Do I have a bad in-range regulator?

No gas reaching the top burners.
Hi all, a bit of background story: just acquired this Magic Chef gas range in new condition as wife is sick and tired of using the electric stove. Time for a replacement.
Not wanting to fork out thousands for a new unit, found this one from someone upgrading, which was running off natural gas. These convert to propane easily, although I suspect I may have caused some damage along the way. Here hoping to get some clarification and how I can get this guy working again.

This being a Magic Chef/Whilrpool, converting to propane was a snap. The instructions manual shows the procedure in detail. What it didn’t say is that I needed to run a regulator off my propane bottle. And this is where things get tricky.
After following the conversion procedure to a tee I run a test using a 20lbs propane bottle and a new 6’ hose. That didn’t go well as too much pressure was being fed into the range, to the point where things got scary. A couple of subsequent tests WITHOUT the flame showed propane whooshing through the top burners, with a loud horn-like sound. That’s when I realized I needed a regulator, as the one inside the range (see pic) clearly didn’t handle the high pressure.

Today I did just that, purchased a twin chamber regulator, new 3/8" hose and an adaptor. Hooked it all up, turned on the propane and nada. There’s no propane reaching the top burners. Nor the oven.

Regulator is a proper 11"/water and it came from a proper propane store, not a big box store. After disconnecting the hose from the range, I could see propane coming out just fine, at a “civilized” pressure. But upon connecting it to the stove, nada. As seen in the pic the point of entry is the built-in regulator. Could the high pressure from my previous test have damaged it? Is there a test I can run to ensure this indeed is what I need before I buy a new one? Or could the issue lie elsewhere? Here hoping for some input. We’re eager to get this nice range working.
range_regulator.jpg (63.2 KB)

UPDATE:
Good news, the regulator works now. After removing the main line into it I could see inside. The green rubber ball was stuck in place. Easing into it got it loose. Now all works beautifully. And I didn’t have to fork out for a new one (3 weeks for this costly part to arrive in Canada).

However I have another problem: oven won’t turn on. Guess this is a separate issue and I may have to start a new thread on that but just in case it’s related, figured I asked.

Basically the glow bar lights up with sufficient heat to heat up the inside of the oven. After 10min it still won’t light. Nor does the broiler. It would seem that no gas is reaching the inside of the oven. Any tips?