Another blinking M140

I have an m140 in a krypton groove. with all anodising removed via caustic soda and polished.
It is driven with a mohgasm 1.8 a linear soldered directly to the diode.
The diode starts to blink at after 30 seconds. and whilst I know there have been similar issues but I cant seen to find a solution I haven't tried except re do ing the whole laser.
I have by-passed the switch and it still happens.
Its running on two aw imr 16340s. that seem to give loads of power.
Is it possible that because it drags so much power from the batteries the protection circuit is doing something its a very regular one second on and one second off.
I have tried other batteries and have used this configuration of two 16340s and a linear driver before without issue.
I could try it with a power supply but you know krytons are fiddly to dis assemble once you have the contact pressed home properly..
Is it possible that this particular m140 doesn't like 1.8 amps? in fact it measured at 1.759

Thermal shutdown

^^^Yup did you heat sink the IC on the Moh linear? :beer:

If it helps, here is my Moh linear at 1.8 A sinked to a bit of copper and then the main heat sink of my Saik:

Mine will do this as well after it heats up. YES from what Ive asked and serched for Ive found it to be "Thermal protection" of the driver

ok nice one I have stuck a big sink on it so ill add even more