TRC-448 Channel readout / segments

[jrd426]

Hi guys, I was recently given a realistic trc-448 am/ssb mobile radio. It seems to be working fine overall other then the channel readout. Missing segments here and there. I figured i would ask the question here before poking around as maybe someone out there is familiar with this model any possibe quirks with this model. Any feedback on this is appreciated before i get into it. thx 73

 

[nomadradio]

More than one way to make segments of those digits go dark.

Oxide buildup on the contacts inside the channel selector is possible, especially for a radio over 40 years old. Control cleaner is probably the cheapest thing to try first. Just stick with alcohol-based solvents so you don't turn the selectors' plastic body into guacamole.

The two LED channel digits are combined into one part in that model, pretty sure. No idea how to identify a replacement that fits *AND* has the pins wired in the same pattern. Bad LEDs in a channel digit are not unusual after 40-plus years. If it's bad, researching a replacement will be necessary. RatShack sure isn't in a position to supply an original replacement.

There is a dropping resistor in the circuit for each segment of each digit. Those resistors can fail, but they're dead last on the hit parade.

Naturally, any wires between the channel selector and the digits may come loose or be damaged. Don't remember how they're laid out in that model.

73

 

[jrd426]

I appreciate your comments here Nomad. I will check out the wiring and connections to the channel display when i go back in to change the micky mouse dc power wires to a heavier one thats fused. Thx and 73's

 

[Xracerx13]

Check for cold solder joints at the pins for the LED segment. Thats usually the culprit. Use a plastic stick or the eraser on a pencil and move the pins for the LED segment. You'll find it.