Yamaha CR-620 - First Yamaha Receiver

[ZeroG]

Found a reasonably decent looking Yammie in....you guessed it...... Goodwill.

Was I surprised? I think the pupils of my eyes raced to the size of dimes. The CR-620 just sat there, plugged in. Probably still there because the lights didn't work, and so was abandoned by the previous buyer. Must not have been an AK'er.

And it even works, mostly. After passing through the requisite Deoxit decontamination chamber, it all works - except the meter lights and the needle pointer light. I checked for voltage, but there was none. Took out the fuses and tested them, & they're good. The lamps are bad, though.

I'm at a loss as to why there's no voltage at the board where the lamp wires are attached. I D/L'd the schematic but have no service manual. Can anyone enlighten me about the lights?

Thanks!

 

[avionic]

http://sportsbil.com/yamaha/cr-620-s-2.pdf
Where did you try measuring the lamp voltage?

 

[merrylander]

The lights are wired as series pairs so unless one of the lamps was still god you would not measure any voltage across the mate. Look at the schematic, IIRC you should find about 22V across L1 and L4, L2 and L3 are just convenient places the pair up the lamps. You need four 12V 60mA lamps.

 

[ZeroG]

Thanks for the tip, Merrylander. Good to know it's not a problem on the supply.

I'm going to try LEDs this time around. They seem simple enough to make and will brighten it up a bit - the incandescents look a little dim.

 

[mrr1]

Wow. A Yamaha at the GW. Nice grab.:thmbsp:

 

[ZeroG]

Pics of the green LED installation, though the green doesn't photograph particularly well. The dial still seems quite underlit with only the one LED at the pointer. One poster on the CR-420 thread suggested adding more LEDs along the dial. Is this electrically possible? Cosmetically recommended?

I used 2.7K resistors. Measuring about 9.9 volts at the three meter LEDs. Is that OK?

Thanks to both Merrylander and Avionic for looking in on this. Nice to have the resident Yamahoppers opinions.

 

[merrylander]

I am quite happy with Yamaha's decision to only illuminate the dial pointer. That is all one needs to find a station, after all it is a receiver, not a reading lamp.

 

[ZeroG]

Yep, not a reading lamp. Haven't tried to cook on it, either. It is the first receiver I've seen with a pointer light only, though.