I would like to avoid shipping this for repair unless it's absolutely necessary. Is there a recommended repair shops page here? Looking for repair shop recommendations within a 200-300 mile radius of Los Angeles, CA?
I picked up a Yamaha B-2 VFet amplifier last year and it sounds wonderful, but sometimes I get distortion on 1 channel and sometimes the sound takes turns between the left and right channels for a second or two. This latter problem is normally at softer volumes, while the distortion is more at higher volumes, with for example, chords on a cello, that may have a hint of dissonance.
My Yamaha B-2 was slightly damaged (casing) when I received it due to the shipper's poor packaging, but everything worked fine at the time, but as I use it more, I am starting to notice that it does need some love soon.
I've called a few repair shops and some are very honest about whether they have worked with this particular amp, while others seem to use some sort of fear tactic. They keep me on the phone and make feel like if I don't bring it in right away to THEM, it's going to blow up.
I know this is a DIY site. I have built 2 of the ACAs, but I wouldn't be able to do that without the amazing step by step instructions on the site. I have the Yamaha manual, but I just don't trust myself with this. If I break something, I just broke my wallet.
Thanks! Any help is appreciated.
I picked up a Yamaha B-2 VFet amplifier last year and it sounds wonderful, but sometimes I get distortion on 1 channel and sometimes the sound takes turns between the left and right channels for a second or two. This latter problem is normally at softer volumes, while the distortion is more at higher volumes, with for example, chords on a cello, that may have a hint of dissonance.
My Yamaha B-2 was slightly damaged (casing) when I received it due to the shipper's poor packaging, but everything worked fine at the time, but as I use it more, I am starting to notice that it does need some love soon.
I've called a few repair shops and some are very honest about whether they have worked with this particular amp, while others seem to use some sort of fear tactic. They keep me on the phone and make feel like if I don't bring it in right away to THEM, it's going to blow up.
I know this is a DIY site. I have built 2 of the ACAs, but I wouldn't be able to do that without the amazing step by step instructions on the site. I have the Yamaha manual, but I just don't trust myself with this. If I break something, I just broke my wallet.
Thanks! Any help is appreciated.
This is the kind of intermittent thing that a typical repair shop, that has to move gear in and out quickly,
may not be able to deal with to your satisfaction. And the fear tactic is a bad sign for sure.
That said, there are a lot of switches and pots in the circuit, and the problem could be as simple as a dirty contact.
Do you know how to use contact cleaner properly?
https://www.hifiengine.com/manual_library/yamaha/b-2.shtmlhttps://www.amazon.com/Hosa-D5S-6-D...ocphy=9018935&hvtargid=pla-382003658380&psc=1
may not be able to deal with to your satisfaction. And the fear tactic is a bad sign for sure.
That said, there are a lot of switches and pots in the circuit, and the problem could be as simple as a dirty contact.
Do you know how to use contact cleaner properly?
https://www.hifiengine.com/manual_library/yamaha/b-2.shtmlhttps://www.amazon.com/Hosa-D5S-6-D...ocphy=9018935&hvtargid=pla-382003658380&psc=1
I've heard about the usage of deoxit but have never used it myself. The extent of my electronics knowledge is building the ACA and soldering background is from building RC cars in my youth. I am very systematic in my approach to any project so taking the switches apart and cleaning is a viable option... I just didn't think I would be doing this on something that I probably can't find parts for anymore in the event that I mess it up.
It's unlikely that the switches and pots are sealed, so taking them apart or removing them
from the board would probably not be necessary. And if it were, paying a tech to do it
would be far too expensive. The mfr has some good videos on their site.
https://caig.com/deoxit-d5-instructional-video-1-cleaning-pots/https://caig.com/how-to-clean-vintage-audio-controls-with-deoxit/It's important to remember that you should only use a very small amount at one time,
and repeat only if necessary. Only really bad grunge will need more than one brief spray,
after which you exercise the switch or pot through its full range several times.
And here are few more videos made by others.
from the board would probably not be necessary. And if it were, paying a tech to do it
would be far too expensive. The mfr has some good videos on their site.
https://caig.com/deoxit-d5-instructional-video-1-cleaning-pots/https://caig.com/how-to-clean-vintage-audio-controls-with-deoxit/It's important to remember that you should only use a very small amount at one time,
and repeat only if necessary. Only really bad grunge will need more than one brief spray,
after which you exercise the switch or pot through its full range several times.
And here are few more videos made by others.
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I noticed a lot of these guys are spraying pots and stuff while it's still in the case. It looks like it drips some dirty liquid, do you recommend taking these out of the case to spray Deoxit into them?
I opened it up and nothing looks obviously off. I have my Deoxit ready to go, but I'm debating on whether I should try to take some things apart so I don't get deoxit dripping on other stuff. From the feedback I've gotten regarding the issues I'm having, it sounds like I should try cleaning the switches and pots on the front face first.
