Well, it seems I have inadvertently stumbled into the "bike helmet" issue of the camera world. An issue filled with vitriol.
baachitraka, your reply was cheerful and I take it in the spirit given.
Shutterfinger, I'll be honest, I stopped reading your second response after it became rude, condescending and insulting. That was before the end of the first sentence.
I'd asked a specific question. Essentially, "Shutter Y is doing X. Does anyone know what causes X in Y shutter?" The answer I got was "needs a CLA." That is the sort of answer that is technically accurate, but functionally useless. It would be like going to a motorcycle forum and asking "My vintage motorcycle is gradually developing a miss at high rpms," and getting the reply "D@#n thing's broke."
For anyone who might stumble across this thread in the future, here's the correct answer.
Q. My Prontor SVS seems to work correctly at all speeds except 1, 1/2, and 1/4. Those speed are exceptionally fast.
A. The low speed mechanism is not engaging. One possible cause is that the low speed pallet (who's tab is circle in orange) is not pivoting into position. The pivot point (orange arrow) may merely need cleaning. However in this particular case the pivot shaft was so rusty that it was pitted. Removal and polishing of the shaft did return some motion, but a replacement will ultimately need to be sourced.
Do keep in mind that there are several versions of the SVS, so I can only state with certainty that it applies to those shutters who's cams look like the one pictured in my previous post and have speeds B,1,2,4,8,15,30,60,125,300. The low speed mechanism is only involved in 1,2,and 4. A mid speed pallet (red circle) is used for 8,15, and 30. Neither are involved in 60,125 or 300.
Woe unto me for using lighter fluid. I'll ignore the fact that it brought the delay timer back to life and had no detrimental impact on the parts that were already working. The issue it didn't fix would not have been fixed by any solvent, but nonetheless. From now on I'll only use proprietary White Magic solvent at $50k per microliter to clean and Unicorn spleen oil as a lubricant.
Seems to be a lot of people who either act like shutters are magic, or worse yet, machines that are so complex only an anointed few could ever hope to understand, let alone work on them.
Mechanical shutters are just machines. Fairly simple ones at that. Springs, gear and levers; and that's it. Anyone with a steady hand and a rudimentary understanding of mechanics can fix one. I'd come here looking for enough info to avoid disassembling the entire thing, which I did not get.