Tektronix Phaser 840, Service Manual

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Service Guide 23
Phaser 840 and Phaser 850 printer differences
Summary of differences between Phaser 840 and Phaser 850
Phaser 850 unique part Details
Main board The main board is based on a 603E processor at 200 MHz. It
features a new rear panel with built-in10/100BaseT and no
SCSI port or riser card. The large Dallas NVRAM chip is no
longer used. Also the RAM connectors are angled. A battery
on the main board will support the real-time clock (10 year
life). The printer supports up to 256 Mbytes of RAM. Only a
Token Ring Card and an IDE Internal Hard Drive are available.
Power control board Improved fusing. Resettable fuses (by disconnecting AC
power) on +5v and +40v Hi-capacity Paper Tray leads. No x-
axis fuse.
RAM DIMMs Unlike the Phaser 840 printer, the Phaser 850 printer is not
as restricted on the height of the RAM DIMMs the main board
will accept since it uses angled RAM DIMM connectors.
Printhead The Phaser 850 printer uses the same printhead as the
Phaser 840 printer. However, the printhead mount has been
factory calibrated so no head-to-drum adjustment is required
when installing the printhead (as long as the printhead’s four
mounting screws have not been loosened nor the printhead tilt
setting altered on the left side of the frame).
Y-axis idler pulley The Y-axis belt drive assembly now features a built-in spring
tension. A Y-axis belt tension tool is not required.
Cap/wipe/purge assembly This is a new assembly. It also uses a new mounting system
that does not require the disassembling of the timing belts in
order to remove the cap/wipe/purge assembly
Preheater entry flags New sensor flags, less prone to snagging paper when
jammed paper is pulled from the printer, are mounted on the
upper feed roller assembly.
Drum maintenance clutch A new clutch is used in the Phaser 850 printer.
Left I/O board A new left I/O board is used in the Phaser 850 printer.
Y-axis drum encoder assembly A new Y-axis drum encoder is used with the Phaser 850
printer. It does not use a separate drum home sensor.
Lower stripper blade holder
and stripper blade The lower stripper fingers of the Phaser 840 printer have been
replaced with a replaceable stripper blade, called a rapid
release guide, and a guide holder.
Rollers and clutches Phaser 850 roller shafts are re-tooled for clutches with C-clips
instead of the Phaser 840 printer’s snap-fit feature. The parts
are reversed compatible only if the shaft, clutch and e-ring
combination replace the Phaser 840 parts.
The bushings for the Phaser 850’s duplex roller are installed
with C-clips from the inside of the chassis.
Preheater A new paper preheater designed to accommodate the travel
of the paper preheater entry flags is used in the Phaser 850
printer. The preheater is reverse compatible into the
Phaser 840 printer.
Inks The Phaser 850 printer uses new inks using a different
formulation. The inks are not compatible with a Phaser 840
printer. Likewise, Phaser 840 inks are not usable in a Phaser
850 printer.