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Satellite Workshop 14

Stereo Sound

Some questions arise time and time again. A favourite seems to be "when I connect my satellite receiver to my Nicam stereo video recorder with the RF cable, I don't get stereo sound." The answer is to connect the left and right audio connections via Scart or Phono sockets (whichever is provided). Even then, the "Nicam" light will not be displayed on the video recorder because "Nicam" stereo is not available via satellite. However, Dolby Pro-Logic is used on many films and a suitable receiver and amplifier combination (or MSS1000) will provide amazing sound effects.

Cambridge RD480

This receiver seems to have received a new lease of life as it appears on the second-hand market at ridiculously low prices. However, it is invariably sold without a User Handbook and this produces the same question (even from dealers): "How do I get the on-screen menu?" Well, you don't because this model does not produce one. It is limited to the front panel display only. Since the display does not show frequency, you can't easily tell what program you are watching.
However, the receiver is actually more versatile than it appears. Channels 01 to 16 cover Astra 1A, 17 to 32 cover 1B, 33 to 48 cover 1C and 49 to 54 cover Telecom 1C. Channels 55 to 99 cover the range 950 to 1710 MHz in 20 MHz steps. These are factory-set to horizontal so you will need a remote control handset to change the polarisation to vertical for some of them. Channels 55 to 99 are ideal for "Hot Bird" or for radio programmes.
Note that ALL channels are fixed (pre-tuned) and only fine-tuning is possible. Channels P1 to P8 are "favourites" and you can set these to mirror any of the other 99 channels. The programming is not very straightforward but a User Guide is (was) available ( 6.95) from SatCure. This comprehensive booklet includes channel frequency listings for both standard (10.0 GHz) LNB and Enhanced (9.75GHz) LNB as well as channel settings when an ADX Plus is used. In addition, a special 2-LNB switching box " VH7" is available. The RD480 sends a special pulsed code up the LNB cable for each channel. The switching box recognises the code and selects the appropriate LNB of the pair. Cambridge developed this system long before 22kHz tone switching was considered and it works very well.


Having just attended the dealer training course at Pace's factory in Shipley, I should now be expert at repairing this model. However, I simply haven't had many to repair. Early problems seem to have been solved during the warranty period and the ones I see are those which have suffered from animal urine or mains surge due to lightning.
The latter seems to destroy the switching transistor without otherwise doing much damage. I recommend that you always replace the 47uF/400v capacitor since I've seen a few which had failed.
Pace's training courses, by the way, are really excellent. Whereas other manufacturers in the past have charged 99 and thrown in a buffet lunch, Pace gave the course and provided a full works restaurant meal plus Service Manual and updates free of charge. Since spaces are limited, the training is limited to dealers and you should book early. I don't know what future courses are planned but you should be able to find out from Tricia Payter on 01274 532000.

Grundig Manual

Talking about Service Manuals reminds me that I've just received one for the following models: GRD100/150/200/250/280/300, JVC TU-C200, Matsui RD600, Philips STU3301/3501/3601. The price was 14.95 plus 1 postage from: Grove Farm Publications, Grove Farm, Long Lane, Barnby in The Willows, Newark, Notts, NG24 2SG. The manual is excellent and comprehensive. Circuits and circuit descriptions plus parts lists are included.

Discus Ellipse Manual

This receiver forms the basis for a budget cost motorised system. There are plenty of them in use and they are generally quite reliable. When a fault does occur, however, life becomes difficult without Service information. The manual ( 10) and spare parts are now available from Satellite Surplus (Telford). Give Frank Martin a ring on 01952 598173 for more details. Frank is well known on the Radio Rally circuit and has all sorts of satellite equipment bargains.

Philips STU824 Ignores Remote

This receiver has been mentioned previously as being susceptible to some sort of microprocessor "lock-up" which prevents it from responding to the remote control. Apart from the obvious need to press "SAT" on the Remote, instead of "TV", various solutions have been found to work some of the time: Replace the microcontroller with one from a PRDxxx then put the original back (or, as one enterprising dealer told me, leave the Pace micro in, supply a Pace Remote and sell the Philips remote at a profit!) Alternatively, fit a new, blank EEprom.
You will be interested to know that a secret button sequence was written into the firmware in order to force the receiver to ignore the Remote (don't ask me why). Hold "Standby" and "+" while applying mains power. You will see "P10" in the display. The Remote will now be ignored. To reverse the process hold "Standby and "-" while applying mains power. You will see "P8" in the display. The remote will now work again. Obvious, really!

Pace SS9000

Although this model is not Astra 1D compatible, a lot of people still use it and are happy to pay for repair when it goes wrong. A fault which is becoming increasingly prevalent is the demise of C21 and C25 at the front of the power supply. Amongst other things, C25 failure causes streaks on decoded pictures and C21 causes the 5 volt rail to decrease in voltage. A common symptom is that the receiver will remain in standby until it has warmed up, after which it may work but the pictures will be sparkly and tuning drift occurs. I replace these capacitors, now, as a matter of routine.
Dry solder joints on the transformer pins, T2, is also quite common. The symptoms usually include factory reset occurring at power-on or intermittent loss of picture. I've even seen one which would flash its LEDs in a random sequence before going off completely. The customer's fault description often includes the words "when tapped" or "loses memory" so look out for this.

