Pure luxury: stereo tape recorder TK 147

If one reads the type designation of the Grundig TK 147, one expect probably a direct successor of the TK 145. In fact, the two devices resemble each other. The drives of both tape recorders are also very similar. The TK 147 is a fully transistorized stereo device, while the TK 145 is still equipped with tubes. Apart from the fact that it is a stereo device, on the TK 147 the user is looking for some luxury equipment in vain. The advantage of the automatic recording control also led to the fact that this device is missing the pointer instrument. Its place is filled out by the letters "AUTOMATIC", which are illuminated during a recording. Otherwise you are looking for nice gimmicks in vain. On the left, five buttons and two controls to control the most necessary functions. On the right is the lever for the drive control, similar to the TK 145.

As you can see, the unit is in the recording mode. The rotary knob for the drive control is somewhat slimmer as the one on the TK 145. Obviously, Grundig considered this as a luxury. However, one must say that the drive control by the rotary knob is actually quite practical. In the true sense of the word, all drive functions are in one hand.

Here again a look at the knobs and controls of the TK 147. To the left the track switch with the additional button for the stereo operation is, to the right the volume and tone controls are placed. The other two buttons are used to turn the unit on and off and to select the recording function.

The microphone connector is located under a small cover. When the cover is opened, a switch is pressed inside the unit, which switches the unit into the recording mode with a microphone amplifier. By the way, the cover is closed by itself by a spring.

There is a cover on the back of the unit, which can be removed after loosening a single screw. Here the operating voltage of the device can be changed. When a fuse burn through, in the cover the same replacement is to be found. Actually, this is quite handy. As you can see, with this device is obviously no fuse burnt through. The spare fuses had not yet been used and are still located in the provided bracket on the cover.

The other connections on the back. Not visible in this picture is another loudspeaker socket, which is located under the three connectors right-hand.

The red part is used to switch the operating voltage. As you can see, the TK 147 can be operated with either 220 or 110 volts. If it is necessary to remove the cover, pull out the mains voltage cord out of the wall socket. The cover it must never be forgotten to put it back into operation before connecting the mains voltage cord. In case of accidental touching of the fuse holders, a dangerous electrical shock can occur.

The Grundig TK 147 with housing top removed. This unit is somewhat different from most other tape recorders. It does not have a single removable housing cover. Instead, the complete housing is removed, leaving only the chassis and the base plate. The disassembly takes place as follows:

First remove the five screws on the top of the unit. Then the knobs of the two knobs and the rotary knob for the drive control have to be removed. The small cover on the back should not be forgotten. It is fixed with only one screw. Before the housing part can be removed, the handle and the retaining screws must be removed. The carrying handle is first pushed slightly towards the housing. The best way to do this is to place the device as if You wanted to carry it on the handle. In doing so, the handle is carefully pressed downwards and then pulled out on one side, then on the other side towards the outside. The two handle holders can be simply turned out with a slotted screwdriver. Now the housing of the TK 147 can be pulled carefully upwards and the chassis of the device is left over, as can be seen in the picture above.

The tape guides and heads of the device. Here a thorough cleaning was necessary. In the foreground the control light can be seen, which illuminates the word "AUTOMATIC" when recording.

The loudspeaker is attached directly to the device chassis in this unit and not in the housing, as is often the case with other tape recorders. This is actually quite practical, as you do not have to worry about removing the speaker cable when you remove the housing. The loudspeaker, by the way, has a good sound, but only if the device is installed in the case.

When I got the Grundig TK 147, it had a very common error known as normal in devices of this series. The knob for the drive control was in the rewind position and couldn't be moved away from this position. The reason for this was the small white part in the foreground of the picture. This is a small plastic sleeve which is located on a metal pin. The original part was unfortunately crumbled. As a result, the large metal lever tilted backwards with the rotary knob in such a way that it could not be rotated at all. This error could be corrected by attaching a new sleeve. Because of course no original spare part was available, I had to do something improvising. In a small plastic tube from an old ballpoint pen, I finally found the right replacement for the defective original part.

In the lower right part of the picture the already mentioned second loudspeaker socket can be seen, which is normally covered by the housing. I don't know for what it is used.

This is what the Grundig TK 147 looks like when the floor slab is removed. All in all quite clear, one could say. As with most devices, the drive motor, which also serves as a power transformer, is located at the center. To the left is the power amplifier board. Probably for reasons of cost, the device has only a single output stage. For stereo operation during playback, it must then be connected to a suitable amplifier or to a stereo system. Alternatively, headphone operation is possible in stereo. On the far right is the preamplifier board.

Such and similar motors were used in most Grundig tape recorders. They are quite sturdy and drive pretty much everything, which should turn afterwards somehow. In order to simultaneously serve as a power transformer, the motors have additional secondary windings at which the corresponding output voltages are available for supplying the amplifier part.

Here again a look at the power stage of the TK 147. To the right in the picture is the large heat sink for the final stage transistors. The rectifier is located to the left of the circuit board.

The preamplifier board of the tape recorder. The switch for recording and playback is clearly visible.

There is a further spare fuse on the bottom of the housing. It can be took out after the housing floor has been removed.

The Grundig TK 147 during a first test with a pre-recorded tape. After a thorough cleaning of all parts in contact with the tape, the sound reproduction was clear. Even all drive belts are still in a perfectly usable condition. I'm always amazed at how long these drives are workable.

But even the best drive once needs new lubricants. In any case, I did not want to disassemble the large metal plate on the top of the device chassis. Fortunately, the shaft of the flywheel can be lubricated after removing a small plate on the bottom of the unit that contains the bearing. However, thorough cleaning was necessary before applying new lubricants.

On this occasion, I also dismantled the winding discs and equipped them with new lubricants. In addition, the device chassis was cleaned as well as possible.

The sliding couplings of the winding discs represent rather unique constructions. When disassembling one should pay close attention to how the parts were assembled beforehand. Fortunately, I've done before disassembling pictures, as it can be seen.

Of course, I also cleaned the housing thoroughly before the assembly took place. In any case, the repair of the device was worth it. Now the TK 147 workes perfectly, and also the playback is clear and clear. The automatic recording level reacts somewhat slowly, but is quite useful. After all, it is possible to make good recordings.

Grundig's 100 series were the successors of the equally successful 10s and 20s series (TK 14, 17, 19 and 23 and 27). There are certainly no high-end tape machines, but you were made relatively cheaply manufactured and offered. After all, the manufacturer Grundig was able to produce relatively inexpensive tape recorders, which were also affordable for the normal consumer.