AR3000A bulletin page

Reset

Battery

Pre-amp switching

PLUS modifications discriminator out, WEFAX filter, narrow AM filter, 10.7MHz i.f. out etc

AGC & RSSI - receiver signal strength indicator

Intermittent or open squelch

Replacement of L780S09 regulator - Acrobat PDF file 130kB

AR3000A 5V SMD regulator replacement

Adding an external signal meter to the AR3000A - Acrobat PDF file 44kB

AR3000A PLL ERROR display

Microprocessor instability on very early units

AR3000 / AR3000A PC leads & wiring

800 memory channel modification to AR3000A (non AOR developed or approved)

AR3000A audio output level

AR3000A for DRM - digital AM reception

AR3000A frequency configuration - 6kb PDF file

Both the AR3000 and AR3000A reset is the same manner (but the switches are in slightly different places). Remove both top and bottom covers, the reset switch is located on the rear of the front CPU board. The required switch is the small momentary push switch located in the corner of the PCB (behind the X10 button - not the slide switch which sets RS232 baud rate). With the set connected to power and the on/off switch on, push this switch, hold for one second then release. The reset will take a short while and all LCD characters will appear for a few seconds. When the reset is complete, the AR3000 reverts to its normal operating mode (clock set back to zero, memories back to factory defaults etc).

When battery voltage drops below 2.80V (using a DVM) it is time to replace the battery... its nominal voltage is 3.0V The battery is a solder type CR2032 and is available from UK stock priced at £4.82 including postage and VAT, the part number is: W09203205/ I12

The memory back up battery can be replaced quite easily with the use of screwdrivers and a soldering iron. This involves removal of the top and bottom case halves (6 screws) and the front panel (4 screws). With the CPU board exposed, the battery can be located behind it on the right hand side. This is best de-soldered from the front of the board in between the keyboard switches. Care must be taken not to short the new battery when fitting it and check that the polarity is correct (+ & - are marked on the board). Carry out a micro reset once the new battery has been fitted as it is possible for the unit to be in a crashed state and a higher than normal amount of current may be drawn, shortening battery life.

If you are left looking at a small black plastic gate, it has fallen out from the space between the front panel of the radio and microprocessor PCB. Look carefully at the gate, you will notice that there is a cut-out... this is to enable the gate to fit roughly in the middle of the microprocessor PCB with the cut-out facing the PCB so that it sits flat against the board, avoiding the raised solder contacts. The gate appears to be a mechanical protection device to prevent the front panel from smashing into the microprocessor PCB if a very heavy blow is encountered. Occasionally the gate causes poor mechanical operation of the keys... if so, slacken the four screws which hold the front panel in position, manoeuvre the panel and re-tighten the screws so that the keys operate smoothly. If you cannot achieve positive action of the keys (or can't work out where to place the gate), throw the gate away! Occasionally the gate is omitted during manufacture. The microprocessor PCB has five holes for the screws to secure it to the metal chassis, however there are usually only four screws fitted (don't look for the missing screw under your chair, its not there).

Of course we are happy to repair your receiver in our workshop. Our workshop rate is £33.00 per hour + VAT with 95% of repairs being carried out within the first hour on the bench. Parts are provided at trade cost, return carriage & insurance extra, the total would be about £50.00 based on the assumption that the battery is to blame.

A pre-amp is fitted to the 3000 models for use over the short wave range (100kHz to 30MHz). This is normally switched on. If additional attenuation is required or mixing problems experienced (using large antennas?) then turn the pre-amp off. The switches for this are located under the top cover (both covers will have to be removed) on the front, left hand side. The switches have to be either both ON or both OFF for receive to be possible. If your set appears very deaf below 30MHz, check the position of these switches. - It wouldn't be the first time we have seen a set returned with a reported "no SW RX" due to one switch being ON and the other OFF.

In 1994 a series of modifications were developed by AOR UK LTD for the AR3000/AR3000A receiver, this resulted in the AR3000A PLUS receiver appearing in the UK. Modification may be carried out in the UK workshop, you may also download a PDF file 3000mods.pdf (939kB) to 'have a go yourself' but picture resolution is limited due to the compression required for internet publication. No liability is accepted whatsoever for damage to customers own sets, unless you are very experienced with surface mount components and have the correct tools, don't even consider carrying out the work yourself.

KITS
Unfortunately it is not feasible to offer 'kits' for modification, the handling is just too expensive, also the small PCBs employed are simply made in-house in VERY small quantities using a light box etc... there will be no exceptions so please don't ask!

