BUD C-Band LNB gone bad?

[Bowhunters]

Hello - Long time member but I haven't posted in a while.

It looks like my BUD C-Band LNB has gone bad, it is fairly old LNB and feedhorn (1980's) and up until recently it has worked great on 4DTV and free channels. It still gets a good picture on the free channels like (Home Shopping and Church Channels) that are out there but it refuses to get 4DTV Prescription Channels. the DC light only blinks on and off and the channel picture flashes on and off and the signal goes up and down constantly.

I spent the day changing the cable to the LNB and I checked the voltage at the cable at the LNB, it was dead steady at (20.4 VDC) 'not spiking at all' and for a 922 it is supposed to be in the 18 - 21 VDC window so the voltage to the LNB is good. That 20.4 volts was while it was on a 4DTV channel.

I've never had an LNB go bad before (had Bud since the early 80's) and I'm curious why it still works on the free channels but it won't work on 4DTV channels.

Is anyone else seen an LNB cause this or has anyone seen a DSR 922 receiver do this?

I see some new type LNB's on Sadoun that look interesting (DMS BSC621) and (WSI NS741) Is one better than the other?

Thanks - Ken

 

[beavs2112]

Hello - Long time member but I haven't posted in a while.

It looks like my BUD C-Band LNB has gone bad, it is fairly old LNB and feedhorn (1980's) and up until recently it has worked great on 4DTV and free channels. It still gets a good picture on the free channels like (Home Shopping and Church Channels) that are out there but it refuses to get 4DTV Prescription Channels. the DC light only blinks on and off and the channel picture flashes on and off and the signal goes up and down constantly.

I spent the day changing the cable to the LNB and I checked the voltage at the cable at the LNB, it was dead steady at (20.4 VDC) 'not spiking at all' and for a 922 it is supposed to be in the 18 - 21 VDC window so the voltage to the LNB is good. That 20.4 volts was while it was on a 4DTV channel.

I've never had an LNB go bad before (had Bud since the early 80's) and I'm curious why it still works on the free channels but it won't work on 4DTV channels.

Is anyone else seen an LNB cause this or has anyone seen a DSR 922 receiver do this?

I see some new type LNB's on Sadoun that look interesting (DMS BSC621) and (WSI NS741) Is one better than the other?

Thanks - Ken

hi. I don't have a 4D but I would think if your LNB really is bad you wouldn't get any channels at all. my guess is your 922 is faulty.

 

[Bowhunters]

Thanks Beavs - That's what I thought also that LNB's tend to either work or not work at all but I thought I would ask since the receiver seems to work perfectly other than on 4DTV.

Maybe someone else will have some ideas also.

Bow

 

[FaT Air]

Are these shopping and church channels analog?? If so, it could be the LNB. Analog is more forgiving than digital. Could be it's drifted far enough off frequency that the 922 can no longer hold lock on the signal. Does the Az or TBS card scan in FTA transponders on the correct freq???
Before doing anything 'drastic' I'd want a response from a someone with a 4D unit to confirm. Seems I've read some posts where there's a way to check in a screen in those units. But danged if I can find one.

 

[beavs2112]

Are these shopping and church channels analog?? If so, it could be the LNB. Analog is more forgiving than digital. Could be it's drifted far enough off frequency that the 922 can no longer hold lock on the signal. Does the Az or TBS card scan in FTA transponders on the correct freq???
Before doing anything 'drastic' I'd want a response from a someone with a 4D unit to confirm. Seems I've read some posts where there's a way to check in a screen in those units. But danged if I can find one.

+1. Hope someone with 4D unit can assist.

 

[waylew]

Are these shopping and church channels analog?? If so, it could be the LNB. Analog is more forgiving than digital. Could be it's drifted far enough off frequency that the 922 can no longer hold lock on the signal. Does the Az or TBS card scan in FTA transponders on the correct freq???
Before doing anything 'drastic' I'd want a response from a someone with a 4D unit to confirm. Seems I've read some posts where there's a way to check in a screen in those units. But danged if I can find one.

Ya mean like this
? http://www.satelliteguys.us/threads/331701-4dtv-sound-dropouts/page2

 

[waylew]

There's a good possibility that one of the small electrolytic capacitors right near the tuner is bad,you'll get analog fine but digital won't lock.If you have an oscilloscope it's relatively easy to find,just check for AC on the + leg of the caps that run right alongside the tuner.

 

[Bowhunters]

Thanks Weylew but its not the same problem as the other person's, his problem was only on TCM if I read his posts correctly. Mine is failing to lock on all the subscription channels so your last post about a capacitor being bad near the tuner could be the problem as I get all the free analogs just fine.

Unfortunately I do not have a oscilloscope so its looking more like I need to send in the box for repairs.

Under Diagnostics A the very first numbers is 922

Under Diagnostics C that you guys discussed in the other thread the second line first number is 1.375 and the last number on line 3 changes back and forth from 1.4 to 6.6 while I sit here watching it. Some other numbers change also.

Thanks

 

[waylew]

I realize that the problem was different,the main thing was the instructions to get the diagnostics.
The local oscillator "LO" @1.375 isn't awful,the other number,which I think is the BER(bit error rate),I'm not sure and can't find the web pages that explained all this stuff anymore,is not good.Like to see that about +7 or higher and steady.
It's possible that the LNB is just getting "noisy" and while it's ok for analog,it just won't cut it for digital anymore.It's also quite possible that it is a bad cap in the 4D generating the "noise" in the receiver.
The biggest problem with sending it somewhere to get fixed is that there really isn't anywhere to send it anymore.If you have a local radio/tv guy he might be willing to take a look at it.
You might just want to try a new lnb or lnbf just to see if that's the problem.

