Master's instructions: How not to buy junk on the secondary market

Over the years of working in the service, I have seen enough of upset people who come running to me a day after a purchase with Avito: * “Master, I paid 45 thousand for the D750, but its mirror sticks and there is a stripe on the closed aperture!”*.

To prevent you from getting into this situation, I have compiled a strict **15-point service checklist** with which you need to go to any meeting with the seller.

Checklist: 15 Express diagnostic points

1. Appearance of rubber bands and screws:The presence of licked splines on the screws of the bottom cover indicates that that the carcass had already been picked at in artisanal workshops.
2. Condition of the mount (brass ring):A heavily worn brass ring is a sign of frequent replacement heavy televisions.
3. Checking the shutter using EXIF ​​through our service:We take 1 photo on our flash drive and instantly we pull out the actual shooting from the `ShutterCount` tag.
4. Matrix test for dead and hot pixels:Close the lens cap, set ISO 1600 and shutter speed 1 second. We look at the crop of a pure black frame.
5. Checking for dust on the sensor:Close the aperture to f/16 or f/22 and shoot a white wall or sky.
6. Continuous Shooting (CH Mode):We make a series of 8-10 frames. Listen to the sound: the curtains should run out smooth, without ringing or delay.
7. Flash operation (built-in or external):The puff should fire exactly at the sync speed (1/200 sec).
8. Focusing on high-aperture glass:Testing phase autofocus via RES (Back/Front focus).
9. Checking memory card slots:Alternate insertion of SD / XQD into the first and second slots.
10. Battery compartment condition:No oxides on contacts.
11. Performance of all sub-command dials:No slippage during rotation.
12. Checking the viewfinder:Cleanliness of the focusing screen and pentaprism.
13. In-lens stabilizer test (VR):No knocking sound when the trigger is pressed halfway.
14. Serial number verification:The serial number in EXIF ​​must match 100% with the serial number on the bottom of the carcass!
15. Checking the diaphragm drive mechanism (“Leash”):The bayonet lever should spring perfectly exactly.

Meeting Check Summary Table

Verification stage	What to look for	Defect criticality
Mileage by EXIF	Correspondence of real shooting to description	Critical (reason for bargaining or refusal)
Dust on the matrix	Speckles at f/22	Low (can be eliminated by regular cleaning)
Licked screws	Traces of unskilled repairs	High