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User Instructions for the
Amstrad Fidelity SRD400
© SatCure 1994
No part of this publication may be copied by any means, stored in a retrieval system or
transmitted in any form without the prior consent of the copyright holder.
First edition 1994
Converted to PDF October 18, 2000
All rights reserved.
Amstrad is a registered trademark of Amstrad plc.
Videocrypt is a registered trademark of Ferguson plc.
All other trademarks are acknowledged.
DISCLAIMER
The information given in this booklet is given in good faith and is believed to be correct at
the time of writing. Neither the author nor the publisher will accept any liability for death,
injury, loss or litigation which arises directly or indirectly as a result of the use of
information published in this booklet. It is the responsibility of the reader to check the
facts. In addition, it is recommended that work on satellite receivers be carried out only by
qualified personnel.
Page 1
Introduction
Amstrad plc made it possible for the “man in the street” to purchase a low-cost satellite
receiver in order to watch satellite TV programmes from the Astra satellite designated
“Astra 1A”. The first receiver produced was the 16 channel SRX100 which did not have
an internal decoder. This receiver was upgraded to the SRX200 which worked with a
remote control handset. The SRX200 was later given 48 channels to cope with the
additional channels from the Astra 1B satellite and from the proposed Astra 1C.
Then the SRD400 was introduced, still with 48 channels and remote handset but also
containing a Videocrypt™ decoder which is needed to watch the scrambled channels
transmitted by "SKYTelevision".
Later receivers such as the SRD510, SRD520, SRD540, SRD550 have proved to be
somewhat less reliable than the early models, although they do have the benefit of
additional features such as on-screen menus, additional audio frequencies and more
channels.
Compared with more expensive receivers, the SRD400 has rather grainy pictures and the
audio does not use the true Wegener Panda™ stereo noise reduction circuitry. However,
unless you are a very discerning listener and watcher, you are unlikely to notice the
difference. In fact, compared with the average terrestrial television picture, the SRD400
satellite pictures are superb!
So, no matter whether you bought this receiver new or at a car boot sale, you may be
assured that you have got good value for money.
Now read on to find out how to use and improve on your purchase:–
If your SRD400 is not already installed you need our “How to Make Money from Satellite
TV” guide which explains all about installing satellite TV systems with a minimum of
equipment. Without following the professional methods described in the guide, you could
make mistakes which will fail to get the best from your equipment or even cause damage.
Assuming that your receiver is already connected to a properly installed dish, the
following information will guide you in obtaining the best pictures and sound and in
recording programmes on your video recorder.
Connecting up
The receiver, TV and Video recorder must be “chained” together by connecting them in a
particular order and you can do this by using either coaxial “RF” cable with an ordinary
TVplug at each end or by using a “SCART to SCART” cable.
In order to watch recorded programmes you must connect the TVafter the video recorder.
In order to record satellite programmes, the video recorder must be connected after the
satellite receiver.
Page 2
So the line-up is as follows:
• TV aerial connected into the satellite receiver “RF in” or “TV in”.
• Satellite receiver “RF out” connected to video recorder “RF in” (or use a SCART–
SCART cable from satellite receiver “SCART/ PERITEL” to the appropriate SCART
socket on the video recorder).
• Video recorder “RF out” to TV (or use the appropriate SCARTconnector between the
two).
There are more complicated ways of connecting with SCART cables or a combination of
SCART and RF leads but the method depends upon the sockets available on your
equipment.
If in doubt, use the RF connection method to begin with.
The advantages gained by using SCART are as follows:
• No need to “tune” the TV to the satellite receiver.
• Marginally better picture quality, provided that high quality SCART leads are used
(some cheap ones can make the picture worse!)
• Stereo sound from your TV (if it is equipped for stereo).
You can also link the Left and Right stereo outputs to the “Auxiliary” or “CD” input on
your Hi-Fi system.
It’s not obvious to most people but your video recorder has a built-in TV tuner. In fact it is
a TV except that it has no screen! You can prove this by unplugging your TV set whilst
recording a TV programme. The video still works! This is why you must tune the video
recorder in to each of the watchable TV channels when you first install it. It does not get
pictures from the TV – it produces them from the aerial signal, direct.
Your satellite receiver sends its programmes out of its “RF out” socket on one TV channel
frequency (usually channel 38). You must tune your TV set to this channel and store it as
button 6 (for instance). Your TV will already be tuned to the video recorder (usually on
channel 5 or 0). With TV channel button number 6 selected you can now watch any
satellite channel you care to select with the satelliteremote control.
