I.F. Alignment in under 2 minutes? Yes, it can be done. Grundig 2140 restoration - part 5
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The I.F. alignment procedure on my restorations can become somewhat repetitive, so I decided to try something different. Some of you have also asked if I could show an I.F. alignment with minimal equipment, so I decided to make this video showing the various ways that this can be done. From an all-out equipment-rich method, to using nothing but my ears and an adjustment tool, I think I cover just about all the ways to do this procedure.
Hope you learn something and enjoy the video.
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There are pros and cons to all measurement techniques and thinking about them all helps us understand more about these devices. Thanks for advancing our enjoyment of the hobby!
My pleasure
I think Paul (Mr Carlsons Lab) has a rather extreme amount of equipment, but apparently he does use all of it :).
Thank you for this video. I have only a small amount of equipment, and I can't justify buying things that I would rarely use as this is just a little hobby for me, not something I do for a living or would do regularly. It's great to see techniques that can be done with simple, lower cost equipment. Sending a little thank you/Chistmas bonus to show my appreciation of your work.
Thank you, Brendan. I really appreciate it.
Oh yeah, MCL has so much gear, even if we're just talking tube Tek scopes! Ha.
More than enough to do the job the perfect way. Us people on tighter budgets have to do with less optimal solutions. It's a good thing I finally got a frequency meter, makes tuning my generator to the exact frequency a lot easier than looking at my scope and measuring the time.
True. The scope is not particularly accurate
Love the simplicity of your alignment !! 👍👍 👍 I prefer the 'off-tune' or my expensive HP.
👍
Thanks for taking the time to make this video and explain this in a simple straightforward way that's easily understood. This is pretty much what I had in mind while trying to decide what to do about not having the VTVM that the particular CB radio I'm aligning calls for in the service manual for aligning the receiver circuits. I have a nice older analog oscilloscope, analog and digital multimeters, nice accurate frequency counter, half decent signal generator that will produce a clean AM signal modulated with a tone at 30% and can even set it to the exact amplitude the manual calls for. I even have a Tinysa to look for any spurs and make sure it transmits a nice clean signal. However, I've been stuck on not having the VTVM specifically, and of course the know it alls of the Internet tell me I'm completely stupid for thinking I could even do a proper alignment without one, as well as a sinad meter... I realize some decent calibrated equipment is necessary, but I don't believe one must have every single piece of test equipment ever invented to do a good alignment on an old AM\SSB transceiver. I was actually thinking of using my oscilloscope since it's only necessary to adjust the cores for peak values, but since I've seen how well this works and how simple it is, I believe I will try this instead. I feel like I can finally do a proper alignment on this old Cobra that's been waiting on my bench with all kinds of nice new caps and been cleaned up all nice and pretty, just waiting to finally get tuned up and back on the air. Thanks again for helping me make sense of something I foolishly allowed some folks to make way more complicated than it really is. Can't wait to check out some more of your videos and see what else I can learn!
There are two ways to do restorations and alignments: you either have a huge lab full of equipment, or you just have to get creative with what you have on hand 😃 I subscribe to the latter option
Very useful information simplified. Thank you very much.
Second two methods we do have a problem like we cant be certain of the intermediate frequency .(in this case 460khz)
Well done for a very clear explanation about tuning methods for IF's in valve radios.
Thanks 🙏
Hi Manuel, As usual your explanations are exceptional. Understanding why a method works and showing us multiple methods certainly leads to a much better understanding of how these radios work. Great video! Thanks.
Thanks Peter.
Thank you for this video. You've presented options under any conditions and equipment access.
My pleasure
Really good video that was missing from YT. I think you covered it well.
Thanks.
Thanks 🙏
Most interesting.
Very clear explanations. Thank you it makes it much more clear now. I Appreciate your videos.
Pleasure
I found the little signal generator that was a kit lacked the range to align a multi-band shortwave set. I did the full procedure using the background static, alignment tool, and ears. Peak for loudest noise.
