Repairman wants to replace the deck on DVD player.
If the subtitute deck has a similar type with the original deck, then the replacement process can be done without any adjustment process.

But, if the subtitute deck has a different type with original deck, then the adjustment process has to be done before the replacement process.

There are two type of deck that can be applied for DVD-D series which are DP-26 VE and DP-31 deck.

The difference between DP-26 VE and DP-31 deck is like picture below: