I wouldn't touch any adjustments until associated capacitors are replaced FIRST.
"Next" to the multiplex chip means nothing to me, unless they directly control the operation of the chip.
Schematic needed.... location of caps.
Schematic needed.... location of caps.
This tuner has a complex system of multiplex operation.
besides the chip, there are complex transistor circuits fed from the chip, and a muli-position selector switch, which may be dirty.
Voltages and other items are to be checked, something I cannot do over the internet for people.
besides the chip, there are complex transistor circuits fed from the chip, and a muli-position selector switch, which may be dirty.
Voltages and other items are to be checked, something I cannot do over the internet for people.
That's just amateur guessing, and not a professional approach to proper troubleshooting.
The 2 pots just below the LA3350 adjust the local oscillator, they may have drifted or worse gone open over time as they are not sealed.
Having the appropriate test and alignment equipment is the proper way to rectify any tuner issues.
AND..... having the needed experience to use them.
Instead of the internet-born and often highly inaccurate guessing and speculation.
Nothing beats having it on a qualified service bench in reality.
AND..... having the needed experience to use them.
Instead of the internet-born and often highly inaccurate guessing and speculation.
Nothing beats having it on a qualified service bench in reality.
You only need tuner guy if you are working on front end or mf detector. Stereodecoder is all low frequency audio. Hand held oscilloscope is all you need. 19kHz and 38kHz should be easy to detect.
This might be helpful:
https://elektrotanya.com/yamaha_ct-1010_adjust.pdf/download.html
https://elektrotanya.com/yamaha_ct-1010_full_sm.pdf/download.html
Don't adjust the trimmers randomly. At least mark their position with a sharp permanent pen. Also those through hole galvanisations might be the culprit, but I know it is nearly impossible to test each of them. You don't have an oscilloscope or an audio frequency voltmeter? Plain DMM won't do.
https://elektrotanya.com/yamaha_ct-1010_adjust.pdf/download.html
https://elektrotanya.com/yamaha_ct-1010_full_sm.pdf/download.html
Don't adjust the trimmers randomly. At least mark their position with a sharp permanent pen. Also those through hole galvanisations might be the culprit, but I know it is nearly impossible to test each of them. You don't have an oscilloscope or an audio frequency voltmeter? Plain DMM won't do.
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You are only going to get enough composite signal, both level and bandwidth, to produce stereo or even audio if the front end and IF strip and detector are correctly aligned. We don't know what the problem is with this tuner.
It is still possible that the IF isn't delivering enough level or enough bandwidth for stereo.
Stereo faults are not confined to the multiplexer.
A tuner guy would know that.
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Tune to a strong signal > 3 on signal meter
There is a pot marked osc by the main selector switch. Mark jts position and turn a bit in either direction. Repeat with other pots near the stereo decoder. The 10.7 mhz IF is the large can near the tuning cap. If the signal meter is showing strong this will be OK.
There is a pot marked osc by the main selector switch. Mark jts position and turn a bit in either direction. Repeat with other pots near the stereo decoder. The 10.7 mhz IF is the large can near the tuning cap. If the signal meter is showing strong this will be OK.