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SIMCHECK II Line
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SIMCHECK II PLUS
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- Q. What do the values from the
Relative Refresh and Relative Spikes tests mean?
A. These are relative or comparative values given during our data retention
tests. The Relative Refresh provides a value for the ability of the memory
module to retain data between refresh cycles, while the Spikes figure gives a
value on how well a module can sustain voltage spikes before data loss occurs.
See Section 5.3.3 in your SIMCHECK II Manual for further information.
- Q. What does the "Device Type
Warning" message mean?
A. This message indicates that the tester has detected a difference in the
architecture of the module when compared to the national standard. It does not
necessarily mean that there is a problem with your memory device. This message
is meant to inform the user that the tested device may not be a drop-in
replacement for modules that meet the national standard. Additional information
will follow this message, giving specific details as to what difference the
tester found. Some differences include the detection of Assymetric 4K refresh
or the detection of shorted RAS lines (RAS0 to RAS2 and RAS1 to RAS3). See the
questions below for further information on these messages.
- Q. What is the difference between 2K
and 4K refresh and can SIMCHECK II support these refresh varieties?
A. The DRAM memory array is arranged along a matrix of Rows and Columns. Each
memory cell is accessed by multiplexing first the Row address and then the
Column address. The row is the main access, and all the cells in a row are
refreshed when the row is accessed. When the number of rows is equal to the
number of columns, we say that the DRAM is symmetric, when the rows number is
different than the columns number, we say that the DRAM is asymmetric.
Asymmetric DRAM has the advantage of reduced power consumption, as less refresh
is required. A symmetric 4M device with 11 address lines for both rows and
columns has 2K refresh. An asymmetric 4M device with 12 rows and only 10
columns is called 4K refresh. SIMCHECK II automatically detects the refresh
type (1K, 2K, 4K and the new 8K). Since historically symmetric devices were
first used, SIMCHECK II regards symmetric devices as default, and puts a
structure note message when an asymmetric device is encountered.
- Q. What does the message RAS0 shorted
to RAS2 (or RAS1 shorted to RAS3) mean?
A. The tester has detected the Row Address lines as being shorted together as
opposed to having them operate independently. This does not render the module
as defective as it will still work in many machines, but it may cause it to not
function in motherboards that require independent signals.
- Q. After just receiving my SIMCHECK II
PLUS, why am I getting constant memory errors when testing my 30-pin or 72-pin
modules, and why does the tester prompt for testing only Sync modules?
A. The SIMCHECK II PLUS is comprised of two pieces. The base tester SIMCHECK II
and the additional test adapter Sync DIMMCHECK 168. In packaging, the Sync
DIMMCHECK 168 is connected to SIMCHECK II, and when left in this fashion,
SIMCHECK II will only work with 168-pin memory (the display will flash
"Sync DIMMCHECK 168").
To test 30-pin or 72-pin modules, you will need to remove the Sync DIMMCHECK
168 adapter from the base unit. Removal is performed by TURNING OFF SIMCHECK II
and working the adapter upwards while gripping it on its left and right side.
When returning to 168-pin testing, TURN OFF SIMCHECK II and reconnect the Sync
- Q. What are parity emulation chips?
What does the "p" mean on the display 1Mx8p or 2Mx32p?
A. Parity emulation chips are logic devices that provide parity information by
being tied directly to your module's data lines, and thusly, bypassing the true
parity function. It is important to note that these devices are NOT memory
chips, therefore modules detected as having these chips will be identified with
the "p" suffix.
Please contact our
department for pricing information concerning the available upgrade services
for your test systems.