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ZL3AI > APRDIG 04.05.03 20:07l 46 Lines 1598 Bytes #999 (0) @ WW
BID : 1259-ZL3AI
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Subj: TAPR Digest, May 01, 4/4
Path: DB0FHN<DB0ZWI<DB0CHZ<DB0ERF<DB0MRW<OK0PPL<RZ6HXA<SP7MGD<VK7AX<ZL2BAU<
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Sent: 030503/1336Z @:ZL3VML.#80.NZL.OC #:65033 [Chch-NZ] FBB7.00i $:1259-ZL3AI
From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: kpc3 schematic
From: wes@johnston.net
Date: Thu, 01 May 2003 23:16:47 -0400 (EDT)
X-Message-Number: 37
I'm stuck in a hotel room... looking at a kpc3 tnc for a friend. It
decodes packets intermittantly, and w/o a scope, I think the problem is
that the 5v supply voltage is too high causing distortion on the 3105 modem
chip's input. Supply voltage is 5.65 volts, where my good kpc3 shows 4.97v.
I think this could be enough of a diff to bias the modem's input and maybe
cause some clipping. I'd like to replace the VR1 with a 78L05. Has anyone
got a scan of that part of the schematic I could review before making this
component swap?
An interesting note is that when turning on the TNC, the power led is at a
normal brightness for about .5 seconds, then it jumps to a little brighter.
My DVM can't read that fast, but it leads me to think that the VR1 is/has
failing.
Thanks
Wes
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Subject: Re: Still no joy....TM-D700A TNC locked up...
From: "Chris Rose" <kb8uih@arrl.net>
Date: Thu, 1 May 2003 23:44:11 -0400
X-Message-Number: 38
I have taken the modular plugs apart and gently tweaked the wires that make
connections there to be sure they are doing what they are supposed to be
doing too. My D700 gives me a fit once in a while and my Icom mic plug
acted up till I straightened up the plug wires. Anywhere a plug is to be
plugged in, there is a chance for failure or bad connection due to vibration
or just kicking the rig.
Chris
KB8UIH
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END OF DIGEST
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