Yamaha A-1000 Repair and Info Thread

It's better if you list the transistor name to figure out substitutes, but I think I know which ones most of those are from memory.
Let me know if I missed anything.

Outputs:
2SA1333 -> 2SA1494 (bdent, digikey, chip1stop)
2SC3370 -> 2SC3858 (bdent, digikey, chip1stop)

Drivers:
2SA1306 -> 2SA1837 (bdent only)
2SC3298 -> 2SC4793 (bdent only)

Predrivers and bias generation (not compensation):
2SA1145 -> KSA1013, or optionally KSC3503 (mouser, etc)
2SC2705 -> KSC2383, or optionally KSA1381 (mouser, etc)

Bias compensation transistor:
2SD400 -> BD135, fairchild (mouser, etc)

Notes:
  • The KSA1381 / KSC3503 are slightly closer matches (via avionic), but they use a different package so you have to modify the legs to fit. I cut them down the middle with cutters to halve their width and they fit perfectly but if you want to avoid the hassle just get the KSA1013 / KSC2383 which match factory packages and also work fine.
  • BD135 is my suggestion for the compensation transistor, I matched this one myself since I feel the TO-126 screwhole package (along with its thicker more durable legs) is important to avoid this problem in the future. This is the closest match I found in this package, alternatively at least from my numbers KSD882 should also be a match. I'd take BD135 as first choice. Alternatively you can just get another 2SD400 (bdent probably have it) but I'd advise against that for obvious reasons.
  • Your cement resistors are likely fine, especially if the other channel's values match. I found those are tricky to measure, and while they do fail in a lot of amps along with the outputs, in these ones in my experience they live through it fine. If you want to buy them anyway though, Vishay CP 0.22Ω at mouser.
  • Mouser sells everything except for the drivers (which are no longer made, if you order from bdent I'd grab a couple extras just because soon they won't exist at all) and outputs.
  • For flameproofs, use the Yageo FRM-25 series. FRM-25 33Ω at mouser for example.
 
zaibatsu said:
It's better if you list the transistor name to figure out substitutes,
Click to expand...

I'm sorry about that. I was so excited to have made some progress after not being able to get anything done this last week that I didn't even think to put the part numbers up.:oops:

It will take me a bit to go through you post; that was a lot of time in research on your part and I appreciate it. :biggrin:
 
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tmsears said:
...A few minutes go by, and I hear the sizzling, crackling noise. I turn my head think, "what the hell?", just in time to see a resistor, R230, Light up like a white Christmas tree light...
Click to expand...
tmsears said:
Here is the list of everything that tested bad:
TR128
TR130
TR140
TR158
TR160
TR172
Click to expand...
It's possible that I've missed something, but are you 100% certain that TR142 (item 10 in the picture or the equivalent item on the other heatsink) is fully-functional?
It probably took a beating when R230 lit up and you've stated that TR130 & TR160 are bad. It's also the complement of TR140 (with R230 between them) and you've stated that it's bad.

Yamaha_A1000_TR142.jpg

tmsears said:
...
R264*
R268*

* These tested iffy. They tested at 0.16k instead of 0.22k -but- so did the resistors on the other channel, which I removed and tested to verify.
Click to expand...
That's 160R (or 160 Ohms)! :wtf: They should measure less than 1R (or 1 Ohm).
Set your meter to the lowest resistance range available and measure again. The 'k' (for kilo) designator is inappropriate for this measurement (I'm bustin' chops...). :blah:

Good Luck!
 
Hello Hamish!

The k is an error on my part. I will correct it. "ohm was what I was going for, but I have been ill lately.
As for TR142, I just tested it again to be sure, but it seems ok. I will probably change it anyway, for the reasons you've stated. :)
 
zaibatsu said:
It's better if you list the transistor name to figure out substitutes, but I think I know which ones most of those are from memory.
Let me know if I missed anything.

Outputs:
2SA1333 -> 2SA1494 (bdent, digikey, chip1stop)
2SC3370 -> 2SC3858 (bdent, digikey, chip1stop)

Drivers:
2SA1306 -> 2SA1837 (bdent only)
2SC3298 -> 2SC4793 (bdent only)

Predrivers and bias generation (not compensation):
2SA1145 -> KSA1013, or optionally KSC3503 (mouser, etc)
2SC2705 -> KSC2383, or optionally KSA1381 (mouser, etc)

Bias compensation transistor:
2SD400 -> BD135, fairchild (mouser, etc)

