06-05-2024, 01:05 PM
My psu has a pair of 5b254m.
I had a box of 350 to 450v electrolytics to test and reform.
I used some tag board and as I had a load of 9k1 resistors, used one in series to each + lead of the 6 I had. The 6 negative leads paralled up, both leads terminating with miniature insulated hook spring clips.
6 capacitors standing like soldiers, tags at the top and all my insulated clips attached.
Started psu at around 200v, gradually increasing. I monitored the voltage drop across each resistor in turn to check I wasn't charging too high a current.
The times when I reached across to adjust the voltage knob behind this set up on my bench (situated about 5 inches above my bench) and my bare arm brushed against a pair of terminals!
I am VERY sensitive to shocks. At work, I used to repair a lot of ground radio ATC equipment using the 28V dc input to give better monitoring of curent, especially some tx drawing 16A. Then final test on mains.
Sometimes, when fault finding, if my bare arm or elbow (we wore tee shirts) brushed lightly against the chassis -ve and the same or other hand touched the supply rail, I would rapidly react. Yes, 28V.
Now, imagine around the same year having nerve conductivity tests for hand and arm nerve testing. One electrode clipped on my finger and other elsewhere whilst pulses were fired at me.
I was going OOH OUCH etc. Very loudly.
The doctor had to abandon the tests because I was getting so stressed. "It's only a few milliamps" she said. What voltage I asked, but never was told.
She then explained there may be another way to investigate, but not very pleasant but described the method, to which I agreed to give it a go.
This involved 2 electrode wires attached to the likes of tiny needles. One was stuck just under the skin on my foot, the other into my tongue. This didnt really bother me.
What was more intereesting wac the oscilloscopetype display showing what looked like a load of audio crackling and sounding like it on the loudapeaker. I neede a gulp of servisol!
My wife had been in the waiting room outside, together with other patients waiting their turn.
She said they all looked at each other very worried indeed at the time when they heard me shouting!
Rob
I had a box of 350 to 450v electrolytics to test and reform.
I used some tag board and as I had a load of 9k1 resistors, used one in series to each + lead of the 6 I had. The 6 negative leads paralled up, both leads terminating with miniature insulated hook spring clips.
6 capacitors standing like soldiers, tags at the top and all my insulated clips attached.
Started psu at around 200v, gradually increasing. I monitored the voltage drop across each resistor in turn to check I wasn't charging too high a current.
The times when I reached across to adjust the voltage knob behind this set up on my bench (situated about 5 inches above my bench) and my bare arm brushed against a pair of terminals!
I am VERY sensitive to shocks. At work, I used to repair a lot of ground radio ATC equipment using the 28V dc input to give better monitoring of curent, especially some tx drawing 16A. Then final test on mains.
Sometimes, when fault finding, if my bare arm or elbow (we wore tee shirts) brushed lightly against the chassis -ve and the same or other hand touched the supply rail, I would rapidly react. Yes, 28V.
Now, imagine around the same year having nerve conductivity tests for hand and arm nerve testing. One electrode clipped on my finger and other elsewhere whilst pulses were fired at me.
I was going OOH OUCH etc. Very loudly.
The doctor had to abandon the tests because I was getting so stressed. "It's only a few milliamps" she said. What voltage I asked, but never was told.
She then explained there may be another way to investigate, but not very pleasant but described the method, to which I agreed to give it a go.
This involved 2 electrode wires attached to the likes of tiny needles. One was stuck just under the skin on my foot, the other into my tongue. This didnt really bother me.
What was more intereesting wac the oscilloscopetype display showing what looked like a load of audio crackling and sounding like it on the loudapeaker. I neede a gulp of servisol!
My wife had been in the waiting room outside, together with other patients waiting their turn.
She said they all looked at each other very worried indeed at the time when they heard me shouting!
Rob
