Frequently Asked Questions - Pace MSS100/Prima

1. Why did my power supply fail?
2. How do I repair the power supply?
3. Can I get extra channels?
4. Are there any "secret" handset codes?
5. I get only a blue screen. What has happened?
6. I get "LNB Short" on the screen - why?
7. Can I use a "Universal" LNB?
8. Why do I get no front panel display?
9. How can I tell how old my receiver is?
10. Why won't my remote control work?
11. Why do I get interference on terrestrial TV pictures?
12. Why do I get "sparklies" on the picture?
13. Excessive contrast level and/or audio interference
14. Why are my TV pictures grainy through the satellite receiver?
15. Can I add a decoder Scart to my Prima?
16. How can I disable the internal decoder to watch MTV2 and VH1 ?

Pace MSS100inside view

The following answers apply to BOTH models unless stated otherwise.

Pace Prima inside view



1. Why did my power supply fail?

The usual cause of failure is a mains electricity power surge. Perhaps you had a power-cut or perhaps you plugged in an electric lawnmower or drill (or similar) nearby or perhaps you have faulty wiring in the plug, socket or somewhere in your house. Another common cause of failure is that the receiver has been dropped or banged heavily. In this case the board around the transformer will be cracked. If the receiver has been subjected to too much heat, the capacitors may fail. The big 47uF/400v is a favourite, together with the smaller ones near it. If the 47uF/400v is marked "LCC" then I recommend you change it immediately as these seem to cause failure.

2. How do I repair the power supply?

There is a special IC labelled TOPxxx. This is included in the repair kit SATKIT 8.
Remember, these are classed as "Safety Critical" components. You MUST use the Pace-approved parts. If you don't you risk damage and fire hazard.

MSS100 PSU pulses.
D11 UF5402 (use BYW98-50)

3. Can I get extra channels?

Yes for the Prima. An upgrade kit is available from SatCure to give 250 channels.

The Primakit 250 Upgrade. Questions, Questions, Questions (and answers!)
by Allan Gibbs - Prescot, Merseyside, U.K

Q. What is it?
The kit consists of a small but powerful pre-programmed 8 pin "chip"
along with a socket into which the chip is plugged.

Q. What does upgrading involve?
The existing chip must be removed from the circuit board inside the
receiver. The socket is then soldered in its place and the upgrade chip
(or any future upgrades) is simply plugged in. The easiest way to remove
the existing chip is to cut it out and remove the remaining bits of pins
by touching a hot soldering iron onto each pad in turn. As the iron is
removed, the remaining pin should come away with the hot solder. This
method will destroy the chip.

Alternatively, the chip can be removed intact by either desoldering each
pin in turn using desoldering braid, or by using a desoldering tool if
you have, or can borrow one. This should preserve your chip for future
use if necessary.

Q. What expertise and tools do I need?
You must be able to solder reasonably well and own, or be able to
borrow, a good *small* soldering iron, a pair of small cutters if you
intend to cut out the old chip, or desoldering braid (or desoldering
tool for your iron) which will allow you to remove it (hopefully)
undamaged. You will also need a crosshead screwdriver and a spanner -
about 14mm - to undo the retaining nut on the LNB input socket.

Q. Any points to watch out for?
Only one, really. The upgrade will almost certainly destroy the channel
settings and system setup - type of LNB etc. - that you already have
programmed into your receiver. I suggest you make a note of these from
the "installation" and "setup" menus *before* you make the upgrade, as
well as any personal preferences you may have set.

Q. How do I actually do the upgrade?

Follow these steps.

Firstly, you *have* unplugged the receiver from the mains..............
- of course you have. Nobody's that daft, are they. Silly me!!

The circuit board needs to be completely removed from the case. Remove
the top cover by unscrewing the retaining screws, one on each side at
the front and three on the back. Carefully remove the top cover.

On the back panel, remove the screws above the mains input socket, by
the audio phono connectors and between the two aerial sockets. Also
remove the large nut on the LNB input "F" connector.

Next, remove the grey plastic fascia by gently pulling the retaining
clip on either side from the lug and pull the fascia forwards.

Unscrew the single screw at the front lefthand side of the circuit board
and the two screws on the righthand side. The circuit board is now held
underneath by two plastic spacer clips. From the bottom of the case,
manipulate and push these very firmly but carefully, out. The circuit
board should now be free of the case - handle it with care!