Attachments
I noticed some corrosion various places (e.g. on top on the TO-3 transistors).
But also, on fuse holders contacts. The "green stuff" is oxidation from the copper. I would remove the fuses and then clean the contacts and fuses to be sure there is not a bad connection. There could be other connections that needs a clearing. I think overall the amp needs a "cleaning" inside.
But also, on fuse holders contacts. The "green stuff" is oxidation from the copper. I would remove the fuses and then clean the contacts and fuses to be sure there is not a bad connection. There could be other connections that needs a clearing. I think overall the amp needs a "cleaning" inside.
I recommend you to look for a good repair shop, dont use Deoxit.
Looking at the fotos, I see many bad (greenish) contacts, for example on the fuse holders. It is better to clean all this bad contacts mechanically and not chemically.
I am not sure, it the big electrolytics are glued to the print or if some of them already leaking. Anyway they are old and should be replaced.
Looking at the fotos, I see many bad (greenish) contacts, for example on the fuse holders. It is better to clean all this bad contacts mechanically and not chemically.
I am not sure, it the big electrolytics are glued to the print or if some of them already leaking. Anyway they are old and should be replaced.
Good eye! It is pretty dusty inside. I was actually looking for compressed air, unless there is a better way to get all this dust out of here.
The B-2 is a great amp. I have two B-2s and would love to have two more.
I hope you find repairshop, but if you can't, here is my advice.
Regarding the symptoms of your amp, my first recommendation would be to replace the fuses.
There are four fuses on the power supply board.
The fuse holder needs to be cleaned, but the fuses should also be replaced.
The specifications of the fuses you replace should be the same as the ones you removed.
If you have the soldering skills, the next step is to replace the relays. There are two in the center of the power supply board.
OMRON LY20DC12 can be used as a replacement.
Good luck.
I hope you find repairshop, but if you can't, here is my advice.
Regarding the symptoms of your amp, my first recommendation would be to replace the fuses.
There are four fuses on the power supply board.
The fuse holder needs to be cleaned, but the fuses should also be replaced.
The specifications of the fuses you replace should be the same as the ones you removed.
If you have the soldering skills, the next step is to replace the relays. There are two in the center of the power supply board.
OMRON LY20DC12 can be used as a replacement.
Good luck.
Wow, thanks for taking the time to point stuff out! I have been watching some restoration videos and the caps are indeed glued on here from the factory. At some point, I plan to have this restored with some upgrades, but I was hoping to at least attempt to do what I can and see if I can get the sound from skipping from side to side and the distortion I get some times as well. I know I can ship it to a repair shop, and I have a person in mind already, but I'm just a little hesitant because my this B-2 was a little banged up from getting it shipped to me when I bought it. The buyer just refused local pickup when he was only like 40 minutes from me.
Thank you yoshida! Any recommendations for cleaning the fuse holders? sandpaper?
I got some good soldering practice as a child with R/C cars and most recently building 2 ACAs... but de-soldering components on a pc board, not so much.
I just tried to pull off one of the fuses and wow, it feels like it soldered in place. Maybe I can see what the rating is on these without pulling them off.
Your B-2 looks almost original. Please take good care of it.
I would use isopropyl alcohol (IPA) to clean the fuse holder. If the rust is severe, I would use fine sandpaper. After the paper, wipe with IPA.
The two fuses near the MainCap should also be replaced.
The brown stain around the capacitor is glue.
It would be better to replace the electrolytic capacitor as well, but it may not be related to your symptoms.
I would use isopropyl alcohol (IPA) to clean the fuse holder. If the rust is severe, I would use fine sandpaper. After the paper, wipe with IPA.
The two fuses near the MainCap should also be replaced.
The brown stain around the capacitor is glue.
It would be better to replace the electrolytic capacitor as well, but it may not be related to your symptoms.
Well i did some cleaning of the contacts and the heads of the fuses and shot some deoxit in the speaker gain pots, not that i was hearing anything scratchy when i used them. From what i have seen on some restoration videos, signal does goes through them, so i figured, why not?
I'm testing for the distortion with the speaker gain turned up 100% on Channel A. So far so good! I might have to hook this up to my main speakers to test some more.
I noticed one of my vu meter lights are out. If i were to replace it, do i need to desolder this thing? The bulb doesn't just pop out? The pictures shows both inside ones being out, but the right side came on after a few minutes.
I'm testing for the distortion with the speaker gain turned up 100% on Channel A. So far so good! I might have to hook this up to my main speakers to test some more.
I noticed one of my vu meter lights are out. If i were to replace it, do i need to desolder this thing? The bulb doesn't just pop out? The pictures shows both inside ones being out, but the right side came on after a few minutes.
