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Yamaha M-70 Thread

Discussion in 'Yamaha' started by Bratwurst7s, Jan 17, 2018.

  1. brutal

    brutal YamaHoarder

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  2. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Got no idea how that works. Twilight zone. I only wanted to make known that I read your thread and found it useful/informative.

    Cheers,
    James

    edit: My mistake. I accidentally mixed up and added the wrong link. My apologies, nothing bad intended. Corrected. Thanks for letting me know.
     
    Last edited: Jan 28, 2018
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  3. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Take a look at the first post in this thread by Chip Chester...
    http://audiokarma.org/forums/index.php?threads/counterfeit-part-detection.805679/#post-11258492

    Interesting article about spotting fakes.

    Just out of curiosity I just grabbed some old outputs removed from some old amps and kept, because I don't know why I kept them. ;)

    Anyway, here is a before and after photo. In between I scrubbed them vigorously with acetone and a rag. The only thing the acetone did was to make them nice and clean.

    DSC04883.jpg DSC04884.jpg

    I think that with good quality original parts the marking will hold up just fine to a light swipe with acetone. That 1913A wiped clean with only the slightest effort in a single swipe. I have little confidence that the drivers are genuine and think that the outputs are questionable. I don't like the way that their marking is on top of that black field applied to the face.

    Cheers,
    James
     
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  4. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Continuing with subs, Zener diodes:

    RD4.7E: I haven't found any AK references to this one. Looking at the datasheet it looked like this zener without any suffix after the "E" would be the plain "B" version, nominal= 4.69v. I chose a BZX55B4V7-TR
    https://www.mouser.de/ProductDetail...GAEpiMZZMtQ8nqTKtFS/KE3JtglsWdkK68sC7o%2bER0=

    RD6.2EB2: I found several references, pointing to a TZX6V2D-TR and a 1N5233BTR. But looking at the datasheet it looks to me that the nominal for the "EB2" would be 6.115v. So I ordered both the TZX6V2D-TR and TZX6V2C-TR, with the latter giving a nominal 6.15v. I can decide later which to use.
    http://audiokarma.org/forums/index....-my-yamaha-cr-2040.476511/page-2#post-6962658
    http://audiokarma.org/forums/index....ant-power-on-relay-issue.430588/#post-6287783

    WZ120: Found a reference calling for a BZX55B12-TAP and that's what I ordered. The only datasheet that I've been able to find doesn't show any variations, only a flat 12v.
    http://audiokarma.org/forums/index....ant-power-on-relay-issue.430588/#post-6287783

    WZ130: Found no AK references. I simply ordered a BZX55B13-TAP.

    HZ24: Found several references calling for a TZX24B-TR and 1N5252. I made the WAG in this case that with no suffixes stated in the SM that going with a HZ24-2 with a nominal 24.15v would be correct and ordered the TZX24B-TR which gives exactly that 24.15v.
    http://audiokarma.org/forums/index....yamaha-m-65-for-a-friend.646953/#post-8616509
    http://audiokarma.org/forums/index....restoration-advice.712908/page-4#post-9715873

    Cheers,
    James
     
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  5. zaibatsu

    zaibatsu Well-Known Member

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    Yeah fair call, not saying you're wrong but I've wiped text from genuine Toshiba devices with acetone (although only faded it, certainly not all gone in one swipe like you experienced), and in fairness the drivers are Matsushita devices so they may have used a different ink. I might have some genuine versions of those drivers here myself, if I can find them I'll give them a swipe to see / compare to yours.

    The only point I was making is that printing wasn't always consistent / perfect, even on genuine devices, and just because everything "looks" perfect doesn't make it genuine either (obviously - our friends across the sea are getting better and better at visual replicas). I think the only way to really know is with a curve tracer, or on occasion, cutting the device and inspecting the die.

    In any case, if you're replacing all the outputs, you may as well replace the drivers.
    Also given the effort you're going to (or no doubt will) elsewhere, seems best to stay on the safe side.
     
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  6. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    It's a good point. And I could easily be wrong, most likely am but I'll be ordering those replacements that you recommended from Bdent in a couple of days. And I also have 8x of the MJE15032G/15033G on hand.

    Perhaps I've just seized on the theory that someone replaced the drivers and outputs with fakes because of some problem and then couldn't get it working right, resulting in freaking out and severing the high power traces. Just a theory but it might explain things.

    Cheers,
    James
     

     

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  7. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    OK. While I wait for parts, inspiration and money I'll start with some transistor subs. I leaned a heavily on rottalpha's Transistor Substitution thread for many of these. See post#33.
    This is an initial list. I have not cross-checked most of these with datasheets yet! And that is of course within the limitations that I'll understand what I'm looking at.

