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Old 08-31-2018, 10:17 AM   #21
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Default Re: Electron Kinetics Eagle 2C amplifier problem

I just put in '2SC2774' into the search engine and lots of spec sheets come up.

http://www.svntc.com/TPDF/2145.pdf
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Last edited by budm; 08-31-2018 at 11:31 AM..
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Old 08-31-2018, 12:35 PM   #22
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Default Re: Electron Kinetics Eagle 2C amplifier problem

Well that explains it better. I put Sanken 2SC2774 in the search engine and didn't get much. Should have only put 2SC2774..lol

OK, so I see that looking at the front side with writing, the pins from left to right would be B,C,E? If this is correct, then I would use my DMM to check each one and write down the voltages I get? I take it that I will use the ground probe on the 2 green wires and use the red probe only on pin#1(B) then pin #2(C) and finally pin #3(E)

I just don't want to short anything out and damage my DMM or myself for that matter. I'll wait for a reply before I actually try and measure the transistors. Thanks again!
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Old 08-31-2018, 12:46 PM   #23
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Default Re: Electron Kinetics Eagle 2C amplifier problem

Quote:
Originally Posted by Gammaray View Post
Well that explains it better. I put Sanken 2SC2774 in the search engine and didn't get much. Should have only put 2SC2774..lol

OK, so I see that looking at the front side with writing, the pins from left to right would be B,C,E? If this is correct, then I would use my DMM to check each one and write down the voltages I get? I take it that I will use the ground probe on the 2 green wires and use the red probe only on pin#1(B) then pin #2(C) and finally pin #3(E)

I just don't want to short anything out and damage my DMM or myself for that matter. I'll wait for a reply before I actually try and measure the transistors. Thanks again!
Correct.
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Old 08-31-2018, 04:38 PM   #24
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Default Re: Electron Kinetics Eagle 2C amplifier problem

1) Can you please provide good clear hi-res straight shot pictures of the board?
2) Please check the DCV between the RED and BLACK post of the speaker output terminals.
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Old 09-01-2018, 08:51 AM   #25
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Default Re: Electron Kinetics Eagle 2C amplifier problem

Quote:
Originally Posted by budm View Post
1) Can you please provide good clear hi-res straight shot pictures of the board?
2) Please check the DCV between the RED and BLACK post of the speaker output terminals.
I had to remove the transformer to get some photos of the whole board. I also noticed that a capacitor on the board appears to may have leaked. I also can see that the other one like it on the other channel appears to be leaking a little. You can see some brown looking goo around it where it is attached to the pcb. Should I still do any measurements? I can just place the transformer in the spot it was and I can connect the big caps as well. Here are the photos I took. If you zoom in on the last photo you can see the brown looking goo stuff I was talking about. It is marked with C99. My camera, which is a little old, is starting to not zoom in close up well. If you need anymore photos, please let me know. Thanks again!!!
Attached Images
File Type: jpg PICT1363.JPG (1.17 MB, 20 views)
File Type: jpg PICT1365.JPG (1.25 MB, 17 views)
File Type: jpg PICT1368.JPG (934.1 KB, 14 views)
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Old 09-01-2018, 09:03 AM   #26
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Default Re: Electron Kinetics Eagle 2C amplifier problem

B C E are marked on the circuit board . and in that same order .
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Old 09-01-2018, 07:33 PM   #27
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Default Re: Electron Kinetics Eagle 2C amplifier problem

Looking at the board lay out it looks like the audio input of each channel is fed to OP-AMP LF411, those two IC's are socket, you may want to reseat the IC or swap them, also check the Voltages on each pin also.

Last edited by budm; 09-01-2018 at 07:45 PM..
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Old 09-02-2018, 08:39 AM   #28
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Default Re: Electron Kinetics Eagle 2C amplifier problem

I connected the big caps back up and took the following measurements. I have included 2 photos of each side of the board. Each transistor is marked with a number in red. Also, I measured all of the pins on these 2 OP-AMP components. For both OP-AMPS looking at them in the photos, I started with the top left side going down will be pins #1,2,3, and 4. Then on the top right side going down will be pins #5,6,7, and 8.

