How to repair my diplomat apm6855 fridge/freezer?

Switch off fridge freezer at the mains and remove all the baskets.
At the rear is a removable panel with three clips down the right hand side and one at the top, you will need to unclip all four clips and pull the panel forward. You will also need to remove the four stops two on each side. The left hand two stops clip up turning anticlockwise to remove. The right hand two stops clip up but turn clockwise. Once you remove all four stops the rear panel will slide out easily.
You will then see another panel with the fan enclosed at the top. This panel will also have to be removed - pull forward and then detach the fan connection - this panel, together with the fan, can easily be removed.
You will now see the freezer unit enclosed in polystyrene.
The problem causing the H temperature on the fridge is the ice build up on this unit.
We have solved this problem twice by using a hair dryer to melt the ice - takes a little time and patience but once all the ice has been removed the problem is solved.
Replace both the panels in reverse order, of course not forgetting to reconnect the fan.
Then switch on the fridge freezer and allowing some time it will reset itself.
This has worked twice for us, the first repair lasted 2 years and we have just repaired it again using this procedure. Good Luck.

Ken
August 2011