UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - VTVM / Valve Voltmeter articles from magazines in the UK

MrBungle · 12th Jul 2017, 8:09 am

Quick update on this project. I got it working last night, well at least deflecting linearly. Having some stability problems with it however. Not sure what they are but even after 5 minutes warm up the needle drifts up and down a lot. I have shorted the input terminals to get rid of any ambient charge.

I did do something stupid which woke me up though. I soldered the smoothing capacitor in the wrong way around and was greeted with a proper bang. Appears that axial capacitors don't have the same venting system as radial ones do. Joy to safety glasses!

12th Jul 2017, 8:09 am	#27
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: VTVM / Valve Voltmeter articles from magazines in the UK Quick update on this project. I got it working last night, well at least deflecting linearly. Having some stability problems with it however. Not sure what they are but even after 5 minutes warm up the needle drifts up and down a lot. I have shorted the input terminals to get rid of any ambient charge. I did do something stupid which woke me up though. I soldered the smoothing capacitor in the wrong way around and was greeted with a proper bang. Appears that axial capacitors don't have the same venting system as radial ones do. Joy to safety glasses!