dirtyhanfri
Well-known member
Hi
Yesterday, a customer gave me a BAE 500 power supply. The issue was phantom not working. I turned it on and the yellow led wasn't lighting. There are 3 leds, green, red and yellow, I suppose they're +16, -16 & 48V indicators.
Then I opened the box, nothing fancy in there, a pair of made in china power supplies, one for +/- 16V and one for 48V, crappy fuse holders for each transformer, the leds and a not so great soldering & wiring work...
So I measured V in the not working led and my DMM reads 48V DC between them, I took the led apart and it didn't work with 9 or 12 V, so I assume the led was broken by hitting it with 48V without a resistor, I thought something was wrong, I'm not an expert, but, feeding a led with 48v? Seems strange to me, then I followed the wires going to the led and found they're soldered directly to the 48v rail, just paralleled to the DC plugs, measuring them gave me 48V with the led out.
I used a 5k resistor and a spare led as replacement for the original led and it seems to work, voltages are ok (Actually DMM reads oscillates between 48,4 - 49,3V), it was all night long turned on and keeps fine.
I'm worried, that's too easy for the fix, I have not a lunchbox for try, but I'm almost sure it will start failing as I start turning on phantom on modules.
I googled the topic and nothing interesting popped me up, a pair of threads in gearslutz, it looks like the 48v PSU don't like to be shorted, but nothing relevant on the fix.
Any ideas?
Yesterday, a customer gave me a BAE 500 power supply. The issue was phantom not working. I turned it on and the yellow led wasn't lighting. There are 3 leds, green, red and yellow, I suppose they're +16, -16 & 48V indicators.
Then I opened the box, nothing fancy in there, a pair of made in china power supplies, one for +/- 16V and one for 48V, crappy fuse holders for each transformer, the leds and a not so great soldering & wiring work...
So I measured V in the not working led and my DMM reads 48V DC between them, I took the led apart and it didn't work with 9 or 12 V, so I assume the led was broken by hitting it with 48V without a resistor, I thought something was wrong, I'm not an expert, but, feeding a led with 48v? Seems strange to me, then I followed the wires going to the led and found they're soldered directly to the 48v rail, just paralleled to the DC plugs, measuring them gave me 48V with the led out.
I used a 5k resistor and a spare led as replacement for the original led and it seems to work, voltages are ok (Actually DMM reads oscillates between 48,4 - 49,3V), it was all night long turned on and keeps fine.
I'm worried, that's too easy for the fix, I have not a lunchbox for try, but I'm almost sure it will start failing as I start turning on phantom on modules.
I googled the topic and nothing interesting popped me up, a pair of threads in gearslutz, it looks like the 48v PSU don't like to be shorted, but nothing relevant on the fix.
Any ideas?
