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Post by mastertech on Feb 19, 2017 21:19:13 GMT -5
Can you post a picture of your board where ic73 is mounted?
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nashou
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Post by nashou on Feb 20, 2017 6:35:41 GMT -5
Can you post a picture of your board where ic73 is mounted?  |
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Post by mastertech on Feb 20, 2017 11:03:37 GMT -5
I think the pad style might work. At least the part is not real expensive. Worst case you would have to solder small wires to the board and then to the ic. Looks like 22 pads are all that are connected and some could be bridged together to lessen the wire count.
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nashou
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Post by nashou on Feb 20, 2017 11:34:22 GMT -5
I think the pad style might work. At least the part is not real expensive. Worst case you would have to solder small wires to the board and then to the ic. Looks like 22 pads are all that are connected and some could be bridged together to lessen the wire count. Thats what I was thinking. I can make it work I think. Nashou |
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nashou
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Post by nashou on Feb 20, 2017 12:11:38 GMT -5
I ordered the parts and some solder paste . I heard its a bit easier to use for chips like this.
Edit:One more thing. I was looking at the Data sheet for that chip. How do you get the chip to output the voltage you want? usually there is some kind of resistor externally used. I couldn't find anything or may have missed it. Just wondering if maybe one of the external parts could cause the problem and not actually the chip?
nashou
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Post by mastertech on Feb 20, 2017 12:33:49 GMT -5
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Post by mastertech on Feb 20, 2017 13:00:09 GMT -5
If you had corrosion in this area then you can test each component in the area for value and also do a continuity test of all traces connecting each component and to the ic as well. I would think that you should have an output without this circuit but you never know until you try. lol.
Components involved: R721,R723,R724,C734,C739
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nashou
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Post by nashou on Feb 23, 2017 7:56:53 GMT -5
Those parts tested fine. I tried the chip had a hell of a time , those pads are smaller than I am use to with CRT's. But any how I think I got it to where I thought it was good. tested continuity between certain pins to make sure I had no
solder bridges. Three times I found continuity between the 3.4 Vout and the opposite side pins that where NC (SW) . that is I removed and re flowed the chip a few times.
Lost pad 25 , no bigie not used. I measured the same pads on ic77 and that too had continuity betweeen same pads? So I figured all is ok then. Put the transistor back and the 60 ohm ferrite bead. nothing.
Same issue if I used protection mode. So I removed the chip and tried the External PS again and it works fine that way.
And I freaking lost the ferrite bead L713. what can I use for that as I dont want to pay 5 bucks for a .13 cent part. I have that other yamaha with the bad main CPU maybe that has one close to it.
I'll try again tonight. How can I test that Part out of circuit incase I blew it? Should I add the 5.5 volt form the external pos to the Vin pads on the chip and then the neg to gnd pad and see if I get any voltage on the outs?
Might need to many other factors maybe.
EDIT: my RX-671 has the same part at L9010 . Thank God !!!!
Nashou
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Post by mastertech on Feb 23, 2017 19:55:23 GMT -5
You need:
5.5v on pins: 19,20,21,33
gnd. on pins: 13-18,32
3.3v on pin: 27
It should then output voltage on the output pins.
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nashou
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Post by nashou on Feb 23, 2017 20:12:54 GMT -5
You need: 5.5v on pins: 19,20,21,33 gnd. on pins: 13-18,32 3.3v on pin: 27 It should then output voltage on the output pins. Ok, Now since the new chip didn't work do you think I blew it some how? I removed the chip last night and right now I am cleaning off the solder on the chips and off the PCB pads. I also bought a squeeze bottle with a thin needle to dispense the solder paste a little better than the brush method I did last night. Should I install it with out L713 and the Switching transistor? And why Am i getting continuity between pins and GND on ic77 as well but it works with that continuity If I use the external supply? Is it suppose to have continuity between those pins? Couldn't tell with the schematics. I have another chip or should I try the one I first tried and see what happens. Sorry for all the questions Nashou |
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Post by mastertech on Feb 23, 2017 20:37:17 GMT -5
According to the data sheet, Vout and NC(sw) are directly connected internally. So that continuity is normal.
Install and test with L713 and transistor removed.
I would try that one again but when installed make sure you have the voltages on the pins I indicated above. Also make sure you have a good gnd on all required pins. Also test to see if you have 3.3v coming out on pin 28.
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nashou
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Post by nashou on Feb 23, 2017 22:21:36 GMT -5
No luck, something else is wrong. I am getting voltage on pin 22 on both ic73 and 77. Also I get voltage on pins 34-39, 1.7 volts . Pin 33 has 2.1 While ic77 has the correct voltages except for 34-39. On ic73 sync is 0 . Also the amp turns on and two relays click as soon as I plug it in. I can't use the power button to turn it off or on . What's next? I am pretty sure I this is the best I have done with the solder paste.  looks really good. I am pretty sure that chip was fine. I was measuring pins from the #1 pin to all the others and got similar readings going from never used chip to the one I tired. Nashou |
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Post by mastertech on Feb 23, 2017 22:26:46 GMT -5
IC73, what voltage is on pins 19,20,21,33
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nashou
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Post by nashou on Feb 23, 2017 22:39:00 GMT -5
IC73, what voltage is on pins 19,20,21,33 19-21 I have 5.5 33 I have 2.1 |
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Post by mastertech on Feb 23, 2017 22:41:12 GMT -5
You must have a broken trace. These 4 pins are all tied together and should all have the same voltage.
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looks really good.
