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Network and Information Services |
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Technical Services Technical Tips |
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Wollensak Tape RecorderPoor recording quality when using a microphone on the Wollensak 2551AV may be due to feedback from speaker to mic, causing a ringing or howling sound. To kill the speaker, turn the "record monitor" switch on the left side control panel to "off." In general, this applies to any recorder with a "record monitor" or "speaker monitor" switch. Audio TapesThe following can cause audio cassettes to develop internal binding of the tape spools:
Depending on how such a tape is inserted, the player will either shut off during playback, "eat" the tape, or slow down, causing audio to "drag." This binding can usually be corrected by completely rewinding the tape from end to end. Tape Erasure PreventionAs new recordings are made on a tape, previous recordings are automatically erased. However, in order to prevent erasure and accidental recording on a tape, there are two tabs (called erasure prevention tabs) on all compact cassettes, which, if broken off, will prevent new recording on the tape. With the side you want to protect against erasure facing you, break off the left tab to prevent recording on this side. Break off the other tab to protect the other side. Recording on a cassette whose tabs have been broken off is possible by covering the openings with adhesive tape. In most tape players the record key is blocked and will not depress if there is no tape in place or if the tape has a broken tab. When these conditions exist, excess pressure on the record key will bend the mechanism or break the key. LCD Panels and Overhead ProjectorsWhen using LCD panels with overhead projectors, please be sure that the LCD panel does not overheat. The temperature of the LCD surface cannot exceed a specific level, typically 115 degrees Fahrenheit. Your LCD panel operation manual should contain specific instructions regarding the operation environment and usage. Use the following guidelines to insure the safe operation of your LCD panel.
Computer Back-UpsDoing regular backups of your hard drive data is extremely important. If your data is important, do not risk losing it! Many hard drives fail within the lifetime of the computer they are installed in. They can fail at any time and sometimes do so without warning. It can be difficult and sometimes impossible to recover data. Back up critical data daily. By using incremental backups daily, the amount of time required is very small. You can do full backups less frequently. If it is within your budget ask your computer personal to install a Zip Drive or other type of backup media device such as a tape drive. If your operating your system while attached to a Local Area Network (LAN) see if you can use a portion of one of the host drives for a back-up media and back-up your files to it. Computer Error MessagesWhen encountering error messages on a computer, try using "print screen" when the error occurs. Also, note the previous operations before the error messages. Collect as much information as possible. All of this will help the technicians with their diagnosis. Computer TerminologyWhen communicating with technicians, it is helpful to use correct computer terminology so as to avoid confusion. While it is impossible to always know the correct name for everything, some basic vocabulary may help. With the proliferation of hard drives in recent years, there has been a tendency to call a computer a hard drive. A computer is not a hard drive! A hard drive is a mass storage device, usually installed inside the computer. The hard drive is used to store your operating system, applications, and files. Although you can use a computer without a hard drive, you cannot use a hard drive without a computer! When referring to the main box of a computer, you may call it a computer or CPU (central processing unit). Using the correct terminology will help our technicians accurately answer your questions and get to the heart of the problem quickly. All in One Computers & Monitor Safety IssuesThe compact Macintosh computer systems (ones with built-in monitors), require special skills and tools to upgrade or repair. Without proper training and tools, these computers pose a grave threat to the person working on them while the cover is removed. Two major hazards are high voltage and the picture tube's high vacuum. High voltage is almost always present at the CRT (Cathode Ray Tube, or Picture Tube) anode, where the large red wire with rubber boot attaches to the tube. The voltage is present even with the system unplugged! This voltage must be discharged before the system can be safely worked on. Normally, a special tool with an insulated handle and resistor is used to discharge the CRT. The tool must be grounded at the proper point of the system to insure that no damage is done to the electronics during the discharge process. If you have never discharged a CRT, do not attempt this without assistance from an experienced person. Also, never work on a monitor without another person in the area in case something happens. The CRT's high vacuum poses an implosion hazard. If the back side of the tube is hit, it may implode (a reverse explosion). This sends small pieces of glass in all directions at high speeds. We do not recommend that school personnel, and especially students, work around CRTs. Allowing students near CRTs could have dire consequences to the student, school and computer. CRTs can easily be damaged by