> Glenn Maclean <wa7...@...> wrote: > I am putting a 220 repeater together using an ICOM IC-RPP2210. The > repeater is working except the PTT LED remains illuminated > all the time. It goes ever so slightly brighter when the > repeater is keyed up. I measure 1.56 volts dc at the PTT line > between the controller and repeater un-keyed. I measure .67 > volts dc when the repeater is keyed up. > I have tried applying 12 volts to a 10k ohm resistor with > the other end connected to the PTT line with no change. The > PTT LED remains on. I even tried a 1K resistor in the same > configuration. The PTT LED remains on. > The repeater is transmitting and receiving just fine with the RC210 > controller. > Any suggestions?
Try the Pinot Noir maybe..? You might consider the problem a quasi quirk of the Arcom Controller LED Display hardware section, which is different and separate from the controller COS/COR logic that actually meets the controller uP interface/buffer circuit. While the separate logic seen by the uP can deal with COR/COS logic input voltage transitions approaching zero volts... the LED display circuit wants to see the active low (ground) voltage less than the .6 volts you're reading with your meter. So... if you want the LED display to match (correspond) with the uP status... the input voltage need to drop below about .5 volts in/at the low logic voltage transistion (level). I averted a potential commercial radio application bus-crash related to this problem/issue by simply disabling the front panel display... then later fixed/modified the cos circuit interface to drop to nearly zero volts. cheers, skipp
