[TenTec] Orion II Repair Questions

[Bob, W3IDT]

A9 capacitors have been replaced.
Sorry, should have said so in the email.

Bob, w3idt

.......
. Robert F. Teitel, W3IDT
.
. w3idt at comcast.net
. w3idt at arrl.net
........

On 9/23/2022 4:05 PM, dukeshifi wrote:
> 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 at 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 at comcast.net
>> . w3idt at arrl.net
>> ........
>>
>>
>> -------- Forwarded Message --------
>> Subject: 	RE: Status /Orion II
>> Date: 	Thu, 25 Aug 2022 21:42:30 +0000
>> From: 	Steve S <NY3A at hotmail.com>
>> To: 	w3idt at comcast.net <w3idt at 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 at comcast.net>
>> Date: 8/25/22 4:49 PM (GMT-05:00)
>> To: Steve S <ny3a at 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 at comcast.net
>> . w3idt at 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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