Grundig 2147 Restoration pt. 6. RF alignment of the AM bands. What is it and how do we do it?

To continue with the circuit description of this radio, we'll now now look at the alignment of the RF sections of the AM bands. This will allow for a correct reading on the dial when tuning into stations, and optimise the antenna front-end circuitry to produce optimum results.
Hope you enjoy it.
Circuit Analysis of the Grundig 5040W/3D:

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TimeStamps
00:00 Grundig 2147 Restoration pt. 6. RF alignment of the AM bands. What is it and how do we do it?
04:35 Description of the AM front-end alignment theory.
19:28 Actual RF alignment for AM.
34:38 Testing the AM bands.
36:20 Closing

#tuberadios #antiqueradio #radiorestoration

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CAPACITOR LEAKAGE TESTER:

[waynethompson]

One of the many reasons I enjoy and love your videos is that you not only tell us what needs to be done, but you tell us WHY it needs to be done and why it needs to be done in a specific manner. Keep up the excellent work.

[BKGoldDetecting]

Please please don’t think the schematic explanations are boring, far from it, I see them as the highlight. As for saying that your explanations are simply your understanding, I’m sure even the top experts will always haggle over what a circuit does. What your explanations do for me is give me pointers to do more research. You are helping to turn on the lights. Thanks :)

[pdppanelman]

Well I do like your presentation in person. It adds a lot.

[mackfisher]

Bloody Brilliant:
Manuel, your use of explaining what you're doing utilizing the schematics is the best way to learn. The latest teaching aid of Yours go one step further by eliminating clutter on the page which may be distracting to some. P.S. It's nice to see the wizard behind the curtain.

[alfredneumann]

Nice to see a little bit more of your worktable. Cheerio from Germany.

[cbiz]

Excelente idea haber agregado a los videos la introducción en persona frente a camára. Felicitaciones!

[TRXLab]

really nice channel you have! One word to the Grundig analyses at RMorg. It is so fantastic since they still have Hans M. Knoll on board. He is an old Grundig developer working back then at Grundig R&D department in Fürth.... best regards Peter

[lyntonprescott]

This is your best set of videos. Taught me so much. Even got the AM working on my Hacker. Now for the FM!

[rossthompson]

Thank you - now I understand clearly why you have to circle around the lineup adjustments a few times to get the optimum result.

[radio-ged]

It's difficult to explain - but you've managed it. I guess the higher frequencies are affected more by trimming a capacitor and the lower frequencies by trimming a coil. This is why the circuit was designed this way, to minimise the effect of changing the upper and lower frequencies on each other. But as you explained they still do drag each other around a bit, which is why you have to go back and align it again. Nice work, especially because you removed unnecessary clutter on the circuit diagram. I wish there had been someone to explain it better when I was at college, way back in the day... I had to learn the hard way (or easy depending on your point of view) by doing it myself.

[yusdiy]

I am the 'copy first or blow it first and learn later' kind of person 😂. Great video sir as always. I will rewatch this few times.

I have a feeling that tool shelf be filled with gears by december 2021

[martinda]

Great - Glad I found the channel. I recently subscribed. Hello all.

[michaelmacdonald]

Its good to learn from you thanks man picking up hints here and there good stuff keep going.

[mattvoce]

Great video Manuel, enjoying to watch

[stuartmartin]

To know when to leave well alone is a great skill to have 👍😄 been on the wrong end of trying to get a radio perfect and....oops broke a core...just last week as a matter of fact.😂

[DavidTipton]

Nice explanation Manuel, thanks. It looks like two MW coils on the loopstick antenna? I haven't seen that before and the long wave is on the other end I take it. Looking forward to The FM alignment, cheers.

[paulp]

Thanks again Manuel. As for the 'waffle' around IF/RF alignments - that has been extremely helpful to my understanding. It one thing to know of the IF chains, but its another thing to understand WHY they are there and you have been of immense help with the why.
Regarding the slug/wax issue you had in this video. Have you tried to soften or melt the wax with a hot air gun or are things to delicate ?

[geirendre]

Excellent description and fascinating stuff. Will for sure check out that Radiomuseum.org forum.
Looking at the schematics as you described it, I couldn't help focusing on C44 of 2nF in series with the oscillator part of the ganged Cap, and it's effect on the circuit.
It lowers the overall capacitance of the 3 capacitors so a drift in the value of this (from heat or age) would shift the frequency of the oscillator (on all bands) in reference to the input circuit.
Would this be something to consider checking before aligning?
Maybe you could use a hex-nut screwdriver on those trimmer caps?
The hard wax in the coils, could it be warmed up slightly to soften it? Carefully with a heatgun or something...

[reijoliljedahl]

Very nice video again! My way of removing wax is to first use appropriate drill bit with fingers, and then I wrap my sharp soldering tip with kitchen paper. With very low temperature about 100 degrees C the paper sucks the rest of melted wax.

What did you do with the meshed up LW antenna coil? Was it the spare part? Did I miss something?

[EngineeringVignettes]

Hi Manuel, The video is of aligning AM bands, yes? I noticed that the section descriptions are talking about FM theory and alignment.. just wondering if that is correct.
Besides that, a good explanation of dancing between the high and low end of the band to "converge" the alignment.
Cheers,