I have griped about the pain of replacing the antenna relay in Ameritron linears, and today I finally got a decent relay installed in an AL-811. The relay Ameritron sells as a replacement is shoddy at best.
In all fairness, today's amplifier was built in 2001. A relay that lasts for 20-plus years isn't all that bad, but this one became intermittent. Cleaning did not help. It had to go.
The replacement is a TE Conectivity (Potter and Brumfield) KUP14D15 enclosed relay. Contacts are rated at 10 Amps. Has a 12-Volt DC coil same as the factory relay.
Looks a lot like a porcupine when prepped to install. The wire insulation is FEP. Not quite teflon, but won't care about heat or RF voltages.
Ameritron's choice of double-sided pc boards with plate-through holes makes this job doable without exposing the solder side of this board. That would be a chore, and the main reason I decided not to roll the dice and see if a new factory-type relay worked any better.
This type relay used to have a machine screw clamping the clear plastic case to the relay's frame. Pretty much the same as the open-frame style, but with the clear plastic cover. Mounting these was easy, just took one hole and a longer machine screw. The "KUP" style enclosed relay no longer has this screw. The white foam tape seen here is a 3M product called "VHB". It has an adhesive that is incredibly aggressive once you apply sufficient pressure to it. It only gets stronger with exposure to heat, unlike the foam mounting tape sold at the local drug store.
Biggest single justification for doing it this way is that it saved the labor of removing the amplifier's back cabinet panel to expose the solder side of the big pc board. Saved the customer a few bucks as a result.
73
In all fairness, today's amplifier was built in 2001. A relay that lasts for 20-plus years isn't all that bad, but this one became intermittent. Cleaning did not help. It had to go.
The replacement is a TE Conectivity (Potter and Brumfield) KUP14D15 enclosed relay. Contacts are rated at 10 Amps. Has a 12-Volt DC coil same as the factory relay.
Looks a lot like a porcupine when prepped to install. The wire insulation is FEP. Not quite teflon, but won't care about heat or RF voltages.
Ameritron's choice of double-sided pc boards with plate-through holes makes this job doable without exposing the solder side of this board. That would be a chore, and the main reason I decided not to roll the dice and see if a new factory-type relay worked any better.
This type relay used to have a machine screw clamping the clear plastic case to the relay's frame. Pretty much the same as the open-frame style, but with the clear plastic cover. Mounting these was easy, just took one hole and a longer machine screw. The "KUP" style enclosed relay no longer has this screw. The white foam tape seen here is a 3M product called "VHB". It has an adhesive that is incredibly aggressive once you apply sufficient pressure to it. It only gets stronger with exposure to heat, unlike the foam mounting tape sold at the local drug store.
Biggest single justification for doing it this way is that it saved the labor of removing the amplifier's back cabinet panel to expose the solder side of the big pc board. Saved the customer a few bucks as a result.
73
