UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Nicklyons2 · 19th Jul 2014, 11:41 am

Just to add my call to those above not to destroy a good set - find a way to fix it.

A point of clarification here, forgive me if you already know; the best/easiest way of discerning whether there is line drive to the PL36 is, as said above, to see if there is around -45V or so at the control grid but you really need to measure this using an AVO 8 or similar analogue voltmeter with around 20KOhm/Volt sensitivity. Using a very high impendance meter, a cheap 1K/Volt meter or a digital type won't give you the same result and may even disturb the operating conditions.

The AVO was such a universally adopted and respected instrument even when it wasn't giving a 'true' reading (i.e. with pulse waveforms) its 'interpretation' was regarded as a standard measurement.

19th Jul 2014, 11:41 am	#18
Nicklyons2 Octode Join Date: Jan 2013 Location: Barnsley, South Yorkshire, UK. Posts: 1,517	Re: End of my beloved DR101 Just to add my call to those above not to destroy a good set - find a way to fix it. A point of clarification here, forgive me if you already know; the best/easiest way of discerning whether there is line drive to the PL36 is, as said above, to see if there is around -45V or so at the control grid but you really need to measure this using an AVO 8 or similar analogue voltmeter with around 20KOhm/Volt sensitivity. Using a very high impendance meter, a cheap 1K/Volt meter or a digital type won't give you the same result and may even disturb the operating conditions. The AVO was such a universally adopted and respected instrument even when it wasn't giving a 'true' reading (i.e. with pulse waveforms) its 'interpretation' was regarded as a standard measurement.