mooniac15u

Dual regulators to manage two alternators on a 28V system.

That is a 14V regulator. OP said he has a 28V system.

A web search turned up these two photos. One appears to have holes and the other has notches.

My emergency latch cover is in rough shape. I have the replacement part but I can’t tell from my old one what the screw holes/notches should look like. It looks like there were pictures in this thread that are now gone. Anyone have a picture of theirs? Should it have notches or just screw holes? If it’s notches are they v-shaped.

Is the parking brake on? That locks pressure in the hydraulic brake system and if the seals aren't great they can leak over time.

Alternators us an electromagnet so they have a field circuit. The alternator switch turns the field circuit on and off. Generators use a permanent magnet so there's no field circuit to switch on and off.

I have an intercom there in my J. There's quite a bit of space. You can access it by removing the side panel in the pilot footwell. It's only a couple screws to remove the side panel.

I can’t tell from your description exactly what’s interfering so I’ll throw this out there. There’s a small bracket that should have been replaced when your landing gear was converted to the new style of shock discs but I’m not sure this always happens and I think if there’s enough play in older gear it might not cause a problem. It’s described in Mooney service bulletin M20-139 https://www.mooney.com/wp-content/uploads/2020/12/SBM20-139A.pdf. On page 4 item 8 describes the bracket that needs to be replaced. On page 6 under “Main Gear Parts to Install” item 6 is a note that the gear won’t retract unless this bracket is replaced. I’m not saying this is necessarily your problem but it seems worth confirming that you have the new bracket.

When comparing the older models to the J everyone focuses on the speed mods and purchase cost but nobody talks about the single greatest design improvement of the J. It doesn't use one of those accordion air-intake boots made of unobtanium.

When you say the "inside diameter of the nose gear" I'm guessing you're asking about the tube where you insert the towbar. If so, then what you're looking for is here:

Have you turned it on and left it to warm up for a while? Since I don't use mine very often it usually takes a while for the display to warm up. If it's been sitting for a long time it could take a while before you can see anything on the display.

You might be thinking about a different radio. The KNS80 is capable of receiving localizer and glideslope so it works well for flying an ILS or localizer approach. It has some interesting features for en route navigation but even if you never learn how to use those functions it is a perfectly good backup nav radio that includes DME.

On the Aero Classics website it says that part number is for a piper. They have a different part number for the M20J.

The SB I linked references the AD that makes it mandatory (AD 97-26-08 just below the subject line in the SB). Here's the AD. https://drs.faa.gov/browse/excelExternalWindow/3663F2D3749FE48286256A8F006C5ED6.0001

https://www.mooney.com/wp-content/uploads/2020/12/SBM20-259.pdf