The PCF802 was designed as the first stages in television line frequency generation prior to the line output stage. The pentode is described by Mullard as the oscillator while the triode is for service as a reactance valve. This suggests the triode acting as a frequency controlling stage.

This image is of another example of the PCF802 and reveals greater detail.

The pentode on the left is oriented at 90 degrees to the triode on the right.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 46 mm tall.

References: Datasheet, ³⁰⁰² & ¹⁰⁴⁰. Type PCF802 was first introduced^¶ in 1962.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	a(t)	g1	g2	h	h	a	kp,s,g3	k(t)	g1(t)

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	9.0	0.3	100	100	-1	6.0	1.7	0.4M	5.5

Triode	Va	Vg	mAa	ra	gm
	200	-2	3.5	2M	3.5

Thanks to Frank Philipse for supplying the above PDF datasheet

More