UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Comark Early 1905 Insulation Meter Checks

Bazz4CQJ · 20th Jan 2019, 1:48 am

There's also another thread, which I started https://www.vintage-radio.net/forum/...ad.php?t=83980.

As above, there are two versions on the 1905; one uses discrete components and one uses an op-amp. Mine is the former, and was working well well when I first got it, but then developed a fault. Fortunately, there is a known issue with that version, as Bill WME correctly advised me (see thread).

I'm pretty sure (?) the output is DC, the oscillator being rectified by a voltage doubler to charge caps. I vaguely recall checking mine just by stringing resistors across the output and comparing against the instantaneous meter readings 'on test'.

B

20th Jan 2019, 1:48 am	#4
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,934	Re: Comark Early 1905 Insulation Meter Checks There's also another thread, which I started https://www.vintage-radio.net/forum/...ad.php?t=83980. As above, there are two versions on the 1905; one uses discrete components and one uses an op-amp. Mine is the former, and was working well well when I first got it, but then developed a fault. Fortunately, there is a known issue with that version, as Bill WME correctly advised me (see thread). I'm pretty sure (?) the output is DC, the oscillator being rectified by a voltage doubler to charge caps. I vaguely recall checking mine just by stringing resistors across the output and comparing against the instantaneous meter readings 'on test'. B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. Last edited by Bazz4CQJ; 20th Jan 2019 at 1:56 am.