Echostar LT8700 No Picture

garga pista

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Hello!
I'm trying to repair an LT-8700 receiver, looking for a schematic or service manual, or just an advise. It works "halfway". The receiver boots up, front panel display and remote works, but no picture output. No picture, nor OSD on the TV scart, RCA plug, or on the modulator.
The receiver had D2mac and Videocrypt decoder boards, I've removed both, it works without that 2 panels, but still no picture.
But on the VCR scart i can get "sparklies", changing the channels seems working, but no OSD on the VCR scart :(
But if a connect an another receiver on the VCR scart, the receiver switches to it, on the decoder phono out comes out the picture (still without osd).
PSU works, all the voltages measured correct. Does someone has any advice? I've made some pictures from the inside, it looks interesting, that there's a vertical panel in the back with 3 connectors. From the 3 connectors, one has a lot of cables running different places in the main board. Is this normal, or is it retrofitted?

IMG_20200522_190115.jpgIMG_20200522_190122.jpgIMG_20200522_190140.jpgIMG_20200522_190148.jpg
 

Channel Hopper

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You may find the fault is a switching transistor on the main board, diverting signals through the decoder boards when a particular encryption was received.

Have you tried working your way - blind - through the menus to perform a factory reset ?
 

garga pista

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Thanks for the reply, first i tried blind the factory reset, it did not help. Then i removed the 2 decoder boards- still nothing. I couldn't find the service manual, but looked for the chip datasheets from the main board. And bingo! The STV0030 switches between AV,decoder, etc and inserts OSD. So I traced down where the signal goes, and found a bad soldered capacitor under the vertical sound panel (someone already tried to fix it, badly soldered it) So soldering back a new capacitor properly made the receiver back in life :) Here's a picture about it. And here's the datasheet for the STV0030 chip, it could be useful for fault finding, for me this was the solution: Datasheet Archive STV0030 datasheet download
Edit: upload the datasheet here
STV0030_main_board.jpg
 

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