Uniden UST7007

In its day this was a wonderful machine and nothing has changed apart from the public's perception. It has 999 tunable channels with polariser control and a superb picture quality. The drawback is that the tuning range is limited so you must use an ADX to receive Astra 1D. It has no built-in decoder and needed a simple wiring modification to allow it to use an external one. It makes an excellent basis for a motorised system and can be acquired for a song. Remote controls are not available but you don't really need one.
Reliability of the receiver is generally good but a few faults appear on a regular basis: No LNB voltage--check the switch position! Measure the fuses and replace as necessary. Remove the base plate and resolder all the connector pins beneath the rectifier board. Picture problems: Replace the electrolytic capacitors inside the tuner. Make a note of their orientation because it's not marked in the tuner!
There are two 1 F electrolytics situated towards the rear, left side of the board, one on each side of an I.C. I forget their designations but find them and replace if necessary. They cause low video level.
The tracks around the Scart socket are very fragile and intermittent connections to the decoder are common. Bear in mind that the wiring modification allows an external decoder to be plugged into the "VCR" socket and the decoded picture appears at the RF modulator output but not at the TV Scart socket!

Echostar SR-7700

Several of these have arrived for repair, recently. The latest belonged to a "couch potato" who required me to collect the unit from his house because he wanted to remain at home to watch the football on terrestrial TV. As is often the case, the unit was showing "hum bars" on the screen. I replaced the 150 F "Gloria" capacitor in the power supply and all was well. If you catch this problem too late, "Gloria" tends to expire and can often melt the copper tracks below her. In this case, track repair and replacement of the UC3844 will be required. The capacitor and occasionally the BUZ80A will have to be renewed. Often the damage is so extensive that repair is not viable.
Echostar's apparent reluctance to provide parts and service information even to its service agents does not make repairing these units any easier. JD Electronics in Sudbury used to be an appointed agent but now work as independent repairers. Express TV in London seem to be the only "class A" authorised service agent. Protel have been appointed as "class B" service agent but had not, when I spoke to them, received the service manuals or parts! Nor had another "class B" agent, GT Satellites in Swansea.

Amstrad SRD510

Sometimes I wonder about hygiene when I lift the cover off a receiver and look inside. This particular one appeared to have been used as a vacuum cleaner! The fault symptom was "audio but no picture." Not surprising since everything inside looked black. Having cleaned out the dust, fluff and dog hairs, I scraped away the black carbon which had once been glue then replaced C54 and R80 which invariably fail. This didn't make any difference so I resorted to using my oscilloscope. Sometimes it's quicker than guessing! The baseband signal from the tuner was reaching the C-Band switch but going no further.
Failure of this slide-switch is very unusual. I shorted out the switch and traced the signal as far as R9 where, again, it stopped. (Sometimes C1 and C6 also fail but, in this case, they were all right). Replacing R9 (470 ) got the signal to TR1 and no further. The signal coming out of TR1 emitter and going into the decoder was very weak. The voltage on R4/R5 junction should have been 2 volts but was zero. Replacing R5 (12k ) finally produced a picture from the decoder Scart but not from the TV Scart or RF output. A dry joint on C55 was the final culprit and, with this repaired, the receiver worked perfectly. I just can't believe that all these faults occurred simultaneously!
The power supply components looked very blackened and I wondered if it would last the guarantee period before failing. In the end my conscience won and I replaced the suspect components before returning the unit to the customer.

Manhattan 9000

Based on the Winersat, this receiver with built-in positioner was developed by the Eurosat group a couple of years ago. The owner had disconnected his receiver and brought it to my workshop on a wet and windy day following a thunderstorm.
"I've checked the fuse" he informed me, "so it's going to be expensive; but let me have an estimate if it's more than fifty pounds."
He left the unit with me and, having nothing better to do on this particular day, I removed the cover and rummaged inside. The receiver was in good condition; it had not become obviously hot and nobody else had been inside it. In fact I suspected that the fuse which the owner had checked had been the one in his mains plug because there are several inside the Manhattan 9000. I measured each fuse in turn and found that E301, a 630mA fuse, was open circuit. With a new one fitted, I stood well back and switched on the mains power. The receiver lit up and subsequent tests showed that it now worked perfectly.
The customer was delighted when I told him that the cost was within budget and I had no pangs of conscience: I have to make a living.

Ferguson SRD4

When working, these receivers give a good picture and a lot of owners are still happy to have them repaired, even though they are not "1D compatible." When a lady telephoned and asked me to collect and repair her SRD4, therefore, I didn't argue but simply emphasised my standard charge. She thought this was reasonable since it included collection and delivery so the job went ahead. The receiver had, apparently, suffered very poor pictures for a few weeks before finally giving up in a thunderstorm (I love lightning, don't you? I stand at the window and count my bank balance rising with each flash.)
A repair kit from Economic Devices soon had the power supply working but the pictures were tremendously sparkly. It was not difficult to pinpoint the tuner module as the culprit. Sometimes the cause is dry joints inside but not in this instance. A tuner module lifted from an old SRB1 receiver did the trick and, since I'd had this BSB receiver given to me for nothing, I could justify charging only my standard rate for what would otherwise have been an uneconomical repair.

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