[60 oldjohn]

I restored this first generation DAC90 with smooth knobs about 5 years ago and used it in our house most weekends. Last Christmas it was not used for three weeks, when I finally turned it on all I got was a loud hum, quickly switched off.

When I first restored it I used an autotransformer from ED Dinning and disposed of the original asbestos shielded dropper resistor. This effectively turns the DAC90 into an Bush AC90. At the time the only Electrolytic capacitors in the set were the Smoothing and Reservoir caps which reformed ok.

Five years on and the set hums loud regardless of volume settings. I looked at ordering the small Rubicon caps from Farnell but they are out of stock.

A few days ago I got round to removing chassis, checked the double electrolytic,, 32uf, spot on and 20uf should be 16uf, nothing to worry me.

I had read that the EBC33 can give similar results (HK short) so I measure the heater to other pins on all valves and eventually found the CCH33 had a measurable HK short. Lucky I had valve out of another DAC90 to try and it is working well while I get another from my valve supplier David Thompson.

While I had it on my bench with the aerial laid on the bench I was listening BBC Radio Wales, I am on the east coast of Yorkshire so a few miles away!

John.