Having decided whether to remove the existing chip by cutting it out,
which will destroy it, or to remove by desoldering which will hopefully
preserve it, locate the chip on the board. It is towards the back of the
board, midway between the mains and scart sockets and is marked "U701"

Remove the existing chip and clean out the eight holes ready to insert
the socket.

It is absolutely essential that the socket and new chip are inserted the
correct way round. On the socket you will notice at one end a small
indentation in the plastic moulding. This end *must* be inserted at the
end which is marked with a small semicircle in the white outline of the
chips' position on the board.

Having double-checked the correct orientation, solder the socket
carefully into the circuit board. As the tracks are very close together,
make absolutely certain there are no little bridges or whiskers of
solder accidentally linking one track to another.

Take the replacement chip, avoiding handling it as far as possible, and,
before inserting it into the socket, make sure it too is correctly
orientated. A tiny indent on one end of the chip must be at the same end
as both the indent on the socket and the semicircular outline on the
board. When you are satisfied is *is* the right way round, insert gently
but firmly into the socket, making sure all eight pins make proper

If necessary, gently bend the pins to line up correctly with the socket.

Reassemble the receiver by simply reversing the procedure above.

Once completely reassembled, reconnect the power and you will have 250
channels available!

> Hi Martin, just to let you and your prospective customers know, it
> took me 35 minutes to install the Prima 250 channel upgrade kit and
> to switch on. I have never used a soldering iron on a cicuit board
> in my life and still marvel at your de-soldering braid! Brilliant
> instructions didn't arf help! Dan Rowley...

4. Are there any "secret" handset codes?

Yes. The "factory reset" will reset channel 1 only to Sky One. It will also reset the Installation menu settings. It will NOT change the rest of the channels.

Menu, 0, Store, Right arrow, Left arrow.

Later MSS100 and all Prima
There is a hidden function to align the audio PLL frequency offset in the Prima and later MSS100 that uses the RC-10 handset:
Press "Function", "Menu", "Radio" and "Store".
The message "Please Wait" appears while the audio Phase Lock Loop centre frequency is reset.

Early MSS100 only
Press "Function", "Menu", "Radio" and "Store".
The Audio PLL number will flash on the screen. DO NOT adjust this!
Press the Fav key once. The video level value should be flashing now.
Write down the value and adjust with caution.

5. I get only a blue screen. What has happened?

The blue screen appears if there is no signal.
The most obvious cause is that your LNB is not connected or, on a twin-input receiver, is connected to the wrong input. Alternatively, you may have shorted out the LNB cable and damaged something inside the receiver. Make sure that LNB power is ON in the installation menu.

Prima "No Signal" on blue background.
Audio present if channel tuning menu is selected (audio mutes with blue background).
Look for a dry joint on L305.

MSS100 blue screen "No signal" and/or no RF output
Check for dry joint on U200.
5.625 MHz crystal may be faulty (if marked "IQD")
Corruption of the EEprom contents can cause loss of picture or sound. You can cure this by readjusting the VIDEO VALUE number in the secret menu.

MSS100 Intermittent blue screen "No Signal".
Dry joint on D18

6. I get "LNB Short" on the screen, even with the LNB disconnected.

Occasionally this happens if you've selected power for just one LNB in the Installation menu. The simplest way to correct this is to plug the receiver into the mains and press the factory reset sequence. This resets it to "LNB Power 1 & 2".

7. Can I use a "Universal" LNB?

Yes. Select tone ON in the second screen of the tuning menu for the appropriate channels.

8. Why do I get no front panel display?

In the MSS200, check the solder joints of the LED display itself.
In the MSS300, check the soldering of the surface mount components on the front panel display. There is also an upgrade for early MSS300 which suffer from no display intermittently, when warm. This is explained in "The Satellite Repair Manual."
"No display" can also be caused by a faulty microcontroller and various other things.

9. How can I tell how old my receiver is?

The date of manufacture is incorporated in the serial number.
For example: RAAYAH5245xxxxx
The "5" indicates 1995
The "24" indicates week 24 counting from first week in January.
The "5" indicates Friday.

10. Why doesn't my remote control work?

Prima uses a different remote control handset from other models.
This control has the code "RC-10" in the bottom right hand corner of the keypad.
The later model MSS100 also uses this remote.
If you are ordering a remote control for the MSS100 you will need an MSS remote for early models and a Prima RC-10 for later ones. Please open your receiver carefully and look at the number on the big 40-pin chip. If it is 809-8661100 you need an MSS remote. If it is 809-8661101 you need a Prima RC-10 remote.