    2SA913A: 2SA1873 or MJE15033G. See above posts. :)
    2SC1913A: 2SC4793 or MJE15032G. See above posts. :)

    2SA1015: KSA1015.
    2SC1815: KSC1815.
    2SA1145: KSC1013YTA or KSA1381ESTU.
    2SC2705: KSC2383 or KSC3503DS.
    http://audiokarma.org/forums/index....-au-x901-transistor-sub.783261/#post-10771415
    http://audiokarma.org/forums/index.php?threads/yamaha-a-1000-repair-and-info-thread.766289/page-9#post-10684319
    2SC1509: KSC2383YTA or KSC2690AYS.
    2SA777: KSA1013YTA.
    http://audiokarma.org/forums/index.php?threads/technics-sa-5760-one-channel-repair.801240/page-2#post-11171235
    http://audiokarma.org/forums/index.php?threads/1180dc-where-to-start.800551/#post-11108300
    http://audiokarma.org/forums/index.php?threads/kenwood-kr-3090-transistor-and-resistor-replacement.794187/#post-10982190
    2SB649: KSA1220A or KSB546Y or TTA004B.
    2SD669: KSC2690A or TTC004B.
    http://audiokarma.org/forums/index.php?threads/cr1020-restoration-guidance.798122/page-8#post-11227950
    http://audiokarma.org/forums/index.php?threads/2sb649-2sd669-replacement.777027/#post-10885969
    http://audiokarma.org/forums/index....toration-guidance.798122/page-8#post-11227950
    2SA673: KSA708C or KSA1220A.
    http://audiokarma.org/forums/index.php?threads/yamaha-a-1-transistor-id.794515/#post-10989455
    http://audiokarma.org/forums/index....y-guidance-needed.783648/page-3#post-10867036
    http://audiokarma.org/forums/index.php?threads/the-ka-9100-restoration.783947/page-4#post-10879335
    2SC2235: KSC2316Y. Another one where I had found a reference that is now eluding me. So mark this as questionable.


    My beer is empty. That's all for tonight. More tomorrow.
    James
     
    Last edited: Feb 12, 2018
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  8. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    2SA1169: 2SA1494. I found quite a few different references all saying these are the best subs.
    2SC2773: 2SC3858.
    http://audiokarma.org/forums/index....s-up-but-with-protection.502763/#post-6529795

    I just placed an order with Bdent. I probably won't be a regular customer there because of their brutally high international shipping charges. The lowest shipping that I could select was $54.77 on top of a $106 order. Even FedEx is cheaper. That hurt.

    Anyway I ordered 10x of the 2SA1873/2SC4793, 4x 2SA1494/2SC3858 and 8x of the 2SC1186/2SC2837 (these I ordered in spite of them probably being the base hFE versions).

    I saw this post yesterday in DIY and it caused me to also order 4x 2SA1493/2SC3857, just because.
    http://audiokarma.org/forums/index.php?threads/driver-transistors.807198/

    Cheers,
    James

    edit: I got confused again. The 2SA1494/2SC3858 I ordered at DigiKey with some other stuff.
     
    Last edited: Jan 30, 2018
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  9. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    Looks like you have all bases covered with your transistor subs.
     
  10. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Sorry for taking so long to answer. I've been in and out a lot this week doing prep work for an upcoming hospital visit next week.

    I'm getting there concerning subs. I'll try to post some more later today. My Mouser order arrived yesterday so I'm starting to get parts on hand now. I won't actually start working on the amp until I have most of what might be needed here. I'm trying to use some patience and not get in a rush. Heh heh, not always easy to do.

    When your board burned did you have to replace anything on the lower sub-board? Did you replace the trim pots? Triacs etc? I still need to check out Bourns or Vishay trim pot replacements. I just started making a list yesterday. I'm going to try to get them ID'd and get the last of my parts ordered before my OP next week. Trim pots, metal film and some more MOX resistors, the 15 amp bridge rectifier that I should have ordered instead of the 25A one and a few other things.

    https://www.mouser.de/ProductDetail...GAEpiMZZMtQ8nqTKtFS/MRt2/0z7BctEOZfVDsE%2bxM=

    My Bdent order just left New York. I don't know if that is by ship or plane. But it will probably go to Customs here and then I get to pay another 19% tax on it. That includes being taxed for the shipping cost.

    Cheers,
    James
     
  11. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    No need for sorry, our audio interests are a minor priority in comparison to other things in life. Hope all goes well for you next week :thumbsup:.