bumping the neck of the tube. This usually discharges the vacuum and renders the CRT useless. Replacement of a color tube is several hundred dollars when it is available. Many new Apple monitors have no replacement parts available. Please send your compact Macintosh computer systems to the ESD when exposure to the CRT will be required during the service procedure. We have the tools and training to deal with them. Computer Integrated Circuits (ICs and Simms)Whenever you handle or install computer memory or upgrade kits, it is important that you follow certain procedures. Static electricity can destroy ICs. Make sure your body is properly grounded before removing them from their protective packaging. Do not touch any metal pins or socket connectors. All ICs have a particular orientation that needs to be observed when being placed in their sockets. If inserted wrong, they and other electronic components could be destroyed. ICs have markings that need to be matched with those on the circuit board. Do not rely on the printing on the IC for proper orientation. A proper tool for extracting ICs from their sockets should be used. Many people injure their fingers if they do not use the proper instrument. When inserting ICs in sockets, be very careful not to bend any pins. Examine all ICs very closely before applying power as bent pins are often hard to see. "Print Screen" Error MessagesWhen encountering error messages on a computer, another handy item for the technician is a "print screen" made by the user when the problem occurred. Please also note the previous operations that were done before the error messages occurred. Collect as much information as possible when the problem is encountered. Every bit of information helps the technicians determine the source of the problem. Packing Tips for Repair ItemsWhen boxing up items to send to Technical Services, choose and use your packing materials wisely. Foam "popcorn" can be a problem when used to pack items that contain holes. Some examples of equipment in which foam packing can cause problems are VCRs, camcorders, and computers. Popcorn can invade the disk drive openings and tape door openings, causing additional problems. Always use a plastic bag to enclosed susceptible equipment. Laser printers must be kept horizontal when moved if the toner cartridge is installed. The fine powder in the toner cartridge can spill when tipped on its side. If you are going to send the printer in, with the toner cartridge installed, please clearly mark the box that you are shipping it in "This side up" and do this on all sides of the box. Cleaning spilled toner from a printer can be a time-consuming process. Never place a laser printer sideways in a box. The safest way to transport laser printers is to remove the toner cartridge and package it separately in a plastic bag. Video Tape Your ProblemsIf you are faced with an unusual problem with a piece of equipment, you may want to consider catching the symptoms on video tape. Most schools have a camcorder which can be a valuable tool for preliminary troubleshooting. Some problems are intermittent and are hard to duplicate at a repair facility. Using a camcorder to capture intermittent problems can help the technicians locate the source of the problem. Some problems are difficult to describe, and, as the old saying goes, "a picture is worth a thousand words." Camcorder Battery Handling ProceduresCamcorder batteries require special care to maximize their performance and life. The type of battery determines the handling procedures that should be used. There are two types of batteries used in camcorders: Lead Acid (Pb) and Nickel Cadmium (NiCad). Determining your type of battery can be a challenge. Here are some guidelines and suggestions: Check the label on the battery. Some are labeled "No memory" which indicates that it is a lead acid. Look in your camcorder's user manual. It may provide instructions on battery care and state the type of battery that was supplied with the equipment. If you have a non-original battery, it may be of a different type. We currently sell Again & Again brand batteries. Model numbers RC1220, RC1250, RC6034, and RC1017 are all lead acid. Older Panasonic VHS camcorders usually use lead acid batteries. Lead Acid Batteries
Nickel Cadmium Batteries
Security Straps for TVsThe lack of large flat tops on newer TVs make it difficult to strap the TV to the cart. Fortunately, there is a solution to this dilemma. Instead of the traditional cloth strap wrapped around the top of the set, permanently mounted anchor and removable rubber straps can be used. Plastic anchors are permanently attached to the side of the TV with high strength glue. With the anchor mounted on the side of the set, a rubber strap can now be used to attach the TV to the cart. This eliminates the possibility that a strap can slide off the top. Eiki Roller Attachment InstallationWhen installing new roller attachments on your overhead projector, it is a good idea to lubricate the spindle shaft. A couple of drops of lightweight oil (like Three in One or sewing machine oil) placed where the rotating shaft enters the mounting bracket will make it function much more easily. It will also extend the life of the attachment. Some spindle shafts of older attachments become so worn from lack of lubrication that they must be replaced. Technical Services can supply replacements. To order, ask for part number 087310. Lamp InstallationProper installation of lamps is critical to the life of the projector's lamp socket. Improper installation can damage the projector's lamp socket. The lamp must be fully seated into the socket to prevent arcing which can destroy the contacts in the socket. Replacement of sockets costs from about $10 to $35. The following projector and lamp combinations seem to be most prone to problems:
