is there any method to check whether lense good or not?

[thefixer]

hi every body ,i repaired amny vcd players and dvd players.but only to check whether red light comes out or checking wiring ...but i want to ask if there is a tool by which we check lenses of dvd and vcd players.thanks a lot for informing me.

[jts1957]

I presume you mean the Laser.
All CD / DVD units have one (sometimes two) laser assembly. Generally they will emit laser light at their rated output for a certain amount of time (in the high hundreds or thousands of hours).
One person may use their unit very heavily and "wear" the laser out in only a year or so. Another person may use their unit rarely and "wear" the laser out in maybe a dozen years.

They do make a meter that can measure laser output power, but then you have to know your unit's specification.

Usually more economical to change whole laser assembly (or WHOLE PLAYER)

[minnie]