Yamaha CR-1000 meter lamps current

sssboa

Super Member
Hi

I lost all 3 lights on meters in my CR-1000. No other symptoms.
How are these lights powered? I don't think it's from the power board.
I bet it's 17/18VDC coming from tuner board? I looked in schematics, could only find the 3 leds (power/afc/tuning) but not these.
 
All four of the lamps are powered off of TR817 in the power supply. The 3 dial lamps are tied into the MIC Volume circuit board. All 4 lamps are in parallel with each other. Check R830 10Ω 3W if all the lamps check out good with your multimeter. The schematic I have is a poor scan. But it looks like around 10-14 vdc supplied to the four lamps.
 
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All four of the lamps are powered off of TR817 in the power supply. The 3 dial lamps are tied into the MIC Volume circuit board. All 4 lamps are in parallel with each other. Check R830 10Ω 3W if all the lamps check out good with your multimeter. The schematic I have is a poor scan. But it looks like around 10vdc supplied to the four lamps.
Ok. I haven't opened it yet. The 3 lamps just didn't go on at switch-on. The lamp in the pointer is ok though.

I was doing CR-800 recently and the power for meter lamps was between 17 and 18v. The power for the pointer lamp was also between 17 and 18v but different by like 0.5 volts.

In both CR-1000 and cr-800 the 3 meter lamps and the pointer lamp are powered from a separate pair of lugs.

All the above made me think that the pointer lamp was powered from a diffrrent transistor. But what you say negates it.
 
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I used green LED's in mine. I don't recall now what resistor I used (maybe 470 ohms), but they've worked out well.
 
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