Between last night and this afternoon, I was able to get 8 Deltas tested and cleaned up.
After my initial assessment, I spend about an hour or more on each unit, testing and cleaning. At $60 apiece, I am not getting rich selling these. But you can be sure I'm not just throwing some unknown condition p.o.s. in a box and mailing it out. I don't operate like that.
Please keep in mind these are used units. The cases might/will have scratches, nicks, and traces of adhesive residue from labels or tape, etc., even though I cleaned them pretty thoroughly.
Years of greasy drive-thru burgers and fries, sweat, shame, nicotine, barbecue sauce from the fire department's chicken dinner fundraisers, and god knows whatever else ends up on a cop's fingers have taken their toll on the paint lines on the knobs. I use a very mild Dawn dish soap solution which gets them clean, but the crud often takes the paint with it. Some lines are still visible, some aren't. You can easily add your own if you so desire, I'm just not talented or steady-handed enough. Trust me - if I had attempted to add the lines, you'd think Michael J. Fox painted them on.
The backlight bulbs are almost all burned out. That's just a thing with these units. The bulbs are so incredibly tiny and quick to burn out, it's just not feasible to replace them. For me, at least. So I would suggest not even hooking up the screw terminal, it's a waste of time.
Normally I wouldn't offer any kind of guarantee for a used item like this, but I'm going to make an exception for these. This isn't a money back guarantee - if you experience a failure within the first 30 days after receiving the siren, ship it back to me and I will send you a fully tested and cleaned unit to replace it. I will even honor the remainder of your original warranty (if theres any left) for the replacement. So if after a week you lose the siren or the takedowns, and you ship it to me on day 10, your new unit will have 20 days of warranty once you receive it. There's no new 30 day warranty. I gotta draw the line somewhere.
I trust you know what you are doing or the person you have install the siren does. If you drop it on the concrete from 4 feet up, or manage to fry the thing because you hooked it up wrong, that's on you. Installation is pretty self-explanatory, but the manual is available in pdf form on teh interwebz. When in doubt, RTFM.
A few other things I won't cover:
Knobs - if they become loose, adjust them to your liking and tighten the set screw. If you lose one, better get a flashlight. If the switch/pot comes loose from the faceplate, remove the knob and tighten the nut with a 5/16 socket CAREFULLY! If you strip the switch/pot or nut, or you lose the nut, that's on you.
Slider arms - the arms are malleable, they bend. This is by design. If you jack it up, you can easily put it back into a usable shape. The aluminum knob uses a set screw to secure it to the arm. I tightened them when I reinstalled the knobs after cleaning and straightening the arms. Now, if the actual switch portion of the slider fails, I will replace the unit.
Backlights - see my comment about them above. This doesn't include the green/red lighting of the pushbuttons - if that happens to fail, I'll replace it.
Modifications or alterations - it should go without saying, but if you do anything inside the unit beside change the fuse, the warranty is void. Same if you give it to someone else to fix but they can't.
Accidental damage - if you look up from your iphone and suddenly slam on the brakes to avoid running your 85 year old neighbor over on the sidewalk and your Sonic Route 44 Ocean Water drenches the siren and lets all the factory smoke out, I can't help you - unless you want to order another one...