Here’s the insides of my back-up SL30 which started producing smoke recently.
Cheap as chips capacitor and my friendly avionics guy had it back in the aircraft for the cost of a lunch.
This is not GA but a really interesting example of 1980s/90s technology – a Javelin missile computer
There will be a Part 2 apparently.
The guy has a load of other avionics teardown videos.
And here the guts of a 2001 vintage VM1000 engine monitor DPU…
I googled on VM1000 and nothing turns up. The above is a very bad design for anything subject to vibration – those tall electrolytic capacitors for example.
That Javelin computer is a total tour de force job; they must have bought every state of the art chip and jammed it in there 
Seems like a GA engine monitor that JPI built or bought:
http://www.jpitech.com/manuals/010/VM1000PG%20RevB.pdf
https://www.jpinstruments.com/FAQCategory/vm-1000c/
https://www.jpinstruments.com/FAQCategory/epi800-and-vm1000/
So I guess a predecessor of the JPI930 of sorts. I’d have said MVP-50 if it wasn’t JPI that has the info on the Vision ;)
Right, yes, 80C85 CPU, year 2000+
and then there is this great device which dies after about 20 years, and probably contains key config data…
Peter wrote:
this great device which dies after about 20 years
User reports correlate the life of that Timekeeper chip to 15-20 years. I replaced this very one 3 years ago to cure some problems. The VM1000, and the VM1000C were among the first integrated engine monitors, and only installed, AFAIK, in homebuilts.
That Timekeeper is a really stupid idea. Config data is much better stored in an EEPROM which doesn’t need a battery and lasts for ever. But it was an attractive option for lazy circuit designers At a cost: a single sourced and pricey item, and your product will “blow up” after many years which, if your company is still around, is going to get it a bad name. Not something most designers worried about because they would be on their 3rd or 5th job
Peter wrote:
he above is a very bad design for anything subject to vibration
That’s what the silicone snot all over them is to protect against :-)
That board looks more like an early 1980s design than an early 2000s design. All pin through hole and a UV erase eprom and a mid 70s design CPU. By the early 2000s, pretty much everyone had gone to SMD and flash memory. As an early 2000s design it’s something a retrocomputing hobbyist would make as a single board computer hobby project!
That’s what the silicone snot all over them is to protect against
Sure, but not very well.
That board looks more like an early 1980s design than an early 2000s design
I would put it a bit later. On a quick and dirty search the data sheet is dated 1996. Early 80s were the days when the NMOS Z80 was still used a lot. The CMOS versions came out later. UV EPROMs had a very long life.
I agree re SMT (I went to SMT c. 1991) but it depends on lots of factors, one being what parts you stock.
