FM IF Sweep Alignment Nordmende German Radio Final

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Sounds good now after alignment using sweep generator and oscilloscope with the Jason JJ Cruz ABDL Hudl and Mulberry method of redundant analytical and psychological intermediate frequency stratification alignment method

shango066

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No worries Mr Shango, you did a perfect job there aligning that old Nordmende, no Kraut radio repairman could have done better ;-) For starters, the narrow bandwidth just is so on a lot of those old tube jobbies, probably to prevent crosstalk from adjacent stations interfering because in Europe the FM band channels are spaced in 50 kHz steps and not in 200 kHz steps as in the US.
Your asymmetrical trace on the ratio detector signal of the EABC80 tube is because it has only nine pins to accommodate for 4 systems in 1 tube: diode, duodiode, and triode. Due to this there is a compromise solution where the cathode of one of the 2 ratio detector diodes is internally connected to the cathode of the AM detector as well as the cathode of the triode section and leads out only with 1 pin, which is grounded. Had they used a twin diode like the 6AL5 it would have enabled a totally symmetrical construction with corresponding signal on the scope.
Cheers from Germany from a fellow "Kraut techie" :-)

blitzroehre

I picked up one of those little red OScopes several years back. I ordered it in kit form with the Plexiglas case. While some complain about the case, it has saved my unit numerous times from drops, and getting banged around in our motor home while we were on the road. I also purchased the smaller unit in a white plastic case. It has a bit different OS but I think it will serve the same purpose in the long run. Before buying those, I found a video on how to build a mini-scope in an Altoids can using an Arduino, While not as versatile as the other 2 it does serve it's purpose as well when working with audio circuits. In between, I found a plan for a scope built using your sound card. This consisted of a couple of 7805's one for each channel and some resistors and caps. Not a complicated build, it did work fairly well and using a laptop screen gives you a lot of room for read out, and I coupled it with a bit of free software for Windows. Fearing damaging my sound card, I picked up one of those cheap Chinese USB sound cards to hook up to my computer. I guess, overall any of my cheap crappy oscilloscopes could be used to scope out audio circuits, but as you said, none of them would work well if you need them in the repair of, say a ham set.

JerryEricsson

Great job!! I learned a lot about how to do a sophisticated alignment of an FM stereo receiver, and how to pick out subtle component problems. I've done mono assignments, but never this. Not for the technical lightweight, for sure!

waltschannel

How do they expect you to perform radio repair without having music playing? On a lighter note, when I heard "Feliz Navidad", it brought back a funny memory of a former co-worker I worked with in the 90's when we worked at a grocery store. He was in the freezer aisle working with Christmas music playing over the PA. A lady with about a 4 year old child comes down the aisle while "Feliz Navidad" was playing. Then the child said to his mother "Mommy, why is that guy singing "Fleas on a Dog"? The co-worker said he laughed for a good hour.

teacfan

Merry Christmas Shango :) Been listing non-stop to L.A. Oldies for the last 7 weeks on the computer here in Sweden. Nice video content. Keep up creating videos.

oggyosbourne

Nordmende, that was german high end in the 60er! Thank you for your videos and happy holydays from germany (100 Miles from Bremen, where that Radio is build)

geogeo

I’ve never seen an IF can that could be so damn stubborn ! You got skills Shango ! Merry Christmas !

brianfletcher

Still say that would be a beautiful radio with complete restoration...

bonesable

That sounds alive in comparison to the way it was.
Thank you for the great videos, you are a talented man.
Someone said you don't like christmas, so have a happy year end lol.

zxztv