We can however offer the actual filters as follows:

WEFAX filter SFE10.7MFP GBP 4.50 (VAT extra in the EEC, total GBP 5.29 inc VAT P&P extra)
Narrow AM filter SFW455IT GBP 4.50 (VAT extra in the EEC, total GBP 5.29 inc VAT P&P extra)

Postage in the UK add GBP 2.00 inc VAT
Postage to Europe add GBP 2.50 inc VAT
Postage by air as a small packet to the rest of the world add GBP 3.50

In response to your queries regarding s-meter /AGC output from the AGC, our measurements are as follows:

Computer control signal reporting "letter" against dBm signal level provides the following results.
Frequency of test is 130.200MHz AM with 70 percent modulation and 1kHz tone:

The input saturates at this point making the balance of 16 letters unusable.

AGC levels taken directly from AGC line (suitable point, Pin-10 of J9 IF PCB).
Frequency of test is 130.000MHz AM with 70 percent modulation and 1kHz tone:

If the receiver squelch becomes intermittently OPEN regardless of squelch control position and changes with mechanical movement of temperature, the unit may be suffering from a cracked surface mount component on the i.f. PCB.

Have a look at the solder side of the PCB (the i.f. PCB is the bottom board), you will need to temporarily remove it from the radio.

Look on the opposite side of the board to the ceramic resonator marked CF2 (usually orange in colour). There are usually two added conventional components, one being a resistor (12k) and the other a disk ceramic capacitor (possibly green in colour) with a value of 102 (1000pF).

The capacitor is attached to a 3-pin device at one end and is soldered between a SMD resistor and SMD capacitor at the other... the capacitor may be cracked ??

Temporarily lift one leg of the disk capacitor and see if the SMD capacitor falls in two !

Replace the SMD cap (size is 0805), the value is 103 (C170)... in 'real language' this is 0.01uF or may be expressed as 10nF.

One one occasion, it has been reported that another SMD capacitor C82 (103 / 0.01uF / 10nF) was also faulty resulting in confusing squelch problems, this capacitor is situated just one component away from C170, only R190 separates the two components.

A picture of the underside of the IF PCB with close-up of the components is available as a single page Acrobat PDF file (196kB) - click here.

The surface mount 5V regulator IC10 (S-81250HG), runs constantly if power is connected to the unit. It provides the main supply to the microprocessor board and also the back up supply when the power is still connected but the unit not switched on. This prolongs the lithium back up battery life.

The regulator should be able to run constantly for the entire life of the set without problems if required. Occasionally one may fail and require replacing. This is however very unusual and is most probably due to a ‘push’ from some other source. e.g. having to dissipate the extra heat from using a higher than normal voltage power source or some other failure within the set drawing extra current from the 5V line.

If the device fails, the symptoms are that the unit will not power up and the clock is not displayed at all. Don’t get this confused with a crashed microprocessor, as symptoms can be very similar. A re-set, however, will not cure the regulator fault. A failed internal fuse will also give similar symptoms.

Check if the regulator has failed by connecting power (power switch on or off) and measuring for 5V at pin 1, connector J9. These are located on the multi-pin connector close to the remote socket and are clearly labelled. For information, viewed from the top of the SMD device (IC10) with three legs to the left, the designations from top to bottom are G, V-in, V-out). Remove the power again.

Remove two mini coax connectors (J3 & J10) from the left-hand side of the board. Note that these are quite easily damaged and it is best to remove them with a straight upwards pull with a pair of pointed pliers (don’t lever them sideways as the centre connection will be damaged).

This allows the board to hinge towards the rear of the set without removing any further connectors.

Again, looking from the front of the set, IC10 is located on the solder side of the board near the left-hand edge. It is positioned between the screw head (holding regulator IC11) and the side of the board.

Hold the soldering iron on the single leg at the other side and lift the device clear of the board with a pair of fine pliers.

If the device does not lift, do not force it as the tracks may pull away. Try de-soldering the legs again.

Take care not to trap any wires when re-fitting the PCB. Take particular care if the unit is a plus set as several more wires pass down the right hand side of the set.

Note: when re-fitting the connectors, they usually fall back into the correct place. If they don’t;

Before fitting the case, connect power to the set and check that 5v is present on pin 1 of J9. Now refit the cover and test the set.

If a fault occurs within the PLL system of the AR3000A, the microprocessor has been programmed to display a PLL UNLOCK message 'PLL ERR' on the LCD. The following comments are 'general only', based on our experience of
AR3000A servicing:

1. If a CPU corruption occurs, it is possible to encounter a PLL ERROR, first try to reset the CPU to restore normal operation. Reset procedure is available from our web site at http://www.aoruk.com/300abull.htm#reset

This is particularly valid if the backup battery has become exhausted, look at the information in this respect http://www.aoruk.com/300abull.htm#battery

The OPERATING manual in English language is available from http://www.aoruk.com/pdf/ar3000am.pdf

2. We have noted occasional PLL unlock in the 900MHz frequency range due to a VCV supply SMD electrolytic capacitors drying out.

Faulty capacitors C31 (1uF/35V) or C32 (4.7uF/35V). Both are on VCV line.

