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kalee20 · 4th Feb 2020, 5:11 pm

Mine i9s still going strong.

However, bringing up with a Variac does not achieve very much. The rectifier will do nothing until the voltage is high enough to heat the cathode sufficiently, which will be about 80% of full. So you won't be able to bring up slowly over some hours.

Personally, I'd get a 1N4007 or similar and use this as a temporary rectifier to bring up HT on the electrolytic over a few hours, monitoring the DC voltage. You only need to clip two leads onto the can. Start at 50V and gradually increase to 250V. If the can is still cold at this, then it's probably OK.

Then you can disconnect your temporary rectifier leads and bring mains up as normal.

4th Feb 2020, 5:11 pm	#2
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,088	Re: DAC90A Electrolytic capacitors Mine i9s still going strong. However, bringing up with a Variac does not achieve very much. The rectifier will do nothing until the voltage is high enough to heat the cathode sufficiently, which will be about 80% of full. So you won't be able to bring up slowly over some hours. Personally, I'd get a 1N4007 or similar and use this as a temporary rectifier to bring up HT on the electrolytic over a few hours, monitoring the DC voltage. You only need to clip two leads onto the can. Start at 50V and gradually increase to 250V. If the can is still cold at this, then it's probably OK. Then you can disconnect your temporary rectifier leads and bring mains up as normal.