
I was discussing this with a work colleague, and he suggested that perhaps there was a problem with the original memory chips that had not been solved by replacing them, and that the problem might lie elsewhere. He then looked very closely at all the other chips, and noticed that the Memory Interface chip was of the wrong sort, it was supposed to be a Fast chip, but was not.
I left him to unsolder it and replace it with yet another chip socket, while I drove over to RS in Corby to buy two of the correct chip (in case we damaged one), and when plugged in this solved the problem.
Apparently, the timing of the Read/Write and Refresh cycles would get out of synch as the chip warmed up, and would resynch after cooling down.