DM500s Signal Problem

[gokifly]

Hi

I have DM500s and i have problem whit signal on horizontal frequencies (work few seconds and signal go to 0 and i must reboot receiver and than same), vertical frequencies work fine.

I had previously no signal at all and i changed q72 (FDN352AP) and now i have this problem whit horizontal frequencies ...

I already changed 2 different images but same problem.

If anyone know something about this Please Help.

[gokifly]

if someone know how to test tuner .......

[vicentium]

Your STB must be unable to provide 18 Volts to feed the LNB, in order to switch to horizontal; that voltage is provided from the 12 V (the source voltage) by a multiplier; you might have had a shortcut wich led to damage the multiplier and also the transistor for 12V switch (you already replaced). Tuner is not supposed to be damaged: try to locate the multiplier, it includes a ferrite chopper in the front right side as I remember.

[gokifly]

thanks i will try to find

[vicentium]

On the other hand, what if the problem is in your LNB? What if it takes too much current and trigger a protection in your STB (or a HH motor if it is); if I were you I'd check first the output current.