dear sir please help i have dm800hd its tuner no searching signal what is problem tuner BSBE2-801A CLK OUT PIN 2.0 MV OUT OF 1.72 LNB RF POWER INPUT PIN .70 MV box is empty no have any channels what i can do..
without tuner all voltage measurement is ok showing as this fig but with tuner some point 21,52,53,56 different 53 point ov
The lower voltage measurements are not the reason, these may become lower due a inactive, or other type tuner. It could be a tuner issue, thinking of a bad U500-LNBP21PD, or related to the software which is in most cases due the software, the tuner drivers. In any case, based on the information I have no reason to think that it is a issue from the motherboard hardware. Also, Eardatek, rev M tuners gives more often this problem, better would be if you could try it with another tuner. Or else, try another power supply, one with more amps, in any case 3 to 5 amps should be better because these tuners uses a bit more amps that others. Try also other software as openpli or openatv to see if it brings the tuner back to live. Nevertheless these advice's are also based on a good working dish system, which I may assume that you have test it.
thanks sir for reply LNBP21PD voltage measurements are pin ..... volt 1 2.2mv 2 34.2mv 3 18mv 4 2.2mv 5 3.3mv 6 2.2mv 7 2.0mv 8 4.97 v 9 2.6mv 10 2.2mv 11 2.0mv 12 3.25 v 13 3.25 v 14 2.2mv 15 3.16 v 16 2.2mv 17 2.2mv 18 11.94 v 19 11.80 v 20 2.2mv it's ok mother bord no issue i cheked other tuner working fine how can do
Because you have the 5v on the pin 8 (byp) it seems that the lnb chip is working, also you have the 12/13 scl/sda 3v and 18/19 12v. And because you say that you don't have at least the 12v on the lnb, then i'm thinking of a interruption of the inductor L502, 0r a issue with the coil L510, or diode D500. In any case, a diode or inductor, or coil from/to the lnb chip may cause this issue.
By reading this.. box is empty no have any channels. Without a channel list the lnb rf input could be 0 volts. Better is to add a channel list manually to see if you get a voltage on the lnb input. At the other hands, when scanning channels, the lnb rf input must give the 12/18v dc, even without a dish system connected. It only have no voltages when it is not set on a channel. In any case, I've found a picture which shows the lnb circuits on the tuner. Maybe it helps a bit with finding the issue.