#1 Sanken 2SC2774 transistor B=.631 DCV/ C=48.0 DCV/ E=.018 DCV
#2 Sanken C2168 transistor B=1.22 DCV/ C=47.7 DCV/ E=.627 DCV
#3 Sanken 2SC2774 transistor B=.626 DCV/ C=48.0 DCV/ E=.017 DCV
#4 Sanken A958 transistor B=46.4 DCV/ C=1.22 DCV/ E=47.3 DCV

#5 Sanken A958 transistor B=47.8 DCV/ C= -40.0 DCV and appeared to be dropping?/ E=46.1 DCV
#6 Sanken 2SC2774 transistor B= -21.0 DCV and dropping in voltage/ C= 46.8 DCV/ E= -19.6 DCV
#7 Sanken C2168 transistor B= -18.8 DCV/ C=46.8 DCV/ E= -18.9 DCV
#8 Sanken 2SC2774 transistor B= -18.75 DCV/ C=46.9 DCV/ E= -19.4 DCV

Here is what I measured for these OP-AMPS:

OP-AMP (#1) Pin #1= -14.76 DCV/ Pin #2= -.025 DCV/ Pin #3= 15.27 DCV/ Pin #4= .002 DCV Perhaps there was no voltage on this pin #4?
Pin #5= 14.80 DCV/ Both Pins #6 & #7 measured no voltage/ Pin #8= -14.76 DCV

OP-AMP (#2) Pin #1= -14.73 DCV/ Pin #2= -.633 DCV/ Pin #3= -.677 DCV/ Pin #4= -14.8 DCV/ Pin #5= -11.50 DCV/ Pin #6= 15.28 DCV/ Pin #7= -.004 DCV/ Pin #8= -14.75 DCV

Speaker Outputs:

Channel (A)= .001 DCV
Channel (B)= -21.8 DCV and then starts to drop in voltage.

The first/left photo below is channel (A) and the second photo is channel (B)
Attached Images
File Type: jpg Eagle amp measurements 1.jpg (1.44 MB, 7 views)
File Type: jpg Eagle amp measurements 2.jpg (1.33 MB, 1 views)

Last edited by Gammaray; 09-02-2018 at 08:55 AM..
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Old 09-02-2018, 09:04 AM   #29
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Default Re: Electron Kinetics Eagle 2C amplifier problem

P.S. Here is a photo of the bottom of those big caps. It appears as if something leaked out a little!
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File Type: jpg IMG_0981.jpg (539.4 KB, 10 views)
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Old 09-02-2018, 02:37 PM   #30
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Default Re: Electron Kinetics Eagle 2C amplifier problem

you forgot the npn 2sa1170 transistors
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Old 09-02-2018, 04:29 PM   #31
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Default Re: Electron Kinetics Eagle 2C amplifier problem

Quote:
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you forgot the npn 2sa1170 transistors
Those are located at the bottom and more difficult to get to. I will try and see if I can do it. I'll post back the measurements if I can. Thanks!
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Old 09-02-2018, 06:02 PM   #32
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Default Re: Electron Kinetics Eagle 2C amplifier problem

so sorry but they are PNP . i cannot edit my post . they work in pairs with the NPN ones you listed .
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Old 09-02-2018, 06:19 PM   #33
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Default Re: Electron Kinetics Eagle 2C amplifier problem

OK, I will try my best to get those with the voltages. I may have to do a little mod to get to the harder ones.

I have some questions about the 2 big caps. I wanted to make sure that these caps are discharged, so I took a screw driver to the cap located closest to the transformer and grounded the terminals/screws on the top. I didn't get any discharge. So I proceeded to do the one next to it, and BAM, it made a really loud pop and kind of melted the metal on the surface of the screw driver metal. My questions are, is this ok to do to discharge them? Also, Why didn't the first cap discharge and pop like the other? I'm just wanting to know. Thanks!

