Hi all,

(I was advised to x-post this from /r/analog)

Hoping someone can assist with this, and if I'm posting in the wrong place, I apologize. I am new to using a manual flash on an SLR.

I recently picked up a Pentax KM (similar to K1000). It's in good shape, and I sent it off for a CLA. I then bought a Vivitar 283 auto thyristor flash off eBay. "Tested and working."

Here's where the issue comes in.

I put batteries in the flash, it warms up, and discharges properly when I hit the "flash test" button. Seems OK.

I put it on the hot shoe (which tech says they tested/calibrated as part of CLA), set my shutter to 60x to sync it, and the flash doesn't fire. It is locked, and it warms up, but it won't go off even when I push the "flash test" button as it blinks. (The manual says this should work as it activates the "adequate light sensor"). If I take it off the cam, I can press "flash test" and it will pop.

The other thing I noticed is even when the flash is OFF, when the bulb was holding a charge it DID discharge when I attached/removed it from the hot shoe, I think meaning when the contacts touched?

I do not have another flash to test it with, and I'm trying to seek out a local camera shop to find one. Assuming that it the best way to check and isolate any potential issue?

I looked on Pentax forums, but I was not comfortable with their testing suggestions (disassemble camera, "short it" with a screwdriver, etc).

I want to isolate the issue since both tech and flash seller are standing by their service&item, but I am very new to this so I want to make sure I'm not being ignorant and just missing something simple about my new gear.

Thanks in advance for any advice.