I can also tell you about how repair houses "quote" for repairs from first hand experience.
1) Visually check if item blown to bits or damaged beyond hope (note they almost never power up the item at this stage)
2) Google price of new item
3) Quote 60% of price of new item to repair.
4) If accepted begin diagnosis of the fault ![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)
I have the same expieriences, but this time it was somehow different (As I wanted fast to maintain a relyable system, I sent the IMET unit for repair)
1) I got the repair price (it was about 500eur, 30% of a new unit)
2) I payed, 3 days later the unit was home.
3) I installed it, 5 min work, All worked well.
But what did they do? The whole system contains:
-the
Motherboard witch has the transfo and voltage regulation and the connectors for the other boards.
-the
Relay board, simple relays, leds and diodes.
-the
radio module completely RF isolated unit.
-the
logic board witch has the microcontrollers, buffers, converters, and so on. All codes are erased.
Well, they "replaced" the "logic board". So repair contains:
1) test the power supply on the motherboard
2) if this is ok, replace the logic board.
3) if it still doesn't work, replace the radio module.
I am
totally satisfied as a machine user, I have a fast and relyable repair, no worries.
I am
totally unsatisfied as an electronics hobbyist. What signal was wrong, what component was on the origin of it? How are these units tested? ...