Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Dec Fri 15, 2017 2:57 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 14 posts ] 
Author Message
 Post subject: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 1:15 am 
Member

Joined: Mar Fri 27, 2009 8:57 pm
Posts: 473
Location: Alexandria Louisiana
I have a Yamaha R-300 receiver that only plays on left channel. The stereo power amp is STK-2030. I do not see any pin designations on the unit at all. There is a total of 16 pins, but no affiliation which pin is which? Don't know if they are numbered from left to right, ot right to left? Cannot find any info regarding pin designations either. It appears half of it is designated to Left channel, the other half to Right channel. On the schematic there shows no pin 4 at all, which would be the Left channel. My main question is where would one go first; voltage checks? There are voltages listed, but without knowing what pin is which, I find it difficult to pursue the voltage checks? Your thoughts please are welcome. Thanks, Carl-Louisiana


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 2:57 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 16825
Location: Albuquerque, NM 87123
The service manual is on hifiengine. You need to first resolder all the pins on the 2030.

Pins 5 and 12 are output; 1 and 10 are input; 6 and 11 are -37 volts DC; 2 and 15 are + 37 volts DC.

If resoldering doesn't help you need to scope the inputs; the pre-amp STK-3042II may be bad.


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 8:54 am 
Member

Joined: Mar Fri 27, 2009 8:57 pm
Posts: 473
Location: Alexandria Louisiana
First, I don't have a scope to do that. Second, there are no markings on the STK 2030 to indicate which pins are what number? I can see on my schematic which ones are input, output, etc., on both, just don't know about which pin is which without turning the unit on, or tracing from caps, etc. to each of the pins. I would be nice if they were marked; it would be easier. I most likely am going to have to do by voltage checks,, and go from there, on both the STK 2030, and the STK 3042. Thanks Carl-louisiana


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 9:55 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 10969
Location: Mpls, Minnesota
Looking at the front of the chip, pins pointing down, they are numbered 1-16 from left to right.

Dave


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 2:17 pm 
Member

Joined: Mar Fri 27, 2009 8:57 pm
Posts: 473
Location: Alexandria Louisiana
Thanking you for your response. Does that include both the STK- 2030 and the STK-3042 ll? That does help!!! Thanks, Carl-Louisiana


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 3:44 pm 
Member

Joined: Mar Fri 27, 2009 8:57 pm
Posts: 473
Location: Alexandria Louisiana
Have cleaned all the controls with no change in status. A couple of observations though after turning it on, tuning in to a station on FM; left channel lights up as expected, right channel did not. Upon turning the power off though, noticed that the right channel light briefly flashed on , and then took the top off, noticed that the STK-3042ll was slightly warm, but the STK-2030 was cold to touch, not even warm at all, and one would think it should have been warm, or even warmer than the STK-3042ll. Again, your thoughts regarding the latest observations? Will procede with voltage measurements then, unless anyone has a better idea how to go forward. Thanks, Carl-Louisiana


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 5:57 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 359
Location: Manchester, NH
http://pdf.datasheetcatalog.com/datashe ... 3654_1.pdf

This may help --

Griz


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Wed 18, 2017 7:26 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 16825
Location: Albuquerque, NM 87123
YOU NEED TO RESOLDER THE PINS ON THE 2030.

Those 3042s run hot; that's why they fail sometimes.

Without a scope it will be difficult to tell if the 2030 is bad, or the 3042.


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Oct Tue 31, 2017 1:32 pm 
Member

Joined: Mar Fri 27, 2009 8:57 pm
Posts: 473
Location: Alexandria Louisiana
Not having a scope to test the 2 amp ic's, I went ahead and checked the voltages on the STK-2030. The first go around it appeared the voltages were real close to schematic, so decided to try them again. While checking pin no. 11, the original slo-blo fuse blew. I have removed the bridge rectifier, and it checks out ok. I now plan on replacing the 2 Amp IC's, replacing the fuse, and putting it through a variac, or should I be concerned that some other component was compromised when the fuse blew? Thanks, Carl-Louisiana


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Nov Sun 05, 2017 4:15 pm 
Member

Joined: Mar Fri 27, 2009 8:57 pm
Posts: 473
Location: Alexandria Louisiana
I am replacing both the STK-2030, and the STK-3042 ll. I have pulled the bridge rectifier and it checks out ok. Now, once I re-solder that back in place, I plan on using a new Variac to power the receiver up, and see what happens now that I have the appropriate 3A/250V slo-blo fuses. The fuse blew when checking the STK-2030, and all I had was a fast acting 3A/250V fuse, and it blew also. My question is how rapidly should I raise the voltage on the Variac at a time (Voltage) ? Thanks, Carl-Louisiana


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Nov Sun 05, 2017 7:05 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 16825
Location: Albuquerque, NM 87123
You need to monitor AC current. That receiver should not draw anywhere near 3 amps with no audio out. If it draws a lot of current with the STK2030 installed then it is probably bad.


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Nov Sun 05, 2017 9:37 pm 
Member

Joined: Mar Fri 27, 2009 8:57 pm
Posts: 473
Location: Alexandria Louisiana
Johnnysan, please check your PM's. I have a couple of questions for you please. Thanks, Carl-Louisiana


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Nov Wed 15, 2017 2:06 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 17979
Location: Warner Robins, GA
zenith1944 wrote:
I am replacing both the STK-2030, and the STK-3042 ll. I have pulled the bridge rectifier and it checks out ok. Now, once I re-solder that back in place, I plan on using a new Variac to power the receiver up, and see what happens now that I have the appropriate 3A/250V slo-blo fuses. The fuse blew when checking the STK-2030, and all I had was a fast acting 3A/250V fuse, and it blew also. My question is how rapidly should I raise the voltage on the Variac at a time (Voltage) ? Thanks, Carl-Louisiana


I had this exact same receiver with the exact same problem.

If you have not already done so RESOLDER the pins on the 2030 like has been mentioned twice before me.

That will fix your problem and if it doesn't then replace it after ensuring there are no other component failures.

I also would suggest finding one or several (depending on size) of those stick on IC chip heatsinks and put them on the 3042 which might help it to run a bit cooler.


Top
 Profile  
 
 Post subject: Re: Yamaha R-300 receiver
PostPosted: Nov Tue 28, 2017 1:59 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 17979
Location: Warner Robins, GA
One thing I recommend doing is this.

1. Take one of the warm white LED fuse bulbs Parts Express sells
2. Desolder the end caps.
3. Remove the original bulb.
4. Cut a slice out of the green bulb cover.
5. Attach it using super glue to the dial where the bulb shines through ensuring the whole dial edge is covered.
6. Wire the LED in to where the original bulb connected using a resistor to initially put the voltage at 8Vdc.
7. Position the bulb for maximum dial brightness.
8. Epoxy in place.
9. Adjust resistor value for desired dial brightness.

Produces a slightly lighter shade of green that in my opinion goes better with the silver face.

Also you won't have to worry about the bulb going out and trying to find a replacement.

Unfortunately I have no pictures of it to show.


Top
 Profile  
 
Post New Topic Post Reply  [ 14 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: beat_truck, Exabot [Bot], Sean and 5 guests



Search for:
Jump to:  


















Privacy Policy :: Powered by phpBB