Dead Echostar LT8700

R

rt2000

Member
My Satellite Setup
RX's - Echostar AD3000IP, LT8700, SR5500 (mothballed), T-101. Nokia DVB9200. Panasonic TU-DSB30. Humax Foxsat-HD. Dishes - 2.4m Channel Master (CM), 1.6m & 1m John Levick, 2 CM mini dishes. Various LNB's including CM, CA, SMW at Ku, C, S, L bands.
My Location
Hereford and Worcestershire
Hi All

I'm new to the site and came across you folk while looking for a solution to a problem with my LT8700.

In a thread here ... http://www.satellites.co.uk/forums/analogue-systems/55484-echostar-lt8700.html I thought I may be close to it but the problem the thread describes indicates that the power LED is still on. In my case the thing is dead, no power LED or any reaction from buttons on-board or remote.

I have no problem replacing things like the capacitors etc. as long as I know what I need/may need to replace. Has anyone else had the same problem and found the fix? I would more than likely scrap it but I really could do with using it for S-band at the moment (the only thing it does now really :( ).

Thanks in advance
Ron
 
Probably power supply capacitors failed. Here's a schematic for the power supply -
 

Attachments

Thanks for the schematic Llew, I'll study that later. I guessed it may be a cap somewhere on the PSU.

Ron
 
So Ron, what is currently available where you are on S-Band ? (not that you can see it atm)
 
Hi Channel Hopper. Not much at all to be honest, I gave up looking a good while back. However, I do use it for a link to a remote wireless camera, the directional qualities of the feed make for picking it up at a reasonable distance.

I've yet to open the LT back up and identify the capacitors, if there are not too many I may just change the lot! It's a shame the AD dosn't go down that far but the LT has served well over time so worth fixing if I can, I may even have a go at the SR!

Ron
 
rt2000 said:
Thanks for the schematic Llew, I'll study that later. I guessed it may be a cap somewhere on the PSU.

Ron
Click to expand...
As you say the receiver's stone cold dead, might be a good idea to make sure the DC voltage is being applied to the switching circuit before replacing anything.

With a DC meter, check there's a voltage both sides of diode CR14. Should be well over 300V. If nothing, the bridge rectifier may have died. (Use the common ground of the input stage for your meter's ground lead, not the receiver chassis!)

If no signs of life, on the AC side of the bridge rectifier, check back to the AC input from the bridge rectifier for AC voltage. Could be thermistor RT1 dead.
 
Thanks again Llew, I'm hoping to get the top off this week ... well that's the plan, typically, when you want to settle and do something everyone wants a chunk of your time!! :(

Ron
 
I assume you have checked the fuses :o
 
No fuses in the power supply, just the fuse in the mains plug, which Ron will no doubt have checked (hopefully...)
 
Yes, fuse checked :-righton
 
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