DAC90A Voltage tapping - UK Vintage Radio Repair and Restoration Discussion Forum

Ian Paul · 7th Dec 2005, 7:12 pm

I've just finished this set which has a early serial number and is fitted with the white coloured mains dropper. The 250V tapping had been broken off so I've had to use the 230V tapping. Given that our average mains is 238V and the volt drop I get across the 950 + 150 section is 118V, I don't think I'll be giving the heater chain or H.T. section too hard a time. Any Thoughts?

zak · 7th Dec 2005, 7:24 pm

You could always make up a few volts by changing the dial lamps from 3.5v to 6.5v (.15a)

jim_beacon · 7th Dec 2005, 7:25 pm

Ian,

in these cases I look at the HT volts and the heater voltage. If the heater voltage (current in your case) looks OK, then I wouldn't worry - it will stand a little more HT.

I'm in the middle of a KB QB20, and this doesn't like running on the lower tap (238V into the 230V tap, the same as yours) - the heater voltage went up to 7.5V, which I thought was a little excessive....

You can sometimes repair the droppers with a tag from a burnt out one - though it does require some skill (or ceramic smashing

) to get the tag off the scrap dropper.

Jim.

Ian Paul · 7th Dec 2005, 7:39 pm

I read 113V across heater chain inc. dial lamps, which don't seem to be over bright.

7th Dec 2005, 7:12 pm	#1
Ian Paul Retired Dormant Member Join Date: Mar 2005 Location: Shropshire Posts: 5	DAC90A Voltage tapping I've just finished this set which has a early serial number and is fitted with the white coloured mains dropper. The 250V tapping had been broken off so I've had to use the 230V tapping. Given that our average mains is 238V and the volt drop I get across the 950 + 150 section is 118V, I don't think I'll be giving the heater chain or H.T. section too hard a time. Any Thoughts?

7th Dec 2005, 7:24 pm	#2
zak Retired Dormant Member Join Date: Feb 2005 Location: Monmouthshire,on South Wales border Posts: 85	Re: DAC90A Voltage tapping You could always make up a few volts by changing the dial lamps from 3.5v to 6.5v (.15a)

7th Dec 2005, 7:25 pm	#3
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: DAC90A Voltage tapping Ian, in these cases I look at the HT volts and the heater voltage. If the heater voltage (current in your case) looks OK, then I wouldn't worry - it will stand a little more HT. I'm in the middle of a KB QB20, and this doesn't like running on the lower tap (238V into the 230V tap, the same as yours) - the heater voltage went up to 7.5V, which I thought was a little excessive.... You can sometimes repair the droppers with a tag from a burnt out one - though it does require some skill (or ceramic smashing ) to get the tag off the scrap dropper. Jim.

7th Dec 2005, 7:39 pm	#4
Ian Paul Retired Dormant Member Join Date: Mar 2005 Location: Shropshire Posts: 5	Re: DAC90A Voltage tapping I read 113V across heater chain inc. dial lamps, which don't seem to be over bright.