Kenwood L-01T Tuner

Impuls

Impuls

New Member
Hi Guys,

I recently bought me a second hand Kenwood L-01T Tuner.
It looks like during the shipment some thing went wrong, they throw to much with the boxes i think, shame on them post guys..
First problem was a dailing cord who was stuck and slipping inside over his axle, becuase the dailing knob was pushed inside a little but this is fixed.
Second problem is the Tuner does only receive Mono signals so there is no Stereo reception anymore for the
rest the Tuner works and looks fine.
Any idea how to fix this problem?

Thanks for your help or tips.

GrtZ Arie..
 

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Show pics of inside the chassis. You have not provided enough info as the problem could be any number of things, I'm afraid. Do you have an FM antenna hooked up to it? If so, what type?
 
Hi,

I use a 8 elements long Yagi and if you take a close look at the picture the tuner a signal of 80%
 
Impuls said:
Hi,

I use a 8 elements long Yagi and if you take a close look at the picture the tuner a signal of 80%
Click to expand...

Don't normally zoom in on shots. Just receiving shipped and had a rough ride. I would work all the switches and make sure everything operating smoothly. Remove cover and inspect the circuit boards for any damage. Could be the something in the alignment got knocked out of wack.

Step 12 in the alignment is the VCO adjustment to 76Khz. Slightly tweaking this adjustment may return stereo operation.

As you are aware this was a top of the line statement tuner when released. I would highly recommend that someone with proper test equipment and knowledge take a look at it.
 
Hi Punker X,
The circuit board has no visible damage and all the switches are working fine
The VCO is running at 76Khz so that is fine

Thanks..
 
Does the tuning meter react normal? Center when off tuned and normal left and right swing, with peak strength at center? Noticed in picture that muting is turned on. It's odd that your able to get audio even though you don't have stereo.
 
I would check any internal cable connectors - I usually would unseat / re-seat them all, even if they look fine. Also check grounding screws on the circuit boards for corrosion and tightness.
Those 2 have been problems for me in the past with "rough shipped" tuners. Make sure nothing has shifted so something is touching bottom of the board traces.

It also could have been "broken" before shipment. A complete diagnostic test should be done, using the manual, if no simple shipping related problem is found.
Despite what your previous owner may say, it have been sold needing stereo mode repaired - unless there was a demo video showing stereo working before shipment.
I have bought units like that - sometimes when units get flaky, they get put away. Then are later sold by friends or relatives, who can be unaware of "fine points" of operation.
 
Punker X said:
Does the tuning meter react normal? Center when off tuned and normal left and right swing, with peak strength at center? Noticed in picture that muting is turned on. It's odd that your able to get audio even though you don't have stereo.
Click to expand...
Hi,

Yes the tuning meter does work normal, there is always Mono sound with the muting knob pressed or released that makes no difference.
Punker X said:
Does the tuning meter react normal? Center when off tuned and normal left and right swing, with peak strength at center? Noticed in picture that muting is turned on. It's odd that your able to get audio even though you don't have stereo.
Click to expand...
Sgt Shultz said:
Are you sure it's not receiving a stereo signal and just the indicator lamp is out:dunno:
Click to expand...

No the sound is always mono, the indicator lamp is fine..
IC11 Pin8 is 10,5Volts that means Mono
 

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Bob@FM said:
I would check any internal cable connectors - I usually would unseat / re-seat them all, even if they look fine. Also check grounding screws on the circuit boards for corrosion and tightness.
Those 2 have been problems for me in the past with "rough shipped" tuners. Make sure nothing has shifted so something is touching bottom of the board traces.

It also could have been "broken" before shipment. A complete diagnostic test should be done, using the manual, if no simple shipping related problem is found.
Despite what your previous owner may say, it have been sold needing stereo mode repaired - unless there was a demo video showing stereo working before shipment.
I have bought units like that - sometimes when units get flaky, they get put away. Then are later sold by friends or relatives, who can be unaware of "fine points" of operation.
Click to expand...
This tuner has no connectors, each wire is soldered via a pin to the circuit board.
Thx...
 
Impuls said:
Hi,

Yes the tuning meter does work normal, there is always Mono sound with the muting knob pressed or released that makes no difference.



No the sound is always mono, the indicator lamp is fine..
IC11 Pin8 is 10,5Volts that means Mono
Click to expand...

That's the lamp driver. Following the switching goes back through some transistors and a IC based switches, SCA circuit and separation circuit. Have follow it back and to see what is triggering Mono operation.
 
Hi,
IC11 is the stereo Demodulator
HA11223W Datasheet, Equivalent, Stereo Demodulator.

GrtZ Arie
 
Impuls said:
Hi,
IC11 is the stereo Demodulator
HA11223W Datasheet, Equivalent, Stereo Demodulator.

GrtZ Arie
Click to expand...

Of coarse it's the MPX chip, that voltage at pin 8 is turning off stereo disabling the chip. You need to backtrack that input through the transistor switches and IC to figure out where the mono signal is getting turned on. You can trace from that pin back on the the scat, they are other places that are showing stereo/mono voltages.
 
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