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From: Jeroen Belleman <jeroen@nospam.please>
Newsgroups: sci.electronics.repair,sci.electronics.design
Subject: Re: Francophones
Date: Sun, 22 Dec 2024 15:52:08 +0100
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On 12/22/24 14:27, Cursitor Doom wrote:
> On Sun, 22 Dec 2024 12:37:37 +0000, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:
> 
>> Jeroen Belleman <jeroen@nospam.please> wrote:
>>
>>> On 12/21/24 14:57, Cursitor Doom wrote:
>>>> On Sat, 21 Dec 2024 08:57:51 +0000, liz@poppyrecords.invalid.invalid
>>>> (Liz Tuddenham) wrote:
>>>>
>>>>> Cursitor Doom <cd@notformail.com> wrote:
>>>>>
>>>>>> On Sat, 21 Dec 2024 00:05:08 +0100, Jeroen Belleman
>>>>>> <jeroen@nospam.please> wrote:
>>>>>>
>>>>>>> On 12/20/24 22:16, Cursitor Doom wrote:
>>>>>>>> On Fri, 20 Dec 2024 19:32:14 +0000, liz@poppyrecords.invalid.invalid
>>>>>>>> (Liz Tuddenham) wrote:
>>>>>>>>
>>>>>>>>> Cursitor Doom <cd@notformail.com> wrote:
>>>>>>>>>
>>>>>>>>>> Do we have any French speakers on the Panel? I have a radio that's
>>>>>>>>>> badly in need of realignment and the only instructions I can find are
>>>>>>>>>> a set in French. I can't use Google translate because they've used too
>>>>>>>>>> many abbreviations in the text and they won't parse any sense.
>>>>>>>>>
>>>>>>>>> I'm not a particularly fluent French speaker, but I could probably sort
>>>>>>>>> out some technical instructions in French   If you want to send them to
>>>>>>>>> me, I'll have a go (you should be able to work out my e-mail address).
>>>>>>>>
>>>>>>>> Many thanks indeed for your kind offer. I suspect it will probably
>>>>>>>> require a native French speaker to decypher, but who knows?  :-)
>>>>>>>
>>>>>>> I'm not a native French speaker, but I may be able to help anyway.
>>>>>>> Fire away.
>>>>>>
>>>>>> Well that's interesing as I had did think you might respond given some
>>>>>> of the background you've revealed here in the past. I don't have the
>>>>>> relevant page here right now, but will make it available tomorrow. It
>>>>>> is only the one page and only one column of that, so nothing too
>>>>>> onerous. I did show it to a genuine French chum of mine a few weeks
>>>>>> ago, but he was stumped by the technical side of it and couldn't
>>>>>> assist much, unfortunately. So it appears it needs someone who can
>>>>>> speak French fluently *and* understands the process of radio
>>>>>> alignment. I kind of guessed that might be you....
>>>>>
>>>>>
>>>>> Many years ago Practical Wireless published an article about the French
>>>>> 819-line high-definition television service which had been translated
>>>> >from French by someone who knew nothing about television or radio
>>>>> terminologyy.  It was hilarious nonsense but I eventually managed to
>>>>> translate it back into French so that I could understand it.
>>>>>
>>>>> If you post your text here, we can all have a go at it.
>>>>
>>>> Sorry for the delay; took a bit of tracking down but I have it now:
>>>>
>>>> https://disk.yandex.com/i/3SiZ6rN_k-fP4w
>>>>
>>>> It's only page 1 that needs the translation - and of that, in
>>>> particular the abbreviated bits. I haven't read French since I was in
>>>> school about a hundred years ago, so it's all Dutch to me. :-)
>>>
>>>
>>> This was translated from German into French by someone who also
>>> did not know clearly what it all meant. Not everything makes
>>> perfect sense.
>>>
>>> Also, while it doesn't say so, many of the adjustments interact,
>>> so you may have to go back and forth a few times. Anyway, here
>>> goes.
>>>
>>> Jeroen Belleman
>>>
>>>
>>> ===============================================================
>>>
>>> -- DC current adjustments (for 9V supply)
>>>      - Adjustment of the push-pull audio stage:
>>>      Cut the solder bridge marked -x- in the collector trace of the
>>>      AC188 T11 and insert a current meter. Adjust R410 for 6.5mA.
