Fw: [TMC] PMO

[Ira Curtis]

----- Original Message ----- 
From: "Ira Curtis" <kch at tie.cl>
To: "Roy Morgan" <roy.morgan at nist.gov>
Sent: Wednesday, January 17, 2007 6:26 PM
Subject: Re: [TMC] PMO


> Hello Roy,
> Yes it is a total success.
> My TMC group is now is fully operative
> It consists of :
> PMO-2
> SBE-2 with power supply replica. home built.
> PAL-350 And original power supply.
> All built into a BUD  5' rack.
> Works beautifully on all modes, quality on SSB is exceptional, and very 
> good on AM, chirpless CW.
>
> I had several problems with the PMO, first one being out of track, and 
> despite your friend's  advice  I did open it, as I didn't have another 
> choice, And believe me, it is nothing to be afraid off. Someone forced it 
> out of the synch rail, plus he  tried to repair it without knowing the 
> first thing about it. I have completely rebuilt it, disconnected the oven 
> elements that made a short to the ground, was worried about stability, but 
> for no reason, as it is rock solid without them.  realigned, and it was 
> working fine, except that at the lower range, say below 2.500MHz  all of 
> the sudden, stopped oscillating.  And this without any apparent reason. 
> All voltages are fine tubes are new and checked 90% or more, I was against 
> a stone wall.
> The problem was that  the snag came and went without any apparent cause. 
> To make a long story short, Finally I traced the problem to the current 
> regulator. I don't know to date what was wrong with it,(continuity and 
> resistance are OK) but upon replacing it the problem disappeared. putting 
> it back, it surely came back. And another enigma, is why only at the lower 
> range?.. I have concluded, and am not sure it's the right answer, is that 
> it has something to do with the tube's mutual conductance changing with 
> filament conditions...
> There were also some minor problems with the amplifier, and the SBE, but 
> nothing serious, I  have rebuilt the PAL power supply.
> (they have several printing errors in the schematics) etc. lot's of fun.
> I will take some pic's and e-mail it to you.
>
> 73's Ira
> CE3AM

BTW: I am looking for a pair, (Wall receptacle female contacts, and cable 
plug, male contacts for the SBE power supply. these are MIL-C-5015 circular 
connectors. anythig out there at a resonable price?
Ira
>
> ----- Original Message ----- 
> From: "Roy Morgan" <roy.morgan at nist.gov>
> To: "Ira Curtis" <kch at tie.cl>
> Sent: Wednesday, January 17, 2007 12:30 PM
> Subject: Re: [TMC] PMO
>
>
>> At 06:01 PM 1/16/2007, you wrote:
>>>Hi All
>>>Someone  made a question about pmo scale to frequency tracking. I can't 
>>>find the question, can someone repeat it?
>>
>>
>> Ira,
>>
>> Over my mid morning snack, I re-read our messges on the TMC PMOs.  I 
>> wonder if you made any progress on yours.
>>
>> I had a thought: maybe if you can set the lower frequency point to 
>> approximate the error at the high frequency point, the thing will be more 
>> linear and then you can correct the error by changing the mechanical 
>> connection. That is, moving the whole range of the oscillator to match 
>> the dial readout.
>>
>> Roy
>>
>>
>>
>> - Roy Morgan, K1LKY since 1959 - Keep 'em Glowing
>> 13033 Downey Mill Road, Lovettsville, VA 20180
>> Phone 540-822-5911   Cell 301-928-7794
>> Work: Voice: 301-975-3254,  Fax: 301-975-6097
>> roy.morgan at nist.gov -- 
>