Murphy TPG11 TV pattern generator

[Geordie McBoyne]

The Murphy TPG11 pattern generator. This unit can be a source of reliable 405 sync pulses, it also incorporates a modulator which tunes to all five BBC channels. No sound though.
But before any work starts on the restoration a power unit will have to be constructed for the TPG11.  Lots and lots of 6SN7GT double-triodes employed in this unit. (12)  6SN7s are greedy things, requiring 0.6amp for the heaters.    The heater supply from the mains transformer will have to be good for at least 13amps.   HT voltage is only 125 volts @ I guess 100mA  Original HT rectifier valve was a GZ32. I'm considering two EY84s.
Second attachment shows the divider chain adjustments. Everything is done properly in the TPG11.
I've redrawn the 50Hz mains lock circuit, substituted semi conductor diode symbols for the 6D2/EB91 double diodes.
Evidently this was regarded as a very good unit, good enough for the BBC to use for certain purposes.

Geordie McBoyne.

[ppppenguin]

Presumably the dividers are locked oscillators rather than flipflops.

[Geordie McBoyne]

Hi Jeffrey,
Three locked oscillators: 2,250c/s, 250c/s and 50c/s multis giving the two divide by nine and one divide by five functions.
To set up the divider chain the frequency controlling circuit will have to be disabled. Close switch S2.

Geordie McBoyne.

[Geordie McBoyne]

Circuit diagrams of the modulator and power supply units.

Geordie McBoyne.