Re: VSX-1021-k MCACC flashing
I finally had time to look into this, and Redwire you were correct Q484 was bad. when I swapped with the channel next to it the problem moved to the other channel. afterwards I check the other bad channel and the same transistor was bad also. thank-you Redwire and Budwich for your support.
Thank you to the guys at HEGE supporting Badcaps [ HEGE ] [ HEGE DEX Chart ]
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Re: VSX-1021-k MCACC flashing
Redwire, see attached i have taken the values again and updated the drawing, note all the lower values (below 10v) are all variate about 1 or 2 volts and that is a rough middle point I entered. Example the 4.8V reading starts at 5.9 and goes down to 4.4v before going into protect mode again (this is over a 5 second period) the 0.6V and 0v at Q473 and Q479 at stable....
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Re: VSX-1021-k MCACC flashing
Thank-you budwich and redwire for the inputs, I am checking components with a voltmeter, and including caps in the cap setting removed from the circuit, If I am unable to get a reading as I might be out of range I will swap it with the left channel. I will also compare with the left channel. regarding the coarse readings I will go back and double check, some for sure have variable values so I am giving you a mid range as it does not have time to stabilize in the in the 5 seconds it is in release mode. I will check out the other items when I get time...
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Re: VSX-1021-k MCACC flashing
Budwich, the top rail is +58V, and what changed from 12v to 4v is the fact that Q476 and Q482 are now not installed in the circuit(removed) . I also forgot to mention Q481 was also swapped.
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Re: VSX-1021-k MCACC flashing
Over the weekend I did some testing and metering, and attached is what I have come up with. Note when I mention swapped I swapped with between this channel and SBL. my next step would be to remove and test C501 and or C574 however these are surface mount, a little more tedious. I assume this is close to the problem due to the weird readings at Q480 due to the spike with reading. Anyone see something that I am missing? or something else to check?
Also note the main problem is that the 4.8V on the Right side of the drawing should not be...
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Re: VSX-1021-k MCACC flashing
thank you all for the input, I tried what lotas suggested and nothing happens.
now to check for impedance tests at 'strategic points' any suggestions on where to start? I have been concentrating to the right of Q476 and Q482 should I bee looking on the left? Finally @redwire what do you consider the power amp? is it what is within the red square on page 56?
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Re: VSX-1021-k MCACC flashing
contiued looking to find issue and not getting anywhere, and help?
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Re: VSX-1021-k MCACC flashing
Hi Lotas,
thanks for the reply however to clarify unit is stuck in DC protect mode and when trying to release it after about 5 seconds it will return to DC protect mode. What will forcing the unit in standby mode do? is it not the same as release mode (tune down and multi-zone on/off)?
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VSX-1021-k MCACC flashing
Hello All,
I have a VSX-1021-K Pioneer Amplifier that has me stumped. Has MCACC light flashing meaning it is in DC protect mode and will not get out with release mode.
Attached are all the readings I pulled up to narrow down the issue to FR speaker and SBR speaker. I compared resistance values between components in the overload detection circuit of SBR and SBL looking for a short or different values with no luck. note I did not remove any components as nothing stood out of the ordinary.
I have also checked all transistors along the bottom of the amp including Q404...
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Re: LC-52D64U (Sharp Aquos) component ID
Yes both Q7506A and Q7505A were both shorted out between the three Pins (S, D and Gate) so what would cause it to short out like that?
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Re: LC-52D64U (Sharp Aquos) component ID
Thank-you R_J,
I Replaced the part, and luckily it did not blow anything else. I tracked the main issue with the TV not turning on to a shorted mofset P/N K3706, I put in a P/N 13N50CF, and at that point the TV would try to turn on but would shut down after about 5 seconds. After a few tries it shorted out again. I am wondering if it is because the MOSFET specs was too far off what is supposed to be there or there is something else loading it to the point of shorting out. The only K3706 I have found are from china and would take...
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LC-52D64U (Sharp Aquos) component ID
I picked up a Sony LC-52D64U (Sharp Aquos 52 in) TV that will not turn on, while testing Main P/S board DPS-304BP-1 I accidently shorted out a resistor and unfortunately it does not have the lines on it so I don't know its resistance. it is R7641 in the attached drawing and have attached pictures of what is left in case someone familiar with these resistors can identify it or has one of these boards and can check what is it. would like to know resistance and what type it is if it is special, and will a regular resistor work.
After looking at the pictures on the computer and not my...
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Re: Samsung LN40D630/BN96-19438A main board noise
See attached pictures, I was not able to take a picture of the complete screendue to the position on my workbench, however i confirm it is the same across the screen.
this was put up via my laptop and HDMI Cable if it makes a difference
I also have to say thank-you for taking the time to help with this....Last edited by Plane Nuts; 12-30-2020, 04:03 PM.
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Re: Samsung LN40D630/BN96-19438A main board noise
To give a status update, decided to clean the board with Alcohol once again, but a bit more aggressively and used shop air to dry off. It now turns on normally now on the the next issue, image quality. As you can see in the picture, columns of pixels seem to be offset, according to the previous posts once again point to the main board, any magical fix? or way of knowing it really is the main board and not the T-Con? it is looking like a good blast of heat with the heat gun to possibly reflow something as a last desperate...
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Re: Samsung LN40D630/BN96-19438A main board noise
I don't know if I am on to something but Looking at the Board each IC seems to feed power to the large chip located at the bottom of the picture, and looking at the datasheet of that chip they run at 1.8V.... however there is no change in voltage in both situations (working or not)Last edited by Plane Nuts; 12-29-2020, 02:30 PM.
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Re: Samsung LN40D630/BN96-19438A main board noise
IC204 and IC202 are both the same Z1031AI, I also noticed that putting my probe on the COMP pin gives varying results (from .8 to 1.7) and the screen will act up with interference lines and stay until it resets itself, possibly normal? due to what I can induce into it. and Although IC 204 seems to have odd value, it is not in the area Is affected by applying heat this area is between IC 202 and IC204
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Re: Samsung LN40D630/BN96-19438A main board noise
No change on VCC on SPI Flash it is at 3.3. I have been able to narrow down the issue to what is circled in the attached picture and a closeup of that area. I also noticed that Lx on IC204 is at 1.7V however this does not change weather the TV works or not. at the upper one IC 202 I get 3.3V, FB 0.8, comp 0.9, and EN 2.6....
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Re: Samsung LN40D630/BN96-19438A main board noise
I have attached pictures of the Power Supply, I have also tried heating up the Main board with a heat gun and it will start working almost right away. I will try to narrow it down to a single component, I also noticed there is a mofset on the main board that has something, you can see just below and to the left of the circle identifying the SPI flash IC I have attached a close up....
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