|The difference between 433MHz and 315MHz version
from Alarm Remotes http://www.alarmremotes.co.uk/index.htm
if you have a Lucas 5AS security ECU you will see on the label a black
25mm circle with a letter inside it.
Solution for the Alarm Blipper working range Problem ?
Carl , Sweden . Message to the MG Cars BBS on 1/10/1999 15:36
Hi all !
This is going to be a long thread about blipper system
for our beloved "F".
The keyholder contains the TX circuit and after doing some measurements on my 3TXA the following was found:
TX frequency. 433,895 MHz .
- to make a small decent TX isnīt that big deal
DESENSING: Nearby transmitters (not necessary spot on our frequency ) will make a not so good RX more deaf to wanted signals. This means we have to decrease distance to get any action at all.
PULLING: The nature of superreg. makes it fine for AM signals but if another signal off freq. is stronger this will make the RX "lock" onto this signal and further decrease in distance is needed.
SELECTIVITY : This is the costly thing, superreg. is bad news here.
FREQ: OFFSET : As RX and TX may have different temperatures we can have diff. in freq. This is today to some extent solved by the "SAW-resonator. At least the TX has a SAW.
ANTENNAS: For the "bliper" there isnīt much of a choise, size demand small antenna and then for cost reasons printed circuit board loop resonator is the thing to go for. At RX end there is of course more space and normally the antennas on other manufact. are situated as free as possible. In outer mirror casing is one often used spot. In our case the yellow quarter-wave cable under dash is a bit displaced for optimunm reception ,even worse so when coiled together with all other cables !
So summing up I think that the main problem lies in the RX. Maybe a thin coaxial cable from the box and putting the antenna in a better place will give improvements , but this has to be found out. I will take a look at the RX this winter as car is on stands , my range is around 3-5 meters with straight RX-antenna - so not that impressed..... Regards , Carl.
a replacementkit is availiable for that high value part. I think its
interesting for you (one of the oldest MGF) too: YWX101010 - repair kit
for the remote blipper. It contents the both casing? (housing) halfs and
the rubber button thing.
(c) Carl G. B. Sweden, translated by Dieter Koennecke 02.10.99
YWX101010 - repair kit for the remote blipper.
|Access to the self test facility is obtained as follows:-
(The following steps 2 to 4, must be completed within 2 seconds, in order to induce the ECU to enter the self test mode.)
1) The vehicle must be in disarmed mode, unlocked and with the ignition switched off.
2) Lock the driver's door using the driver's door sill button.
3) Turn the ignition ON, OFF then ON again and leave it ON.
4) Unlock the driver's door using the driver's door sill button.
Confirmation that the test mode has been successfully entered is given by the horn sounding a short beep. Once in self test mode, the volumetric sensor (if fitted) is powered up and the vehicle is in an immobilised state.
If an ECU input is then seen to become active i.e. to go from an open circuit to a short circuit (or earthed) condition, the security LED will give a short flash to indicate this.
When the system is in the self test mode, operation of the appropriate switch by moving the associated panel or linkage will instigate the test on each of the following circuits;
1) Driver's door courtesy light switch.
Switch tests need not be made in any particular sequence and any or all may be tested as required.
Correct operation of the circuit being tested will be denoted by the
single flash of the security LED and the same circuit may be tested repeatedly
Failure of the ECU to enter the test mode will probably indicate that it is not receiving inputs from either the ignition power supply or the driver's door sill button switches.
The test facility may also be used to check the operation of te volumetric sensor, either ultrasonic or Doppler microwave (if fitted), by performing the following;
With the system in self test mode and the remote handset previously programmed
and synchronised to the vehicle being tested, press the unlock button
Paul Jameson B.Eng.
Electronics Engineer / Director
Avon Automotive Diagnostics Ltd
Tel +44 (0) 1789 450808
Fax +44 (0) 1789 773262
*Rov 2 Fob* model.
Can be adapted to the ECU without a visit to Testbook.
The MGF Immobiliser and Alarm
The MGF Alarm ECU YWC105330 (Mk1) (Receiver)
if you have a Lucas 5AS security ECU you will see on the
label a black 25mm circle with a letter inside it.
Some cars suffer from false alarms cause of to sensible setup of the volumetric sensor behind the T-bar. The alarm goes off without any visible reason
The solution is almost a reset of the alarm ECU
|Brian, Belfast (message to the MG Cars BBS)
Bruce put the test below up some time back and I copied it and have it below. I have found this useful to find the fault.
|On EKA code:
Dave Morris T6 DCM, Gwent, United Kingdom
Traditionally MGR dealers used to increment the 2nd and 4th digits every time they sold a car on - just to ensure the previous owners couldn't get back in to their old cars.
eg access code 1234 would become 1335 etc
That barcode may be stick inside the MGTF service manual or gets supplied
with the package of a new transmitter.
Pektron SCU YWC001540 YWC001541
back or to my MGF home site www.MGFcar.de