 

[Bowhunters]

I found two brand new C-Band LNB's on Ebay, I mean new as in unused and still in the box and one said it was build in 1996 that will fit my Chapparel feedhorn. One of them is a cheapo brand I've never heard of but the other is made by EchoStar and should be decent quality, I only spent about $25 total between the two including shipping and should get them by Wednesday or Thursday.

The cheapo looking one is a Panorama ER-863 that is 15degree says its for Digital C-Band and says 4DTV.
The other is an EchoStar EA-030 that is 30degree

If neither of these work or make any kind of difference then that only leaves the 4DTV receiver, I thought about getting one of those LNBF's on Sadoun but this is cheaper for two of them and I won't have to play around with tweaking and tuning a new feedhorn.

 

[Cham]

Is your feedhorn a dual or does it have a polarotor? Just wondering if it is changing polarities properly...

 

[waylew]

The er-863 is actually decent,I have 2 of them on my ortho feed on my Paraclipse and they work quite well.The only problem I had was the bolt holes aren't as precise as they could be,so you might have to fiddle with it a bit.

 

[Titanium]

Doubt that the issue is related to the LNB. The religious channels and QVC on G14 are unencrypted digital DVBS channels that do not use the digicipher technology. The problem is likely with the receiver authorization or Digicipher decoding.

 

[migold]

To reach the Diagnostic Screens on the 922, Press Options, 6, 0, 5.
Then go to Diagnostics C
In the Diagnostics C screen, at the end of line three, will be a number with + or - sign, can be any value from -3 to +10.9
The is the 'EBno', and indicates the signal strength that is being received, and is equivalent to a Quality reading. +10.9 is the strongest/highest quality signal. I have had good reception with signal above 8. I don't know the minimum requirement, but I would guess that it would be around 6-7.

 

[waylew]

EBno,that's what I was trying to remember,.It goes higher than 10.9,I've currently got +13 on the dmx channels and if I recall I've seen it higher than that.

 

[migold]

HMMMM... I copied from a document to get that number, so could be wrong, now that I think about it, I think I have had higher than 10.9 also. I had 9.6 when using a LNBF offset from prime focus on my 8 ft solid dish, and that produced a signal with no picture faults. anyway, that is what I used as an indicator for my signal strength.

 

[Bowhunters]

Chan - My feedhorn is a Chapparel with both C-Band and KU-Band LNB's and its on a 10Ft moving BUD, I bought the feedhorn and LNB's back in the 1980's and they were fairly high end from the selection on Skyvision's website. It had worked flawlessly all these years except for one time when the blue Servo motor failed about 6 years ago.

Migold - It sounds like the signal is too low and it constantly changes, I have absolutely zero trees or anything blocking the dish.

Under 605 Diagnostics C that you asked about last number on end of line 3 the readings are constantly changing back and forth from around +1.4 and up to +6.6 and it sometimes jumps to other numbers on the way up and down from that low and high while I sit here watching it. At the same time while the (EBno) cycles up and down the channel picture on the screen pops on and off the same time as the (EBno) constantly cycles up and down every few seconds.

I left the 4DTV off for a while and now I just turned it on and the picture is steady as a rock and number (EBno) is at +7.8 and steady. That (EBno) number goes up and down from +7's to +9's as I change channels (I would assume that's kinda normal) to change signal strength that much on the different transponders, I'm watching BBC America right now and the picture and (EBno) are steady as a rock for right now anyway- LOL.

Would I be correct in assuming the LNB is steady some times (like right now) and other times it is drifting freq when the number constantly cycles between +1.4 - 6.6?

I should also state that the same times that the picture is bad and the (EBno) is cycling down to +1.4 that the DC light on the 4DTV receiver is also flashing off and on constantly. Right now while I am watching tv with it and it is working the DC light is normal (steady on). I'm going to leave the 4DTV on all the time today and see how long the picture stays up and i'll check if the (EBno) number starts cycling up and down again like it did before when I had no picture.

Thanks everyone for helping me, I didn't know about 605 and the Diagnostic windows. A B C D and I wouldn't have had a clue as to what numbers mean what.

Bow

 

[Bowhunters]

Interesting changes here, yesterday (Monday 17th) after shutting down the 4DTV receiver for about 6 hours I turned it back on and on many channels it worked with a steady picture as I mentioned in the post above however I have found that I cannot get a couple channels that now do not come in and the Quality indicator is stuck at ( 1 ) and some other channels the picture still goes in and out and the EBno still drifts up and down between +1.0 - +9.0.

A couple like the Outdoor Channel & Fox Sports 2 do not come in at all it says (Cannot find Channel) and the Tuning Quality is stuck at ( 1 ) even Skewing and bumping the dish does nothing while most all the channels come in perfectly with Quality in the 80's and 90's and high EBno readings of around +9.0.

 

[waylew]

When you say shut down,do you mean just turned off or unplugged from the AC outlet?
Also,is this a Motorola 922 or an older General Instrument?

 

[Bowhunters]

Hi Waylew

It was just turned off from the remote control (not unplugged). So its not like it cooled down overnight if that is what you were thinking.

Its a Motorola 922, even the remote says Motorola.

The Outdoor Channel and Fox Sports 2 still do not work at all (Black Screen and Quality sits at 1) which is actually zero on both of those channels even when the other channels work fine or work intermittently. I went on the Lyngsat site but I couldn't figure out if they are on the same transponder or not.

I can't wait for those new LNB's to arrive in a few days, I'm going to put the receiver on one of those two dead channels and verify its Quality is still at zero before I shut down to change LNB's and then see what happens when I turn it on afterwards, if I get those two to come up and the rest are solid then maybe I will have this beat.

Thanks Bow