Tektronix Phaser 840, Service Manual

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Service Guide 5
Solid inks
Solid inks, sometimes called phase-change inks, are solid at room temperature
and are liquid at the higher temperature used during printing. The inks solidify
almost instantly after being jetted onto the printer’s drum. Because Tektronix'
proprietary solid inks bleed much less than ordinary liquid inks, they allow the
printer to print brilliant colors on plain paper. Each Tektronix solid-ink printer’s
inks are especially formulated for that printer; the inks are not interchangeable.
Note Turning the printer off and allowing it to cool causes it to perform
a printhead cleaning and purge cycle upon power-up. The
printer's purge cycle consumes a significant amount of ink.
During normal use and servicing, turn the printer off and allow it
to cool only when necessary.
About RAM upgrades
The printer features two DIMM connectors which accept both 32- or 64-Mbytes
RAM DIMMs (16-Mbyte RAM DIMMs work but are not offered). The Phaser 850
also supports 128-Mbytes RAM DIMMs. The printer can use SDRAM DIMMs
meeting these specifications:
■
168-pin DIMM
■
Synchronous DRAM
■
3.3 volts
■ 10 nsec speed
■
Valid on-board Serial Presence Detect ROM
■
Unbuffered
■
Latency of 2
■
9 address columns (Phaser 850 printer allows 32-MBytes DIMM to be in
8 columns)
■ Maximum of 2.8 cm (1.1 in.) in height (Phaser 840 printer only).
SDRAM DIMMs from other Phaser printers, such as the Phaser 740 and
Phaser 780 color printers may be too tall to fit inside a Phaser 840
printer.
Upon power-up, the image processor interrogates the 256-byte Serial Presence
Detect EEROM, which describes the DIMM in great detail, such as data width,
clock delay, number of address columns and row, refresh rate and more. If the
DIMM does not meet the required specifications, it will be ignored; no error
message will be reported.