# 508 Troubleshooting



## bill_mcgonigle (Nov 6, 2005)

I'm having some signal issues with my 508 and I'm clearly missing something in my troubleshooting steps.

I started to get some signal drop-outs in October, when we had 3 solid weeks of rain. The point dish screen shows a signal up around 120 which then drops sometimes down as low as 90, or other times stays up near 120 and changes from green to red and goes Locked/Unlocked.

So, a wet line, I figured. So I got a new 100' length of RJ-6, ran it out to the dish and hooked it up. Same problem.

Just to be sure I repointed the dish, but that wasn't it.

So, the LNB I got 10 years ago was my next suspect. So, I replaced it with a new Dual LNB and - that didn't solve the problem (check switch works OK).

At that point the only thing I hadn't replaced was the receiver (OK, and the dish) so I was all set to get that replaced when it got very cold outside. The outside world froze solid and all the signal problems went away. That was a fine solution for a few weeks then we got a warm spell and the problems came back.

So, there I go thinking about a wet line again, but I had already tried replacing the cable.

The DVR works fine when the antenna cable is disconnected, but crashes if the antenna cable is connected and there is a period of signal loss going on. I attributed that to run-of-the-mill 508 bugs.

So... can anybody point me to the variable I'm missing here?


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## P Smith (Jul 25, 2002)

grounding


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## David_Levin (Apr 22, 2002)

bill_mcgonigle said:


> The DVR works fine when the antenna cable is disconnected, but crashes if the antenna cable is connected and there is a period of signal loss going on.


Heat? Are you in a cabinet? When you disconnect the (sat) antenna cable, do you have the box out of the cabinet (or leaving the doors open)? Was it colder in the house during the cold spell when the box was working?

I had a unit that lost signal when it got too hot. Extra ventilation got it working. But, to be safe, I had dish replace it.


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## bill_mcgonigle (Nov 6, 2005)

Thanks for the replies, guys.

I put off dealing with this for a little while because it got nice and cold outside and things were fine.

The past couple days we're having an unreasonably warm spell with lots of rain and the wife made me go outside and try to fix this.

So, here's what I did - I pulled two new lengths of cable, a new coax and a length of #6 stranded for a ground. I brought them in the house, attached the ground directly to the house electrical ground at the panel, and hooked up the new coax. 

And... no better. So, this is counfounding. I guess there's a small chance the new coax is the problem. The ground ought to be really good - I replaced an existing #16 wire that the installer had put in originally. I can't imagine what good that ever did.

Regarding the heat suggestion - the cabinet is not closed and the ambient temperature hasn't flucturated in the room. I'm really glad you mentioned heat, though - when I was down looking at the old ground, the thought from your message made me look at that pipe the installer grounded it to - it was a hot water feed to a radiator! Geeez, that could have been a disaster if I took a lightning strike. Gratefully averted thanks to your post!

Anyway, Toonami looks pretty cool with MPEG pixelation but the acquiring signal screen keeps interrupting it. I'm mystified as to what the weather connection might be - if it weren't for that I'd guess I had a failing receiver but the correlation is exact.


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## RSP-SUI-DCOY (Jan 15, 2006)

Few questions for you. Is there a ground block or a barell connection anywhere in the line, or do you have a straight homerun from the dish to the receiver? If there is a ground block inline, is there a static ground ran from the dish to the ground block? Have you tested the power receptacle that the 508 is plugged into? Is there by chance any trees that have grown in the way of the LOS?


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## bill_mcgonigle (Nov 6, 2005)

RSP-SUI-DCOY said:


> Few questions for you. Is there a ground block or a barell connection anywhere in the line, or do you have a straight homerun from the dish to the receiver?


The coax and ground come into the house from the dish together, to a point near the main service panel. There is a coax grounding block there and a generic ground connector. The generic ground connector is just one of those blocks with multiple set screws in it - for now, one set screw holds down the #6 going out to the dish, another holds down another piece of #6 that goes to the main electrical ground, and a third goes to the ground block for the coax.

The coax goes into said coax grouding block. That grounding block has room for 2 coax though I only need one for my single dish/receiver. I've tried both connections on that grounding block for grins. This part is all inside, in a dry basement about 60 degrees.



RSP-SUI-DCOY said:


> If there is a ground block inline, is there a static ground ran from the dish to the ground block?


I think the above description satisfies that requirement. Please correct me if I'm wrong.



RSP-SUI-DCOY said:


> Have you tested the power receptacle that the 508 is plugged into?


I haven't yet but will. Do you think this could be affected by weather?



RSP-SUI-DCOY said:


> Is there by chance any trees that have grown in the way of the LOS?


If only I could solve it with a chainsaw! The nearest trees are about 300' away and on a cold dry night I'm getting signal ~120 on the meter. I think this means I'm not having a LOS issue.

Thanks for all the questions!


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## robert koerner (Aug 20, 2005)

The ground wire won’t have any effect on signal strength. It is there to provide a low resistance path for near lightening strikes.


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## bill_mcgonigle (Nov 6, 2005)

Just thought I'd drop a note to let folks know I've finally solved this problem. The connections to the antenna were red herrings. It was a bad ground though - the problem came down to a bad ground between a satellite decoder IC and the receiver. 

The chip in question is the 24108 which is right by the coaxial connector for the antenna. Getting desparate (a signal loss every 30 seconds or so now) I took the receiver apart and started looking for cracked solder joints, dirty connections, etc, and decided to Google on some of the chip part numbers. I came across some sites with messages about the 24108 in a 501 that have since went away but Google cache had enough of parts of some messages to piece together a theory and work plan.

The theory goes that from repeated overheating and cooling the solder connecting the lower pin to a combination heatsink and ground cracks, causing said problems.

I took my heat gun (paint melting type) with the directional nozzle, set on full heat and high fan, and heated up the 24108 chip for 55 seconds. You can smell when the solder starts to melt. I then took the heat away, and pushed firmly with a philips screwdriver in the middle of the chip and held it down with some force (I could feel the chip re-seat when I pushed down) for about 40 seconds. This was enough time for the solder to re-solidify. The whole section of the receiver was hotter 'n hell at this point, so I put a small desk fan on it for about 5 minutes until everything was cool to the touch. I reconnected all the cables to the receiver, powered her up, watched the satellite count blib right by, got a good download of the guide, and the family is so delighted we've been watching TV all evening, for the first time in months (we won't make a habit of it). So, going on 4 hours and not a single breakup. Signal alternates between 121 and 122.

What's curious is there's a nice fan mounted right above this IC, seemingly perfect for cooling it. One of the messages I came across said this fan used to always be on but one firmware upgrade disabled it, or put it on a sensor and now it comes on not at all or only "when needed". Mine isn't on now in a moderately warm house in a well-ventilated rack, but does spin when power is first applied. This seems like a bad idea in said "upgrade" since the fan is barely audible. Conspiracy theorists can figure out other reasons.

Anyway, next up would seem to be diverting some power from the hard drive molex connector to run the fan constantly and finding a minature heat sink and some good thermal grease to attach it to prevent a future recurrance. There's another very hot IC nearby that's rated at 70C but it should probably be heatsinked as well.

And the wife figure out five minutes into enjoying the new signal that she didn't really need to help me pull new cable that one frigid winter day...


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