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Yamaha CR-1000 buzz and occasional popping

Yeah, but maybe we will get where we came from. I heard those pops only when I used preamp of this unit, it was ok when only the power amp was used. Are we looking in the right place then? You mentioned power supply for the EQ I think. Is it on this power board? And if not, where should I look?
 
If you can tap on a component and cause a "pop"...... Know where I'm going on this? This is the only PS board.
 
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Your "pop" may be a crack around one of those pass transistors solder pads.
 
Wiggle the pass transistors while observing the solder connection.. If you see a lead wiggling you have a problem.
 
OK, thx for this.
To be honest most transistors on this board causes a pop when tapped or pop + crackle. Just the most sensitive for it are the closest to the left lower corner then the further to the opossite corner the less poppy :) Also switches cause pops although they were cleaned half a year ago with dismantling the front in a repair shop specialized in vintage gear.
These:
2SC1061 use TIP31C --NPN
2SA671 use TIP32C --PNP
are they identical replacements?
I saw on ebay transistors with identical codes as the original i.e. SC1061 and SA671. They were branded Hitachi etc. and quite expensive like £8/1pcs. Are they any better?
I would also need SC1213 as it is in the hottest spot, also saw it on Ebay with identical coding, Hitachi £4/1pcs
The "cold" side of the ps board looks quite messy in the area under the high silver diodes with round heads and radiators/covers that go over them, pics below:
trans0.jpg trans2.jpg trans3.jpg
 
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Get yourself a stiff brush and some acetone. Need to clean up that old flux and very old laquer. I see a few iffy looking connections.But it might just be crap on the board.
 
hard to tell but looks like there could be a solder bridge on the second photo in post 17, between the middle and right facing legs. might just be a reflection but worth taking a look at.
 
I went on it a bit softer, with isopropanol
Only the one in the circle looks a bit dodgy to me. It's from one of the Toshibacleaned1.jpg diodes. The rusty things without soldering above it are from the diodes' radiators.
cleaned2.jpg
 
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center of photo connection looks iffy.
 
sssboa said:
I saw on ebay transistors with identical codes as the original i.e. SC1061 and SA671. They were branded Hitachi etc. and quite expensive like £8/1pcs. Are they any better?
I would also need SC1213 as it is in the hottest spot, also saw it on Ebay with identical coding, Hitachi £4/1pcs
Click to expand...
Throwing ebay parts in this is asking for trouble.95% of the time they are counterfeit parts from China.Buyer beware.
 
So I desoldered one 2SC1061 running the hottest, then 2SC1213A next to it. I tested them with multimeter and they seemed ok. I soldered them back. The popping continues. It's practically first 5 minutes from switching on, 2-3 pops and then no pops at all even when on for hours. When I tap any component on power supply pcb it causes a pop. It was mostly the two components I resoldered. I think because they are running hot and the 2SC1061 was not fixed stiff with a radiotor as other similar transostors there, now I made it stiff and it doesn't pop that much on a tap.
 
So I was finishing replacing all notorious Hitachi 2SC458 with contemporary Fairchild KSC1815Y when power cable from one of the main fuses snapped off. Eureka moment! I resolded the fuses cables on one side before testing. And popping is gone!
I guess the 2SC458 were alright but good riddance, right?
More probable cause was the bad soldering on fuses.
fuses.jpg
 
Bravo for your fix! The wiring in my CR-1000 is fragile too, anytime I wiggled a board, a wire was in danger of disintegrating. BTW, I don't think I replaced the 2SC458's in mine. I was listening to it this morning, it is one of my favorites.
 
I hope you properly seated that fuse before buttoning it up.
 
I got into euphoria too early. After not using the amp for long, 1 minute on turning on I had crackle crackle pop and that's it with popping until another time when I didn't use the amp for long. So I gathered my initial main suspects: the transistors running hottest on the power board 2SC1061, 2SA671, 2SC1213A and replaced them with the ones here suggested TIP31C, TIP32C, KSC2383Y. I have tested on headphones many scenarios for some time now and all clear so far, fingers crossed.
 
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