Bob, sounds very reasonable to me. I will give that
try and let you know how it works. Thanks a million.
Roger
--- Robert & Linda McGraw K4TAX <RMcGraw@Blomand.Net>
wrote:
> My thoughts:
>
> I suspect that C5 on the logic board has reduced
> value due to age. Not
> uncommon. Replace it. It's a 4.7uF that is off of
> the RESET pin #25 of U7.
> If an exact 4.7 uF value is not available then go to
> the next larger size.
> It will only slow the MP initialization process for
> a few milli seconds and
> that won't cause any harm.
>
> I suspect that the MP is trying to initialize before
> Vdd is stable from VCC1
> source. This is caused scrambling of data from
> ROM/RAM addresses.
>
>
> 73
> Bob, K4TAX
>
>
>
> ----- Original Message -----
> From: "Phil Chambley Sr" <k4dpk@comcast.net>
> To: "Discussion of Ten-Tec Equipment"
> <tentec@contesting.com>
> Sent: Saturday, August 27, 2005 5:46 PM
> Subject: Re: [TenTec] Fw: Problem with Paragon I
>
>
> > Bob's references to the effect of unstable voltage
> on the uProcessor
> > reminded me that, about 6 months after I got my
> first Paragon, the logic
> > board began behaving really squirrelly.
> >
> > Dotted lines, lock-ups and every LED lit were the
> symptoms as I recall.
> >
> > Turned out, some of the early matching power
> supplies had the filter caps
> > mounted with #10-32 screws through the PC board.
> Evidently, transformer
> > vibration (or something) had loosened the screws,
> making for arcing due to
> > intermittent contact between the filter cap and
> the board foil.
> >
> > Cure was to re-build the foil with brass shim
> stock, since it had been
> > pretty well burned away by the time I found it.
> After repair, never
> > happened again.
> >
> > Since then, I have repaired several others that
> had loose power
> > connections
> > in various forms, even at the Molex connector.
> All of these were first
> > thought to have Logic Board problems.
> >
> > 73
> >
> > Phil
> > K4DPK
> > www.k4dpk.com
> > VFO Stabilizers and PEP adapters for wattmeters...
> >
> > ----- Original Message -----
> > From: "Robert & Linda McGraw K4TAX"
> <RMcGraw@Blomand.Net>
> > To: "Tentec" <tentec@contesting.com>
> > Sent: Saturday, August 27, 2005 8:15 AM
> > Subject: [TenTec] Fw: Problem with Paragon I
> >
> >
> >> Tried sending this direct to Vic at his address
> but it was rejected by
> >> the
> >> server. Hope he sees this. Thanks for the
> bandwidth on the reflector.
> >>
> >> 73
> >> Bob, K4TAX
> >>
> >> ----- Original Message -----
> >> From: "Robert & Linda McGraw (K4TAX)"
> <RMcGraw@Blomand.Net>
> >> To: <zrdc28@hiwaay.net>
> >> Sent: Saturday, August 27, 2005 6:54 AM
> >> Subject: Re: [TenTec] Problem with Paragon I
> >>
> >>
> >> > Vic:
> >> >
> >> > I've seen your post and several of the
> responses. Before you start
> >> > digging into the radio let me ask a few
> questions to clarify some
> > points.
> >> >
> >> > From my memory of your problem, it appears that
> the microprocessor
> >> > initialization from ROM is not being done
> correctly. MP's do require
> >> > that the Vcc come up to correct value and
> stabilize before running the
> >> > initialization code. The process is controlled
> by the RESET pin and
> >> > the
> >> > external to the MP the RC components. Usually
> if the C value decreases
> >> > with age, typical of electrolytic caps, then
> the initialization is too
> >> > fast thus scrambled data is loaded from RAM .
> I'll look at the
> > schematic,
> >> > but at present it is at my shop and I'm here at
> the house.
> >> >
> >> > Here's the questions: No battery installed in
> all cases.
> >> > 1. With the PS and radio off, turn the radio on
> then turn the power
> > supply
> >> > on in that order. What happens?
> >> >
> >> > 2. With the PS off and the radio on, turn the
> power supply on. What
> >> > happens?
> >> >
> >> > 3. With the PS on and the radio off, turn the
> radio on. What happens?
> >> >
> >> > I think you may have stated these in your post
> but I no longer have it.
> >> > These answers will better allow me to assist
> you with your problem.
> >> >
> >> > 73
> >> > Bob, K4TAX
> >> >
> >> >
> >> >
> >>
> >>
> >> _______________________________________________
> >> TenTec mailing list
> >> TenTec@contesting.com
> >>
> http://lists.contesting.com/mailman/listinfo/tentec
> >>
> >
> >
> > _______________________________________________
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> > TenTec@contesting.com
> >
> http://lists.contesting.com/mailman/listinfo/tentec
> >
>
>
> _______________________________________________
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