Hello Laser Tweaker's!
I've been out from this site for a long time and just happened to check what all is happening in laser path
There was a question why RF exited units are more liked in industry?
1. They are very reliable. Can last N * 10 000 h without any problems. After this Synrad lasers can be serviced only at manufacturers service but if you send back the old unit in good shape - you'll get a another unit with reasonable price (less than a new unit thou).
2. Size is much smaller than with NF DC laser
3. RF unit is much more rigid and solid. Glass is a bit risky.
4. High voltage DC is a bit jumpy! Can cause heart beats
5. Life of a glass tube NF CO2 is short. 500 - 1000 h often realistic.
About the CO2- scanner lenses.
Normally singlet lenses are used. A compromise between F-theta quality vs. price. You can try
http://www.ulooptics.com/ulo_optics/products/scannerlenses.aspor used ones from:
http://www.europalaserboerse.com/eng_product_catalog.phpbut they won't be very cheap there. If you find a cheap one - it's very probably ruined in some cleaning operation and full of scratches. ZnSe is actually a type of salt ie. quite soft. Rough cleaning will destroy it.
BTW. The Synrad laser can be tested just by steering it with 5V DC signal which will put it in ON state with full power.
BR.
Arto