[R-390] replacement R390A gear clamp source

[Renee K6FSB]

If you have a regular pto with the stack...Do NOT take the stack 
apart......(this was ~ 30 yrs ago) It took me a month get the darned 
thing back...i did get it perfect but what a PITR.
the Cosmos are wonderful in terms of easy of corrections.
they both have their issues at this age.
Renée

On 7/25/26 12:16 PM, Bob kb8tq via R-390 wrote:
> Hi
>
> 20 years after Motorola made their last R-390, the girls from that production line still had some
> really nasty stuff to say about setting up PTO’s.
>
> The PTO’s have been an issue since the very beginning.
>
> Bob
>
>> On Jul 25, 2026, at 3:01 PM, Jim Whartenby via R-390 <r-390 at mailman.qth.net> wrote:
>>
>> Interesting document, worth reading before tearing into the R-390A
>> https://vk6ada.com.au/collins-r-390a-urr-ten-most-common-failures-ranked-by-community-report-frequency/
>> Jim
>> Logic is a systematic method of coming to the wrong conclusion with confidence.  Murphy
>>
>>     On Saturday, July 25, 2026 at 01:29:09 PM CDT, SCOTT Barry via R-390 <r-390 at mailman.qth.net> wrote:
>>
>> Rats.  All this talk made me get my counter out and, today, my Collins
>> PTO is running about 1.529 kc too wide (1.001529 mc end-to-end).  I will
>> probably have to see if I can get that closer.
>>
>> 73,
>> Barry - N4BUQ
>>> Paul....
>>>
>>> Seeing that you have a Cosmos PTO, there are 2 seperate adjustments.
>>> One sets the end to end 1Mc ten turn coverage, and another that sets
>>> the 25kc points which is much more involved and difficult to adjust.
>>>
>>> You should do some reading about the Cosmos adjustments...
>>>
>>> 73...Jordan VE6ZT
>>>
>>> ----- Original Message ----- From: "Paul Roche" <rochep at comcast.net>
>>> To: "Jordan Arndt" <Outposter30 at shaw.ca>
>>> Cc: "Barry" <n4buq at knology.net>; "R-390 Mailing List"
>>> <r-390 at mailman.qth.net>
>>> Sent: Saturday, July 25, 2026 9:45 AM
>>> Subject: Re: [R-390] replacement R390A gear clamp source
>>>
>>>
>>> It is a Cosmos 136-1 PTO, SN 21195 (I think that’s means it’s a pretty
>>> late one).
>>> Sent from my iPhone
>>>
>>>> On Jul 25, 2026, at 11:23 AM, Jordan Arndt <Outposter30 at shaw.ca> wrote:
>>>>
>>>> Paul....What you're seeeing is the cover for the adjustment....the
>>>> real adjustemnt is hidden behind that cover screw which you need to
>>>> remove. Behind it is a small slotted brass rod that you adjust...I
>>>> wouldn't try to adjust it until you're sure you have everything
>>>> properly synchronized.
>>>>
>>>> What type of PTO is it...? Collins type or Cosmos type...?
>>>>
>>>> YMMV....73...Jordan VE6ZT
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