Very good plan of attack Granny, Esp. the pictures & labelling
Sorry about your cat, hope all ends well
When my cat became alarmingly weak , could hardly crawl to it's water,
wouldn't eat (happened very fast 1-2 days)
I rushed him to one posh looking
The young woman poked & proded then recommended several "tests"
and would not give any opinions
I was suspicious, thanked her & paid the bill- 5 minutes, $55.00
I thought a (very renowned) Vet further away might be too busy
But drove there next.
He felt it's stomache, (cancer) said yes time to put him to sleep !
As he was in pain (NO noise)
It was heartbreaking, even hurts deeply now years later.
He seemed almost as sorry as us, gave a few minutes to say goodbye
before administering the shot & assured us it was painless, immediate
The cost, FREE > & I KNOW he left other duties when his assistant notified
I admired that man more than ever (DANG - wish had never recalled)
Vehicles now have an onboard diagnostics to plug into
Same computer controls all sensors for fuel injection, ignition timing - emissions
But major component repairs don't happen by themselves, nor can most be found that way
A burnt-out headlight is simple - Electical- circuitry, try to trace - Esp if in solid state dashboards
How about changing the signal switch or ignition keying
The back-yard grease-monkey has NO idea how to trouble-shoot nor have tools & savvy.
Same goes for computers - parts are swapped
How many here have the miniature electronic probes or AVR's etc to trace DC volts
imposed on AC circuits
OR have all the needed OEMs schematics, & power sources to feed
The huge Mfgrs manuals of cross-over parts, electric values of each
BIG difference to swapping parts randomly & knowing which/why as a certainty
TV's are simplistic in comparison
As for fridges - are any familiar to testing closed-loop compressor systems
or the timers for defrosters ?
Hint - think air conditioners
ARE simple, the cycles are controlled either by older mechanical timers or
new solid state (NON repairable modules)
All is AC house voltage - NO condensers retaining lethal charges for days
BTW don't poke around inside PSUs - unless you know what you are doing
"kick" you may get will not be of the fun type
So much for theories ?