Laser Pin issue - Rambo

I switched over to a Rambo 1.4 running Marlin, my laser takes anywhere from 3v-12v for it’s TTL signal. I tried using the Fan1 port but M106/M107 didn’t work - not sure if I have to enable the pin? Then moved my connectors over to Pin45, M03/M05 works there but laser doesn’t seem to be functioning properly, laser comes on but doesn’t do much until the power is turned way up. Any help would be appreciated. Thanks.

I’ve seen issues with the M03/M05 on this forum. The usual solution is to use inline commands instead. That is, use the ‘S’ parameter of the G0 and G1 g-codes to specify the laser power. Try running the test file that Ryan created in the first post of this topic.

Note that like you, the others having problem with the M3/M5 were having quality issues. I’m not sure why since they should work, but the M3/M5 commands are a bit complex since, depending on the firmware settings, the expected values change. I’m betting there is a bug at the root of the problem.

As for the fan pins, I’m guessing that you did not supply he right parameter for the specific fan pin pair you used, but that is only a guess. I’m sure we could get it working, but from everything I’ve read on this forum, inline commands are the way to go.