👍
I do it the Carlson way with my unmodulated sine wave generator that goes up to 1MHz and a frequency meter to get a precise readout. I disable the radio's oscillator and AGC, connect the generator set to my IF, first tune the second filter (either for max signal on the oscilloscope connected to the output, or for max negative DC voltage at the demodulator), looking for the peak, gradually lowering the input signal. Then I tune the first filter.
The restoration I'm doing right now (two early 1950s Polish radios named Mazur) is pretty challenging, gotta replace a lot of unsealed mica capacitors because they deteriorated so badly I couldn't get the IF working at all, same for the oscillator caps. I use the back end of an aquarel brush for tuning, shaped to act as a screwdriver.
Your Simpson multimeter is an absolute thing of beauty and a joy for ever!
Those mica caps can be a true nightmare. Thanks for your input.
It's a very important skill and experiment!BIG GOOD!Home made superheterodyne AM radio must be use this edge tool!
Bom dia!
Your opening statement is very factual. A lot of the fun with electronics is not just the repair or restoration of the device itself, but learning how to make due with often minimum tools or equipment on hand. A lot of that comes with experiences. Really been enjoying watching your channel.
Thanks 🙏
Great teaching video, thank you!
Pleasure
Many thanks for the demonstration. It was very helpful.
👍
Very informative video! Thank you for taking the time to go through each method!
It’s my pleasure
Nice work Manuel, I wish you had done this 4 years ago 😄
😊 me too
A very valuable lesson here at 21:00. There is a time and a place where a high Z meter works best, and also a time and place where a low Z meter works best. This is basic introductory electronics, but sadly many techs have forgotten or were never shown. I have seen numerous hams and automotive service techs get caught up in this trap too. Thanks for another fine video Manuel. Merry Christmas.
Thank you 🙏
Really great and informative video. I was thinking while watching it, that if you align the radio with an unmodulated signal and if the radio like this one has a (working) magic eye, it should be possible to use the magic eye as indicator.
You could do that, even though it would be tough to discern very small changes in the magic eye.
Excellent video. I use carrier only and monitor AGC for both AM/FM since I'm lacking the equipment to modulate FM. Love your coil induction method around the mixer tube for injecting the signal.
👍 works well.
Hi Manuel, excellent explanation. 👍
In regards to a signalgenerator...I guess everybody has a smartphone or tablet...there are numerous tone generator apps to choose from which can serve as a signal generator pretty well. I am using Tone Generator Pro myself...you can choose between a fixed frequency or do a sweep...even attenuate it if necessary.
Maybe this can be a suitable solution for other hobbyists...
The problem with those apps is that they are normally limited to 20kHz (audio range), while we need 460kHz for this purpose. However, for audio, they are truly great.
You are right, my mistake..😊
👍
Excelente tutorial para ajuste do ganho da frequencia intermediaria, estamos sempre aprendendo muito com seus videos, parabens.
Aguardamos os proximos videos.
Saudaçoes - São Paulo - Brasil
Obrigado. Abraço.
I think we used to do the IF alignment for a VCR/TV receiver in about 40s at the factory. This was in the 90s, later with DTV we made alignment free receivers.
👍
Thanks for the idea of aligning the AM IF using the AGC voltage - I have a generator to use but it does not have modulation. I would not have thought of doing that for my Grundig Majestic radio.
👍
i would say the bizzare thing about electronics repair as a hobby is that the more you spend out on test gear the less fun you have
the more you make your own test gear or work out ways to use/modify/adapt what you have the more enjoyable .its all about the success of figuring out a way (and success of the repair itself)
Couldn’t agree more 😊
Merry Christmas Manuell, I hope Santa Claus picked up some sparkly's while you were in Madrid for your two ladies. I understand if you put your shoes out father Christmas may deposit ceramic tuning tools instead of candy. If you were not a good boy you can always revert to chopsticks for IF alignments.
