[R-390] IF Amplifier...new information...

[Tom Bridgers]

Glenn,
Given these two facts:
1.You have several beat up IF decks With the 20-pin connector, J512, chiseled out, and
2. The complexity of a finished, fully populated component 390a IF deck,

Here’s what I would recommend:
1. If all that you’re missing on the other decks that you have is the 20-pin connector, pick your least damaged one, and get a replacement J512.

Now if the gold seekers also chiseled out mini BNC connectors J518, J513, and J514, it really gets interesting... 

But in any event these connectors are probably available from Fair Radio Sales.

2. Once you get the 2O  pin, J512, the fun really begins. 

You’ll need to trace out where each pin is connected in the under belly of the IF Deck, and that will be challenging even though there will be some pigtails of wiring remaining after the original 20-pin connector was chiseled out.  But with patience, good eyesight, and proper illumination of the underchassis, it is doable.

3. Once that is completed, then troubleshoot the fully populated IF Deck, and get it working.

4. That done, Now you can start replacing each capacitor and resistor with 2019 parts as you wish. As you know you’ll be working in very confining and close quarters in the various compartments and it will be extremely tedious work.

Would this “refurbishing” of a R-390a Deck be rewarding? Yes it would. 

A member of our Boatanchors group, who is now deceased, and whose name was Tom from Durham NC, replaced all the capacitors and out of tolerance resistors in an IF deck....  And it worked beautifully according to him. But it took Tom months and months to complete.

Good luck,
-Tom KE4RHH 

Sent from my iPhone

> On Sep 16, 2019, at 9:51 AM, Les Locklear <leslocklear at hotmail.com> wrote:
> 
> Just the highest s/n reported at that time (2002)
> 
> Les
> 
> 
> ----- Original Message -----
> From: Glenn Little WB4UIV <glennmaillist at bellsouth.net>
> To: Les Locklear <leslocklear at hotmail.com>, <r-390 at mailman.qth.net>
> Sent: 9/16/2019 8:34:05 AM
> Subject: Re: [R-390] IF Amplifier...new information...
> ________________________________________________________________________________
> 
> So...
> Does the 24 indicate that there were 24 pieces started or completed or ??
> 
> Glenn
> 
> 
>> On 9/16/2019 9:09 AM, Les Locklear wrote:
>> I went into my old paper files and found some more information regarding spare parts contracts and specific info on the audio module you have.
>> 
>> In 2002 Tom Marcotte N5OFF, Wally Chambers K5OP (SK) and I were involved with contract/order numbers on not just the R390 series, but spare parts, cabinets and other information regarding those particular R-390 series.
>> 
>> Attached you'll see more manufacturers and comments regarding the Comm. Systems audio modules sent to me from Tom Marcotte in 2002.
>> 
>> Les Locklear
>> 
>> ----- Original Message -----
>> From: Glenn Little WB4UIV <glennmaillist at bellsouth.net>
>> To: <r-390 at mailman.qth.net>
>> Sent: 9/15/2019 7:46:47 PM
>> Subject: [R-390] IF Amplifier
>> ________________________________________________________________________________
>> 
>> I have an IF Amplifier that was never completed.
>> It is part number SM-C-343621.
>> I have heard that there are two versions of the IF amplifier and suspect
>> that this is the first and was pulled from the assembly line when the
>> second or later version was approved.
>> There is another number that I do not recognize on the IF Amp.
>> FR-11-C22-C-4-26418(E), possibly a contract number.
>> If there were two versions if the IF Amplifier, what were the changes?
>> I would like to build this amp as if it were a kit to ensure all
>> resistors are in tolerance and the capacitors do not leak.
>> 
>> Any ideas?
>> 
>> 73
>> Glenn
>> WB4UIV
>> 
> 
> -- 
> -----------------------------------------------------------------------
> Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
> Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
> QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
> "It is not the class of license that the Amateur holds but the class
> of the Amateur that holds the license"
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