Re: T922 Power Supply Problem

Harvey White
 

OK, then there's several things to think of.

1) with no power on the other boards, and a decent (several K resistance) to ground on the power leads on the boards themselves, I'm not sure what's holding down the power supply lines on the boards.

2) I assume that without any boards plugged in, the main voltages are down.

with the main voltages down, and having replaced *every* capacitor (and <I'll never tell> all the capacitors in the right way), I'll assume that all the resistance readings are decent.  Then the question is:  *what* if shorted, would pull the voltages down.  You can tell if the voltages are down by looking at the current sense resistors (if any), measuring the voltage across them, and then seeing  what the current is from that.  If the current sense resistor is connected between the base and emitter of a transistor, any reading over about .6 to .7 volts indicates that the supply is trying to current limit.

That indicates that something is pulling too much current.  If the supply feeds another one, check that other supply too.

Harvey

On 7/7/2019 8:37 PM, @DC912 wrote:
Forgot to mention, I also reflowed the solder on the connectors on the power supply board and interface board.



Join TekScopes@groups.io to automatically receive all group messages.