PERQ 3 Dismantling procedures ============================= [courtesy of Tony Duell] To remove outer casing : ------------------------ Unplug mains lead from the rear of the machine. Place machine on right hand side, remove the 2 screws from the bottom of the left hand side plate, and remove side plate. Turn machine over (so that the right hand side is uppermost), and remove the 2 screws and right hand side plate. Place machine upright, remove the 4 screws from the top, and lift off the top plate CPU/memory board removal : -------------------------- Unplug all cables from the rear of the machine and remove the casing. Unplug the SCSI cable (50 wire ribbon) from the CPU board and the OMTI board. Unplug the DDS cable (34 wire ribbon) from the top front of the CPU board. Unplug the 4-wire power connector from the CPU board. Unscrew the 2 screws holding the 5V and ground wires to the distribution bus-bars on the left of the machine behind the floppy drive. Note which way round these wires are connected. Place machine on the left hand side and remove the 2 M3 screws/washers holding the board mounting bracket to the chassis at the front. [Be careful here - my PERQ has some spacers between the bracket and chassis. Don't drop them into the guts of the machine - they're a pain to retrieve! pm215] Place the machine upright, loosen the clamp screw on the distribution panel on the rear of the machine (between the 2 fans) and remove the top and bottom screws on this panel. Carefully ease the board assembly from the chassis. When it is out far enough, unplug the solid state relay drive cable (centre rear of the CPU board) and remove the CPU and memory PCBs from the chassis as a unit. To remove the DDS : ------------------- Remove the outer casing and the CPU/memory PCBs from the machine. Compress the plastic locking tabs on the DDS mounting pillars and pull the DDS PCB rearwards. Once the DDS board is clear of the pillars it can be removed from the machine. Separating the CPU and memory PCBs : ------------------------------------ Remove the outer casing, and then remove the CPU/memory PCB assembly from the chassis. Unplug the video cable from the rear of the memory board. Place the assembly on an anti-static workbench, CPU board uppermost. Remove the 2 M4 screws holding the CPU board to the power busbars and the 4 M3 screws holding the CPU PCB to the fixing pillars. Turn the assembly over, so that the memory PCB is on top. Compress the locking clip on the top of the plastic pillar, and lift up the memoy board. Turn the memory board over (hinging it on the ribbon cables at the lower edge). Unplug the 3 60 way ribbon cables linking the CPU board to the memory board and separate the 2 PCBs. Floppy drive/OMTI board removal : --------------------------------- Remove the outer casing from the machine. Unplug the SCSI cable from the CPU board and OMTI board. Unplug the power cables from the OMTI board and floppy drive. Unplug the control (34 way) and data (20 way) ribbon cables from the hard disk located under the floppy drive assembly. Remove the top mounting screw (M4 countersunk) and the 2 lower mounting screws from the floppy drive assembly. Slide the assembly towards the back of the machine and remove it. To remove the OMTI board and floppy drive casing : -------------------------------------------------- Remove the outer casing and then remove the floppy drive/OMTI board assembly from the machine. Unplug the data cable (34 way ribbon) from the floppy drive. Unscrew the 4 screws holding the OMTI board onto the floppy drive assembly and remove it. If necessary, unplug the ribbon cables from the OMTI board. Remove the 2 screws holding the top mounting bracket to the floppy drive. Remove the 2 countersunk screws on the underside and lift off the inner floppy drive casing. Unscrew the 4 plastic mounting pillars and remove the outer floppy drive casing. To remove the hard disk : ------------------------- Remove the outer casing and the floppy drive/OMTI board assembly. Unplug the power cable from the hard disk (the control and data cables were removed when the floppy drive unit was removed). Place the machine on the right hand side, taking care to avoid damaging the CPU board if this is still in the chassis. Unscrew the 4 countersunk M4 screws on the underside that hold the hard disk mounting bracket to the chassis, supporting the bracket as the screws are removed to prevent damage to the hard disk. Remove the hard disk and mounting bracket. Unscrew the 4 screws holding the hard disk to the mounting bracket and remove it. To remove the PSU : ------------------- Remove the outer casing, CPU/memory PCBs, floppy disk/OMTI board assembly and the hard disk from the machine. [do you get the impression this isn't trivial? pm215] Place the machine on the right hand side. Pull the CPU power cable through the hole in the chassis. Remove the 2 screws holding the monitor power socket's bracket to the chassis, and ease this socket out. Remove the 4 PSU mounting screws and ease the supply upwards. Cut the cable ties holding the earth wire (purple) that runs under the supply to the rest of the loom. Loosen the fixing screw and disconnect this wire from the PSU. Remove the plastic cover from the PSU mains terminal strip (2 self-tapping screws). Loosen the 3 mains terminals and disconnect the live (brown), neutral (blue) and earth (green/yellow) wires from the PSU. Remove the PSU from the machine. Removing the CPM14785 PCB from the PSU : ---------------------------------------- Remove the PSU from the machine as described above. Remove the 3 self tapping screws holding the cover on the PSU and remove the cover. Remove the 2 self tapping screws holding the CPM14785's heatsink to the side of the PSU casing. Remove the single self-tapping screw that holds the CPM14785 board to the plastic mounting pillar in the centre of the board. Ease the PCB upwards. Remove terminal 11 (ACLO) from the terminal strip