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Yamaha CR-840 Stereo Receiver is it Worth Keeping?

Bburdette

Bburdette

New Member
Need some help guys. Today I received a Yamaha CR-840 that I bought on Ebay, The receiver is really nice and in excellent condition, all functions work. But there is an issue. I'm not sure, but I think it is missing the glass that goes over the the radio channels and also the tuning pointer is missing. The receiver tunes great and pulls in stations, but there is no dial to tell where you are in the band. My question is, is it suppose to have a glass and how much of a problem is it to replace the dial pointer even if i could find one. Maybe I should return it? Any help appreciated. Thanks.
 
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avionic said:
Doesn't look like it.. Are you sure the dial pointer is missing or is it just a burnt out light bulb.
Click to expand...
Wow! I feel so stupidI I looked more closely and like you said, the light is burned out. I guess it also doesn't have a glass either, Sorry to waste your time.
 
Bburdette said:
Wow! I feel so stupidI I looked more closely and like you said, the light is burned out. I guess it also doesn't have a glass either, Sorry to waste your time.
Click to expand...
No problem amigo.. How you going to know if you don't ask...:thumbsup: Besides it increases my post count..:rflmao:
 
Looks like the "pointer" is a small yellow box on the bottom of the numbers dial? Right above the one switch in this image
Vintage-Yamaha-CR-840-Natural-Sound-AM-FM-Stereo-Receiver.jpg

NOT a conventional pointer.

As for glass, can't tell from Google images, but would seem to be rare a tuner scale with no glass(or polycarbonate/plexiglass) at all..
 
I saw 2020 once, but it was years ago.
So at least two models out of how many receivers ever sold didn't have dial glass. Not sure how that rates on the rarity scale since there must have been hundreds of receiver models through the years.
Seems like it would attract dust and hold dust in the little channel the "pointer" slides along?
 
I have a 2020 and a 2040. Yes the 2020 has dial glass. The 2040 does not. The 2040 walks all over the 2020. Unlike the 640,840 and 1040. The 2040 has and all discreet amplifiers. Where as the lower models all have STK " chip amplifiers".
 
So I bought a Yamaha CR 840 at a garage sale for $30.00. Original owner hadn't used it in decades but I immediately fell in love with how cool it looked and
knew Yamaha had a decent reputation.

I applied deoxit to all knobs/pots etc, and thoroughly
dusted upon getting it home. I was running CD's
through it for a number of weeks and it was sounding
fantastic. As is my luck, as soon as I purchased an LED kit on eBay to replace burned out bulbs, the receiver began to give me grief.

Midway through an album, the left channel would
suddenly grow faint. I'd check connections, swap
speakers, try different inputs, etc. to no avail and would dumbfoundedly turn it off. The following day, I'd come back to it, and the other channel would now be incredibly faint.

After reading up on these receivers I learned these
used "output modules" (?) rather than discrete output
transistors making them prone to overheat and die.
Soooo… do any of y'all have experience with these? Is this unit worth paying a technician to diagnose the problem and a repair? Or should I cut bait now and list it on ebay for parts and move on?
 
Budgetphile said:
So I bought a Yamaha CR 840 at a garage sale for $30.00. Original owner hadn't used it in decades but I immediately fell in love with how cool it looked and
knew Yamaha had a decent reputation.

I applied deoxit to all knobs/pots etc, and thoroughly
dusted upon getting it home. I was running CD's
through it for a number of weeks and it was sounding
fantastic. As is my luck, as soon as I purchased an LED kit on eBay to replace burned out bulbs, the receiver began to give me grief.

Midway through an album, the left channel would
suddenly grow faint. I'd check connections, swap
speakers, try different inputs, etc. to no avail and would dumbfoundedly turn it off. The following day, I'd come back to it, and the other channel would now be incredibly faint.

After reading up on these receivers I learned these
used "output modules" (?) rather than discrete output
transistors making them prone to overheat and die.
Soooo… do any of y'all have experience with these? Is this unit worth paying a technician to diagnose the problem and a repair? Or should I cut bait now and list it on ebay for parts and move on?
Click to expand...

I don’t know what the cost is to repair the likely problem. If no one here chimes in, I would call your local service shop and see if they can give you some idea of what a likely repair may run. I would pay up to $300 to repair it.
 
If you get output from both channels it's unlikely that the STK modules is failing. They generally work,or they don't.

It is not uncommon to have to clean an older unit 2 - 3 times as after the first cleaning it may loosen other more stubborn imbedded debris. Be sure to get ALL switches and pots thoroughly.
 
Budgetphile said:
Midway through an album, the left channel would
suddenly grow faint.
Click to expand...

Flaky contacts in the protection relay would be my guess. If so, typically the sound would come back for a while if you crank up the volume. (Or, a bit more safely for your ears, tap on the relay. It's the black box on the circuit board, more or less behind the headphone jacks.)

If confirmed to be the relay, replacing it is the surest fix.

Budgetphile said:
"output modules" (?) rather than discrete output
transistors making them prone to overheat and die.
Click to expand...

My opinions: This is not a valid criticism. There is plenty of heat extraction. It's not unusual to find these receivers, with their original output modules, being used today - like yours, probably. I believe the vast majority of failures are the result of abuse, like shorted speaker wiring. Much of the bad press is due to the lack of quality replacement parts when failures do occur (and that is a valid criticism, though not really Yamaha's fault).
 
One thing to note, because that unit was designed with no dial glass you need to be careful you dont scratch the tuner dial if you attempt to dust or clean it. The material is very susceptible to scratching.
 
^^^^ Even worse......the finish on those units are notorious for flaking off, use extreme caution: mild soap / warm water on a soft rag
 
Bill S said:
One thing to note, because that unit was designed with no dial glass you need to be careful you dont scratch the tuner dial if you attempt to dust or clean it. The material is very susceptible to scratching.
Click to expand...
Two words...

Canned air. That area looks to be a good candidate for just blowing out the dust from time to time to make sure it is all happy.
 
Budgetphile said:
So I bought a Yamaha CR 840 at a garage sale for $30.00. Original owner hadn't used it in decades but I immediately fell in love with how cool it looked and
knew Yamaha had a decent reputation.

I applied deoxit to all knobs/pots etc, and thoroughly
dusted upon getting it home. I was running CD's
through it for a number of weeks and it was sounding
fantastic. As is my luck, as soon as I purchased an LED kit on eBay to replace burned out bulbs, the receiver began to give me grief.

Midway through an album, the left channel would
suddenly grow faint. I'd check connections, swap
speakers, try different inputs, etc. to no avail and would dumbfoundedly turn it off. The following day, I'd come back to it, and the other channel would now be incredibly faint.

After reading up on these receivers I learned these
used "output modules" (?) rather than discrete output
transistors making them prone to overheat and die.
Soooo… do any of y'all have experience with these? Is this unit worth paying a technician to diagnose the problem and a repair? Or should I cut bait now and list it on ebay for parts and move on?
Click to expand...
Don't jump in your mind straight to outputs. It could be something in the preamp section. Try running the balance from side to side. Try turning volume up and then down. Try pushing input switches a few times. Speaker selector. Etc.

Or it could also be something like the speaker relay and often times turning the volume up and then down again will show that to be the culprit.
 
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