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Old 23rd Sep 2018, 1:29 am   #1
Richard
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Default Technics SA-5460

Hi

This was made in 1976, not sure if its vintage or modern for this post, mods feel free to move if this is the wrong section.

My workshops receiver / amp is playing up.

It will no longer receive stereo, and the stereo light wont come on.
Aerial appears fine, and has worked fine for years, and signal strength is 4/5 for radio 2, station sounds clear and strong, but it just wont shift into stereo.
There was always a slight delay, but now tuning in and past, nothing, no stereo.

What is this likely to be?

Richard.
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Old 23rd Sep 2018, 8:18 am   #2
Nickthedentist
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Default Re: Technics SA-5460

see here: https://www.vintage-radio.net/forum/...d.php?t=146150
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Old 23rd Sep 2018, 12:11 pm   #3
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Default Re: Technics SA-5460

Hi Richard,

hifiengine has a service manual for the radio, that should help:
https://www.hifiengine.com/manual_li.../sa-5460.shtml

Regards, Peter
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Old 23rd Sep 2018, 1:17 pm   #4
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Default Re: Technics SA-5460

Hi

Thanks for links, I had found the manual last night and downloaded it, reading it made my head hurt..

Will read the forum thread and see if it helps

Richard
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Old 23rd Sep 2018, 9:50 pm   #5
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Default Re: Technics SA-5460

Hi Richard,

The key to check out the stereo decoder is to get the datasheet.
You radio uses the Hitachi HA1156 stereo decoder chip. Here is a datasheet on it:
http://www.datasheet.hk/view_downloa...6w_4376049.pdf

First thing is to check is the free running frequency of the oscillator in the decoder chip.
It has to be 19kHz. Do measure it at pin 10 with a frequency counter with no stereo station received (see pg. 3 of the datasheet). Adjust it with VR102, a 10k trim pot in your radio.

Some people adjust the frequency without a frequency counter: Tune the radio to a strong stereo channel, adjust VR102 so that the stereo light comes on, and then adjust the pot to the middle of the range where the light is on.

If that does not fix your radio then you need to do some more debugging.

Good luck, Peter
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Old 23rd Sep 2018, 10:55 pm   #6
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Default Re: Technics SA-5460

First thing I would do is to change all the low value electrolytics around IC102, I'm sure this has come up before on the forum; typical values are 0.22uF, 0.47uF,0.33uF and 4.7uF
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Old 23rd Sep 2018, 11:14 pm   #7
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Default Re: Technics SA-5460

Thanks
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