I’ve solved the mirror retainer problem. My friend’s resin printer spit out a few wonderfully clean fitting mirror plugs with finger grips, so that part is good. The tube has aged out, and a visit of about 35 miles got me a new tube.
In the process of effectively rebuilding the laser, I discovered that two years of sitting idle allows algae to grow profusely. More orders for appropriately sized tubing, which has resulted in my discovery of the flow sensor.
I neglected to note which way the water flows prior to pulling the old stuff out. My test was to connect a long tubing to one end, let the other dump in a bucket and pour water via funnel. Rough timing for the emptying of the funnel, swapping directions of the sensor and picking the faster of the two gave me a sense of flow direction.
I had checked with a multi-meter for continuity after removing one leg of the wiring from the circuit, but the results were ambiguous. I had previously thought that the controller would have an LED to indicate flow, but that’s a no-go.
Somewhere in my travels on the internet, I saw a photo of a screen in the controller panel perhaps representing the state of the sensor.
Does anyone know how to access that particular aspect of the controller? It’s an RD644x Ruida unit, installed on a red/black clone.
On a somewhat related note, I learned that I can reduce algae growth by restricting exposure of the tubing to light. Had I known that before this portion of the rebuild, I could have more easily sleeved the tubing during the installation. No big deal.
Split wire tubing, a corrugated plastic sleeve more commonly used for organizing wiring, should give me the darkness I seek. The original configuration had the low power wiring routed and taped to the water line, so I can use the split tubing to tuck that in as well.
The sad part of all this rebuilding is that the laser went idle because I could not make progress in closing the circle. None of what I’ve done thus far addresses this, but I’ll have a pretty well tuned laser up to that, by the time I’m done.