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Title: Viking 500 Post by: KB5MD on August 09, 2024, 06:47:32 PM My Viking 500 let the smoke out of the high voltage filter choke. I am considering installing a replacement in the center tap of the plate transformer secondary rather than in the b+ hv line as originally installed. This method was used by Hallicrafters in the HT 33 amp. Has anyone else done this? It removes the hv off the choke.
Title: Re: Viking 500 Post by: w7fox on August 10, 2024, 09:32:58 AM I wouldn't do it. It puts high voltage ripple on the center tap of the plate transformer, which may not have sufficient insulation. Some power transformers have a warning on the label to keep the center tap within one volt of ground.
Title: Re: Viking 500 Post by: WD5JKO on August 10, 2024, 11:14:46 AM That choke is a swinging choke. Replacing it with a fixed choke might cause diminished voltage regulation, and ripple issues. As it is, the 811A's are operating beyond specifications. I'd try to purchase a new one from a Hammond distributor. Save up some food stamps though! AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
I attached the datasheet from Peter Dahl. https://www.hammfg.com/electronics/transformers/classic/pwdahl Jim Wd5JKO |