>>>      Restore the bridge.
>>>      - Adjustment of the IF amplifier:
>>>      Set R515 to obtain 1.35V across T4's emitter resistor R518.
>>>
>>> -- Adjustment of the FM-IF stages. The radio should be set to "FM".
>>>      Connect a wobbulator centered on 10.7MHz at MP5 and the diode
>>>      detector shown at ZF VII (I think...) MP6. Detune ZF VIII (a).
>>>      Then tune ZFVII (b) for a symmetrical maximum response.
>>>      - Inject signal at MP3 and tune ZF VI (c) and ZF V (d) for
>>>      symmetrical maximum response.
>>>      - Inject signal on MP2 and adjust ZF IV (e) and ZF III (f) for
>>>      symmetrical maximum response.
>>>      - Inject a weakly coupled signal at the mixer (MP1?) and adjust
>>>      ZF II (g) and ZF I (h) for symmetrical maximum response.
>>>      - Discriminator: Inject signal at MP5, with a level low
>>>      enough that no limiting occurs in the IF strip. Observe the
>>>      signal at MP11 (audio amplifier input) with load impedance 50k.
>>>      Adjust ZF VIII (a) for symmetrical response.
>>>
>>> -- Adjustment of the AM IF (460kHz) stages. The radio should be
>>>      set to "PO" (AM, 560-1450kHz). Connect a measurement instrument
>>>      at MP4 (Weakly coupled).
>>>      - Inject a wobbulator signal at MP3 and adjust ZF XIII and ZF XII
>>>      for symmetrical maximum response.
>>>      - Inject signal at MP8 and adjust ZF XI for symmetrical maximum
>>>      response.
>>>      - Inject signal at MP7 and adjust ZF X and ZF IX for symmetrical
>>>      maximum response.
>>>
>>> -- Adjustment of local oscillator and AM input. For short and
>>>      medium wave, couple signal into the ferrite rod antenna using
>>>      the frame. For short wave, remove the rod antenna and couple
>>>      signal at the antenna connection through 15pF.
>>>      Tune to 560kHz and adjust (1) and (3) for maximum response.
>>>      Mixer sensitivity 13uV and oscillator output 60-90mV.
>>>      Tune to 1450 kHz and adjust (2) and (4) for maximum response.
>>>      - Set the radio to GO (Long wave, 160-240kHz).
>>>      Tune to 160kHz and adjust (5) and (6) for maximum response.
>>>      Mixer sensitivity 13uV and oscillator output 65-95mV.
>>>      - Set the radio to OC (Short wave, 6.5-15MHz)
>>>      Tune to 6.5MHz and adjust (8) and (10) for maximum response.
>>>      Tune to 15MHz and adjust (9) and (11) for maximum response.
>>>      Mixer sensitivity 5uV and oscillator output 35-90mV.
>>>
>>> -- Adjustment of the FM LO. Signal from an RF generator with
>>>      60 Ohm output impedance injected directly at the mixer (MP1?)
>>>      with a loaded signal level <2mV. Set the radio to FM.
>>>      - Tune to 88MHz and adjust (A) and (C) for maximum response.
>>>      - Tune to 106MHz and adjust (B) and (D) for maximum response,
>>>      Noise level is about 5 times kT0. Oscillator output voltage
>>>      75-85mV (at T2's emitter).
>>
>> It is interesting to compare the different approaches Jeroen and I have
>> taken.  Although we began with exactly the same source material, we have
>> produced two markedly different ways of saying the same thing.
> 
> Well, the important thing is that you agree on the key points.
> Now it just so happens I have a vintage wobbulator (made by Knight
> IIRC) which would be ideal for this job. It hasn't been used for about
> 20 years so it'll probably explode at switch-on, but that's nothing
> unusual around here as my neighbours will attest.

I went back and forth between the text and the schematics to
try and clear up some inaccuracies in the text. Comparing with
the original German text, the G->F translator did an honourable
job, in fact.

I believe you have a VNA. I'd use that instead of a wobbulator.
You won't need the diode detector then. You'll need a high-Z
probe though. You'll also need an oscilloscope to observe the
audio amplifier input (to adjust the discriminator).

Jeroen Belleman