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VK2ZRG > TECH 13.12.05 13:04l 29 Lines 972 Bytes #999 (0) @ WW
BID : 1758_VK2ZRG
Read: DL1LCA GUEST OE7FMI
Subj: Re: KPC-3 info (VK2ZRG)
Path: DB0FHN<DB0MRW<OK0PPL<DB0RES<DK0WUE<I0TVL<VK2TGB<VK2IO<VK2WI
Sent: 051213/0954Z @:VK2WI.#SYD.NSW.AUS.OC #:706 [SYDNEY] FBB7 $:1758_VK2ZRG
From: VK2ZRG@VK2WI.#SYD.NSW.AUS.OC
To : TECH@WW
VK2ZRG/TPK 1.83d Msg #:1758 Date:13-12-05 Time:9:46Z
Hello all,
Geoff G0EJO posted this info re the voltages on the 14C88 in a PKC-3 TNC
>Mine measures + and - 9V without any external connections.
>With it connected to my laptop pin1 is at -5V and pin14 is at +7.75V
Thanks Geoff, It does look like the capacitors in the charge pump supply
are a bit on the small size. I've reduced the feedback resistor value by
blobbing a 15 k, on the top of the board, in parallel with R45. Maybe I
should increase the capacitor values as well. With the TTL 1488 plugged in
and the KPC-3 connected to the PC, I measure +7.3 volts and -3.8 volts.
Thes voltages vary a little depending upon which of the 4 com ports I
connect the KPC-3 to. So I'm in no rush to get a 14C88.
73s from Ralph VK2ZRG@VK2WI.#SYD.NSW.AUS.OC
/ack
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