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Onkyo TX-3000, tuned lamp always lit. any help out there?

Blue Shadow

Blue Shadow

Waiting for Vintage Gear from this century
This Onkyo TX-3000 has a burned out lamp for the Tuned Indicator. All other lamps work except the dial indicator which I replaced.

Investigating the Tuned Indicator, the lamp should light when the tuning knob is released and the unit is on the station.

The Stereo Lamp for stereo stations, the Locked Lamp for the stations within locking range on the dial both light but releasing the knob did not light the tuned lamp. Investigations indicate the lamp is receiving about 20 volts whenever the unit is on. The voltage drops when the tuning knob is touched so I'm guessing that sensor is working. Does this in all three settings for the sensor sensitivity.

The SM is on HFE: https://www.hifiengine.com/manual_library/onkyo/tx-3000.shtml

Lamp receives voltage on all inputs when the unit is on. The tuned lamp is under the tuning meter just to the left of the transformer.
 
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Looks like it should receive constant +, and the ground side is switched. + side feeds from the 19.7v supply that is common to "locked" "tuned" and "stereo" as well as other stuff.

If I'm not too far off here, and considering solid state is damn confusing, Q708 should be what switches it on. Looks like that can be triggered with the mute/lock switch being set in whatever position connects it to ground, or through the output of Q705. If the "locked" lamp works like it should, I suspect Q705 is OK since Q705 seems to be used in both circuits. Quick and dirty check, see if you can measure any voltage change on the banded end of D706. If you see voltage change there from what appears to be 0v to about 11v based on whether that light should be on or not, the circuit through Q705 is OK and likely Q708 is bad. A diode check on that part out of circuit should tell the tale. If D707 has shorted, the light will also be on constantly.
 
Thanks for these thoughts. I'll be looking at the components that provide the path to ground for this lamp.
 
Well no joy, yet. Still 15 volts on the lamp circuit all the time after testing Q708, Q707 and D707 along with the paths to ground with the resistors, R721, R722 and R723 reading about what they are spec'd.


Tuned Lamp.jpg

Guess it is time to find out where that 15 volts goes to allow the lamp to light/why it has a path to ground when it shouldn't. Sensor circuit gets a look now, too.
 
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Binkman said:
any evidence that lamp was replaced? wrong mA?
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The lamp same as the other two with long brown leads wire tied with other wires that look as new. Using a .025A LED the lamp stayed on all the time. Checked the sensor switch positions and the voltage at the lamp connections and got voltage. There were changes one time, need to check it again. But without touching the tuning knob I was getting 20V and a drop to 15 when touching the knob. Now if that would have dropped to 0 when touching it, we would be in business.
 
Does that thread I posted give any hints? pcb ground screws? put a couple screws in to the case cover? thats what happened in the link when he put the cover on.... Maybe your hand is wrong polarity, stand on the floor if sitting at the bench? :D
 
I need to try that. I'll move to the other side of the table when I test it again. Gonna wait on bulbs before going back in and want to finish up a couple other projects...yeah right finish up something...what a concept.

I'll give the assembled idea a try, too.
 
Got this unit cleaned up and relamped. In doing so the all three tuning lamps were working as they are designed to. All good, nice unit, just wish Onkyo had used better markings on the faceplate as these can be removed over time just using the unit.
 
Blue Shadow said:
Got this unit cleaned up and relamped. In doing so the all three tuning lamps were working as they are designed to. All good, nice unit, just wish Onkyo had used better markings on the faceplate as these can be removed over time just using the unit.
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Bringing this back from the dead. Did you use led? Trying to upgrade to led. Thanks
 
suzook said:
Trying to upgrade to led.
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Picked the wrong guy to say that to, I think LED is a downgrade. Many issues, easily solved, generally, wrong colors, but they are getting better and well I'm gonna croak before the new incandescents stop working in 40 years.

I use LEDs on some units. All a matter of finding the right ones for the application. Many work on a range of voltages, ones made up by the guys selling parts for stereo, not necessarily the raw LEDs from Mouser Digikey.
 
Blue Shadow said:
Picked the wrong guy to say that to, I think LED is a downgrade. Many issues, easily solved, generally, wrong colors, but they are getting better and well I'm gonna croak before the new incandescents stop working in 40 years.

I use LEDs on some units. All a matter of finding the right ones for the application. Many work on a range of voltages, ones made up by the guys selling parts for stereo, not necessarily the raw LEDs from Mouser Digikey.
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Lol. Thanks anyway. I found what I need. Nice little receiver.
 
Blue Shadow said:
Picked the wrong guy to say that to, I think LED is a downgrade. Many issues, easily solved, generally, wrong colors, but they are getting better and well I'm gonna croak before the new incandescents stop working in 40 years.

I use LEDs on some units. All a matter of finding the right ones for the application. Many work on a range of voltages, ones made up by the guys selling parts for stereo, not necessarily the raw LEDs from Mouser Digikey.
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No you're not. The incandescents are all Chinese. Do you plan on kicking the bucket this week? The LED's are Chinese too. Even the devil can make LED's outlast tungsten. Buy the LED's and learn how to stick series resistors in. Die with all your gear still working.
 
I throw LEDs in gear that looks good with them. I use tungsten and prefer it for any unit that looks wrong with LED. Those radioactive blue dials are toooooo much. LED technology will have the color output figured out soon enough for those.
 
This TX belongs to a friend and I don't recall what I threw in it. If I didn't find the proper bulbs I probably used some 5-12V LEDs from wjoe.com.
 
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