5v pin on LCRU2?

The 7805 output pin would be my first location.

Also, a different work around- changing a resistor for the serial data line output.

https://ogrforum.com/topic/82382494787166183

Thanks!

in the last few minutes I discovered that the pin we never use on the 4 pin railsounds header on this LCRU2 is sitting at 5.1vdc with respect to AC common. Any thoughts on the suitability of that pin or what it’s intended use was?

thanks again!

@christie posted:

Thanks!

in the last few minutes I discovered that the pin we never use on the 4 pin railsounds header on this LCRU2 is sitting at 5.1vdc with respect to AC common. Any thoughts on the suitability of that pin or what it’s intended use was?

thanks again!

Catch22, you measured voltage using a low impedance meter, but that says nothing for how much current that pin can put out or if there is an in series resistor to that pin. My gut says that is a terrible source to use for the buffer- likely is current limited and under load, the voltage drops.

Again, I would go direct off the 5V output of the 7805 since you know that is the source. That is what is supplying regulated power to the microprocessor and the radio receiver sections and thus a known good source for just such a buffer.

Great info, Pin 3 on the triac it is!

(Correction: Voltage Regulator)

Thanks again

@christie posted:

Great info, Pin 3 on the triac it is!

Thanks again

It's not a TRIAC, it's a voltage regulator. The case style TO-220 tabbed 3 pin is used for many things.

If you end up needing to buffer the serial data, here's a tried-n-true method, I stopped using the emitter following buffer after some failures with it.

Improved R2LC/R4LC Serial Data Buffer

@Vernon Barry posted:

It's not a TRIAC, it's a voltage regulator. The case style TO-220 tabbed 3 pin is used for many things.

Yes I knew that… Honestly this GG-1 conversion has made me so I can’t see or think straight anymore…

@gunrunnerjohn posted:

If you end up needing to buffer the serial data, here's a tried-n-true method

Thanks John,

Luckily my buffer cable worked in this case. Patched to pin 3 on the 7805 and everything works.

Nothing left to do now but bundle up the cables and screw down the shell.