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 Post subject: KLH Model 21 - No stations
PostPosted: Jan Sat 18, 2020 9:04 pm 
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Hello all, new here. Picked up a Model 21 from an estate sale and it turns on, volume control works, treble and bass works but it doesn't pick up any stations. Just static throughout the whole range of the tuner. Internet research hasn't led me to much, mostly instances where a certain range of the tuner doesn't work. Anybody have an idea of what can be issue with this scenario? Seems to be in good condition otherwise. Guess I'm hoping this is an easy fix, I'm not well versed in EE or anything so if I shouldn't touch anything please let me know. The tuner seems to be different than from what I've seen online and from the service manual floating around the internet. Doesn't look like a TRF-3. Aug 7, 1969 is the date stamp and it's not a Model 21 II.


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Sat 18, 2020 11:56 pm 
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Get on one of the Hi Fi forums. That was a very popular radio in its day.

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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Sun 19, 2020 3:51 am 
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Location: Ashhurst, New Zealand
VHF FM only - did you connect an antenna to the two terminals on the back?

https://antiqueradio.org/KLHModelTwentyOne21FMRadio.htm

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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Sun 19, 2020 7:23 am 
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No I haven't tried an external antennae yet. Thought the internal one should work, I've got another solid state radio from the same era that picks up stations beautifully. I'll try the external though, thanks!


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Sun 19, 2020 7:16 pm 
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Location: Santa Clara, CA
rufio wrote:
No I haven't tried an external antennae yet. Thought the internal one should work.


I'm not seeing an internal antenna, at least in the images provided...I think you're probably going to need a 300-ohm dipole.


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Sun 19, 2020 8:48 pm 
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It appears that they connect the antenna terminal to the line cord via a capacitor - this is fine if you live close to the transmitter but is more likely to pick up noise than a proper dipole.

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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Sun 19, 2020 10:41 pm 
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majoco wrote:
It appears that they connect the antenna terminal to the line cord via a capacitor - this is fine if you live close to the transmitter but is more likely to pick up noise than a proper dipole.


Still. should get *something*. That sort of arrangement is pretty standard and generally works OK for any reasonably close stations.

Brett


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Mon 20, 2020 1:25 am 
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An FM receiver wouldn't necessarily have any kind of internal antenna. If it has two screw connectors on the back labeled, "antenna", you can simply try connecting a length of wire to each, at least a few feet long, and should then be able to get a few stronger stations.

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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Mon 20, 2020 11:34 am 
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Location: Mountains of Mourne. Ireland.
As already mentioned... :)

With this left/hand lug connected as shown below, the set will utilize the power-line cord as an antenna.

Image
https://i.ebayimg.com/images/g/qJkAAOSw ... -l1600.jpg

For an indoor or outside F.M. dipole, make or buy one, and connect it to the two terminals.
viewtopic.php?p=3018373#p3018373

Greg.


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Mon 20, 2020 12:45 pm 
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How about a basic "aliveness check"? If you crank up the volume, is there any kind of noise? If so, does it change with tuning?

What kind of test equipment do you have?

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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Mon 20, 2020 10:31 pm 
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When I bought my model 21, it had the same issue. Problem was in the RF board. Not one, but two dead transistors. The guy at the antique shop said it just needed an antenna, but connecting one did not make any difference. Just that wooshing sound you get when you are between stations. Download the service manual for this radio. It is full of clear schematics and lots of helpful info. I have mine next to my bed. Make sure you put the pillow back in or it will not sound as good.


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Tue 21, 2020 3:56 am 
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I acquired a 300ohm dipole antenna and plugged it into the lugs, unplugged the other wire. Had a faint country station playing so I tried finding that same station with my main audio receiver and couldn't find it. So I then plugged another vintage radio Panasonic Solid State RE-6137 next to the KLH to find the station but then the KLH started playing whatever was tuned to the Panasonic. So I moved it farther away and still couldn't find the station.

Quote:
How about a basic "aliveness check"? If you crank up the volume, is there any kind of noise? If so, does it change with tuning?

Yes it turns on and makes the wooshing, white-noise sound. Kinda pleasant but I already have a white noise machine. It slightly changes w/ tuning, gets quieter in parts of the lower stations.

Quote:
What kind of test equipment do you have?

Only basic digital multimeter.

Quote:
When I bought my model 21, it had the same issue. Problem was in the RF board. Not one, but two dead transistors. The guy at the antique shop said it just needed an antenna, but connecting one did not make any difference. Just that wooshing sound you get when you are between stations.

Yes! That's the exact sound. Thanks maybe it's similar to your issue. I've downloaded the service manual but I don't think the version I have uses the TRF-3 board. I know the Model 21/II uses the Waller tuner, maybe that's what it is? If you compare the image of the tuner I attached in the original post to this one https://antiqueradio.org/art/KLHTwentyOne21RadioTuner.jpg you can see my hesitation with trusting the schematics.


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Wed 22, 2020 1:33 am 
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Mine looks like the second image.


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Thu 23, 2020 4:14 pm 
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MarkinK-zoo wrote:
Mine looks like the second image.


Okay, thank you that makes me feel better. I'll start testing things out.


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 Post subject: Re: KLH Model 21 - No stations
PostPosted: Jan Fri 24, 2020 12:35 am 
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Joined: Feb Mon 20, 2017 8:12 pm
Posts: 28
This was the first transistor radio I had worked on and so there was a lot of learning to do, but once I caught on it wasn't so intimidating. Learn all about PNP and NPN transistors. I was thinking that it would be impossible to find replacements, but it wasn't. I just couldn't use the parts numbers in the manual. Had to do some searching to figure out what I was looking for. Good luck. These radios sound fantastic, but they aren't great for reception. Good, not great.


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