According to Motorola the shield should be grounded to the black wire. This is necessary to protect the radio and the computer from power supply glitches from power supplies, like chargers for laptops according to Motorola engineers. This makes a revised B cable for programming.
@@VA3HDL You guys are missing the whole point of the ground. Ground on the radio is not bonded to the case of the radio. On a computer the ground is bonded to the negative. When you tie the shield to the negative black wire you are bonding the two negative is to get. And the reason for it is to reduce spikes from the power supply. When you bond to pin 16 that is a case round of radio. You are not bonding to the negative side of the radio which is supplying power for programming. What you are doing will work but you are take a chance to damage the radio from spikes from the power supply. This will work on a laptop that is not plugged into power with little trouble but this would be a revised A cable that is why Motorola came up with revised B. I hope you guys can figure this out.
@@philklingeman5483 After reading your note, I grabbed a spare Motorola radio I have with the same connector (XPR-4350.) I placed my multimeter in continuity test mode and the beeping on. I verified that pin 16 on the connector has continuity with the power connector negative pin, the radio case, the RF connector, and the pin 4 that is the USB negative power. Everything is bonded together case, RF connectors, negative power connector, and pins 4 and 16 on the programming port. To be clear the radio is not connected to anything when I made the measurements. So all these bonding is internal to the radio. Please explain what I'm missing. Thank you!
@@VA3HDL Motorola was getting a bunch of returns and this is the engineers doing, not mine. This was a service bulletin from Motorola to replace the programming cable. They told us to stop using revision A and replace it with revision B. I would not take a chance on blowing up the radio as where to connect ground shield. I do not have a couple hundred radios play around with to see if that would work. Because you got a D. C. ground does not prove anything it could be an inductor between the to; are a protection diode showing the ground I do not know the schematic that well of the radio. It’s your choice to take a chance whether your solution works are not. Personally, I would not take a chance.
You have the order wrong I believe. For the XPR4550 and XPR5550 you need to reverse the order of your white and black cable. White under Green and Black under Red. AA6PP
