UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Trio TS830S. First power after 30yr hibernation. Any safeguards/precautions?

G6Tanuki · 25th Nov 2020, 9:51 pm

Make sure - before trying to feed rf into an antenna - that your antenna is actually resonant at the necessary frequencies. Good to see you're using a dummy-load.

Some Japanese radios from that era had issues with the coupling-capacitors between the driver- and PA-stages. When [and it was a matter of when, not if] these went leaky/failed, they would put a few hundred volts onto the control-grids of the poor unfortunate 6146 PA valves, which then passed vastly-unnatural levels of standing-current.

Whether the 6146s failed first, so saving the power-transformer - or they struggled-on and the power-transformer was the first to go - was a lottery.

Changing a few -relatively- cheap parts before trying to drive it in anger could be a sensible pathto follow.

25th Nov 2020, 9:51 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Trio TS830S. First power after 30yr hibernation. Any safeguards/precautions? Make sure - before trying to feed rf into an antenna - that your antenna is actually resonant at the necessary frequencies. Good to see you're using a dummy-load. Some Japanese radios from that era had issues with the coupling-capacitors between the driver- and PA-stages. When [and it was a matter of when, not if] these went leaky/failed, they would put a few hundred volts onto the control-grids of the poor unfortunate 6146 PA valves, which then passed vastly-unnatural levels of standing-current. Whether the 6146s failed first, so saving the power-transformer - or they struggled-on and the power-transformer was the first to go - was a lottery. Changing a few -relatively- cheap parts before trying to drive it in anger could be a sensible pathto follow.