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 Post subject: Integrated Circuit LS1800
PostPosted: Sep Wed 22, 2021 3:30 pm 
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Joined: Mar Wed 09, 2016 6:15 pm
Posts: 7
Hi

Has anyone come across this IC LS1800 and found any data on it?

I have a kids "AM/FM Sing-A-Long Radio". It is a TRF with a C9014 transistor, UTC7368 audio power amplifier and the LS1800.

The LS1800 is a 22 pin DIP.

The radio works very well for what it is and is very sensitive.

thanks

Allan


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 Post subject: Re: Integrated Circuit LS1800
PostPosted: Sep Wed 22, 2021 5:40 pm 
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Joined: Sep Fri 07, 2007 2:27 am
Posts: 6693
Location: Grand Chute, Wisconsin
That number doesn't sound right to me. Can you post photos of the unit and the chip?

.


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 Post subject: Re: Integrated Circuit LS1800
PostPosted: Sep Wed 22, 2021 6:19 pm 
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Joined: Apr Wed 21, 2010 12:01 am
Posts: 382
It's LA 1800 made by Sanyo. I've seen some basic low part count am/fm kid/novelty radios that are poor performing low cost. The data sheet has this simple circuit.
Ken


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 Post subject: Re: Integrated Circuit LS1800
PostPosted: Sep Wed 22, 2021 6:20 pm 
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Joined: Mar Wed 09, 2016 6:15 pm
Posts: 7
Here are photos of the circuit board

Allan


Attachments:
P1030666.JPG
P1030666.JPG [ 941.82 KiB | Viewed 284 times ]
P1030667.JPG
P1030667.JPG [ 830.16 KiB | Viewed 284 times ]
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 Post subject: Re: Integrated Circuit LS1800
PostPosted: Sep Wed 22, 2021 10:19 pm 
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Joined: Jun Sun 15, 2014 5:37 pm
Posts: 1370
Location: Montreal, Quebec
National had the LM1800, but that was a stereo decoder.

There were some 18xx numbered ICs that were most of an AM/FM receiver, but surekly a second source would use the same number.

No IF transformers, and I see no ceramic filters. Not much to make a radio unless they are on the other side of the board.

There are ICs for making simple FM receivers, using active filters at a low IF. "7088" comes to. mind. But those use two buttons, and scan the band, until an fm signal is found.

There are also 3 terminal TRF radios for the AM broadcast band, descended from the ZN414. Those need a variable capacitor.

But I've yet to come across an IC that integrates both.


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 Post subject: Re: Integrated Circuit LS1800
PostPosted: Sep Wed 22, 2021 11:18 pm 
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Joined: Jan Tue 16, 2007 7:02 am
Posts: 4712
Location: Lexington, KY USA
I think Ken figured it out.

https://pdf1.alldatasheet.com/datasheet-pdf/view/39992/SANYO/LA1800.html

Ted


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 Post subject: Re: Integrated Circuit LS1800
PostPosted: Sep Thu 23, 2021 2:04 pm 
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Joined: Mar Wed 09, 2016 6:15 pm
Posts: 7
On the underside of the pwb, there is only one small capacitor which is attached to the tuning capacitor.

Looking at the pwb wiring and the circuit for the LA1800, I think that my LS1800 is a LA1800 with a different number.

Thanks to all who responded.

Allan


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