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I have two Yamaha receivers from the 1980s, an R-50 and an R-70. I just picked up the R-70 to replace the R-50 that has been in my workshop for a few years, and is showing its age. The R-70 volume/balance control needed a bit of TLC but nothing serious, and the receiver is working great now; with one exception.The FM tuner regularly reverts to an even number frequency (e.g. 100.5 displays 100.4), even though it seems to be tuned correctly. You can see in the photo that it doesn't happen all the time. Oddly enough, BOTH Yamaha receivers have the exact same quirk. I only have one other digital tuner, an Accuphase T-107B, but it has never had this problem.
Any ideas?
Hey, Donnie. Since you need a new place to live, maybe Dennis Rodman can help you find a place in Pyongyang with your buddy 'Little Rocket Man'.
Edits: 12/20/20 12/20/20Follow Ups:
Both those units have the same FM tuner section, with 3 gangs and 2 ceramic filters. They use the Yamaha CSL tuning circuit, which is found on other Yamaha tuners that came later.
Most likely, it needs one or both adjustments -
* detector balance (set to zero)
* IF offset
Both are detailed in the service manual.
Thank you. I will check it out, but my electronic skills are limited. Often these manuals talk about the specs, but they assume that you know where and how to check them.
I suspect that BFitz is right. If it's an analog tuner, then they've drift a bit. You wouldn't notice 102.1 vs 102.2 exactly on a dial. I thing that the analog is tuning in correctly, but tells the digital otherwise.
If assuming it sounds fine, then do you care if it's off by .1?
Aligning it might work to get it in sync. The question is whether is worth it?
My old Yamaha 2500 just lost it's HDMI output which is strange. I'm pondering the same question. Is it worth it to figure out why?
-Rod
I can live with the display, but I would fix it if it was something simple. I was selling the R-50 though, and I know that many buyers suffer from AudiOCD and stuff like this bothers them. Oddly enough though, it clears up if you leave the receiver plugged in.
HDMI is a scourge. I have held onto my Yamaha RX-V1500 for a long time because I didn't want to deal with HDMI, and I don't use those inputs on my Arcam AV9 because I know it would only be a matter of time before they get wonky.
Without knowing how the tuner works -- if it is an analog tuner with a digital frequency counter, that could be the explanation (I would think).
Could be drift if there is anything that could drift in the circuit, or maybe it is indicative of misalignment (again, if there's anything to align ).
One other, tangential thought. I think (???) US and European FM band frequency spacing may be different (I am pretty sure that AM channel spacing is different in the US and Europe); is there a switch on the back?
Just brainstorming here -- I have no real clue!
all the best,
mrh
I think it is purely digital, and I think it is odd that BOTH receivers have the same problem. I wonder if anyone else has run into it and figured out the problem.
Looks like a normal analog front end, but, yeah -- probably something else going on.
So, it randomly jumps up, or down, 0.1 MHz sometime after tuning? Does the signal quality change (i.e., does it sound off-center-channel/distorted)?
Yeah, I have no idea -- but it's curious.
all the best,
mrh
It doesn't fade to that frequency, it tunes there as if that is where the centre of the channel is. I just find it very odd that both should have the same issue.
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