scott k wilson writes:

Have read the solid state laser FAQ....

some info to add: Got one of these with an attached power supply
(lambda). The power is wired in on the 15 pin connector with +5 going
to pin 1 and 2 and 6 to ground. These connections are apparently in

Isn't the 2-6 connection the interlock?

parallel with the 5 pin din connections. There is also a nine pin D
wired to the peltier controller board.
S/n is 4601-005-0413 which (inferring from the FAQ) that is a 5 mw
version. Has the old hybrid B 2.3 controller.

Symptoms...no Lasing

Power comes on ,
second led(red) from near edge Optomech board comes on
relay clicks
green led on peltier board comes on
4th led (green) comes on faintly....
goes off
1st led(yellow) comes on faintly
4th led comes on again more brightly.

there is heat dissipated from controller....

no significan heat from laser head.

any suggestions would be appreciated.

I don't yet have docs on what the LEDs mean.

If you're willing to go inside the head or open one end of the cable,
with power off, securely attach a multimeter on DCV to the laser diode
pins 13 and 15 of the head connector. When you power it up, once the relay
clicks, there should be 1.5 to 2 V on the laser diode. (After a couple
minutes, it may jump by a few tenths of a volt indicating that the laser
has entered constant light mode which of course won't work.) This means the
LD is being powered. Power down and move the meter to TEC1 and see if it's
getting power - should initially go high and then decrease to a fairly low
steady voltage. Same for TEC2. Report back. The DC supply current to
the controller will peak at 4 or 5 A and then drop down to 2 or 3 A once
it's stabilized.

You should also be able to see some faint red light between the laser diode
block and the cavity block in the head from the laser diode. This indicates
that the laser diode is lasing, though not anything about its power output.

If these tests come back confirming reasonable behavior, it's probably a
laser diode or alignment problem.

CAUTION: Follow antistatic procedures and only change connections with
power off!

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
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