mitsos
Well-known member
- Joined
- May 4, 2007
- Messages
- 2,886
HI, so I built this thing to do +24V, and +48V. I left the negative rail stuff off with no problem (see big green X in pic). My +24V is working OK (23.9) but the phantom is not and I'm not sure if I've messed up the doubler. (using 220R and 8K25 resistors with the LM317, by the way)
I'm using a 2x20 VAC trafo, which gives me 28VDC at the junction of the first two diodes in the multiplier. At the cathode of the second diode I was getting 59V yesterday (and at the regulator input) but my output was 30VDC (triple-checked the resistors). I then put in the 100uF cap marked in the attached picture, but now am getting 48VDC at that 2nd diode cathode (so this keeps the regulator from working atm, what happened to my 59V?). The green line is a jumper in place of the third diode and the small X is it's respective cap which I left out (for an unneeded tripler, I thought, tried it anyway but gave me 89VDC or something).
I had to scrounge to find caps to finish this board, and ended up using 220uF in place of the 2x 47uF 63V caps in the multiplier. I didn't think that would make a difference ??? I think the multiplier was working fine yesterday (is the addition of the 100uF the reason I am now getting 48VDC after the multiplier?) but at no time has the regulation worked. I swapped the regulators (with each other) and got the same results (+24V worked fine, but still got 30VDC on the 48V output). Anything obvious stick out?
thanks for any help!
I'm using a 2x20 VAC trafo, which gives me 28VDC at the junction of the first two diodes in the multiplier. At the cathode of the second diode I was getting 59V yesterday (and at the regulator input) but my output was 30VDC (triple-checked the resistors). I then put in the 100uF cap marked in the attached picture, but now am getting 48VDC at that 2nd diode cathode (so this keeps the regulator from working atm, what happened to my 59V?). The green line is a jumper in place of the third diode and the small X is it's respective cap which I left out (for an unneeded tripler, I thought, tried it anyway but gave me 89VDC or something).
I had to scrounge to find caps to finish this board, and ended up using 220uF in place of the 2x 47uF 63V caps in the multiplier. I didn't think that would make a difference ??? I think the multiplier was working fine yesterday (is the addition of the 100uF the reason I am now getting 48VDC after the multiplier?) but at no time has the regulation worked. I swapped the regulators (with each other) and got the same results (+24V worked fine, but still got 30VDC on the 48V output). Anything obvious stick out?
thanks for any help!