AOR AR8000


5 November 1994

Some owners of early AR8000 have reported that the audio scan feature does not appear to work correctly, this appears to have been a "problem" that AOR had already acknowledged if the problem was brought to their attention. To rectify this problem it is necessary to remove three surface mount components and replace them with ones of different values.

If the audio scan feature is something that you make no or little use of or you find that it works to your satisfaction then you may not feel that this modification is worth carrying out.

I do not know the exact s/n at which point production models started to benefit from the component changes however AOR (UK) do tell me that the most recent shipment we received had the modification implemented in production. The lowest s/n we had on that batch was 0123**.

They revision number of the circuit board may also help to determine whether this modification is required. When the back of the radio is taken off (see instructions below) at the bottom left of the upper board is printed: R004A** AOR JAPAN.

We have a very early AR8000 that as R004A11, on the latest batch we received the revision number is R004A13. I cannot say if this is definitive or not & amp I am unable to obtain confirmation from AOR at the time of writing. I could *assume* that maybe anything below A13 has the "old audio scan", but as I do not have a record of the revision numbers of previous shipments I stress that this is a "guess" only.

I would suggest that you make contact with the dealer from whom you purchased your AR8000 to check whether the radio you have will benefit from this modification.

It is important that you are happy working with very small surface mount components. If this is rather like performing "brain surgery with a broken bottle" for you it might be best to seek help from a friend or colleague who is familiar with surface mount work as any damage to the AR8000 that you may inadvertently cause will probably invalidate your warranty.

No responsibility can be held by the author for any damage that may be caused to the radio or other devices in carrying out this modification.


Remove the 2 screws from the back half of the radio (one from each side)

Remove the batteries from the battery compartment. Due to a rather strange design you may find that the two battery connectors at the top left & amp right spring out when removing batteries (you may already have discovered this), so be careful and make sure you watch them fly across the room so you can recover them before the vacuum cleaner does ! On later models it appears that this problem has been fixed

Remove the 2 screws from the battery compartment

Remove the round plastic knobs on the top (On/Off/Volume, Squelch and Rotary Encoder

Remove the locking rings from the above three knobs

Carefully split the radio in two. There are no connecting wires between the front & amp back halves just two connector blocks. Carefully place the front half (with the keypad & amp LCD screen) to one side.

The back half of the radio contains two circuit boards on top of each other.

It is necessary to remove the top board as this is the board with which we are going to "play" ! You will also see the revision number of the board at the bottom left.

Remove the two screws at the bottom left & amp right corner of the top board.

Providing you have removed the three locking nuts from the rotary control knobs at the top this board will know lift up and slide off the bottom board. Again there are no interconnecting wires so the board will separate completely.

As mentioned above the battery connectors in the battery compartment may have sprung out. If they haven't or the board seems to be held down it will probably be due to the leg of the negative battery connector being "bent over" slightly. As you look at the board approximately one third of the way up on the left hand side is a small 3 section connector block labelled J4-2. The battery connector leg passes through a hole in the underside of the board into the right hand side of this connector block. You may see that the connector leg has been slightly bent to stop it being pulled out by regular replacement of batteries in the battery compartment so you may just need to gently return it to the vertical with a pair of small pliers or similar.

On the uppermost side of this board are the on/off dial & amp squelch dial.

On the underside side is the rotary encoder/dial and the earphone socket.

The components that need changing are just below the Rotary Dial/Encoder on the underside.

The components that need to be removed and replaced with ones of a different value are:-

The circuit board is unfortunately not labelled to identify the components so please refer to the diagram below on which the components that need changing are marked and identified by the asterisks.

This diagram is orientated with the board horizontal, the rotary dial and earphone socket are to the right & amp uppermost.

| |
_______ _______ | |
| R84 | | R85 | | |
|_______| |_______| | |
| |_________
______________ | ROTARY | )
_______ | C99 | | | (
|**R83**| |______________| | DIAL | )
|_______| | | (
| |_________)
_______ _______ _______ | |
|**C98**| |**R82**| | C97 | | |
|_______| |_______| |_______| | |
| |
__|____|____|____|___ ___ ___ |_________|
| | | | | | |
| | |R75| |C91| |
| | |___| | | |
| U5 | | | |
| | | | |
| | |___| |
| | |
_ | uPC358 | |
| | |_____________________| |
|_| | | | | |
_____ |
| | ___|___ ______ |
|_____| | | |______| |
__ |_______| |
| | _ | | |
|__| | | _____ |
|_| |_____| ________________________________|__
| |
_|___|_ | J2 | |
| | | | |
|_______| | | |
| | HSJ0807-01-010 |____|
| |
___ ___ |___________________________________|
|___| |___| |
_ _ |
| | | | |
|_| |_| |
_ ______________________ |
| | | | |
|_| _____ | | |
| | | U4 | |
| | | | |
| | | MJH2070 | |
|_____| |______________________| |
_______ |
| C82 | |
___________ |_______| |
| | |
| R70 | |
|___________| |

Carefully remove the three components identified and replace them with the values shown. As already mentioned if you are not familiar with surface mount components or feel the job "is too much" then it would be far better to try and get assistance from somebody else, these components are *small*. Using a small pair of tweezers will help in holding the components when you are replacing them.

Once the three surface mount components have been changed carefully replace the circuit board ensuring that the 15 Leg Connector is correctly aligned with the Jumper block on the board located in the bottom of the back half of the radio.

Replace the two screws at the bottom left & amp right corners. Replace the locking nuts on the Rotary Dials on the top of the radio. Replace the two battery connectors into the battery compartment pushing them carefully through the holes in the compartment and ensuring that they fit correctly in connectors J4-2 on the left and J4-1 on the opposite right hand side. To stop them springing out when removing batteries it is a good idea to carefully bend the legs over slightly just to restrain them.

Carefully put the front and back half of the radio back together making sure that the 12(J5) & amp 10(J6) pin connector blocks locate correctly.

Replace the two screws in the battery compartment together with the two screws on the side.

Away you go !

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