    I didn't have to replace the trim pots as all parts on the upper part of that top board were untouched in the disaster. The components on the lower board however were a different story, l replaced most things on this board including the triacs, regulators, caps and resistors, l do remember checking every single component on the power supply. Just going off memory here, please correct me if l am referring to the wrong board. If you list the numbers maybe l can help, l didn't write down the parts l used (l should be doing this on all units l repair, arggh) but it might come back to me or l could look up one of my parts orders if helpful?
     
    Last edited: Feb 1, 2018

     

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  12. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Yes, it would be very helpful. And yes, we are talking about the same board. I'll post the part numbers etc a little later today. When I get done with this project I'll be entering all of the parts into a spreadsheet and posting it for future use by other members as I did for my CX-1 etc.

    As for next week, Thanks! it's just a hernia OP, shouldn't be a big deal. Makes me feel like I'm not as young as I used to be tho. ;):eek:

    Cheers,
    James

    edit: Just curious. What time of day is it down there? 12:50 here and snowing.
     
  13. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    It's 2° and snow/raining here. Ugh. I want spring!

    DSC04890.jpg

    Cheers,
    James
     
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  14. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    OK, the items on the lower Control C-2 board that I'm puzzling over are:

    SCR601: SFOR3G42 Thyristor.
    SCR602: SMOR5G42 Triac.
    SCR603: AC16DGM-L Triac.
    TR606: TLP508 (V) Photo Coupler.

    The only AK search results that I've been able to find lead here:
    http://audiokarma.org/forums/index....-experts-out-there.650961/page-2#post-8671779

    I have no reason to think that they are bad in my amp but am interested nonetheless to try to find viable subs.

    The Yamaha IC601 chip, iG04080 chip I'm guessing is unobtainum from what little I've been able to find.

    Cheers,
    James
     
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  15. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    I think we all feel like this at times, all the best with the op.

    We are 10 hours ahead of you at the moment with daylight saving time.

    Yeah very cold indeed, the snow looks nice though. Could trade you some high 30's, low 40's weather? Has cooled down this week though.

    This document is very good for cross referencing these parts, all of the littlefuse numbers come up in Mouser search. Not sure on the photo coupler though, may require further investigation.
    http://www.littelfuse.com/~/media/e...s_sidacs_rectifiers_cross_reference_guide.pdf

    I think it would be hard to find a replacement apart from a secondhand unit?
     
  16. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Oh! Very nice. Thanks very much, that was very helpful. None of them are very expensive either.

    Looks like:
    SCR601: SFOR3G42 0.3A Thyristor = S4X8ES. (except that I'm not sure which gate current would be the correct one.)
    https://www.mouser.de/ProductDetail/?qs=15vVnywjPfgsqGnkJ5bM2A==
    https://www.mouser.de/Search/Refine.aspx?Keyword=S4X8ES
    SCR602: SMOR5G42 0.5A Triac = LX807DE.
    https://www.mouser.de/ProductDetail/Littelfuse/LX807DE/?qs=sGAEpiMZZMuAO0%2bGuNbnQkuvYQs8s5xk69Rw05VSo/g=
    SCR603: AC16DGM-L 16A Triac = Qxx16xx. (again, not sure which gate current, have to find a datasheet and compare).
    https://www.mouser.de/Semiconductor...xx-Series/_/N-ax240?P=1yxz803Z1yx67s1Z1z0z63x

    I've started searching for a datasheet on the photo coupler.

    Yes, it looks like a parts donor might be the only choice for the IC. I'll have to start looking into if all of or which of the X-PSU models use it. So far I see that the B-6 does, that'd be a pretty expensive donor. I'll have to start collecting SM's for the different A-series (A-x60 at least, not sure about the A-x50's) integrated amps with the X-PSU. They come up pretty often on ebay in non-working condition.

    Cheers,
    James

    edit: WARINING! The subs that I chose for SCR601 & SCR692 work but their pin-out is different than the original parts. Legs 2 & 3 must be position swapped and the parts installed 180° from the originals. See post #157!!!
     
    Last edited: Mar 31, 2018
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  17. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Found a datasheet for the SFOR3G42 thyristor. 200µA gate trigger current. So that first S4X8ES listed above would work.
    Found a datasheet for the AG16DGM-L. Shows 30mA and 80mA, I'm still trying to figure out which is applicable.

    Cheers,
    James
     

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  18. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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  19. Oldsansui441

    Oldsansui441 AK Subscriber Subscriber

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    No worries. You have been busy, looks like you have all the part numbers sorted. Yes trying to get a cheap donor for that ic would be hard, l think the A-760 was the lowest model with the X power supply but l have no idea if it also utilises this same part.
     
  20. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Amplifier Archaeology. Kinda fun sometimes.

    James
     
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