DM800HD PVR CLONE PCP REV J

Discussion in 'DM800HD Hardware troubles and Repair support.' started by Vincenzo, Jan 9, 2019.

  1. Vincenzo

    Vincenzo New Member

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    Dear all,
    I've a DM800HD PVR clone with REV. J PCB. The box is ten years old ;-) and last month it stopped to work. I just see only two lan port led on, no red led no display. P5 voltages are ok, I measured the 8 main capacitors, and the are fine. The voltage on the three oscillators seems to be ok. Could someone help me?
    Please let me know if I need to provide more details.
    Thanks in advance.
    Vincenzo
     
  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    I think, remove the tuner and check if it works without.
    Check also the power supply, better is to test it on another 12vdc psu with at least 2 amps delivery or higher, however check the center hole, this must be the positive side.
    Other idea, connect/check the box with the service rs232 port to see if you still get some data output in a terminal program as putty or windows hyperterminal.

    However, keep in mind that when all the voltages are present, then it could be a cpu issue, but when the P5 ohm measurements are in range, then it could be another cause.

    Ohm measurements values were measured between the ground and the P5 pin.
    [​IMG]
     
  3. Vincenzo

    Vincenzo New Member

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    Hi JB,
    thanks for your answer.
    I tried several tests.
    Same issue without tuner: only lan port leds light
    No signal on serial port
    Voltages P5-GND
    Pin 1 1,25 Volt
    Pin 2 2,59 Volt
    Pin 3 3,33 Volt
    Pin 4 3,27 Volt
    Pin 5 5,06 Volt
    Pin 6 12,15 Volt

    Impedances P5-GND
    Pin 1 83 Ohm
    Pin 2 118 Ohm
    Pin 3 93 Ohm
    Pin 4 1172 Ohm
    Pin 5 557 Ohm
    Pin 6 971 Ohm

    Any idea different from trash?
     
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Based on the ohm measurements which shows a issue with the pin2, pin3, pin5 while the voltages are delivered, it seems to me that it could be a cpu issue.
    It may consume to much amps of these voltages and so not starting up.

    Pin 1-1.3v, 83 Ohm
    Pin 2-2.6v, 118 Ohm
    Pin 3-3.3v, 93 Ohm

    Pin 4-3.3v, 1172 Ohm
    Pin 5-5v, 557 Ohm
    Pin 6-12v, 971 Ohm