Temperature Drop - 1st few layers

Hi

My printer hot end temp has started dropping from an initial temperature of 205 dec C to around 185 deg C for the first few layers of the print and then gradually raises to the correct print temperature. The pre heat temp is correct, however as soon as printing starts the temp drops.

Ive replaced the theristor and heater cartridge twice to eliminate bad wires etc.

Ive also tried Slic3r and Cura and its still the same.

Any ideas what could be causing the issue ?

Using Ramps 1.4
Cura and Sic3r

Edited 1 time(s). Last edit at 04/20/2015 05:48AM by grezmel.

I had a similar problem but it was due to the fans. When the fans started turning on, the temperature dropped 8-9 degrees and then stabilized at the correct temperature. Do you have the fans turned on at the beginning of the print?