Inside the Silvercrest SL65


There are security seals to prevent you disrobing your receiver. Sure, you can whip the box open quite easily but you'll invalidate your guarantee, and if you don't take precautions you can either kill your box or kill yourself - switchmode power supplies bite, so does the mains.
So don't follow my example. Look at the pictures and keep your own receiver in one piece...


A first look

Inside the SL65
Click to see a larger version of this picture.
Inside the SL65. (click to see larger version - 1277×764, 217Kb)

On the left is a compact and efficient switchmode power supply. It runs cool, outputting 24V, 9V, and 3.3V DC.
The middle and right is the motherboard. The tuner top-right, SCARTS and interfacing along the back. The bundle of wires disappearing to the front is for the front panel LED and switches.


The heart of the receiver

The heart of the SL65.
Click to see a larger version of this picture.
The heart of the SL65. (click to see larger version - 2048×1024, 402Kb)

This is it. Seriously.
On the left, an SRAM memory device (capacity unknown - 8Mb seems common for FTA receivers). I don't know what the link (centre left of the picture, behind that capacitor) is for. Write-protecting the FlashROM perhaps? Below the SRAM are 6 pins. I would imagine that is a JTAG interface. This is used for in-situ programming of the flash memory and is intended for production line programming. It is also useful to try to rescue a dead box after a flash burn failed for any reason.
To the bottom, and beside that the bundle of wires leading to the front panel display/buttons, an EON device - a FlashROM. I don't exactly know the capacity, however the generic firmware from Comag's website is 1.6Mb so it would seem logical to assume around 2Mb.
You will notice just below this, printed onto the circuit, is part of a "pb free" notice. This receiver is 'green' in that not only is it low consumption, it is also lead free.
The little silver thing, just going off the upper right, is the 27MHz clock source from which the system runs.

This leaves only one thing. That big square lump with the piece of metal on top. This is the heart of the receiver. It does everything, sorting out what stream to display, the zooms and mosaics, the user interface (including a game of Tetris!), managing the memory, programming the flash memory, responding to the remote, outputting a signal in PAL or NTSC, 50Hz/625 or 60Hz/525; or RGB, or S-video. Very impressive, no?
This device is an ALI STi5518-alike chip, which contains everything necessary to create a digital satellite receiver. Not only that, but it apparently offers an ATAPI interface to connect to low-cost DVD readers and the audio system supports MP3. In short, with the required hardware this one chip could provide a fully integrated satellite/terrestrial/DVD unit with the optional ability to play CD-Rs full of MP3s.
This device runs warm to the touch - however as you can see the heatsink isn't much more than a flat piece of metal stuck to the top, so it doesn't belt out loads of heat.

We cannot draw direct comparisons with the Digibox due to the need to handle encrypted streams, however this one device performs the job of three or four separate ICs in the Digibox (Pace 2500B). The speed difference between the two units is really quite astonishing. The Digibox always seems a little slow to respond, like it is busy doing loads of other things in the background (which may be true), while the SL65 is like one of those annoying yappy little puppies - always responsive and eager to please.
While I say we cannot draw direct comparisons, I can point out that both receivers are based upon the ST20 RISC core, and both have a crystal clocking 27MHz. I suspect that there is a lot to be gained by having more of the system on a single piece of silicon.


The tuner

Tuner module.
Click to see a larger version of this picture.
The tuner module. (click to see larger version - 1024×600, 120Kb)

Your LNB receives horizontally polarised frequencies, or vertically polarised frequencies. However, rather like your television antenna, the LNB receives all frequencies within the limits of the reception capabilities of the LNB (remember, universal LNBs split the reception range into two bands - for technical reasons of what it is possible to push down a co-ax wire).
The tuner must then take all of this stuff and extract from it the exact frequencies that the user requires. It must be sensitive to be able to pick out a workable signal from less than optimal input, without being so sensitive that it is easily swamped by stronger signals. In addition, it is expected to output a 22kHz tone to select the upper or lower reception band, along with a pulsed 22kHz signal for controlling satellite switching devices. Oh, and providing up to 300mA to power the LNB(s) and switch(es).
As an analogy, this is like trying to follow a conversation in a crowded railway station while providing a running translation into sign language.
All in all, quite a lot is asked of this module.

