TRANSNATIONAL RESEARCH ASSOCIATES
[Technical and Scientific Communication]
Elenco Electronics Cassette Player -- Model AK-200 /TR-18K
Repair and Replacement Procedures for Tape Deck Assembly
Art Madsen, M.Ed.
Model AK-200/TR-18K is a simple battery powered Cassette Tape Player designed for voice recording and portable use by business personnel and journalists. The Tape Deck Assembly occasionally requires repair or adjustment due to rough handling, jarring or dropping of the unit. These repairs are not difficult and can be successfully accomplished by the owner.
Description of Equipment and Theory of Operation
The Tape Deck Assembly features three main parts, namely the Drive Train, the Push-Button Controls and the Tape Heads. Repair is usually focused on the first two components of the Tape Deck Assembly, since the Tape Heads are factory-sealed units seldom damaged.
The Drive Train is comprised of a motor turning at a constant speed. This motor powers a drive belt linked to a large ‘pinch-roller equipped’ pulley, all of which turns a capstan. The capstan holds both the large pulley, driving the feed reel, and a smaller pulley, linked by another drive belt, serving as a take-up reel. The large pulley pulls the tape across the tape heads at a non-fluctuating speed as the take-up reel holds tape that has been previously passed across the head. The take-up reel is equipped with a slip clutch to allow it to turn at various speeds as its load increases.
The Three Push-Button Controls consist of a PLAY function, a FAST FORWARD control and a STOP button. The play function button activates the audio, the motion controls and the motor, whereas the fast forward function disengages the slip clutch allowing the tape to whisk rapidly forward. The stop function deactivates all functions and, when pushed twice, releases the cassette from the body of the player.
The Tape Heads, which do not require repair under most circumstances, convert the magnetic properties of the tape to an electrical signal, on the basis of the principles of ferromagnetism. They do, however, require periodic cleaning with alcohol.
Repairable or Replaceable Components and Equipment: I. Control Button Assemblies and II. Drive Train
I. Stop Function Button Assembly
Fast Forward Button Assembly
Play Button Assembly
II. Capstan Assembly
Large Drive Belt
Small Drive Belt
Motor Case and Unit
Internal On Switch
Several symptoms of malfunction pertaining to the Control Button Assemblies and the Drive Train mechanisms are obvious to the owner. If one reel is functional and the other is not, a broken drive belt may be at fault. If the main capstan or motor seems inoperative, the problem could be the main drive belt or a burned-out motor, replaceable by direct order from Elenco.
It is best to remove the plastic casing and examine visible red wiring connections, pulley drive belts and positioning of control buttons to determine if jarring has dislodged any of these components. Reference to Figure 1 is important to properly understand the functional positions of these components.
The following Groups of Steps for Repair and/or Replacement of any of these drive train or button assembly components are offered for your convenience in personally attending to the most common malfunctions. There is no danger of electric shock, since the entire system operates on only 3 Volts.
Incidentally, please make sure that batteries are energized, contacts are clean and that electricity is reaching the player before resorting to these repair measures.
Repair and Replacement Directions
(For all 24 replacement / repair steps presented below, refer to Figure One above for visual reference)
I. All three Control Button Assemblies are self-contained units, but may be knocked out of position by mishandling of the cassette deck. First, remove the cassette player’s plastic casing, by gentle prying at the groove provided on the left and right ends of the unit. Repair or repositioning of each Button Assembly differs slightly as follows:
- The Stop Button Assembly is located in the top left of Figure1. An interconnecting bar supports it in relation to the other two button control units.
- Check to make sure that the interconnecting bar is in its proper position and that the Stop Button Assembly is exactly at 90 degrees to the bar. If not adjust it accordingly.
- The Fast Forward Assembly, located in the center of the three buttons, is more complex. The slip clutch mechanism may have been dislodged. It is located under the assembly and can be accessed by screwdriver or metallic probe. Reposition the slip clutch, which should click into place with a gentle nudge.
- Like the Stop Assembly, the Fast Forward Button Assembly may also require manual repositioning. It must be 90 degrees in relation to the interconnecting bars.
