[TenTec] Fw: Problem with Paragon I

[Phil Chambley, Sr.]

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 at Blomand.Net>
To: "Tentec" <tentec at 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 at Blomand.Net>
> To: <zrdc28 at 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
> >
> >
> >
>
>
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