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Argus25 · 30th Sep 2019, 11:07 pm

As I noted I would expect the V sync system in the TMB272 would be fine with a short time constant high amplitude pulse. There is a balance though, and the sync injection level can be too high and if it is the noise in the sync can cause a reset or restart effect on the V osc and you end up with a sudden black blanking bar appearing in the middle of the screen somewhere and rolling upwards after that to re-lock. Also the filtering has to be enough to smooth out the edges of the H pulses on the V sync pulse. The Bush TV22 was simply miles off.

30th Sep 2019, 11:07 pm	#85
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Bush TV22 with TC184 B3 converter. As I noted I would expect the V sync system in the TMB272 would be fine with a short time constant high amplitude pulse. There is a balance though, and the sync injection level can be too high and if it is the noise in the sync can cause a reset or restart effect on the V osc and you end up with a sudden black blanking bar appearing in the middle of the screen somewhere and rolling upwards after that to re-lock. Also the filtering has to be enough to smooth out the edges of the H pulses on the V sync pulse. The Bush TV22 was simply miles off.