11. Why do I get interference on Terrestrial TV pictures?

MSS100 Radiated interference from PSU affecting VHF and UHF reception.

Radiation from the snubber diode can affect VHF and UHF TV reception when ready made RF connecting leads are used. Many of these leads do not have full screening and allow the ingress of interference. Receivers fitted with a new transformer, part number 237-1000201, also require an 82uH inductor to be placed in series with R3 and D8. It is also necessary to change R3 from 22R to 47R. To reduce or remove the emitted radiation the following modifications are advised:

Change C7 (should this be C2 ?) to lnF lKV Ceramic Cap. Part No 159-1029951
Fit a 200nH coil, Part No 134-0200080, across track cut between C2 and D5.

Only on units fitted with Transformer, Part No 237-1000201: Change R3 to 47 ohms. Cut track between R3 and D8, and bridge the cut with an 82uH axial lead inductor. (82uH inductor has Part No 134-0820601).

There is also a kit to get rid of "hum bars" on terrestrial pictures. This kit improves protection against high voltage "static" which builds up on your TV aerial during windy/stormy weather and which results in no terrestrial loop-through (very grainy Tv pictures).

12. Why do I get "sparklies" on the picture?

Sparklies on picture when receiver is cold.
This is normal. If you use the receiver straight from a cold van or workshop the tuner will take at least half an hour to reach normal operating temperature.
If sparklies are present all the time, read the SPARKLIES FAQ.

13. MSS100 Excessive contrast level and/or audio interference

This problem can be experienced when receiving some transmissions from the ASTRA satellites or on a transmission using 36MHz deviation. An improvement can be gained by accessing a hidden video level adjustment menu using the following steps:

a) Press F, then MENU, then RADIO then STORE on the remote control handset.
b) Press the Fav key once. The video level value should be flashing now.

c) Make a note of the values before alteration. Adjust the VIDEO VALUE number using the left arrow key from 47(Default) to 37 for Ku Band transmissions. If C Band transmissions are being received, adjust from 111 (Default) to 101.
d) Press STORE on the remote control handset to save the new values.
DO NOT adjust the first menu option, Audio PLL unless there is an obvious sound problem and the displayed value is a long way from zero. If any alteration is made to this option by mistake, exit the set-up by pressing 'NORM'.

The adjustment is simple to perform. A change has been implemented on all units which display a date code greater than 6204 to overcome the problem. By way of example, XXXXXXX6213XXXXX is new production having the changes incorporated, and will not require adjustment.

You can remove the blue screen and NO SIGNAL screen, to determine if there is a signal, by pressing F followed by STORE.

Early MSS100 Audio distortion on narrow deviation subcarriers, especially 7.90, 8.35 and 8.50 MHz

Fit two 1.4V diodes type BZV86 (Part No 125-0014501) to copper side of PCB under U500, as shown in diagram supplied in Pace Service Matters volume 5. Most units had these fitted in the factory.

14. Why are my TV pictures grainy through the satellite receiver?

Pace MSS100 inside view
MSS100 poor RF terrestrial loop through.
Solder pad broken beneath the RF output socket.
Also dead UHF I.C. (see picture)

There is also a kit to get rid of "hum bars" on terrestrial pictures. This kit improves protection against high voltage "static" which builds up on your TV aerial during windy/stormy weather and which results in no terrestrial loop-through (very grainy Tv pictures).

15. Can I add a decoder Scart to my Prima?

Well, there are around 90 SMDs which would need to be fitted to support the full compliment of SCART sockets, and many of them are for the decoder. Pace used to make a VC2 version of the Prima for Multichoice Holland which had all the sockets fitted and that is why the PCB has places for the sockets. I am definitely NOT considering a decoder socket kit!

16. How can I disable the internal decoder to watch MTV2 and VH1 ?

You can use a switch to disconnect one wire of the 1uF capacitor next to the PTV111. This should work OK in Pace MSS, later Nokia models etc.

A complete fault-finding guide called "The Satellite Repair Manual V" is available.

This information is given in good faith, based on several years of workshop experience involving thousands of repairs. No responsibility will be accepted for any death, damage or injury caused either directly or indirectly by the use of this information. The reader should check the facts himself. It is assumed and stressed that the reader will be familiar with good, safe, electronic workshop practice and will be familiar with all tools, components and terms used. If there is any doubt about the reader's ability to carry out such work competently and safely, the work should be referred to a specialist engineer.


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