How to fix satellite box?

Hi all.
First of all i don’t know if its the right place to ask.

Yesterday, i was connecting satellite cable to the LNB and satellite box became silent.
Power LED is lighting but there is not ON or OFF or Channel Number on its display.
I couldn’t find any burned part on circuits.

I have analog multimeter, digital multimeter and google.
Where should i start to search broken part without powering it.
I know the danger of 220V :slight_smile:

Thanks in advance.

beingobserver:
First of all i don't know if its the right place to ask.

Well, to be honest, it is probably as good as any, insofar as there probably is no other site with actual information!

beingobserver:
Yesterday, i was connecting satellite cable to the LNB and satellite box became silent.

If the box was turned off while you did that, then it may be that it was ready to fail and when you turned it off, the fault became evident when it tried to reboot. I have had that happen. If it was turned on at the time, there was obviously some sort of static discharge and - it's toast!

beingobserver:
Power LED is lighting but there is not ON or OFF or Channel Number on its display. I couldn't find any burned part on circuits.

Suggests power supply is OK.

beingobserver:
I have analog multimeter, digital multimeter and Google.

But no circuit diagram or service manual. ("Service manual" - that's a joke. Analog multimeter? What's that for?)

beingobserver:
Where should i start to search broken part without powering it.
I know the danger of 220V :slight_smile:

Start by powering it of course. There appear to be three voltages from the supply or two and a control line, you need to know what they are and guess what they should be.

Beyond that - well, the fact is - go buy a new one.

Check the output to the lnb with the cable disconnected there should be volts on it , 12 i think

I used to design sattlite boxes for a living.

If you have no display on the box itself and nothing on the output to the TV then without a schematic and an oscilloscope you don't stand a chance. Even with them the chance is slim.
Sorry.

Grumpy_Mike:
I used to design sattlite boxes for a living.

If you have no display on the box itself and nothing on the output to the TV then without a schematic and an oscilloscope you don't stand a chance. Even with them the chance is slim.
Sorry.

So it's you we all have to blame for the convoluted technology that defies intuitive logic :smiley:



Well we were working to a satellite operators specification so that bit was down to them.

Check the voltage readings on all your outputs to the main board, rule out a power supply fault first...

Careful not to touch anything while its live or you may end up not so...

You might as well check any fuses, diodes and transistors. You might just get lucky.

A common problem in consumer grade electronics with a switch mode power supply, is that over time the electrolytic capacitors which filter the output voltages dry out , and go hi ESR.
Its most common in electronics which is enclosed in a box with poor ventilation.
This causes the output supply rails to become noisy, which stops any Micros on the main board from booting up.
You can sometimes spot capacitors which have gone hi ESR, as they bulge out .
Without a CRO though, its hard to fix , unless you replace all the electrolytics in the power supply.

mauried:
Without a CRO though, its hard to fix , unless you replace all the electrolytics in the power supply.

Which - now you come to mention it - is probably the most (and possibly only) productive approach.

Yes if one has gone the others are not far behind, might as well change them all.