The tuner in most Digiboxes runs, if not "quite warm" then simply "hot". Touch the top of your Digibox, I bet the hottest part, which might be worrying hot, will be above the tuner module (you can easily tell where this is, just look for where the satellite cable plugs in).
The tuner in the SL65 runs 'cool'. I previously said that it ran warm, but I was mistaken - that warmth was coming from the rather obvious big heatsink (you can see this in the picture, the blurred thing lower centre).
It is interesting to me that the tuner is a plug-in unit. I wonder if replacement tuners can be purchased - either perhaps even more sentitive, or maybe operating on a different band?
Or, here's an idea... a UHF tuner and different firmware, it could be a DTT receiver!


Power supply

The power supply for the receiver is a small, efficient, switchmode unit. When fully operational, the receiver draws 13W. Then in standby, much of the receiver is shut down, so the unit draws an impressively tiny 3W! Three!
These figures are from the SL65 user guide downloaded from the Comag website.

The power connection on the motherboard.   The power supply unit.
Click to see a larger version of this picture.
The power connection on the left; the power supply module on the right (click for big; 980×530; 124K)



There are four versions of the SL65.
Two are mains-powered satellite receivers. One is a 12V 'camping' satellite receiver. One is a DTT receiver.

We shall concentrate on the two regular satellite receivers. The 2005 model (screws at the side of the case) is based upon an STi5518 chip, and much of the stuff on-line is said to refer to this.
My receiver is the later model, 2006, version (screws at the back) is based upon an ALI chip which I assume is an STi5518 clone; sadly there are a number of changes in how this works - which appears to extend to potential incompatibility with software such as the channel editor provided by Comag - you need to visit the Silvercrest website as it goes under the Silvercrest branding, even though it is Comag equipment... Also the setup and menus are slightly different.

       Number of TV programmes  ? Up to 4500 programmes in total.
    Number of radio programmes  ? Up to 4500 programmes in total.
 Number of user added channels  4500
          'Favourite' channels  Yes
       Channel categorisations  Yes, choose from categories like 'news' or 'music'

              Timer facilities  Yes, up to eight timed events
                  Timer repeat  Optional - daily, weekly, monthly, annually

         Input frequency range  950MHz - 2150MHz
     Actual frequency coverage  3000MHz - 13450MHz (C band to Ku band; depends on LNB)
     DiSEqC versions supported  1.0-1.2
                         USALS  Supported
          Channels managed by?  Automatic scan, or user-defined
    User choice of VID/AID/PID  Yes
            User choice of FEC  No, it is automatically determined

             On-screen display  Yes, banners and menu-driven
            OSD multi-language  Yes, several (GB, F, D, E, GR, T, etc etc)
           Front panel display  4×7-segment LED, plus power LED

             QPSK demodulation  MCPC - SCPC / MP@ML
                      Bitrates  1000 to 45000 Mbaud
       Supported image formats  4:3 full (pan&scan), 4:3 letterbox, 16:9
 Supported broadcast standards  PAL (720×576), PAL-M/NTSC (720×480)
                  Picture zoom  Choice of 2:1, 4:1, 6:1, 8:1, 12:1, 16:1
                 Multi-picture  Up to 9 thumbnails, one 'active' at any time
   Picture stretch/resize blit  Not supported except for 'zoom' mode; internally
                                supported for menu resizing, 16:9 stretch, etc.

                Audio decoding  MPEG-2 layer 1 and 2; mono mix, stereo, left, right
      Audio channel selection?  Yes - press 'audio' key and choose from available
          Digital audio output  SPDIF

                           EPG  Now and next; description of current programme
                   Interactive  Not supported
          Teletext (WST 1/1.5)  Supported; large 800 page smart cache
                                Teletext also inserted into VBI for TVs/capture
            Videotext services  Not supported
                    Subtitling  Supported; may be switched on if required
                     Date/time  Supported; can set GMT offset in 30min units

                PIN/child lock  Provided, specific channels may be locked

           Microprocessor core  ALI (STi5518-alike?)
             FlashROM capacity  2Mb?
                SDRAM capacity  8Mb?
                          JTAG  Appears to be so, 6-pin interface
              FlashROM protect  Appears to be so, jumper near Flash device

            On-line facilities  None
                         Modem  Not supported

                    LNB inputs  1
             LNB loop-through?  Yes

                   UHF outputs  Not provided
              UHF loop-through  Not provided
                        SCARTs  2×
                   SCART modes  CVBS / RGB / YUV
        Composite video output  Yes
          S-video (Y/C) output  Yes
      Left/right audio outputs  Yes
          Digital audio output  Yes
          Optical audio output  Yes

         Upgrade via satellite  Yes (from Astra 19.2°E)
 Upgrade via serial connection  Yes
       You can backup firmware  Yes
       You can backup channels  Yes
  You can backup configuration  Yes
      You can replace firmware  :-)
           GUI settings editor  Yes, MS Windows software is available.

