OPERATION, SAFETY AND PROTECTION

In addition to recording and producing great video every Beta VCR had to be smart. To keep on top of things there were a number of sensors and switches whose job it was to monitor important operations. Integrated circuits used the information they provided to turn on the VCR, accept a cassette, control every tape motion and handle all the various commands. Not only was this required for operation but it was necessary for protecting your precious tapes. All these components worked together to make possible the tape handling prowess and exceptional features for which the Beta format was famous. They were located throughout the VCR and are identified and described below.

1. Overload fuses: There are a number of these fuses located at critical points throughout the VCR. They protect its circuits from power surges that could cause damage to vital components. If the amperage or voltage going across the fuse becomes too high it will open before a major meltdown can occur. Most of these are located in the power section where the various operating voltages are supplied. Others are positioned next to a group of circuits or a critical IC. These are single event protection devices and are not reversible. Their failure requires replacement (repair).
2. Overheat fuses: There are a number of solenoids in the VCR that perform various functions. Every one has a temperature and voltage sensitive fuse wrapped within or next to their windings that will open if it gets too hot or too much voltage is applied. This cuts the power off to the solenoid and prevents possible combustion. These are single event protection devices that do not reverse. Their failure requires replacement (repair).
3. ON/OFF switch: In the off mode the VCR it is basically a clock, but it has potential. Pressing the ON/OFF (or power) switch begins the basic operation of the VCR. Depending on the model it can also be turned on by pressing the on/off button on the remote, by inserting a cassette or pressing the SET TIMER button. Once the VCR is turned on all the settings, functions and features become accessible. It is now ready to perform video magic. All the sensors and detectors that are listed next are now available to insure that everything performs correctly, and that you have an outstanding Beta experience. Pressing ON/OFF again stops all operation of the VCR unless it is in timer record mode. Note: some models have a separate button for ON and for OFF.
4. Cassette detection switch: For front loading VCRs this switch recognizes that a cassette has been inserted and to start the loading process. If a cassette is inserted at an angle or is not placed far enough inward (to securely locate it inside the loading mechanism) the detection switch will not be activated and loading will not begin. Reverse usually occurs after a set time interval and the cassette is ejected. For proper loading the cassette should be pushed gently in at the front and centered so it goes in squarely all the way forward and into the compartment. This allows the cassette grippers of the loading assembly to securely capture the cassette. If there is an obstruction preventing forward movement it must be removed. Repair might be needed if the cassette continues to load improperly. For top loading VCRs, such as the portables, the detection switch activates when the cassette is all the way down and correctly seated upon the location bosses (or pins). Once in position the tape can automatically be (safely) drawn from inside the cassette and into the tape path.
5. Cassette down switch: This switch recognizes that the cassette has been received, traveled inward and is now seated correctly inside the tape compartment on the locating bosses (or pins). Only then can tape threading begin. If there is an obstruction that prevents the cassette from going all the way down this switch will not be activated and after about seven seconds the threading attempt will be aborted. Failure will normally cause loading to reverse and the cassette to be ejected. If this problem continues repair might be needed. For portables this function begins when the cassette is all the way down and the lid in the locked position.
6. End of threading switch: Once threading begins the main processor allows approximately five seconds for threading to be completed. If this end switch is not activated in the allotted time threading will reverse and the cassette will be ejected. This action usually is an indication that it could not be completed for some reason. Correcting this problem usually requires repair.
7. Splice avoidance routine: Once a cassette has been loaded and secured in the path (threading completed) the VCR uses the rewind stop sensor to detect if the foil leader has been drawn out into harms way. If it has the VCR will perform the splice avoidance routine. The take-up reel will turn slowly forward and pull the tape through the path and into the cassette until it clears the sensor. The heads do not spin as this is being done. This safety procedure prevents the splice between the foil leader and the tape from passing around the video drum when play or record is requested. This could damage the delicate video heads. None of the function buttons will respond until this operation is completed. This splice avoidance routine commonly occurs when a new or fully rewound cassette is loaded into the VCR. It is not a defect.
8. Tape recognition sensor: Some models have an LED emitter and detector that senses if the tape is located in the correct position before threading occurs. If it does not break the beam between the two sensors the cassette will be ejected. This is an indication that the tape has either threaded incorrectly, missed the detector or the tape is separated. This problem requires using a different cassette or repair if it continues.
9. Record lockout switch: This switch checks to see if the record prevention tab has been removed from the cassette. If recording is attempted using a cassette that is missing its safety tab the VCR will prevent it. Depending on the model it will either do nothing and wait for you to discover the problem or eject the cassette. If there is a "cassette inside" indicator in the display it might flash to show the cassette cannot be recorded. To use a protected cassette place a strip of tape over the protection hole. This will defeat the cassette protection feature.
10. Capstan rotation sensor: If play or record is requested and the capstan cannot turn the VCR will shut down. To executer this safety feature the capstan employs a rotation sensor to inform the main processor that it is turning. Failure to rotate can be caused by a damaged cassette, damaged capstan or tape wrapped around the spindle. Another culprit might be that the cassette is not going down completely flat inside the tape compartment due to an obstruction. Capstan monitoring is necessary to prevent the tape from bunching up inside the machine and causing damage. In most cases after a rotation failure only the power or eject switches will function. If the capstan continues to cause a shutdown repair is needed.
