On 12/12/2019 3:59 PM, Mark Pilant wrote:
Success.Two things come to mind on that.
First, do not attempt to power on the 1502 immediately after plugging
in the AC cord or wall wart supply. Give it a few seconds to charge
the cap, then turn the 1502 on.
Second, the cap may be too small. I used 4700uF which works
fine for me - I think the wiki recommends 2200.
Finally, if using an external supply (wall wart or otherwise),
put a diode in series between the supply and the cap/resistor
combo. The diode is to protect the 1502 against plugging in a
wall wart or supply with the opposite polarity, and protect "backfeeding" the wall wart or supply. The TDR tries to put
about 17 volts across the bananna jacks to charge the battery.