Now, you must tune your video recorder to channel 38 and store this as number 6 (or
Page 3
whatever number you wish). To do this, select the video recorder channel with your TV
remote and select a satellite channel with the satellite remote. Now follow the tuning
instructions for your video recorder and tune it to see the satellite channel on the TV. (It is
easier if you flip the TEST SIGNAL switch ON in order to see the test bars on the TV
screen when the video is tuned).
Leave the satellite receiver switched ON to record the satellite channel which is selected.
Channel customisation
The receiver’s channels are factory-set to Astra satellite frequencies.
The only way to reset your receiver to these values (maybe somebody messed up the
settings or the audio disappeared) is to get an engineer to fit a new (blank) channel
memory I.C. (SDA2516), which will automatically set the correct channels, or to tune
every channel manually by pressing buttons.
To do this, set channel 1 as the lowest frequency as follows:
Select channel 1 by pressing the [1] button.
Press Tune ▼ until the lowest number in the display is shown (about 0960). If you
overshoot simply press Tune ▲ until the number is displayed. then press [PRESET] twice,
to store this frequency as channel 1.
Then press the following sequence repeatedly:
[PRESET] [Tune ▲] [PRESET] then [Channel ▲]
Make sure that each time you press [Tune ▲] the [H/V] light changes from on to off or
vice versa; if it does not change, immediately press [Tune ▲] again then carry on with the
sequence.
This method puts the channels into transponder order.
If you want them set with all SKYor English channels first you must customise each
channel by pressing [Tune ▲] repeatedly until the required channel appears. The actual
frequency displayed is only approximate and you must imagine a "1" in front of it so that
it matches the channel frequencies listed in the satellite magazines.
H/V
This setting determines the channel polarisation: horizontal or vertical. The H/V POL
setting can be adjusted between horizontal and vertical. You don’t really need to know
what this means but the technically minded might be interested to know that when you
select vertical polarisation, the receiver sends 13 volts up the cable to the LNB on the
dish. When you select horizontal the receiver sends 17 volts. The LNB looks for the
Page 4
appropriately polarised signal, reflected from the dish, according to the voltage it receives.
In standby, the receiver turns off the LNB voltage. You will not need to change this setting
for pre-programmed Astra channels but you may need to change it if you customise any
channels to receive broadcasts from another satellite.
AUDIO
The AUDIO setting can be adjusted from sound tracks 1 to 7. Some channels use several
sound tracks for different languages. For these channels, select the sound track with the
appropriate language. Some channels use two TVsound tracks together to produce left
and right stereo. Most channels also use some of the sound tracks for mono or stereo radio
channels. For instance, you will find BBC Radio 1 to 5 on satellite in MONO but, because
the SRD400 can not provide all of the available audio frequencies, you will not be able to
receive them all.
To select a channel for radio it is best to use channels 48 downwards, to avoid confusion.
Find out what satellite TVchannel carries the radio that you like and tune the picture in.
Then press the [AUDIO] button to get the radio sound track and store it by pressing
[PRESET] twice.
FINE TUNE
This setting determines the fine tuning of ALL channels to match a particular LNB on the
dish.
You may need to adjust it if some channels seem slightly off-tune despite their frequencies
being displayed correctly in the menu (you will see either black "sparklies" or white ones
on the satellite picture).
To adjust it, locate the tiny hole, near the front of the receiver, underneath. The adjuster
slot is recessed deep within this hole. Turn it slowly with a suitable screwdriver until the
sparklies disappear from the satellite picture.
Checking the receiver status
Press [RECALL] once. The channel frequency will appear on the display then disappear
after a few seconds to show the AUDIO selection (1 — 6) which will also then disappear.
Pressing [RECALL] has no effect on the settings but simply allows you to check them.
Using a D2Mac Decoder
The SRD400 can not be guaranteed to work with every D2Mac decoder on the market so
this is intended as a brief guide. Try to see it working with your SRD400 in the shop
before you buy the decoder.
Page 5
The video output comes from from the Baseband Phono socket at the rear of the receiver.
For D2Mac decoders, a standard "D" to SCART lead will not work without modification.
Modify a standard lead for your SRD400 as follows:
Remove the cover from the Scart plug. Locate pin 19 in the plug and cut the wire. Solder
a wire to this wire to extend it out of the socket and replace the cover. Solder the wire to
the centre pin of a Phono plug. Plug the Scart plug into the TV SCART socket on the
SRD400 and plug the Phono plug into the Baseband Out socket.
D2Mac channels are mostly scrambled using the Eurocrypt™ method and require a smart
card which is not legally available in Britain because of copyright reasons. Pirate cards
may be available but can not be relied upon and may damage your decoder.
Channel Lock facilities
Press [H/V] [H/V] [Recall] on the front panel.
