OEM CD-4000 + AH! NJOE TJOEB 4000 FURTHER TECHNICAL INFO
This information is given under the restriction that only professional technicians use this information to do repairs or modifications. No responsibility for any personal or material damage is taken by us and it's the full responsability of the person who uses this information to open, repair or modify the AH! Njoe Tjoeb 4000.
Before you decide to go and work on the AH! Njoe Tjoeb
4000 (and
on whatever other piece of electronic equipment):
1. Switch off all equipment with the on/off switch.
2. Remove all ac-cables from the ac-sockets.
3. Remove all other cables like interconnect cables, antenna cables and speakercables.
4. Make sure that you are connected with the same potential as the mass of the set via a
wrist wrap with resistance. Keep components and tools also at this potential. All ICs and
many other semi-conductors are susceptible to electrostatic discharges (ESD). Careless
handling during repair can reduce life drastically.
Remove the 4 screws on the side of the machine and the 3 screws on the back of the machine v with a T(orx) 10. Place the AH! Njoe Tjoeb 4000 with the back towards you. Lift topcover at frontside and pull backwards (keep 2 thumbs on top of the frontcover and the fingers of your both hands on the sides of the topcover). Place the topcover carefully on the side, away from the location where you are going to work on the AH! Njoe Tjoeb 4000.
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Press open/close button to open the tray. If the tray doesn't work, turn counterclockwise a small screwdriver into the hole as shown in the picture. Then the tray comes out. After the first centimeter it is possible to pull the tray out further by hand. |
Release the doorcover of the tray by gently pressing upwards as shown in the pictures below.
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1. Read introduction and general instructions on the top of this page.
2. Connect your AH! Njoe Tjoeb 4000 to AC voltage.
3. Press open/close button to open the drawer.
4. While the drawer is open, disconnect your AH! Njoe Tjoeb 4000 from AC voltage.
5. Read and follow instructions to remove the front of the drawer as described earlier on this page.
6. After having removed the front of the drawer, gently push in the drawer by hand.
7. Read and follow instructions to remove the topcover as described earlier on this page.
8. Place your AH! Njoe Tjoeb 4000 with backside towards you.
9. Disconnect the single ground wire connected from the ECO SL Mk3 module to the bottomplate from the chassis.
10. Unscrew the 2 Torx 10 screws which attach the back of the ECO SL Mk3 to the chassis.
11. Pull the ECO SL Mk3 gently towards you while lifting it up a little.
12. Disconnect the cables on the right side of ECO SL Mk3 module from the ECO SL Mk3 pc-board (seen from behind).
13. Now the ECO SL Mk3 is totally free and can be taken out.
14. Mount a new ECO SL Mk3 mechanism by following the given instructions in reverse order.
Will be added later as instruction for distributors, dealers and their technicians.
To be added
In case you have the feeling that 1 channel is reacting different from the other channel, it might be that the reason for that is a defective / noisy tube. Of course, before you think in that direction, you have checked and exchanged all external cables to find out if the problem can be found and solved externally. If that's not the case than you can check the tube by taking out the 2 tubes. Support your hands in such a way that you can pull the tubes straight up with very gentle side-moves. Also support at the same time the pcboardtry to avoid any bending of it. Exchange these tubes with each other to see if the problematic channel stays problematic or if the problem goes to the other channel. If the other channel becomes problematic you know that 1 tube is faulty. You can solve the problem by putting in 1 new tube (of the same brand and kind!!; we have always used Philips ECC88 6922 Jan Military Grade), but better is to replace both tubes.
Untill about november 1, 1999, the AH! Tjoeb '99 had a relatively high outputvoltage (3.5V). We lowered this to 2.5V. Reason why we initially decided for 3.5V, was that during all initial listeningtests, the panels choose this setting as being the best, most favorable or whatever you want to name it. All the listeningtests were done with highest quality preamps, which apparently did not suffer from "overload".
The AH! Njoe Tjoeb comes factory preset with an outputvoltage of 2.5V. We do however supply the opportunity to choose for another (lower or higher) outputvoltage. For some AH! Tjoeb '98 and '99 owners we replaced the small blue output potmeters with fixed resistors. This was considered as being an audible improvement and for sure gurantees that you will never get dirty and/or noisy potmeters. Reason why in the AH! Njoe Tjoeb 4000 you will find another way to choose the outputvoltage (if you want). You now can readjust the outputvoltage without any other tools than a solderinggun, (eventually) a sharp knife and some good (2% or better) silversolder.