Notes:
  • The KSA1381 / KSC3503 are slightly closer matches (via avionic), but they use a different package so you have to modify the legs to fit. I cut them down the middle with cutters to halve their width and they fit perfectly but if you want to avoid the hassle just get the KSA1013 / KSC2383 which match factory packages and also work fine.
  • BD135 is my suggestion for the compensation transistor, I matched this one myself since I feel the TO-126 screwhole package (along with its thicker more durable legs) is important to avoid this problem in the future. This is the closest match I found in this package, alternatively at least from my numbers KSD882 should also be a match. I'd take BD135 as first choice. Alternatively you can just get another 2SD400 (bdent probably have it) but I'd advise against that for obvious reasons.
  • Your cement resistors are likely fine, especially if the other channel's values match. I found those are tricky to measure, and while they do fail in a lot of amps along with the outputs, in these ones in my experience they live through it fine. If you want to buy them anyway though, Vishay CP 0.22Ω at mouser.
  • Mouser sells everything except for the drivers (which are no longer made, if you order from bdent I'd grab a couple extras just because soon they won't exist at all) and outputs.
  • For flameproofs, use the Yageo FRM-25 series. FRM-25 33Ω at mouser for example.
Click to expand...
Did you get the Predrivers PNP and NPN Swapped by accident? Or is my dizziness making me see things? No biggie, just want to make sure it isn't just me :D.
 
Update: Ordered the outputs and the drivers from B+D. Will work on the rest when I am doing a little better.
 
Yeah swap the A1381 and C3503 in my post, just a typo.

RE: TR142 as I said somewhere earlier, I'd always sub the complement as well if substituting one transistor in a complementary pair. The substitutes often don't have exact same specs as the original so it's better if they go in as pairs.
 
zaibatsu said:
Click to expand...

For the flameproofs, I noticed you spec'd out rather beefy one's were the originals 1/4 watts or were they higher like the one you suggested. I have been looking through the SM but it doesn't say

EDIT: I have apparently am not on the ball, which is why I haven't been posting. The higher wattage I pulled out of my head from looking on mouser and some of the values needed are only only in higher wattages...This ear infection is killing me. Concentration is gone. RETRACTED
 
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FRM-25 is a 1/4W part (The 25 means 0.25W), stock vertically standing green flameproofs are all 1/4W.

If there are some values you can't find, it's probably okay to substitute a 1/4W metal oxide resistor with flameproof coating or something like that - but it's not the same thing (coating /= actually flameproof/fusible) so there's a mild fire hazard risk. As you've discovered these resistors rarely "save" any important parts anyway, so the only thing they really have to do is burn up without catching fire. If you can't find actual flameproofs for any values, just mount replacements up off the board and away from other components.
 
zaibatsu said:
FRM-25 is a 1/4W part (The 25 means 0.25W), stock vertically standing green flameproofs are all 1/4W.

If there are some values you can't find, it's probably okay to substitute a 1/4W metal oxide resistor with flameproof coating or something like that - but it's not the same thing (coating /= actually flameproof/fusible) so there's a mild fire hazard risk. As you've discovered these resistors rarely "save" any important parts anyway, so the only thing they really have to do is burn up without catching fire. If you can't find actual flameproofs for any values, just mount replacements up off the board and away from other components.
Click to expand...

Good to know. I think I found some vishay on mouser in all the values I need, would these in 1 watt be okay? or is my ear pain giving me the stupids : http://www.mouser.com/Search/Produc...0virtualkey59420000virtualkey594-5073NW33R00J
 
tmsears said:
Good to know. I think I found some vishay on mouser in all the values I need, would these in 1 watt be okay? or is my ear pain giving me the stupids : http://www.mouser.com/Search/Produc...0virtualkey59420000virtualkey594-5073NW33R00J
Click to expand...

No !!!!..... Not for fusible resistors.Vertically standing greenish resistors are usually fusible flameproof. Stick with 1/4 watt..
Thats like putting a 15A fuse where a 10A is suppose to be. ie. " fusible "
And 1 watt resistor takes alot longer to burn open than 1/4 watt does.
 
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avionic said:
No !!!!..... Not for fusible resistors.Vertically standing greenish resistors are usually fusible flameproof. Stick with 1/4 watt..
Thats like putting a 15A fuse where a 10A is suppose to be. ie. " fusible "
And 1 watt resistor takes alot longer to burn open than 1/4 watt does.
Click to expand...

I read you loud and clear. :thumbsup:

At least for the moment I read you clearly, before that damn earache comes back... comes and goes in waves. I thought about the "fuse in fusible" last night before I went to bed, wondering if that was the wisest idea.
I figured one of you would probably step in and rescue me from my stupidity :rolleyes:. After all, that's what friends are for:D!
 
zaibatsu said:
...If there are some values you can't find, it's probably okay to substitute a 1/4W metal oxide resistor with flameproof coating...
Click to expand...

The search continues then, as I cant seem to find metal oxides in the values I need. I am up for the challenge though!
 
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