Chassis Grounding Question on Newly Resurrected 55 YO Heathkit GR62 Shortwave Re - Page 1
Forum section: electronics / rf-microwave

author: electromotivetrains
author_rank: Newbie
timestamp: November 14, 2024, 04:08:50 pm
content: Hello all: I have just resurrected my 55 year old Heathkit GR62 shortwave receiver that I built in about 1971 .This receiver was designed in the mid 1960's. My question is the grounding setup for this receiver. Please see the attached image that is from the Heathkit assembly manual.The line cord is currently a 2 prong (no ground) setup. The assembly instructions require a separate ground wire from the grounding lug on the back of the receiver chassis to a new independent 6-8 ft. grounding rod.Quote from the assembly manual: "The GRD terminal on the rear of the receiver should be grounded to a water pipe or a 6-8 ft. long grounding rod driven into the earth".My question is this:1). Should I replace the existing 2 prong line cord with a 3 prong (grounding one). The ground wire I would connect to the receiver chassis. This would provide the grounding (to earth) of the receiver chassis via my main circuit breaker panel grounding rods.OR2). Stay with the 2 prong line cord and use the independent grounding rod setup as shown in the attached image and described in the Heathkit assembly instructions.OR3). Do bothMy initial thought was to use the independent grounding rod setup to maybe reduce any noise interference/hum that may be on my homes electrical system that would make it back into the receiver. But I really have no idea.Thoughts please.....Thank-you (11/14/2024 11am EST New York)

author: electromotivetrains
author_rank: Newbie
timestamp: November 14, 2024, 05:13:07 pm
content: Sorry. Here is the attachment..

author: TimFox
author_rank: Super Contributor
timestamp: November 14, 2024, 05:18:20 pm
content: Does this receiver use a transformer in the internal power supply, or do the rectifier and heaters run directly from the mains input?

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: November 14, 2024, 05:58:28 pm
content: On the Heathkit 64, the B+ is from the transformer and voltage doubler. Two diodes are used. The 12 Volt filament volts are from a transformer secondary winding also.The B voltage is referenced to chassis ground. However one end of the 12 Volt heater voltage is also grounded to chassis.See the last page of this:https://ia801302.us.archive.org/25/items/Heathkit_GR-64_Shortwave_Receiver/Heathkit_GR-64_Shortwave_Receiver_text.pdf

author: TimFox
author_rank: Super Contributor
timestamp: November 14, 2024, 06:04:11 pm
content: With a proper transformer power supply, I would recommend changing to a 3-prong line cord.The "ground" on the antenna connection is presumably to a primary on the RF input circuit, and should be connected to a proper ground, such as the ground stake.Is that connection also connected internally to the chassis?Edit: it took a while to download the manual, but both the RF primaries and the power supply are connected to the chassis.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: November 14, 2024, 06:11:40 pm
content: I think he can use a three pin power cord without a problem but an additional direct ground is usually helpful for reception.