Yamaha DSBG thread

brutal

YamaHoarder
Subscriber
I get a lot of questions and PM's regarding the "Dreaded Sony Bond Glue" issue, a.k.a. DSBG so I thought I'd start a thread dedicated to the usual and customary parts list for each amp, etc., we've all run into.

I'll start with the most commonly asked about amp, the Yamaha M-80, and try to build from there. If everyone contributes, we can make this a nice reference thread for DIY repair. Please add to the thread, I will try to combine them all into the first post. We can expand the R&R items to include values and descriptions if anyone desires. Let's try to keep this as a reference for parts and basic R&R requirements, and not clutter up the thread with ongoing repair help. Please start your own thread if you need assistance with a repair.

Yamaha M-80:
Detailed M-80 Thread

  • C111, C112 | 220uf/6.3V
    • I use Nichicon KZ's if possible, Any quality audio grade cap OK. FG's seem to be plentiful lately (March 2015), you may have to step up +1 or +2 voltages.
  • C162, C163 | 1000uf/100V
    • I use Nichicon KW, KG, or FW, hard to find. (1-17-11) Digikey has FW in stock. Mouser had stock March 2015.
  • D119, D120
    • RD3.0EB2 3.01-3.22 20mA .5W - use any .5W 20mA 3V DO-35 Zener (1N5225B)
  • R125, 126
    • 390 Ohm .25W Carbon Film Flameproof (per schematic) 330 Ohm per parts list and pulls.
  • R137, 138
    • 1K Ohm .25W Carbon Film Flameproof
  • R233, 234
    • 430/470 Ohm .25W Carbon Film Flameproof (measure as the schem differs on these) Parts LIST shows 430
  • R123/229/231 - R124/230/232
    • 330K Ohm Carbon Film
  • Often R226
  • Often C123, 124
    • | 39pf 500V mica cap | WIMA, Panasonic or any quality polypro or pps film cap
  • Usually have to remove and clean the busbars and TR113, 114, 123, 124 and replace a whole grip of jumpers.
  • C164 is a 47uf/25V BIPOLAR cap, not the 100uf cap indicated in the schematic.
  • Watch out for the schematic errors, particularly for units over serial 2401. The schematic does not include the TSB66H. There's an updated schematic I made with the TSB on sportsbill. I'm going to try to find time to add the TSB66H to the PCB images. There are caps and resistors that are part of the TSB that are not in the SM PCB diagrams.

Link to Pics: http://www.audiokarma.org/forums/showpost.php?p=3433046&postcount=4

Multiple models DSBG Thread

Excellent newer post by member amr2 on repairs here: http://www.audiokarma.org/forums/showthread.php?t=591887
 
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Very much appreciated. Great pictures also. Found R226 open on mine this morning while cleaning up the glue. Still replacing all above components. Going with 3 watt R226, SM says 2 watt, pictures show 3 watt. D119, D120 badly corroded. All power transistors are good, completely removed heat sinks to clean, about 2 pounds of dust inside unit. All speaker terminal are good, not so brittle, probably wait on new binding posts.
 
Great info!

Hello,

Just wanted to thank you all for the great information on this thread.

I have an m-60 i have cleaned and didn't need to replace anything :music:

My m-80 is another story. I haven't used it much in fear of all the horror stories.
I opened it and it looks like the machine barfed the glue onto the board. It is everywhere. I am cleaning and replacing parts now. 2 diodes 14 resistors 4 caps and 2 mica's. I am so glad i read this thread and am doing the repairs BEFORE the amp blew up. Thank you all again.

Phil
 
Great information, they used this hard glue in the 640P's it upgrade, I scrape it off with an exacto knife or similar, once you start chipping away it comes off pretty easily.
 
Resistor values

Just an edit for the M-80:
R123/229/231 - R124/230/232 | 330 Ohm Carbon Film are 330k ohm
R125, 126 | 390 Ohm .25W Carbon Film Flameproof are 330 ohm.
Just finished mine and it sounds superb! I'll have pics to post this evening.
 
Just an edit for the M-80:
R123/229/231 - R124/230/232 | 330 Ohm Carbon Film are 330k ohm
R125, 126 | 390 Ohm .25W Carbon Film Flameproof are 330 ohm.
Just finished mine and it sounds superb! I'll have pics to post this evening.

Thanks, I misread the value on the 330K group.

As is often the case, the installed value may differ from the schematic due to production run changes or prior repairs. The schematic lists R125/126 as 390 Ohm. I honestly don't recall what they were in the four amps I redid.
 