Attention! The following pictures are taken from an empty outputstage pc-board. That way it will be easier to find the location on the board.
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This part of the board defines the outputvoltage of the right channel. Notice the resistor definitions R40, R41 and R42. The picture shows 3 solderpads next to the locations of the SMD resistors. For the factory set output of 2.5V a (standard) connection is made between R40 and the solderpad next to it. The spaces between R41, R42 and the solderpads next to it are open (this means: no connection exists). |
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This part of the board defines the outputvoltage of the left channel. Notice the resistor definitions R54, R55 and R56. The picture shows 3 solderpads next to the locations of the SMD resistors. For the factory set output of 2.5V a (standard) connection is made between R54 and the solderpad next to it. The spaces between R55, R56 and the solderpads next to it are open (this means: no connection exists). |
Lowering the output on the tube-output board is a matter of adding solderjoints. The following pictures show you how to create an outputvoltage of 1.25V. If for whatever reason you plan to do this, disconnect all external AC and signal cable-connections, remove the board from the AH! Njoe Tjoeb 4000 (see instructions) and solder without touching any of the components on the board!
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This part of the board defines the outputvoltage of the right channel. Notice the resistor definitions R40, R41 and R42. The picture shows 3 solderpads next to the locations of the SMD resistors. For the non-standard output of 1.25V an extra connection is made between R41 and the solderpad next to it. The space between R42 and the solderpad next to it remains open (this means: no connection exists). |
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This part of the board defines the outputvoltage of the left channel. Notice the resistor definitions R54, R55 and R56. The picture shows 3 solderpads next to the locations of the SMD resistors. For the non-standard output of 1.25V an extra connection is made between R55 and the solderpad next to it. The space between R56 and the solderpad next to it remains open (this means: no connection exists). |
The following pictures show you how to create an outputvoltage of 0.7V. If for whatever reason you plan to do this, disconnect all external AC and signal cable-connections, remove the board from the AH! Njoe Tjoeb 4000 (see instructions) and solder without touching any of the components on the board!
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This part of the board defines the outputvoltage of the right channel. Notice the resistor definitions R40, R41 and R42. The picture shows 3 solderpads next to the locations of the SMD resistors. For the non-standard output of 0.7V an extra connection is made between R42 and the solderpad next to it. The space between R41 and the solderpad next to it remains open (this means: no connection exists). |
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This part of the board defines the outputvoltage of the left channel. Notice the resistor definitions R54, R55 and R56. The picture shows 3 solderpads next to the locations of the SMD resistors. For the non-standard output of 0.7V an extra connection is made between R56 and the solderpad next to it. The space between R55 and the solderpad next to it remains open (this means: no connection exists). |
Raising the output on the tube-output board is a matter of cutting the standard connection. The following pictures show you how to create an outputvoltage of 5.0V. If for whatever reason you plan to do this, disconnect all external AC and signal cable-connections, remove the board from the AH! Njoe Tjoeb 4000 (see instructions) and cut the standard connection without touching any of the components on the board!
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This part of the board defines the outputvoltage of the right channel. Notice the resistor definitions R40, R41 and R42. The picture shows 3 solderpads next to the locations of the SMD resistors. For the non-standard output of 5.0V the standard connection between R40 and the solderpad next to it, has to be cut. The spaces between R41, R42 and the solderpads next to it remain open (this means: no connections exists). |
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This part of the board defines the outputvoltage of the left channel. Notice the resistor definitions R54, R55 and R56. The picture shows 3 solderpads next to the locations of the SMD resistors. For the non-standard output of 5.0V the standard connection between R54 and the solderpad next to it, has to be cut. The spaces between R55, R56 and the solderpads next to it remain open (this means: no connections exists). |
You need our TjoebSjoes kit in which you find: 4 TjoebSjoes and 4 small copper screws to mount the TjoebSjoes to the bottom of the cabinet.
1. Screw the small copper screws in the
TjoebShoes.
2. Remove the 4 standard Marantz feet.
3. Screw the 4 TjoebSjoes handtight into the original threaded holes.
Transportation can give some unexpected and unwanted results. In case the AH! Njoe Tjoeb 4000 display gives the message "disc not finalized" while a normal cd is inserted, please contact us for a quick solution.
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