11. Tape slack sensor: During play or record if the tape becomes too loose the VCR will shut down. The slack sensor detects if the tape is not traveling properly and informs the main processor that it has lost forward tension. This can be caused by a damaged cassette, damaged capstan, reel rotation failure or a broken tape. Tension monitoring is necessary to prevent the tape from bunching up inside the machine and causing damage. In most cases after a tape slack failure only the power or eject switches will function. If tape tension cannot be maintained repair is needed.
12. Tape movement sensor: Rotation sensors detect if the tape reels are moving correctly and the tape is traveling through the VCR. A failure here causes the VCR to shut down and in most cases only the power and eject buttons will work. This rotation shut down is usually caused by a take-up reel that fails to turn properly. The cassette also might not be going down completely flat inside the tape compartment due to an obstruction. Continued rotation problems indicates repair is needed.
13. Tape tracking controls: The tracking adjustment is used to achieve tape interchangeability between VCRs. Technically not a sensor but important when playing back tapes that were recorded on another Beta VCR. Turning this control or pressing the tracking buttons will slow and speed up the capstan slightly. This removes unwanted noise from the picture caused by the minor mechanical differences in machines. It has no affect during recording, only playback. Adjustment is normally not needed when playing back tapes recorded on the same VCR. If a model features single-frame, slow-motion or step-motion playback it could also have a separate tracking adjustment for these special modes.
14. Pause time-out circuit: Detects if the VCR has been held in the pause for too long (over eight minutes). A timer program in the main processor tells the VCR to abort pause and return to playback or record. It can also default to the stop mode. This is done to prevent damaging the spinning video heads and tape. Prolonged pause time can cause excessive heat build-up to the heads (and the tape) from them striking the same area repeatedly. Heat will cause the tape binder to soften and deposited itself on the head surfaces. It then becomes bonded to the heads causing picture problems. Cleaning or repair is usually needed if this happens. If the heads will not come clean then replacement will be needed.
15. Tape stop sensors: There are usually two of these, one for each direction. They detect the foil (film) tape leader attached to each end of the tape. This foil activates the top end sensors (coils) and triggers a circuit that stops tape movement. Depending on the model the tape will be rewound at the end of playback or record. If the end is reached during timer record the machine turns off. These sensors are located on either side of the tape path near the cassette openings. Failure can cause the tape to continue to run when it should stop. If this happens the tape movement sensor will step in and shut the machine off. If it occurs during winding it can be very abrupt and damage to tape or machine can result. Repair is usually needed is a tape end sensor fails.
16. Motor overload sensor: During rewind and fast forward the force required to turn the reel drive motor and pull the tape is monitored by the servo processor. If the effort exceeds a certain amount it will stop the motor to prevent overheating (see overheat fuses). After a shut down usually only the power and eject buttons will work. Continued failure indicates repair is needed.
17. Tape unthreading switch: When eject is requested the tape is threaded back into the cassette and is then lifted up and out of the tape compartment. The end of unthreading switch sensor verifies that the tape threading components have successfully parked in the correct location before the loader lifts the cassette up and out. If the position is not satisfied the tape will re-thread and the VCR will wait for further instructions. Continued failure to unthread and unload requires a repair.
18. End of eject switch: Usually the same switch that is used to recognize a cassette is also used to detect if it has been successfully ejected. This switch opens which tells the loading motor to stop turning (ejecting) once the cassette is resting in the entryway. Failure here will cause the loader to reverse and send the cassette back into the VCR. Usually an ejection problem requires repair.
19. DEW sensor: It detects when DEW (moisture) has accumulated on the surface of the aluminum video drum. One of the physical traits of aluminum is that it can attract moisture if there is a sudden change in temperature. If the drum becomes damp the thin ribbon of video tape will stick to it and will not move. This can cause damage or mechanical failure. Some Betas will only indicate if it has been detected and others will prevent operation until it is gone. The DEW indicator with shut down feature is most common in portable Betas because they are easily moved from one environment to another. Some have a drum heater to accelerate the drying time. How the DEW function behaves depends on the model. Consult the VCRs description to see if it has the detection sensor and/or heater function. Always give your Beta VCR about an hour to acclimate itself after it has been moved from a warm to cold climate or vice versa. Not all Betas have a DEW sensor, depends on the model.
20. Reset switch: Pressing this switch restarts the VCR. If it should become unresponsive or fails to program correctly this safety feature erases all input and returns the VCR from a neutral or powered down condition. If this event continues to occur then repair is needed.

Note: From the beginning many safeguards and protectors were hard wired into every Beta VCR. The very first Betas (like the ones with the piano-type keys) didn't have as many as those models that came later. As Beta matured more safety and operation features were added and became standard. To find out about the other ways that Beta VCRs strived to enhance your home video experience open the "Auto functions" panel here or on its link in the features list. Also refer to the "Features and Benefits" panel that explains the beauty of the Beta format by clicking here.

If you have a Beta and you feel repair is indicated click here to go to my form for getting service. It will appear in the browser window.


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