27-11-2019, 06:33 PM
(This post was last modified: 27-11-2019, 06:40 PM by Jac Janssen.)
The frame frequency is indeed within the range of the frame hold control, as Jeffrey already remarked.
I included a series resistor for the hor sync for 405 and a potmeter for vertical amplitude and one for line sync and a few capacitors.
Also I had to include a few diodes in series with the supply for the LOPT (to lower the voltage; the LOPT is made for 625).
And some switches of course.
Horizontal linearity is very bad at 405, but the characteristics of the picture can be seen nevertheless.
The little monitor has served me well during 567 line experiments.
A quarter of a century ago I adapted an old Taxan computer monitor for 405 line use.
This came in handy for aligning my Marconiphone 702 TRF section (this set has a very bad CRT, and the power supply was not yet working, so a means to see what was going on was required).
Jac
p.s. since I have no circuit details of the little TV, an amount of trial and error was involved...
I included a series resistor for the hor sync for 405 and a potmeter for vertical amplitude and one for line sync and a few capacitors.
Also I had to include a few diodes in series with the supply for the LOPT (to lower the voltage; the LOPT is made for 625).
And some switches of course.
Horizontal linearity is very bad at 405, but the characteristics of the picture can be seen nevertheless.
The little monitor has served me well during 567 line experiments.
A quarter of a century ago I adapted an old Taxan computer monitor for 405 line use.
This came in handy for aligning my Marconiphone 702 TRF section (this set has a very bad CRT, and the power supply was not yet working, so a means to see what was going on was required).
Jac
p.s. since I have no circuit details of the little TV, an amount of trial and error was involved...
