Printer Ram And Printer Capabilities; Cru Life Counter Behavior - Tektronix 1235N - Phaser Color Laser Printer Service Manual

Printer RAM and printer capabilities

The printer features three DIMM connectors which accept 64-, 128-, and 256-Mbytes
RAM DIMMs. The printer can use off-the-shelf RAM meeting these specifications:
168-pin DIMM
Synchronous DRAM
3.3 volt
9 nsec speed
Valid on-board Serial Presence Detect ROM.
The Startup page and the Configuration Page list the amount of RAM installed in the
printer.
Upon power-up, the image processor interrogates the 256 byte Serial Presence Detect
ROM which describes the DIMM with details such as data width, clock delay, number
of address columns and row, refresh rate and more. If the DIMM does not meets the
required specifications it the printer reports and "Invalid Memory DIMM
Configuration" message and stops the booting process.
If the power-up self-test diagnostics detect a DIMM with defective memory cells the
printer declares "Diagnostics Failed - Press Enter to Continue." After the enter key is
pressed the boot process continues and the defective RAM DIMM is ignored. Note
that a seriously defective RAM DIMMs (with grounded address lines, for example)
can keep the system controller board from booting up at all.
With more memory the printer gains the capabilities of printing without having to use
image compression (which trades less installed RAM for longer image processing
time) and dual frame buffers for printing one image while processing a second image
(which gives greater printing throughput).
The printer features three slots each of which can contain a 64-, 128-, or 256-Mbytes
SDRAM DIMM. Any slot may be used for any size DIMM. However, 256 Mbyte
RAM DIMMs cannot be mixed with smaller RAM DIMMs. DRAM memory totalling
beyond 512 Mbytes will be ignored. The image-processing controller board also
contains 16 Kbytes of non-volatile memory (NVRAM), to store all for the necessary
values that can be set on the printer.

CRU life counter behavior

Internal counters track customer replaceable unit (CRU) life usage and store the
values in NVRAM. The controller monitors these counters in order to display the near
end of use and end of use messages.
The toner states displayed are OK, Low, and Empty, where the engine senses and
automatically reports the Low and Empty states. When the empty state is reached for
toner, the printer terminates printing at the end of current page and displays the
appropriate message on the control panel. No further jobs are accepted from any
input port.
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Phaser 1235 Network Color Printer