Abstract: Wicking-resistant solder preforms and methods for making such preforms are provided. The preforms include a solder layer for electrically mounting a lead to a printed circuit board upon heating the solder above its flow temperature. The preform also includes a flux layer disposed in contact with the solder layer and a wicking barrier disposed on a component-facing side of the solder layer for minimizing solder wicking along the lead during subsequent reflow soldering operations.

Abstract: A natural convection cooled electronic device utilizing a box-like plastic enclosure surrounding the circuitry of the electronic device. The apparatus further includes aluminum heat sinks fastened in good thermal contact with heat dissipating components of the electronic device, wherein the heat sinks include heat fin members which run parallel to the inner walls of the enclosure and are separated from the walls by an air gap. The inner walls of the enclosure are lined with a layer of thermally conductive material, such as copper foil, which spreads the internal heat flux across the total surface area of the enclosure. The exposed surface of the heat flux spreader layer and the facing surface of the heat fin members are further made semi-rough and stained black to eliminate potential hot spots and to increase radiant heat transfer between the heat sinks and the enclosure.

Abstract: The top sheet is separated and removed from a paper sheet stack by a paper feed mechanism which is selectively movable downwardly toward the stack. As the feed mechanism downwardly approaches the stack, a foot portion of the mechanism frictionally contacts the top sheet and is upwardly pivoted by the stationary paper stack. Upward pivoting of the foot portion causes it to frictionally shift the top sheet in a first horizontal direction relative to the rest of the sheets. A drive wheel portion of the feed mechanism, supported for conjoint pivoting with the foot portion about its pivot axis, then frictionally engages the shifted top sheet in place of the foot portion. In response to the upward pivoting of the foot portion, a driven gear supported for pivotal movement therewith and rotationally locked to the drive wheel portion is caused to mesh with a drive gear operative to rotate the driven gear and thus the drive wheel portion.

Abstract: A power supply which senses whether a primary battery is discharging to below a predetermined dead battery level or the primary battery has been removed and the system is operating from an auxiliary battery, which has a lower voltage. When the battery voltage goes below the dead voltage level, the system is in a low power mode and the power supply output voltages are satisfactory, a timer may be started. If the battery voltage does not drop to the auxiliary battery voltage level within a predetermined time, a shutdown signal is generated and the power supply ceases providing output voltage levels. In this manner the primary battery can be removed and the system can continue running on the auxiliary battery until a charged primary battery is installed and yet the primary battery discharge rate will be greatly slowed when the primary battery voltage is below a given level and the primary battery is still installed in the system.

Abstract: An electrical system wherein the electrical conductive traces on the circuit boards are routed to achieve a balanced net to reduce noise caused by transmission line reflections. A trace is routed from the source terminal of the net to a balanced junction wherein if there are an odd number of load terminals, or loads, the balanced junction is located at one of the loads. The remaining loads are grouped into branches wherein each branch includes an equal number of loads. A trace is routed between each of the loads of each branch to serially connect the loads of each branch together, or, a trace is routed from a center one of the branch loads to each of the remaining branch loads, forming subbranches. In an alternate embodiment, a balanced subbranch is developed. The balanced load is connected to a pseudo-balanced load, which further receives an equal number of branches. The pseudo-balanced load is then connected to another pseudo-balanced load, which may also receive an equal number of branches.

Abstract: A laptop personal computer system according to this invention comprises a base unit including a microcomputer subsystem, a cover unit including a display subsystem, a hinge unit for coupling the cover unit to the base unit, the hinge unit having a clutch spring to control torque from opening or closing the cover unit, and conductive elements cooperatively coupled within the hinge unit for suppressing electromagnetic interference in operations of the microcomputer subsystem.

Abstract: A keyboard controller which scans entered input sequences for an input sequence to activate a display blanking feature. A password and particular hot key are loaded by the system microprocessor. The keyboard controller then scans until the designated sequence is activated. The display on the monitor is blanked until a password sequence is entered. The password mode may be directly activated from the system microprocessor. The display blanking feature is especially useful in conjunction with a keyboard password lock.

Abstract: A keyboard structure is recessed within an open-topped base housing portion of a compact portable computer such as a notebook or laptop computer. Front corner portions of the keyboard structure are secured to the base housing in a manner permitting the keyboard structure to be pivoted relative to the base housing between a storage/transport orientation in which the top side of the keyboard structure is generally parallel to the bottom side of the base housing, and an ergonomically improved tilted use orientation in which the top side of the keyboard structure slopes forwardly and downwardly toward the user of the computer. With the computer opened, the keyboard may also be used in its storage/transport orientation. Compact spring biased latch assemblies are disposed within interior side surface recesses of the base housing and are operable to releasably lock the keyboard structure in a selected one of its storage/transport and tilted use orientations.

Abstract: A bus arbitration protocol and accompanying bus arbitration logic for multiple-processor computer systems in which each processing module has a local cache. Several bus arbitration policies are enforced on contending devices which effectively introduce delay states into the arbitration behavior exhibited by each device. The bus arbitration protocol employs a distributed method of arbitration control involving an essentially fixed prioritization of arbitrating devices.