and disconnect the white wire leading to the CPM14875 board. Unplug the spade terminals on the ends of the other wires, noting that the connection points on the 2 boards carry the same markings. Remove the CPM14785 board. Rear panel removal : -------------------- Remove the outer casing, CPU/memory PCBs, floppy drive/OMTI board assembly, hard drive and PSU from the machine. Unscrew the 2 fixing screws and remove the plastic cover from the solid-state relay. Unscrew the rearmost 2 terminals on this relay and disconnect the mains wires from it. Unscrew the 4 fixing screws from the rear panel (2 at the centre top, 2 countersunk on the underside of the machine), and remove the rear panel. To remove the MUX board : ------------------------- Unplug all cables (power, video, keyboard, mouse, tablet, speech) from the monitor unit. Place the monitor screen-side down. Remove the 9 screws holding the baseplate on the monitor - 7 from the base and 2 from the connector panel. Ease the left side (as you look at it) of the baseplate away from the monitor, and slide the entire baseplate to the left by about 0.5". Ease the baseplate away from the monitor, and unplug the 4 cables (monitor power, monitor input, loudspeaker and brightness control) linking the Mux PCB to the rest of the monitor. Remove the baseplate and mux PCB as a unit. Pull off the 2 control knobs from the brightness and volume controls. [On my monitor these two steps have to be done simultaneously - the PCB won't slide out fully until the knobs have been removed. pm215] Remove the 6 locking posts from the D-connectors on the rear panel (a 3/16" A/F spanner is needed here) noting that the slidelock posts are fitted to the video connector. Remove the screws holding the Mux PCB to the baseplate and remove the PCB and the cardboard insulator under it. Removing the monitor casing : ----------------------------- Unplug the cables from the monitor unit and place it screen-side down. Remove the 2 fixing screws from the rear of the monitor and lift off the rear plastic cover. Remove the 4 fixing screws that hold the screening cover over the rear of the CRT, swing this cover towards the top of the monitor and unhook the fixing tabs. Remove the screening cover. To remove the CRT base PCB : ---------------------------- Remove the monitor casing. Pull the CRT base PCB straight up off the CRT pins, taking great care to avoid damaging the CRT. Unplug the power cable (8 pin) and video cable (2 pin) from the CRT base PCB. Disconnect the 2 earth leads from the 'Dag' and 'Bleed' terminals on the PCB and remove the PCB from the monitor. To remove the monitor PSU regulator : ------------------------------------- Remove the monitor casing and the CRT base PCB. Remove the 4 screws holding the regulator heatsink to the left side of the monitor chassis, supporting the heatsink as the last screw is removed. Ease the regulator assembly away from the monitor and unplug the 4-pin connector. Remove the regulator assembly Removing the monitor PCB assembly : ----------------------------------- Remove the monitor casing, CRT base PCB and monitor PSU regulator. Unplug the 2 scanning yoke connections from the monitor PCB. Unscrew the clamping nut from the flyback transformer's EHT connection and pull the EHT cable out of the transformer. Remove the 2 screws that fix the monitor PCB to the chassis, taking care to support the PCB assembly and avoid it striking the CRT. Carefully ease out the PCB and unplug the input cable (8 way) and brightness control cable (3 way). Remove the monitor PCB assembly. To dismantle the keyboard : --------------------------- Unplug the keyboard from the monitor. Turn in upside-down, and carefully release the hooks (2 at the rear edge, one on each side) holding the top cover to the base with a flat-blade screwdriver. Turn the keyboard the right way up and lift off the cover. Unplug the keyboard cable from the PCB, and remove it. Pull out the 4 rubber cylindrical wedges and release the keyboard frame from the hooks at the right hand side. Lift out the keyboard assembly and screening plate. Remove the M3 nut, lockwasher and plain washer that fixes the screening plate to the PCB and remove the plate. Turn the assembly upside down. Remove the earthing screw and the fixing screws that fasten the PCB to the keyboard frame. Remove the PCB. Dismantling the mouse : ----------------------- Unplug the mouse from the monitor. Remove the ball retaining plate and the ball from the underside of the mouse. Remove the 2 screws on the underside of the mouse and lift off the top cover, taking care to avoid damaging the buttons. Remove the 3 screws the anchor the PCB to the baseplate and lift off the PCB. Remove the leaf spring on the idler roller, and lift off the top ball housing. Remove the idler roller and the disk/roller assemblies. Slide the bearings from the end of these assemblies. CPU Power Connections | V +-----------------------------------------------------------+ | +-------------------+ +--------------------------+ | | | | == == | | | | | | | Omti Board | | | | | | | | | | | | (floppy drive behind) | | | | | | | | | | | | | | | | | | | | | | PSU | +--------------------------+ | | | | +--------------------------+ | | | | | | | | | | | | | | | | | Hard Drive | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +-------------------+ +--------------------------+ | +-----------------------------------------------------------+ PERQ 3A Left side view (covers removed) DDS | V + CPU PCB + | ----------------------------------------------------- | | | Memory PCB | | | ------------------------------------------------- | | +------------------------------------------------------------+ | +------------------+ +----------------------------+ | | | | | Floppy Drive | | | | | | | | | | PSU | +----------------------------+ | | | | || || | | | | ------------------------------ | | +------------------+ OMTI PCB | PERQ 3A top view (covers removed)