Faulty capacitors C24 & 25 (2.2uF/20V) - back to back caps in VCV circuit. These may be faulty even though they don't measure leaky.

There are no really common failures but if none of above appear at fault, check supply lines at:

Connector J1. Pin 1 is 5V, pin 2 is 9V

Check voltage is multiplied through IC5 (TL499)

Check for 6.2V on output from IC6

Check for 12.8MHz oscillator output

IC1, IC2, IC4, module NIS130 etc.

It is possible for us to supply the printed service manual for the AR3000A, refer to the operating & service manual page.

The AR3000A appeared in relatively small quantities at the end of 1991. A small percentage of production units (up until March 1992) suffered from microprocessor instability (crash). This was addressed by the addition of a few resistors to the CPU PCB. A bulletin was generated in March 1992 and is reproduced here as a two page Acrobat PDF file (277kb) - click here.

It is possible for AOR UK to provide a screened RS232 cable for the AR3000 and AR3000A, they are made to order in the UK workshop:

a)	AR3000 for a 25 way COM port on a PC (PC3000-25)
b)	AR3000 for a 9 way COM port on a PC (PC3000-9)
c)	AR3000A for a 25 way COM port on a PC (PC3000A-25)
d)	AR3000A for a 9 way COM port on a PC (PC3000A-9)

[At September 2004, each lead is priced at GBP 12.00 inc VAT, P&P to a UK address is an additional GBP 2.00 inc VAT. The leads are around 2m in length, additional length can be provided at GBP 2.00 per metre (covers the cost of cable, extra postage and handling). We do not recommend leads longer than 10m.... also the longer the cable, the higher the potential 'noise' problem. Be clear to state AR3000 or AR3000A as the former requires an extra link wire between pins 1 + 7.]

Payment information is available from http://www.aoruk.com/payment.htm

AR3000/A 25 male plug required	PC 25 way female plug required
1 *	1 SCREENED CABLE only to PC end
2	2
3	3
4	4
5	5
7 *	7 SIGNAL GROUND

* If the AR3000 is in use, add a link between pin-1 and pin-7 on the AR3000 end of cable, not required for the AR3000A.

* If the AR3000 is in use, add a link between pin-1 and pin-7 on the AR3000 end of cable, not required for the AR3000A.

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The AUX socket audio level is however not specified. The results of UK workshop measurement are given here:

Using a 1k OHM load (for want of a better value), pin 2 is ground.

Note: The audio output at pin 4 is simply a tap straight from audio output stage of the receiver before the volume control and audio IC. It is capacitively coupled back to the previous stage but is DC coupled straight across the 50k OHM volume potentiometer. The low level output is the same output but with a 220K ohm resistor in series - the output into a very high impedance load with therefore be much greater than 5mV.

For an overview on DRM and a link to a modifications page for several receivers, have a look art the AOR DRM page.

Currently it is necessary to extract a signal centred on 12kHz to feed through the sound card of a PC so that demodulation to audio can take place using Fraunhofer PC software.

We have not carried out any tests with the AR3000/A so can only speculate on the position... this text was generated in response to a customer query on the subject.

The AR3000/A uses a final I.F. of 455kHz on SSB/NFM/AM receive modes and the NFM filter is of 12dB in bandwidth, it may be possible.

The following has been suggested from the AOR UK workshop:

Two possibilities;

If additional filtering is going to be used, take the 455kHz output straight from the IF IC (IC1, pin3 -MC3357). Bandwidth here is 35khz so will need that additional filtering.

In AM, the signal is then fed through CF1 (455F). This is about 7.5kHz wide. If this is not too narrow (should be ok, I think), take the signal straight from the filter output or perhaps more reasonably at pin 5, IC1. At this point the 455 signal has been fed out of the filter, through Q23 and is about to re-enter IC1 again. Q23 should have brought it to a usable level.

All that said, its going to be a try it and see job.

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Due to continuous developments, AOR reserves the right to make design and specification changes for product improvement without prior notice. The performance specification figures indicated are nominal values of production units. There may be some deviation from these values in individual units.

dBm range	RS232 letter
-110 to -108	A
-107 to -105	B
-104 to -102	C
-101 to -99	D
-98 to -96	E
-95 to -92	F
-91 to -88	G
-87 to -83	H
-82 to -76	I
-75 to -63	J
-62 to -40	K
-39 to -38	L

Input signal (uV)	AGC voltage
0	4.83
1	4.01
3	3.20
5	2.90
10	2.60
14	2.48
16	2.46
20	2.37
50	2.12
100	1.97

AR3000/A 25 male plug required	PC 9 way female plug required
1 *	1 SCREENED CABLE only to PC end
2	3
3	2
4	7
5	8
7 *	5 SIGNAL GROUND, also attach the SCREENED CABLE only to PC end

AR3000A Bulletin Page