Panasonic SA-HT820V Home Theater System

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  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by CapsDude
    Any way to find out if it's either one of those?
    Nope, no way to tell

    Leave a comment:


  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    If D1270 cathode (white band) to ground measures 4.6M Ohms you either damaged a trace or the transformer winding is open.
    Any way to find out if it's either one of those?

    Leave a comment:


  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by CapsDude
    Didn't get -30 on TL1030.

    TL1030 read 7.8 M Ohms
    D1270 read 4.6 M Ohms
    If D1270 cathode (white band) to ground measures 4.6M Ohms you either damaged a trace or the transformer winding is open.
    Attached Files
    Last edited by R_J; 03-17-2021, 10:45 AM.

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  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Didn't get -30 on TL1030.

    TL1030 read 7.8 M Ohms
    D1270 read 4.6 M Ohms

    Leave a comment:


  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by CapsDude
    Pin number 6 is reading .6V. All other pins are good.
    Without -30 volts you won't get a display. To make sure there are no shorts on that line, CARFULLY remove the flat cable from P1102 and check if the negative -30v is on TL1030, if not, Unplug the unit and check the resistance of TL1030 to ground, it should be very high. Then as a last check, measure the transformer winding resistance It can be checked between D1270 cathode and ground (W56)
    Last edited by R_J; 03-16-2021, 07:40 PM.

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  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    And the voltage is?
    Pin number 6 is reading .6V. All other pins are good.
    Last edited by CapsDude; 03-16-2021, 07:12 PM.

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  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    And the voltage is?

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  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Got the part and soldered it. Nothing shows up on the display. It powers up tho because the vhs side starts up. The connector tape is fine.
    Attached Files

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  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    200ma 200v would be the minimum, that -30v supply is fairly low current, so any fast recovery diode greater than 200ma/200v would work.
    Ok, I'll get some and try it out. I appreciate your help so far.

    Leave a comment:


  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    200ma 200v would be the minimum, that -30v supply is fairly low current, so any fast recovery diode greater than 200ma/200v would work.

    Leave a comment:


  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    Just replace the diode, that should get the display back to normal. and then you can get back to the other problems. Any 1 amp 200v fast recovery diode will work
    Oh ok, I was already searching for a Panasonic 200V 200mA diode since thats what the schematic said it was. So it doesn't matter?

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  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Just replace the diode, that should get the display back to normal. and then you can get back to the other problems. Any 1 amp 200v fast recovery diode will work

    Leave a comment:


  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    It is likely shorted, You can unplug P1102 and check the diode again (don't damage the cable) just to be sure, or unsolder one end of the diode.
    If the diode is shorted, that would explain the way the display looks. It is likely that when the flat cable twisted and partly came out of the socket it shorted the unregulated -30 to ground as the pins are side by side.
    P1102 was already unplugged when I was doing the test. So if I wanted to fix it, is it a new diode or the power board itself?

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  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by CapsDude
    Negative (L) Positive (R): .324V
    Positive(L) Negative(R): .202V
    It is likely shorted, You can unplug P1102 and check the diode again (don't damage the cable) just to be sure, or unsolder one end of the diode.
    If the diode is shorted, that would explain the way the display looks. It is likely that when the flat cable twisted and partly came out of the socket it shorted the unregulated -30 to ground as the pins are side by side.
    Last edited by R_J; 03-10-2021, 07:35 PM.

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  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    Check it on the board first, Use you meter in diode test and check it one way then reverse the leads and check it the other way.
    Negative (L) Positive (R): .324V
    Positive(L) Negative(R): .202V

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  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by CapsDude
    Do I have to desolder and take the diode out to test it?
    Check it on the board first, Use you meter in diode test and check it one way then reverse the leads and check it the other way.

    Leave a comment:


  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    Your problem seems to be that you are missing the Display -30 volts (UNREG_-30V) I suspect D1270 might be damaged. OR you have something on the unregulated -30v line that is shorted.
    I suspect the the diode is burnt open or is shorted, and this is where the burnt smell came from.
    Do I have to desolder and take the diode out to test it?

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  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by Diah
    My post #5 i wrote its mechanic issue and need to put all at zero point.

    yours display photo its tell same you have Order JAM ( because the lost of zero point and there are 2 or more micro switch sending order.) though this can damage the main IC. not C or R.
    I think we set the VCR to zero point but not the DVD. How do you go about doing that?

    Here's the top and bottom. Do I need to take the trays out?
    Attached Files

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  • R_J
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Your problem seems to be that you are missing the Display -30 volts (UNREG_-30V) I suspect D1270 might be damaged. OR you have something on the unregulated -30v line that is shorted.
    I suspect the the diode is burnt open or is shorted, and this is where the burnt smell came from.
    Last edited by R_J; 03-10-2021, 06:01 PM.

    Leave a comment:


  • CapsDude
    replied
    Re: Panasonic SA-HT820V Home Theater System

    Originally posted by R_J
    4.94 what?
    P1102 pins 3&4 are the same connection, how can you have 2 different voltages? You must be reading the pins wrong. Check the voltages on the test points TL10xx instead. IP1240 is a fuse, check if it is still good.
    4.94 Volts.

    Ok so I was reading the schematic wrong because its a little different from my power board. I was reading it in the opposite direction. So it should read:

    Pin 2: 31.8V
    3: 6V
    4: 6V
    5: 16.5V
    6: -.03V
    11: 3.5V
    12: 13.4V

    TL1004: 3.5V
    TL1006: 6V
    TL1009: 13.4V
    TL1016: 16.4V
    TL1030: -.33V
    TL1038: 31.6V

    Fuse read good.

    Leave a comment:

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