开云体育

Ok, update on the X5105, the modules from Ebay, whilst very nice, the IC looks the same but doesn't work when just the IC is fitted into the Xiegu.
It has a very similar type number stamped onm top, but there is no volts out of it whatsoever.
I was about to remove all the SMD bits around the old regulator in the radio and fit one of the entire PCB's in its place, which would have worked I am sure, but I noticed a tiny white spot on the? X5105 silkscreen, I hadn't noticed it before and as a result, I had assumed the incorrect placement of Pin 1 on the original regulator.
Now having spotted the pin 1 mark, I have also found out teh regulator type, it is an MP 1496S made by Monolithic Power systems, called a 2A 16v 500KHz synchronous step down converter.
The package is an 8 pin TSOT-23, even better Farnell UK have them in stock, the part number is 3357935 and they cost ?1.11 each, shame there is a minimum order of ?30 but I bought several of them plus some other bits i'll probably never use

Here is the datasheet for the regulator if anyone is interested.



So I fitted the IC, and re-assembled the radio, it works perfectly, has been on JS8 call all afternoon.
Interesting that the device has an absolute maximum input voltage of 17v, inside the X5105, it is fed via a big Shottky diode from the power socket but that will only drop 0.2v or so.

I now need to figure out a way to prevent it happening again, possibly some kind of crowbar circuit inside the radio using an SCR and zener to blow the line power fuse if more than 14v goes into the regulators, but that is a project for another day..

Tony
G1HMO