JensenHealey
pfm Member
Even back in the late 1970s when I was working on mainframe computers (for ICL) there was a tug between board and component level repair. In the interest of speed and uptime we would typically fix any device to board level. The bean counters of course knew that that system needed a huge and expensive set of boards. There were thousands. But there were many times fewer components.... in those days CPUS were not built on chips - the chipe we had had a few independent logic gates.
BUT, against the idea of component level repair, it was very slow by comparison. It might take 20 minutes to identify a faulty board. It might take hours to probe with a high speed oscilloscope and a hand written looping machine code program to identify the faulty component. Then changing the component was not so easy - even in the 70s the boards were many layers and not easy to de-solder, especially on-site, rather than a workshop. And how much is the downtime of a large computer system worth? So we rapidly went back to swapping boards.
On the general subject being discussed here, I think it is probably important for devices that are using specialised and programmed special chips--- it is not practical to provide spares for a 30-40-50 year life span. Better to design it to be easily recycled and elements of value recovered. A digital device for streaming (for arguments sake) does not need a 40 year life - the internet/streaming technology will have changed somewhat by then.
BUT, against the idea of component level repair, it was very slow by comparison. It might take 20 minutes to identify a faulty board. It might take hours to probe with a high speed oscilloscope and a hand written looping machine code program to identify the faulty component. Then changing the component was not so easy - even in the 70s the boards were many layers and not easy to de-solder, especially on-site, rather than a workshop. And how much is the downtime of a large computer system worth? So we rapidly went back to swapping boards.
On the general subject being discussed here, I think it is probably important for devices that are using specialised and programmed special chips--- it is not practical to provide spares for a 30-40-50 year life span. Better to design it to be easily recycled and elements of value recovered. A digital device for streaming (for arguments sake) does not need a 40 year life - the internet/streaming technology will have changed somewhat by then.