 Startup time (from power off)  About 4 seconds
   Startup time (from standby)  About 4 seconds

 Power consumption (operating)  10W (from user guide) - 100/240V autoranging
   Power consumption (standby)  3W  (from user guide)   (according to user guide)

       Manuafacturer's website  User guide:

If you can help clarify or correct the information on this page, please do email me!


In comparison with...

For what it is worth, we'll hold the same yardstick to the Digibox (model Pace 2500B):
       Number of TV programmes  Max ~898 (channels 101 to 999)
    Number of radio programmes  Max ~898 (channels 0101 to 0999)
 Number of user added channels  50, which are frequently 'forgotten'!
          'Favourite' channels  Yes, up to 50 may be assigned as favourites
       Channel categorisations  Yes, provided by the EPG list

              Timer facilities  Comprehensive 7-day timer by programme
                  Timer repeat  Optional, programmes may be 'series link'ed

         Input frequency range  950MHz - 2150MHz
     Actual frequency coverage  10700MHz - 12750MHz (Ku band)
     DiSEqC versions supported  None
                         USALS  Not supported
          Channels managed by?  EPG list provides all channels and categories
    User choice of VID/AID/PID  No
            User choice of FEC  Yes - 1/2 2/3 3/4 5/6 7/8

             On-screen display  Yes, banners and menu-driven
            OSD multi-language  No, just English
           Front panel display  4 LEDs - on/stby, remote, message, online

             QPSK demodulation  MCPC / MP@ML (?)
                      Bitrates  ~22000 and ~27500 Mbaud only
       Supported image formats  4:3 full (pan&scan), 4:3 letterbox, 16:9
 Supported broadcast standards  PAL (720×576)
                  Picture zoom  Not supported
                 Multi-picture  Not supported; unless by interactive content
   Picture stretch/resize blit  Frequently used to make more interactive content,
                                but no zoom facility is available to the user
                                aside from TV aspect ratio setting.

                Audio decoding  MPEG-2 layer 1 and 2
      Audio channel selection?  Only if specifically provided in interactive
          Digital audio output  No

                           EPG  Full & complete 7-day listings of all TV channels
                   Interactive  Supported
          Teletext (WST 1/1.5)  Not supported; teletext inserted into VBI
            Videotext services  Supported
                    Subtitling  Supported; may be switched on if required
                     Date/time  Supported; fixed to UK time, auto BST change

                PIN/child lock  Provided, but inactive without a viewing card

                                The following is specific to the 2500B. The Sky
                                specification dictates how the receiver will
                                behave. Internals are left to the manufacturer.
           Microprocessor core  ST20
             FlashROM capacity  2Mb?
                SDRAM capacity  4Mb?
                          JTAG  Apparently, from some on-line reports, where?
              FlashROM protect  No

            On-line facilities  Dial-up including TCP/IP support
                         Modem  33k6 (?)

                    LNB inputs  1
             LNB loop-through?  No

                                The following is specific to the 2500B. Some
                                manufacturers added non-standard things to the
                                design, it is alleged that Sky sulked greatly...
                   UHF outputs  2×, including one which can output 9VDC
              UHF loop-through  Yes
                        SCARTs  2×
                   SCART modes  CVBS / RGB
        Composite video output  No
          S-video (Y/C) output  No
      Left/right audio outputs  Yes
          Digital audio output  No
          Optical audio output  No
         Upgrade via satellite  Yes - user-requested or broadcast-forced
 Upgrade via serial connection  No
       You can backup firmware  No
       You can backup channels  No
  You can backup configuration  No
      You can replace firmware  No
           GUI settings editor  No

 Startup time (from power off)  About 83 seconds!  [timed @ 3pm CET on 2007/03/02]
                                ~26 seconds to initialise
                                ~49 seconds to load the EPG channels list
                                ~ 8 seconds until you can then change channel
   Startup time (from standby)  Instant, as receiver does not shut down

 Power consumption (operating)  25W (estimate)
   Power consumption (standby)  25W (estimate) - receiver operates when in standby!

       Manuafacturer's website, see also


Next: ( Geekfest! ) Communicating with the SL65 ( Geekfest! )...


Back to non-Sky receiver index · Digibox main index

Copyright © 2007 Richard Murray