You will see four dashes in the display.
Use the handset to enter a four digit number.
Press [Recall]
The receiver will now be locked on the currently selected channel.
If you unplug the power cord then plug it back in, the receiver will remain locked in
Standby.
To unlock the receiver:
Press [H/V] [H/V] [Audio] on the front panel
You will see four dashes in the display.
Enter the four digit number which you used to lock it.
Press [Audio] on the front panel.
If the lock number is not known:
Unplug the power cord then plug it back it.
Hide the handset and don’t let anybody press buttons on the receiver.
After 48 hours the receiver will unlock itself.
Looking After your Receiver
The main enemies your receiver must contend with are:
• Heat
• Moisture
• Mains surges
You should do your utmost to protect your receiver from these.
Page 6
Heat
Mount the receiver on a smooth surface so that air can go beneath. Never place it on a
carpet or cloth. If possible, put small spacers beneath it to allow better air flow
underneath.
Do not put anything on top of it. There should be at least 3 inches (75mm) clearance
above it.
Do not place it on or near anything which becomes at all warm.
Shield it from sunlight and heat from a fire.
If you must put it on top of other equipment, make a small shelf out of plywood or
hardboard, painted to match. Put spacers beneath the shelf to allow air to circulate. If the
receiver is in an enclosed cabinet you must fit a small fan to keep the air circulating.
Moisture
Don’t put drinks on your receiver. Don’t use polish on it. If you must have it looking clean
and shiny, use a water repellent spray such as WD-40™ or Duck Oil™. Spray this onto a
polishing cloth, not directly onto the receiver. Stains and marks can be removed by
applying a little windscreen De-icer spray to a rag and wiping the receiver with this.
Disconnect it from the mains electricity first!
Mains Surges
Your Receiver has an internal fuse designed to melt in the event of a power surge. You
can avoid problems by ensuring that you do not plug in a vacuum cleaner, lawnmower,
etc. near to the receiver (or unplug it first) and by unplugging it during a storm. You can
also fit a “spike suppressor” mains plug to it.
Faults
If your receiver appears to be faulty, the first thing you should do is to unplug it from the
mains power for a few minutes. If this cures the fault then it was probably caused by a
mains surge. Make sure that no wires inside the mains plug are loose – all screws tight –
and that the outer plastic sheath of the mains cable is clamped firmly where it enters the
plug.
Read the section about mains surges.
If unplugging it for a few minutes does not cure the fault then overheating may be to
blame. Try leaving the receiver unplugged for an hour or two. If this cures the fault tem-
porarily then it is suffering from an intermittent fault and must be repaired and upgraded
before it becomes worse.
No decoder messages: if unplugging the receiver from the mains for a minute does not
cure this then the decoder board may need to be replaced. However, decoders are not
cheap. See if you can find another one in a car boot sale or send yours for repair.
Page 7
Sparkly pictures can have a multitude of causes. If sparklies are both black and white
then a poor signal is the cause. The tuner module may be at fault but it is possible that the
dish has moved out of line or the cable or LNB are faulty. Of course, very heavy rain or
snow can also cause this fault, as can anything obstructing the dish (such as a tree). If the
sparklies are only black or only white then the tuning is incorrect. Make sure that the
affected channels have the correct frequency set then try the fine tune OFFSET adjust-
ment (described earlier) for the best picture quality on all channels.
Sometimes you can trick the receiver into tuning correctly. If you can’t get rid of white
sparklies, press [tune down] then immediately press [H/V] and wait. If the picture clears
press [Preset] [Preset]. to store it. If the sparklies are black, press [tune up] then [H/V].
No pictures or sound, just a grey screen with "snow":
Probably caused by no LNB voltage from the receiver. Try replacing the 630mA fuse
inside your receiver. If the fuse melts again then you probably have a short circuit in your
cable screw connectors. If the fuse is intact but you can measure no LNB voltage (use a
volt meter with one test probe held on the cable input connector thread and one touching
the centre) then the 6R8 resistor may be damaged and need replacing.
Can’t Tune receiver to TV:
Sometimes the receiver is tuned to a channel which is already in use by a terrestrial TV
station. In this case, pick an unused channel on your TV and turn the screw marked
CH.ADJ at the rear of the SRD400 until the satellite picture appears on the TV screen.
Pictures are grainy and of poor quality or interference on pictures:
Use good quality RF leads made with double-screened coaxial cable. The TV plugs on
these leads must be soldered on.
