Hi to all,
Hi TinCanAlley,
About "top of the picture flagging when playing VHS/Betamax tapes":
Before VCRs became common, TVs horizontal AFC had a long time constant to ensure good sync when receiving a TV RF signal from a transmitter, especially with a noisy signal.
Consumer VCRs have jitter and cannot ensure the precise timing of a Broadcast TV station, hence the flagging when replaying a consumer tape.
As VCRs became popular, TVs began to have a channel preset with a shorter time constant to accomodate VCR signals and of course on the SCART/EuroConnector on Euro TVs (i live in the Eu).
Older TVs usually had a maintenance bulletin issued by the manufacturer instructing how to modify the H AFC circuit to solve the VCR flagging issue. It's usually a simple modification involving the change of a few R/C values in the H AFC circuit.
In your position, i would look for the service bulletins from the manufacturer of your exact TV model and find their recommended modification.
VCRs with TBCs are a luxury item which came very late in consumer VCR technology when reasonably priced A to D, D to A and Field/Frame digital storage memory could be offered at consumer prices.
95% of consumer VCRs don't have TBCs and millions of consumers have enjoyed flagless TV playback of VHS/Beta cassettes.
I used to sell TBCs as companions to 1" type C Broadcast VTRs (Ampex Corp).
a TBC was 35k$ to 70k$ in the 80s/90s.
Best Regards
jhalphen
Paris/France
PS: on this topic in VK archives, dated 2013:
http://www.videokarma.org/archive/in.../t-258501.html
Video Monitor modifications; Dropbox file by Cliff Benham (RIP):
https://www.dropbox.com/s/1fw8311noq...ing%20Modifica tions%20-%20HI%20Speed%20Hor.%20Timing%20for%20VCRs.PDF
or here, same file:
https://www.dropbox.com/scl/fi/qm4xa...31c2w7ninl&e=1
General knowledge about TBCs, if anyone is interested:
https://www.digitalfaq.com/forum/vid...time-base.html