Last edited by Gammaray; 09-02-2018 at 06:20 PM..
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Old 09-02-2018, 07:17 PM   #34
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Default Re: Electron Kinetics Eagle 2C amplifier problem

something drained the empty one and worth noting . shorting to drain is not recognised as a good idea .. a resistor or light bulb is kinder to the capacitor .

Last edited by petehall347; 09-02-2018 at 07:18 PM..
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Old 09-02-2018, 07:31 PM   #35
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Default Re: Electron Kinetics Eagle 2C amplifier problem

Use resistor or incandescent lamp (25W will do) for discharging the caps.
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Old 09-03-2018, 08:53 AM   #36
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Default Re: Electron Kinetics Eagle 2C amplifier problem

OK guys Thanks! I have some 1/4 and 1/2 watt resistors, but not sure if I were to parallel them to get a higher wattage and also what ohm value should I use?

I saw a video on someone using an incandescent bulb to drain a larger cap, but it seems to still pop and damages the filament. I also see that they use neon bulbs, but not sure how well that works.

I will try and get the rest of those measurements for the bottom section of those transistors. I just need to be extra careful not to accidently touch those big caps!
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Old 09-03-2018, 11:29 AM   #37
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Default Re: Electron Kinetics Eagle 2C amplifier problem

I just finished measuring the bottom transistors! I also attached 2 photos showing the numbered transistors marked in red from each side. Here are the voltages I have measured:

#1(2SA1170) B= .603 DCV/ C= -46.55 DCV/ E= -.012 DCV
#2(A958) B= -1.22 DCV/ C= -46.33 DCV/ E= -.600 DCV
#3(2SA1170) B= -.593 DCV/ C= -47.3 DCV/ E= -.002 DCV
#4(2SC2168 ???) B= -44.7 DCV/ C= -1.20 DCV/ E= -44.8 DCV

#5(2SC2168???) B= -44.8 DCV/ C= -2.27 DCV/ E= -44.8 DCV
#6(2SA1170) B= -1.15 DCV/ C= -45.9 DCV/ E= -.63 DCV
#7(A958) B= -1.9 DCV/ C= -46.7 DCV/ E= -1.22 DCV
#8(2SA1170) B= -1.42 DCV/ C= -46.1 DCV/ E= -.75 DCV
Attached Images
File Type: jpg Bottom transistor measurements.jpg (1.49 MB, 5 views)
File Type: jpg Bottom transistor measurements right side.jpg (1.38 MB, 4 views)

Last edited by Gammaray; 09-03-2018 at 11:34 AM..
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Old 09-03-2018, 01:52 PM   #38
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Default Re: Electron Kinetics Eagle 2C amplifier problem

Quote:
Originally Posted by Gammaray View Post
OK guys Thanks! I have some 1/4 and 1/2 watt resistors, but not sure if I were to parallel them to get a higher wattage and also what ohm value should I use?

I saw a video on someone using an incandescent bulb to drain a larger cap, but it seems to still pop and damages the filament. I also see that they use neon bulbs, but not sure how well that works.

I will try and get the rest of those measurements for the bottom section of those transistors. I just need to be extra careful not to accidently touch those big caps!
the only way to pop the filament if the lamp Voltage is a lot lower than the charged Voltage on the cap. Use <25W 120V incandescent for discharging.

Last edited by budm; 09-03-2018 at 01:54 PM..
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Old 09-03-2018, 02:22 PM   #39
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Default Re: Electron Kinetics Eagle 2C amplifier problem

OK, I'll try that..Thanks!!!

BTW, what do you think with these voltages I have taken for the transistors? Do they seem to be OK, or should I replace any? Not sure what to do at this point. I know that you mentioned changing out the OP-AMPS. I just want to order all of the components in one order if possible. I will also order that resistor for the Sony TV..lol Thanks again Bud!!!
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Old 09-03-2018, 02:28 PM   #40
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Default Re: Electron Kinetics Eagle 2C amplifier problem

test the diodes next to where it says bias on the board .
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