Davinci Resolve Edit to tape failing and driving me crazy!

Hi all.

Hoping someone can shed some light. Long story short. I want to make tape backups of my completed projects and no matter what I do I cannot for the life of me get Davinci to edit to tape properly.
The timeline settings are HD 10bit, interlaced @ 50 fields. Timeline start timecode is 09:59:30:00
Davinci delivery settings are to output SD to tape.
I've got a Decklink Studio 2.
Decklink SDI out goes into a tape deck [Sony Beta SX or Panasonic DVCPRO 50]
Decklink SDI in comes from said tape deck.
VTR control hooked up correctly. I can control the deck from within Davinci delivery page no issues. Now here is my issue that is pulling my hair out!

Tape in either deck and blacked with a timecode starting at 09:59:20:00 and onwards. I set Davinci to edit the in point on the tape at 09:59:30:00 and end 09:59:59:24 using the Insert edit. It cues the tape up correctly with it's preroll. Soon as it hits the in point, the tape deck stops, then hunts around like its looking for the cue / in point. It then shortly gives up and goes into standby. This happens on either tape deck.
If I set the edit to be an Assemble edit, it cues up the tape, then 50/50 of the time it's start recording to the tape and insert some random timecode that I've not actually set. It will also show a edit point at double the length of the actual timeline duration.
I'm trying to cue up bars and slate. Duration is 29:24 as you can probably see. But it seems to output at double the timeline duration.

I am starting to loose my patience. I've gone over all the settings a million times, double checked everything. Tried on 3 different tape decks and still come out with the same issue. It seems like its a Davinci issue and not a tape deck issue.
My only thought as to a potential cause could be the fact there is no reference into the tape deck or Decklink card. I can't see it being an issue with a single tape deck linked to a single computer, but I'm not sure. I'm really hoping someone can shed some light as I am at a total loss now for something that should be so blindingly obvious to accomplish!!

Many thanks for your help!

[Peter Chamberlain]

Is the media in Resolve interlaced?
Can u do a test with a progressive timeline and 25fps export?
Have u tried using Media Express?

Also, check the record deck settings to ensure the correct timecode stream is being used for cueing. Some machines can be set to read VITC timecode and switch between VITC and LTC depending upon the deck transport speed. This can upset the fine cueing for the preroll point if the LTC and/or the VITC is missing or different. Sony Digital Betacam decks used to show this issue if not set correctly.

I want to make tape backups of my completed projects and no matter what I do I cannot for the life of me get Davinci to edit to tape properly.

You might try a Addenda Rosetta Stone RS232-to-RS422 converter from the serial port of your PC (if you have one) older Decklink's RS422s were a bit flaky if I recall, in that regard. Here with a US 4K Mini I can directly connect to a tape deck and control it accurately in Avid, Resolve and Media Express, from it's RS422, without issue.

Is the media in Resolve interlaced?
Can u do a test with a progressive timeline and 25fps export?
Have u tried using Media Express?

Sorry for the late replies.
So all the footage is interlaced, the timeline is also set to interlaced but when exported to tape it will double the length, like it sees each field and a frame instead. But I did notice that if I then dropped the project on another 25p timeline it seemed to delivery to tape fine. it's almost as if the decklink / davinci cannot output interlaced over the SDI correctly. Even if I use the SD-SDI out and with the video preferences set correctly in the decklink settings. It sort of seems to be a work around but I'm worried that Resolve is converting the interlaced timeline to progressive which is what I don't want it to do. I want and need to have it's source and interlaced and delivered as interlaced. I know these are only for archive purposes but I'd like to get this right the first time without writing to a load of tapes to find out they're not correctly recorded.

Is the media in Resolve interlaced?
Can u do a test with a progressive timeline and 25fps export?
Have u tried using Media Express?

I did think to do this, but annoyingly Media Express won't import ANY footage. It can capture it fine, but I did try exporting from Resolve, then importing to Media Express but I just get a hardware error saying it's not compatible for some reason. No matter what export type I use. So quickly gave up with that method.

Also, check the record deck settings to ensure the correct timecode stream is being used for cueing. Some machines can be set to read VITC timecode and switch between VITC and LTC depending upon the deck transport speed. This can upset the fine cueing for the preroll point if the LTC and/or the VITC is missing or different. Sony Digital Betacam decks used to show this issue if not set correctly.

Yes, did check this and it was reading timecode perfectly. As above I seemed to have temporarily figured out and workaround but I'm not keen on the idea. It just seems like a Decklink issue where it can't actually output interlaced over SDI and instead seems the interlaced fields and individual frames [so 50fps and not 50i]