I think I’ll get the chopsticks, just in case 😊
Super Glue your alignment tool so it won't slip out.
👍
Everypne skips one important point in doing IF alignment properly. No one mentions to disable the local oscillator. The LO gets heterodyned with the IF 455Kc creating false spurious signals. Just check out my thoughts using a Spectrum Analyzer. Secondly, using the station reception to tune the IF means the Local oscillator needs to be correctly adjusted to the station frequency in order to produce 455KC. The is great room fir error tuning to a station. Sweep alignment is the best method or employing a spectrum analyzer, like the TinySA perhaps. Using the AVC is clever however there is a delay involved in that circuitry you have to consider. My preference is using a scope to observe 455 KC detection at the top of the volume control. My TEK scope will amplify that signal that can be fed to. VOM or VTVM effectively either way.
👍
I used to this series in the net . It is easy to follow the information and it helps me to recolle my earlier knowledge in the subject . I have a doubt to clear. The if transformers play a vital role in amplifying the low level rf signal recieved at the antenna coil upper end . The two stages of amplificatio between detector and mixer valve usually fails within the function of if transformer and the valves combined. The if t ransformers 😢; it is gets weak and unable to give 5he required strength to the signal and it 8s replaced to correct the reception of weak rf signals from distant stations . Is it right that the if transformers function poorly due to over aged use. ?
No, these transformers almost never change their their properties. If you notice weakening signal, it will be due to the other components in that part of the circuit.
I've used the sweep generator method, which I discovered from your earlier videos, to good effect - thanks. There was a video edit after you described the pi attenuator and then showed the croc clip: did mention of the fact that the attenuator is capacitatively coupled get lost?
Yes, the attenuator is capacitively coupled.
Great video! There are other videos on using a modulated IF frequency, but I didn't run across any that stated what the percent modulation should be. I would like to try the unmodulated IF monitoring the AVC voltage method. I'm not sure where to pick up the AVC voltage. Is there a standard location or does it vary with the radio design? I did like your idea of using a dummy load in place of the speaker.
You need to identify the AGC capacitor and measure across that. You can also go back a bit and measure at the detector diode (on the tube) itself, but it will have a lot of high frequency noise.
Well, I have a Zenith Transoceanic 6T40Z chassis that I restored and it's working but needs alignment. I'll be darned if I can locate the AVC cap. The schematic shows the filament and AVC circuit, but there's no capacitor in that circuit (either that or it's farther down the AVC bus, but I'm not sure where to look). I was thinking of just measuring across the volume control. I was going this route because I currently don't have a way to modulate my signal generator. I'm not sure the AVC is working properly. When I turn on the radio, even at minimum volume, the radio is quite loud. Thank you for the suggestion, I'll keep looking! @@electronicsoldandnew
Good luck 🤞
Do you pay for the service manuals or you have a few good links for that?
There is a lot of web sites selling service manuals but we have no idea of the quality. I really really don’t trust them. Right now looking for the servie manual for Grinding 2520U. Thanks.
I never buy the manuals. These are freely available. Here is a link to a video in which I give some of my sources:
Find Tube Radio schematics and track checking with Adobe Acrobat Reader DC
th-cam.com/video/oJtVijfc1Ds/w-d-xo.html
Thank you, very usefull.
If you find a copy of the Sams service info, watch out for errors. I've had two different Grundig models for the US market where the Sams had IF cores misidentified, tone pots swapped, and errors in the schematic diagram. Cross check with the original German service papers; they seem to be more accurate.
Even the original German manuals can have errors. have found a few 😊
Can you show us use the oscilloscope alignment AM radio 455Kzh? Step by Step?😀
I link a video where I do exactly that.
@@electronicsoldandnew Thank you!😀
I was going to collect a Marconi TF2016A today, but it turned out to be dead. Not a mV output
😞
.................video starts @ 2:30
And ?