[time-nuts] GPS-TMG-RCVR232 Update!

[John Miller]

Hello Everyone,
The GPS-TMG-RCVR232 came in today, and I’ve been spending the past couple of hours working on understanding it. 

Pictures here: https://photos.millerjs.org/?f=GPS-TMG-RCVR232 <https://photos.millerjs.org/?f=GPS-TMG-RCVR232>

This thing is very nicely designed. With the plastic dome removed, you can see a PCB with the helical antenna mounted on top. a Trimble Copernicus II is mounted to the bottom of this board. A board to board interconnect connects it to the bottom PCB which handles the RS232-UART translating (with an LT2803) and voltage regulating.

On that note, the TSOP5 part that regulated the 8-12v in fron the DIN connector is completely blown. All I can do is hope that it didn’t take anything with it. There are two unused pins on the DIN connector, presumably for the differential signals of Rx/Tx for the RS485 model. For the short therm, what I am planning to do is just jump one of those unused pins of the DIN connector to the Vcc pin of the unpopulated U9 and just feed regulated 5v directly in. Eventually I will replace that regulator once I figure out what part it is. 

I should get a couple of compatible DIN plugs in the mail soon so I’ll be able to test it out. I think it’s a bit too tight to run wires between the boards, but I would rather use  the DIN connector on the bottom anyway.

John