If an Orion is voltage sensitive in any way, change the electrolytic capacitors
on the A9 Power Distribution Board, ALL OF THEM.
90% of the time, tis will resolve the issues.
Gary
W0DVN
PS: This is the same advice you would get from Ten Tec service, back when you
could call them on the phone...
> On Sep 23, 2022, at 1:35 PM, Bob, W3IDT <w3idt@comcast.net> wrote:
>
> Some time ago I asked about an issue I was having with my Orion II:
> The RX would stop after TX with FT* or SSB above about 10 watts (CW at 100
> watts was fine). Only a power down/up cycle would unlock the RX. RFI was
> suspected, but it is not the cause.
>
> Steve, NY3A, with a complete test shop, has been digging into the issue.
> He has discovered two problems. I am asking for any knowledge or advice on
> either one.
>
> 1. The problem almost never happens if the input power supply is below about
> 13volts. Almost always happens at 14.5volts. So, there is something that
> seems very input voltage sensitive, though the various voltage regulators all
> seem OK.
>
> 2. The proximate cause of the RX shutdown is the "REF-IN" signal from the CPU
> going "low"... As Steve says,
> ---------------
> VCO1 and 2 are unlocking. The reason they're unlocking is their reference is
> going away. The reference is a DDS, direct digital synthesizer. The reason
> it's going away is the REF_EN signal is going low. This removes a crystal
> oscillator reference signal from the DDS. This REF_EN sig comes directly from
> the microprocessor board.
> --------------------
>
> Steve's complete message (and earlier messages) copied below.
>
> Does anyone have a clue as to the cause of the REF-IN signal going low? OR
> about the voltage sensitivity?
>
> Any advice greatly appreciated.
>
> Bob, w3idt
>
> .......
> . Robert F. Teitel, W3IDT
> .
> . w3idt@comcast.net
> . w3idt@arrl.net
> ........
>
>
> -------- Forwarded Message --------
> Subject: RE: Status /Orion II
> Date: Thu, 25 Aug 2022 21:42:30 +0000
> From: Steve S <NY3A@hotmail.com>
> To: w3idt@comcast.net <w3idt@comcast.net>
>
>
>
> Made progress today.
>
> VCO1 and 2 are unlocking. The reason they're unlocking is their reference is
> going away. The reference is a DDS, direct digital synthesizer. The reason
> it's going away is the REF_EN signal is going low. This removes a crystal
> oscillator reference signal from the DDS. This REF_EN sig comes directly from
> the microprocessor board.
>
> This happens only at higher Power Supply voltage. I've been testing it at
> 14.5-14.7V. The manual says the upper limit is 15V. It unlocks is either rcv
> or xmit at this higher voltage.
>
> So why is the micro pulling this sig low at higher PS voltage? Sometimes
> there is a PLL unlock signal which if true, triggers radio shutdown. I see no
> such signal from the PLL. Bottom line is I don't know right now. If Ten Tec
> was around I'd send email that software guy would eventually see, and he
> could tell me.
>
> I started signup for Ten Tec group on Groups.io forum and will ask what
> triggers Ref En shutdown and will see if anyone knows. Odds are slim, but
> hopeful.
>
> Possibly there is A/D monitoring PS voltage through voltage divider
> somewhere, or micro PS may have issue. This seems unlikely since micro seems
> to be running fine otherwise.
>
> In any case, standby...
>
>
> -------- Original message --------
> From: "Bob, W3IDT" <w3idt@comcast.net>
> Date: 8/25/22 4:49 PM (GMT-05:00)
> To: Steve S <ny3a@hotmail.com>
> Subject: Re: Status /Orion II
>
> Thanks for the update.
> Hope you're considering it a technical challenge.
> Certainly far beyond me.
>
> Should I post something in the Orion reflector?
> Maybe someone else has had this issue.
>
> Bob, w3idt
>
> .......
> . Robert F. Teitel, W3IDT
> .
> . w3idt@comcast.net
> . w3idt@arrl.net
> ........
>
> On 8/25/2022 1:59 PM, Steve S wrote:
>> Hi Bob
>> Just a note...
>> I replaced final amp caps, no change.
>> I've noticed running at higher PS voltage, 14.5V, will make unit unlock
>> quickly when xmit SSB,CW or even occasionally even in RX. Lower PS voltage,
>> 13V, never seems to unlock.
>> I've checked input 1st stage voltage regulators on PLL, and looks ok. Almost
>> all of PLL is double regulated so those should be ok. Mystery right now why
>> PS voltage influences unlock if PLL Vregs don't change. Wondering if PLL
>> control getting messed up somewhere else.
>> Ten Tec has info in manual on PLL control details in manual, per band. I'm
>> just starting to get into PLL details to see if I can learn more. e.g. which
>> VCO is unlocking and why.
>> Next Wed or Thurs I'm heading to NC for Shelby hamfest, then continuing to
>> FL for relative visit. Should be back in couple weeks.
>> 73
>> Steve
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> TenTec@contesting.com
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