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nice pics, the glue didnt look that bad when i first took my amp apart but then when it was told to me about the DSBG issue on here, i had it serviced. ill put up some pics when i take the cover off again. Although ive tinkered with everything my whole life (not in a dirty way at all.... i swear...) my amp being passed down to me (stolen) from my dad, i didnt want to have a go at it myself. id rather buy other amps that i can ruin and not worry about :D interesting thread though, lots of components i need to become familiar with. thanks!
 
I just wanted to say thanks to brutal for this thread, which helped me quickly figure out an issue with a C-65 I just bought. Luckily in my case the glue had not caused any corrosion but the glue joints had broken in transit, allowing the two small heatsinks on the transistors to break loose, and as they rattled around broke the solder joints on those transistors. I cleaned up the old glue residue, applied some fresh silicone glue and bolted the sinks down and re-soldered the joints, and now she's singing again. :thmbsp:
 
Hi everyone first post. Long story short I am the first owner of 3 Yamaha M-80s with the C-80 T-80 etc. I bought them in the Marine Corps in 1984 while stationed in Hawaii with Polk SDA SRS speakers which I still love. Although I have had them all in there original boxes in the garage for the last 12 years I thought it was time to rebuild them. They all worked when I packed them and moved from japan in 2001 So glad I didn't plug them in and found this thread. All three of them have the DSBG rot. One has the Lead on R226 completely gone with all the other damage seen in brutal's photos. I have ordered all the componets as suggested from this post that effect the DSBG area. My question is.......should I replace all the other 30 year blackgate Caps through out the whole amp and if so what is everybody using for replacements. I ask because I looked for C125,126,168 Electrolytic 100 uF 6.3V on Moser and could not find Nichicon KW, KG, or FW series replacements. What is everyone using? Thanks
 
Hi everyone first post. Long story short I am the first owner of 3 Yamaha M-80s with the C-80 T-80 etc. I bought them in the Marine Corps in 1984 while stationed in Hawaii with Polk SDA SRS speakers which I still love. Although I have had them all in there original boxes in the garage for the last 12 years I thought it was time to rebuild them. They all worked when I packed them and moved from japan in 2001 So glad I didn't plug them in and found this thread. All three of them have the DSBG rot. One has the Lead on R226 completely gone with all the other damage seen in brutal's photos. I have ordered all the componets as suggested from this post that effect the DSBG area. My question is.......should I replace all the other 30 year blackgate Caps through out the whole amp and if so what is everybody using for replacements. I ask because I looked for C125,126,168 Electrolytic 100 uF 6.3V on Moser and could not find Nichicon KW, KG, or FW series replacements. What is everyone using? Thanks

Welcome to AK!

Best to start a thread specific to your amp and undertaking. Step up in voltage to the next one or two levels (10-16v) and you'll probably be able to find something. Modern caps are smaller so fitment isn't generally an issue if you move up. I've gone to pretty much FG (easiest to source) or KZ (hard to source) or KW for audio caps, PM/PW for power series. KT are good for general purpose and are high temp.
 
Brutal

Thanks for alerting me to this problem, glue rot.

Carlson has done some very good videos and is worthy of recognition, he gives us a great glue rot video for our enjoyment.... here.

Worth a look.

Wash State a few miles from Vancouver is where his shop is located.

https://www.youtube.com/watch?v=yy8NS2zejhQ
 
A-1000

attachment.php
 
New devices also infected?

Attached is a picture of the power supply caps of the NP-S2000 network player. I am wondering if they have changed the formula of the glue or if it will produce the same problems after 15 years or so.
 

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Attached is a picture of the power supply caps of the NP-S2000 network player. I am wondering if they have changed the formula of the glue or if it will produce the same problems after 15 years or so.

That white glue, perhaps silicone based, has been used in all the new gear going back 25 years now without issue. Present in the MX-2000 released in 1988.

Likely Loctite 5145 silicone, but perhaps one of these other 2-part adhesives or a potting compound? http://www.digikey.com/Web Export/S...F/ledil-glue-down-guidelines.pdf?redirected=1

When necessary for fastening larger caps, I use black RTV adhesive/sealant.
 
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Thanks to this thread I've scraped away all the glue on all my M series amps that used it.
Luckily I found no corrosion on nearby resistors and hopefully none under the capacitors the glue was used.
Perhaps climate is the key?
 
M-45 and C-45 both seem to be working. Ive cracked the lids and found the evil stuff. Even though they're working I'm now in the know so the goo's gotta go. I dont see much on the 45's so ill start a new thread and post pics. I say both working but the C-45 has some intermittent cutout. I HATE intermittent. Usually when I first turn the system on I get no output. I jiggle the cd, tuner rca group and sound comes out again. Hints to a cold solder issue that may repair if I reflow the connections. Ill tear it down and start a new thread for that one too. Great stuff here in this thread and the forum in general. Thanks to all!
 
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