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A common problem with LED type peak meter displays is failure of the individual LEDs (light emitting diodes). It is seen above happening to the SL-HF300. The cause for these failures is difficult to pin down. It could be a combination of vibration, mechanical impacts, or age. These displays are no longer available* new. Replacing their individual diodes is a challenge because they are very tiny, and the replacements are difficult to work with. Here is why they can fail and two methods for reclaiming these displays. The component illustration in the lower left shows the type of LED assembly used in the manufacture of the SL-HF300, SL-HF500, and SL-HF750 meter boards. The individual diodes are printed onto a circuit board along with other surface-mounted components. The diode's construction consists of a conductive anode pot (reflector) and an ultra-thin cathode wire. The compound in the pot is called the semiconductor (diode). Semi because it only becomes active when the right DC current is applied going the right direction. When energized, it emits colored light. In the circuit, the reflector pot is bonded to a thin layer of copper called a trace. It is what remains from an etched copper-coated fiberboard sheet. This is the printed circuit board of the meter assembly. There is another trace next to the pot that has the wire coming from it and protruding into the semiconductor pot. The bowel of the pot is parabolic-shaped for the best reflection and protected from contamination by a protective gel. Under certain circumstances, the gel separates from the pot and wire comes out of the compound. The LED stops lighting up. The evidence of this is seen in the peak level meter display of the SL-HF300 above. Sometimes these meters can be repaired. Click on the picture, and the display assembly is shown removed from the VCR. Click on it again, and the repair method is illustrated. Seen here in the upper left are two dead LED sites. Notice the traces and the pot mounted on those tiny square areas. The replacement LED in the center is shown laying on a penny next to Lincoln's nose. This is to illustrate its size and the complexity of making this repair. Notice it has the epoxy resin covering its diode instead of the gel. Upper right is the repair with one of the tiny LEDs soldered in place. Click the picture again, and the front of the SL-HF300 is seen with the six LEDs replaced, and all are now illuminated. Another Beta that has this same problem is the SL-HF750. Click on the picture, and it is shown here having several failed LEDs. The graphic in the upper left is the same as the one earlier and is for your reference. Click the picture again, and here is the assembly being removed from the SL-HF750 linear skating assembly (cassette loading tray). This LED assembly is almost always non-repairable. I have had moderate success in the past, but the main problem is the repair doesn't replace the remaining LEDs of the meter. They are subject to the same vibration as the originals and probably will fail sometime in the future. For a long while this was the only way to mark a repair. A better solution needed to be found. The best repair would be to replace the meter with one that has the LEDs protected by the hard resin. They are virtually indestructible. Since no new Betahi-fi VCRs are being made, no new parts are no longer available. Any replacement would have to come from a parts unit that is very common and has the same unit spacing as the SL-HF750. It seems that there are several common models that fit that requirement. Harvesting these from damaged VCRs has allowed a workaround to be created. The assemblies had to be modified so they would mount inside the SL-HF750, and the size and spacing had to modified. The meter drive circuit in the VCR also had to be changed so it could drive this dependable replacement. It is shown being fabricated in the upper left and mounted in the loading tray's faceplate (from the back). The next photo shows the meter in operation. To return to the previous page, click here. *All manufacturers pledge to continue manufacturing replacement parts for their products for a certain period of time. Normally two years once the models goes out of production, but it can be longer depending on the item. After this grace period ends, a remaining stockpile of replacement parts is held in inventory. The type and the amount depend on a number of factors. Such as how popular the model was, how often a certain component failed, plus things such as size and complexity. The first items to run out are whole units, appearance items, and accessories. Usually these only need replacement due to loss or damage. These include component doors, cabinets, faceplates, knobs and remotes— anything used to replace loss from handling or damage. Replacement parts for these shortly after production cut-off is almost a non-starter. After these metal frameworks, molded plastics, glides, master CPUs, wiring, complete circuit boards and assemblies go next; whatever is left over from the unit's construction. Electrical components and small consumable parts hold out the longest because manufacturers guess that a larger number of these will be wanted to fill the needs of units still in operation. As time goes by, all of the options disappear, and the unit is considered to be non-repairable. Time has passed it by. The only parts available after this happens is left to the mercy of third party sources, found inventory, and scrounging the boneyards. As far as the maker is concerned it is thanks for your support, and please by one of our newer products. ©Misterßetamax
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