Abstract: A circuit board is capable of indicating whether it is located in an 8 bit slot and is capable of operating on an 8 bit or 16 bit wide data path. The user can indicate the desired operating data width. Based on determinations of slot size, desired operating width and the presence of other 8 or 16 bit devices, the operating data path width is automatically set. Warnings are given for selected operating conditions.

Abstract: A specially designed resilient probe device is used in place of the usual series of pogo pins in the electrical testing of a printed circuit board. The device includes a strip-like, nonconductive elastomeric body having upper and lower side edges. Imbedded in the body are a spaced series of vertically elongated metal conductor strips arranged in staggered rows and having upper and lower ends that respectively project slightly beyond the upper and lower body side edges. The body is frictionally retained in a vertical slot formed in a plastic holder, with the upper and lower side edges of the body respectively projecting outwardly beyond the top and bottom ends of the holder.

Abstract: Method for determining the susceptibility of a protective device protected electronic assembly to electrostatic discharge events. The protective component is subjected to an electrostatic discharge event and the amount of kinetic energy transferred to the protective component during the electrostatic discharge event is determined. The susceptibility of the assembly to electrostatic discharge events is then determined based upon the amount of kinetic energy transferred to the protective component during the electrostatic discharge event.

Abstract: A method for automatically remapping a disk after receiving a bad sector indication without requiring system operator intervention, initiation of a diagnostic program or system down time. When the disk controller receives the error and mirroring or parity operation is activated, a remap routine is initiated. The routine finds the bad sector in the request, builds a good track of data and stores this good track of data in a reserved area on all the disk units on the controller. The data in the reserved area is then read, and if successful, the track having the bad sector is remapped to remove the bad sector from use. The saved data is then rewritten to the track, thus restoring the disk unit to full operation. A flag is set during the process so that should power fail the process can be restarted.

Abstract: A computer system which utilizes two different sets of address control and state information signals for transferring information of the same or different widths is disclosed. The use of two sets of signals allows master units to utilize only one set and a system board determines when the second set of signals must be used to complete the transfer and controls the second set of signals as necessary. The system board provides the necessary information routing and latching to properly transfer the information.

Abstract: A dual bin paper feed tray is removably insertable into the standard height tray-receiving housing opening of an image reproduction machine such as a printer or copier. The tray has adjacent front and rear paper holding bin areas each configured to hold a stack of approximately 250 cut paper sheets, the overall tray thus being adapted to hold the entire contents of a standard one ream package of cut paper sheets. In operation, the loaded tray is inserted, front end first, into the housing opening and the machine's paper feed system operates to sequentially feed paper sheets from the front tray bin into the machine. When the machine's paper sensing system detects that the front bin has been emptied, a shift structure incorporating a motor-driven gear train and associated cam/follower apparatus is automatically operated to move the rear paper stack into the front tray bin for infeed to the machine.

Abstract: An improved structure for testing the operability of a completed circuit board having components thereon and improved method of fabricating same are disclosed. The structure and process include the use of an insulator portion with a printed circuit board adhered thereto which includes a testing pattern to evaluate the operability of a completed printed circuit board. The insulator portion which provides support for the test pattern extends past the edge of the printed circuit board thereby providing a remote means to test the operability of the printed circuit board without having to utilize valuable space and contact points on the printed board itself to test the operability of the completed printed circuit board once components have been installed.

Abstract: An enhanced processor lock cycle management system for computer systems including a processor 10 and a cache memory controller 12 which accommodates existing methodologies and provides an enhanced mode wherein processor lock cycles are not passed to the controlled 12 but control of the system bus 14 by controller 12 is maintained by inhibiting hold requests to the controller 12 by other system elements.

Abstract: An AC-powerable portable computer has an interior sheet metal chassis portion within which computer operating components are operatively disposed. The chassis has a removable metal access wall portion and is positioned within a plastic outer housing of the computer having a removable access wall that outwardly overlies the sheet metal access wall portion. A key-operable security locking system incorporated in the computer has a pawl portion positioned within the sheet metal chassis. The pawl is selectively movable to a locking position in which it interlocks with each of the plastic and sheet metal access walls and precludes their normal removal from the computer. When the plastic and sheet metal access walls are locked to the computer in this manner, entry into the chassis interior requires that the plastic access wall be broken, and that the metal access wall be forcibly bent away from the balance of the chassis structure.

Abstract: A computer program permits a user to simulate configuring add-in boards for a computer system. A board may be "pulled" from an inventory list for inspection, and may be "inserted" into any legal slot in the computer system. The program can automatically generate any permissible configurations for the board, i.e., configuration of the board's address resource allocations that avoid conflicts with the address resource allocations of other, already-installed boards. The user may select from among permissible configurations; for a selected configuration, the user may display to screen or printer a drawing of the switch- and jumper settings on the board that are needed to implement the selected configuration.