Channel Expander for Astra 1D
Tune Astra 1D channels with Channel expander light on:
frequency pol dish
Sky Movies Gold/Weather channel 1.377 V B
Granada Talk TV 1.332 H B
Granada Good Life 1.347 V B
The Warner Channel 1.362 H B
Country Music TV 1.244 H B
CNBC 1.229 V B
(There are also other foreign stations and radio channels available)
Page 8
Amstrad SRD400 Channel Expander Control
The Amstrad SRD400 satellite receiver has proved to be a reliable workhorse since its
introduction over six years ago. Despite its technological age and 48 channel limitation, it
can still give excellent sound and picture quality. In fact the only real limitation is its tun-
ing range.
With the introduction of the Global Communications “ADX-plus” Channel Expander,
even this limitation has been removed. You can now watch programmes from Astra’s
fourth satellite, “1D”, along with the best. The ADX can shift the entire band of frequen-
cies 500MHz higher. However, the ADX has to be selected manually when you want it to
do this — a drawback for “couch potatoes” like I am. (like me?)
The only switching function which can readily be used on the SRD400 is the
TV/SAT button. However, this selection can not be stored on a per-channel basis. The
ideal solution would be to allocate a specific number of channels for Astra 1D pro-
grammes and to have the ADX switch on automatically when each of these channels is
selected.
Help is at hand! This article will explain in detail a simple, low cost solution.
My initial thought was that it would be
a simple matter to select a number-display
segment which lit up only for a specific
range of channels. The top left segment of
display three was chosen as being ideal in
that it lights only for channels 40 through
48 (see Fig.1)
The initial enthusiasm was dampened when a glance at the circuit showed that the
LED segments are multiplexed. They are actually pulsed by the display driver IC which,
in turn, receives serial data, from the microcontroller, that would be difficult to interpret.
In addition, the common cathode of each seven-segment display unit is strobed. There is
no steady DC voltage or even usable pulses with respect to the zero volt reference.
Luckily the old bonce, being entirely uncumbered by folicular growths, remains fair-
ly cool and immediately (well, seven months after the original idea to be truthful) came
up with a solution. An optocoupler hooked across the relevant LED segment would give
a pulse output which could be “smoothed” and used to control the ADX. Thus was the
present design conceived.
Since every SRD510 power supply uses a CNY17 optocoupler (or equivalent) I was-
n’t short of these. The optocoupler LED was connected between pin 16 of the LED dri-
ver, IC151 on the front panel, and the centre leg (collector) of the PNP strobe transistor,
Q152. With the optocoupler transistor emitter grounded and a 1kΩ resistor between col-
lector and 12 volt supply, the goal was achieved. The pulses from the optocoupler are fed
via a 10kΩ resistor to a PNP
BC557B (anything will do) and smoothed by a 100µF elec
-
trolytic. The BC557B is connected via a 270Ω to the ADX
The circuit is shown in Fig.2
Page 9
Fig.1
The few components required cost very little and can easily be assembled onto a
piece of “Veroboard”™ or similar. The complete assemby should be kept small. After
attaching wires, insulate it and tuck it away beneath the decoder board.
The sketch of the SRD400 front panel board, Fig.3, shows where to solder the three
wires. Zero volts is point “1”, Q152 collector is point “2” and IC151 pin 16 is point “3”.
The 12 volts is derived from point “4” on the small regulator board which is bolted
to the heatsink in the SRD400.
A minor drawback of the system is that the chosen segment will light while you are tun-
ing the receiver. To overcome this nuisance, disconnect the wire and switch the ADX ON
while tuning. Once the channels are tuned and stored, switch the ADX OFF, reconnect
the control wire, and it will then be switched on automatically for channels 40 to 48 only.
Page 10
Fig.3 Front Panel
Fig.2 Circuit
This system will also work for the Amstrad SRX200, the later version of which has 48
channels. You will have to hunt for the 12 volt supply (it’s on one of the ICs near the rear
of the receiver) but the front panel connections are very similar.
This book is NOT free!
Please send £2.95 to
SatCure
PO Box 12
Sandbach,
CW11 1XA
England
Postal order, Stamps, UK coins, Scottish pound notes or 3 dollar bills please.
Be sure to include your e-mail address so I can say thanks :o)
See our web sites at:
http://www.satcure.co.uk
(Sky Digibox only) and
http://www.netcentral.co.uk/satcure
Packed with “FAQ” information about common faults and cures for faulty satellite
receivers and decoders. Repair kits, upgrade kits, spare parts, surplus compo-
nents plus links to other satellite information sites. Also Valve (tube) Audio stuff,
Electronic Hobby kits, Dolls House & Model Railway electrical stuff, Beginners’
electronics course, Apple Mac accessories, smokers clay pipes and lots of other
information that will keep you occupied for days!
Page 11
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