ENX and ELH lamps slide into a holder and socket assembly. Be sure to completely insert the lamp in these assemblies. Pay close attention to where the lamp's terminals are in relationship to the slot in the socket. They should be inside the slot, not merely at the top of the slot. Tape Erasure PreventionAs new recordings are made on a tape, previous recordings are automatically erased. However, in order to prevent erasure and accidental recording on a tape, there are two tabs (called erasure prevention tabs) on all compact cassettes, which, if broken off, will prevent new recording on the tape. With the side you want to protect against erasure facing you, break off the left tab to prevent recording on this side. Break off the other tab to protect the other side. Recording on an audio cassette when the tabs have been broken off is possible by covering the openings with adhesive tape. In most tape players, the record key is blocked and will not depress if there is no tape in place or if the tape has a broken tab. When these conditions exist, excess pressure on the record key will bend the mechanism or break the key. Hints for good tape performanceBefore inserting a cassette tape into the deck, make sure the tape is not slack. To take up any slackness, insert a pencil into one of the cassette hubs and rotate until the slack is removed. Take out cassette tapes after playback or recording. Letting the cassettes sit in the compartments will cause gradual deterioration of the tape. When not in use, keep your cassettes in their cases and store in a place not exposed to direct sunlight or sources of heat, and avoid places with high humidity. Cleaning Tape HeadsIn order to assure continued high performance from the recording/playback heads, they need to be cleaned regularly. Use a high quality cleaning tape for this purpose, or use a cotton stick moistened with rubbing alcohol and carefully wipe off the recording/playback and erasure heads, and other parts which come into contact with the tape. Do not use the cassette deck for approximately 5-10 minutes after cleaning the deck to allow the heads and cleaned components to dry. Binding TapesThe following can cause audio cassettes to develop internal binding of the tape spools:
Depending on how such a tape is inserted, the player will either shut off during playback, "eat" the tape, or slow down, causing audio to "drag." This binding can usually be corrected by completely rewinding the tape from end to end. Television on Channel 2Some electronic tune TVs will default to receiving only Channel 2 when the power is interrupted. This can happen after moving a television to another room. When you do not have a remote control for the set, it may be necessary to reprogram the television's tuner to receive the channel you want. This is done by pressing the auto program button after turning on the TV and connecting to your antenna, cable system, or VCR. This button is usually located under a flip down cover in front of the set. When the button is activated, the TV seeks out and selects all active channels that you can receive. These channels are placed in the TV's memory, allowing you to tune in the channels. If you are attempting to play a videotape and are using the VHF Out connection from a VCR, use the following procedure to program the TV tuner:
Procedures for setting up your TV can be found in the TV Owner/Operator Manual Equipment Packing TipsChoose your packing materials wisely. Foam "pop corn" can be hazardous when used to pack items that contain holes. Some examples are VCRs, camcorders, and computers. Pop corn can invade the disk drive and tape door openings, causing additional problems. Always use a plastic bag to enclose such equipment. Laser printers with toner cartridge installed must be kept in the horizontal position when moved. The fine powder in the cartridge can spill when the printer is tipped on its side. It is a messy and time-consuming process to clean spilled toner from a printer. The safest way to transport laser printers is to remove the toner cartridge and package it separately in a plastic bag. Cellophane TapeUsing clear cellophane tape to attach service forms to equipment causes some difficulties. The tape is hard to remove and often leaves adhesive behind. Chemicals are then required to remove the adhesive. Please use an alternative to cellophane tape such as a quality masking tape. The inexpensive masking tape can also be difficult to remove if left on for more than a few days. Zenith MonitorsIf the Zenith 27" monitor, model SM2767, is locked in the AUX mode: This mode can be deactivated using the front panel controls. If all channels are erased from the channel scan memory only the AUX channel can be selected. To add channels back into memory, you must access the Setup Menu. However, in the AUX mode, only an abbreviated Setup Menu is available which has no channel setup options. To restore operation, follow these instructions:
These procedures will probably apply to other Zenith monitors as well. Overhead ProjectorsBefore discarding old acetate rolls, be sure to extract the cardboard
inner rolls. These rolls are not available for purchase and are very hard
to find when you need one. Keep a small supply of rolls so that you have
