Uploaded August 2015 | Updated September 2026, 2 weeks ago
SW7800 purchased Not Working . Initial problem was a bad RF choke coil .Once this was replaced the receiver operated but had a hum in the received signals and the least significant digits of the digital dial
would change to most any numbers . Powering the SW7800 with a good regulated 12 volt DC power supply it was found to work very well with no hum and the digits were stable . A simple TO220 regulator was installed in series with the 15 volt power supply and a single filter capacitor was added .This improved the power supply reducing the ac ripple from .5 VOLTS to less than 20MV
the received signals no longer have any hum and the dial digits are very stable and reading correctly . The SW7800 was one of the last heathkits produced and was done in a hurry as the company was going out of business very few SW7800 kits were sold . 73 Bob
SW7800 purchased Not Working . Initial problem was a bad RF choke coil .Once this was replaced the receiver operated but had a hum in the received signals and the least significant digits of the digital dial
would change to most any numbers . Powering the SW7800 with a good regulated 12 volt DC power supply it was found to work very well with no hum and the digits were stable . A simple TO220 regulator was installed in series with the 15 volt power supply and a single filter capacitor was added .This improved the power supply reducing the ac ripple from .5 VOLTS to less than 20MV
the received signals no longer have any hum and the dial digits are very stable and reading correctly . The SW7800 was one of the last heathkits produced and was done in a hurry as the company was going out of business very few SW7800 kits were sold . 73 Bob
