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Tech Head - The Technology Section
The Work Bench and Soldering Station
Schematic for Echostar AD3000ip LNB switching circuit
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<blockquote data-quote="Llew" data-source="post: 684734" data-attributes="member: 175007"><p>If you have a digital multimeter, you can do a quick and dirty check on whether the 22kHz signal is coming from the processor.</p><p></p><p>Switch to AC and a low scale (2V or whatever your meter has around this voltage).</p><p></p><p>Locate Q910 (just below the copper heatsink to the left of the tuner).</p><p></p><p>Place your +ve probe on the bottom pin of Q910. That's the left-hand terminal of the two pins looking 'sideways'. Your -ve probe to ground (chassis).</p><p></p><p>If you go to Menu - 6 - 1 of your box (Program Satellites) you can then easily switch between high and low band frequencies of your satellite in the TP bar for testing whether the 22kHz is switching on.</p><p></p><p>You're checking for a 22kHz square wave, which should show around 1V or more on your meter when you switch to a high band channel. Switching to a low band channel should show around zero.</p><p></p><p>As I say, it's a rough check, but it will confirm whether your processor is actually sending out the signal.</p><p></p><p>Just do another check first though to confirm that you LNB settings are definitely correct.</p><p></p><p>**Be ultra careful when checking circuitry in the box - the power supply on the left is exposed, and in particular the heatsinks in that area can deliver a mighty shock! Don't connect your -ve probe to them, only to the box's chassis**</p></blockquote><p></p>
[QUOTE="Llew, post: 684734, member: 175007"] If you have a digital multimeter, you can do a quick and dirty check on whether the 22kHz signal is coming from the processor. Switch to AC and a low scale (2V or whatever your meter has around this voltage). Locate Q910 (just below the copper heatsink to the left of the tuner). Place your +ve probe on the bottom pin of Q910. That's the left-hand terminal of the two pins looking 'sideways'. Your -ve probe to ground (chassis). If you go to Menu - 6 - 1 of your box (Program Satellites) you can then easily switch between high and low band frequencies of your satellite in the TP bar for testing whether the 22kHz is switching on. You're checking for a 22kHz square wave, which should show around 1V or more on your meter when you switch to a high band channel. Switching to a low band channel should show around zero. As I say, it's a rough check, but it will confirm whether your processor is actually sending out the signal. Just do another check first though to confirm that you LNB settings are definitely correct. **Be ultra careful when checking circuitry in the box - the power supply on the left is exposed, and in particular the heatsinks in that area can deliver a mighty shock! Don't connect your -ve probe to them, only to the box's chassis** [/QUOTE]
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Tech Head - The Technology Section
The Work Bench and Soldering Station
Schematic for Echostar AD3000ip LNB switching circuit
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