one handy when needed. Allow overhead projectors to cool down before moving them. The projection lamp may be damaged if moved when still hot. Audio-Visual Cart Power StripsThe newer style Wilson power strips (with the power sockets in molded rubber) are not serviceable when the rubber warps, causing the sockets to fail. While we cannot repair this problem, the cords from these defective strips may be used to repair other older power strips. Please save the power cords from these and send them in with other strips to be repaired. Tripod Broken LegsWhile a tripod is mounted on a dolly, do not attempt to lower or reposition the legs. The main casting of the tripod may be broken by the stress created. This is true of all brands of tripods. The bottom of the leg must be free to move laterally when it is extended or retracted. If the leg is held in position by a dolly, extreme pressure is exerted on the casting supporting the upper part of the leg. This results in cracking of the casting and requiring its replacement. Videotape JamsAny time a tape becomes wedged in a VCR, it is best not to attempt to pull it out by tearing the VCR apart. This may damage the mechanism of the VCR, as well as damage the tape. Send the tape to Technical Services and we will remove it for you and often we can repair the tape as well. Projection Lamp InsertionProjection lamps that are not inserted completely into their sockets can create major problems. When this happens, it can burn up the contacts inside the socket, and the socket will have to be replaced. Replacement of the socket costs between $10 and $40, plus the cost of the lamp. Also, remember to use the plastic that it comes in to install the lamp. Do not move the projection equipment while the lamp is still hot. It is very brittle at high temperatures and can break. Overhead Fresnel LensesCleaning the plastic Fresnel lenses used in overhead projectors requires special care. The lens can be easily damaged by chemicals and abrasives. Use only water or plastic cleaner and a soft towel to clean. Apply the water or cleaner to the towel, not the lens, for best results. Plastic cleaner may be purchased at marine, automotive, or some hardware stores. A good plastic cleaner is made by Permatex. Ask for part number 403D. Shipping Power Cords and CablesWhen sending in equipment for repair coil up cables tightly or secure them with tape or rubber bands. Loose power cords are a hazard to the equipment being shipped and a danger to the couriers. Surge ProtectorsThere are many types, configurations and price levels of surge protectors available. When Technical Services decided to stock one for sale to schools, we tested and examined over a dozen different types and brands. The minimum requirements that we established were:
Surge protectors use a component called an MOV as the active protection device. The number and configuration used determines the level of protection. Inexpensive surge protectors use only one, whereas three or more are required for full protection. The quality of the MOVs also varies. MOVs are designed to be damaged when a large power surge occurs and weakened from smaller ones. Since it is impossible to know if such surges have occurred, an indicator light is necessary to show if protection is being provided. Radio frequency interference (RFI) filtering helps cut line noise and provides cleaner power. Inexpensive surge protectors do not have this feature or, if they do, it is often not adequate. To be a versatile power strip, a lighted on/off switch and circuit breaker are needed. Many do not have one or more of these features. Inexpensive surge protectors are not well constructed and most are not repairable. Those supplied by Technical Services have an industrial duty case and sockets. All of the components can be repaired or replaced as needed. Warranty ServiceWhen sending equipment to Technical Services for repair, it is very important to note on the bottom of the service form that it is under warranty. With the exception of IBM equipment purchased through the ESD, we have no purchase records. Please enclose a photocopy of the packing slip or invoice issued by the dealer because a receipt is always necessary before warranty work is started. Providing us with this information will speed up the process. Electrical Plug SafetyAn important safety issue involves the common practice of deforming the blades of electrical plugs in order to ensure good contact in a worn wall outlet. A worn outlet constitutes a slight fire hazard. Bending the blades of a plug can often break the internal connection between the wire and blade and increase the fire hazard. A plug with deformed blades can also ruin a good wall outlet by stretching out the outlet. The safe way to deal with this problem is replacement of the electrical outlet. P C SoftwareTipsMany questions can be answered by doing some DOS exploration of your hard drive files. Often software publishers will embed "readme.txt" or "readme.doc" files into the program's installation setup. These files are not always accessible using the software itself and it may have been some time since the installation of the software when it was recommended that you read these files. Discovering them and reading them again can offer solutions to problems especially if the software "hard copy" manual is also somewhere not to be found. Below is a listing of some very useful DOS Prompt commands that will give you some tools with which to do that exploration. A good Dos Reference Manual is available at most good book stores and it is recommended that you purchase one for more in depth explanation of the following commands. *******
Contact Technical Services at (503) 675-4045 or email Jason Lovell. |
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