- The Play Button Assembly is interlinked with the internal on switch, in addition to wiring linking it to the audio electronics. Check to ensure that all wiring is intact.
- As with the other two button assemblies, the Play Button must be at a 90 degree angle in relation to the interconnecting bar. The bar itself may require repositioning, allowing all three buttons to function freely.
II. For repair or replacement of the Drive Train, the following inspection and adjustment steps must be performed.
- The Capstan Assembly is the central power-drive transmission of the cassette player. It is located under the large pulley and turns both the large and small pulleys. Remove the large pulley to inspect the capstan. It should be re-lubricated with a drop of "3-in-1 Oil", and re-centered if out of vertical alignment using a miniature torque wrench.
- Under the large pulley, the capstan supports the drive belt for the smaller pulley. Check to ensure that the belt is snugly fit into the second groove provided on the capstan.
- Before replacing the large pulley, visually ensure that the capstan is turning freely and is not obstructed by foreign matter.
Large Pulley & Drive Belt
- The Large Pulley should fit firmly onto the capstan without slippage. If the pulley is slipping, an abrasive fluid, other than glue, can be applied to the interior of the pulley’s central hole, and allowed to dry prior to refitting onto the capstan.
- Make sure that the tension of the drive belt connecting the motor to the large pulley and capstan assembly is sufficient to avoid slippage at either belt terminal.
- The Large Drive Belt may be broken. It can be replaced by ordering from Elenco, or by using the spare drive belt provided in Elenco’s General Repair Kit, optionally purchased with the cassette player. When replacing, make sure the tension is sufficient to ensure power transmission from the motor to the capstan assembly. This can be done by slightly repositioning the capstan assembly, not the motor shaft.
- If still intact, check the drive belt to ensure that no lubricant has accumulated on the edges of the large pulley or the motor shaft, and that no weak or frayed spots are visible along the surface of the belt.
Small Pulley and Drive Belt
- The Small Pulley is more complex than the large. It drives the take-up reel; there is a slip clutch between it and the take-up reel. When performing the same repair or replacement steps as outlined above for the large pulley, care must be taken not to disrupt the functioning of the slip clutch.
- The large pulley must be removed to ensure the proper positioning of the small pulley’s drive belt, connected to the feed-reel capstan. Ensure that no lubricant is on the small pulley or its belt.
- The Small Drive Belt should be inspected in the same manner as the large belt. It may be replaced from the Elenco Repair Kit, if broken.
- Because the small drive belt is being driven through the feed-reel’s capstan, belt tension should be checked carefully to ensure proper functioning and minimal belt slippage, thus enabling the clutch to function properly.
Motor Case and Unit
- The Motor Case and Unit are a factory-sealed component. If a burnt smell is emanating from the motor area, this unit may be replaced by ordering direct from Elenco.
- The motor is situated near the edge of the player’s right edge. A jolt or blow to this area of the player may have dislodged the motor, without damaging its internal components. Check to ensure that the motor is re-secured in its original position.
- After making sure that the batteries are properly energized and that contacts are clean (see above notes), 3-in-1 Oil may be applied to the motor assembly if it seems operational, but sluggish.
Red Wires and Internal "On" Switch
- The Red Wires lead from the Play Button Assembly to the Audio and Motion sectors of the unit.. They are connected to a switch. These connections must be visually verified to ensure that physical contact is intact.
- If contact is not being made, the red wires may be soldered into place, as noted on Figure I.
- The On Switch is usually not damaged by even severe jarring of the player. It may be replaced from the Elenco Repair Kit optionally available.
- Verification of its functioning is difficult to determine visually; but a voltmeter can be used to isolate a potential problem with the "on" switch.
The foregoing steps should alleviate approximately 75% of all electro-mechanical problems with your Elenco AK-200/TR-18K Cassette Player. If you are still experiencing problems, please send the entire unit, with a brief description of the problem, to our factory in Wheeling, Illinois, at the postal address provided. Thank you.