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Sync DIMMCHECK® 168/144/100 Manual Addendum

Picture of Sync DIMMCHECK 168

The SIMCHECK II line provides comprehensive support for testing SDRAM DIMMs and SO DIMMs using the Sync DIMMCHECK 168 (p/n INN-8558-6) and the new Sync DIMMCHECK 144 (p/n INN-8558-7) and Sync DIMMCHECK 100 (p/n INN-8558-8). The Sync DIMMCHECK 168 utilizes a patent-pending133MHz test engine to achieve true 133MHz testing of your SDRAM modules. All Sync DIMMCHECK units utilize our powerful patent-pending 133MHz test engine. These devices are combined with the SIMCHECK II line's 1nS technology to achieve true high-speed testing of your SDRAM modules. This manual addendum describes the operation of both units. In this document we ommit the '168' or '144' or '100' descriptor unless it is necessary to distinguish one unit from the other.

The Sync DIMMCHECK 168 enables SIMCHECK II, or SIMCHECK II se, to test 168-pin SDRAM DIMMs up to 133MHz, as well as standard 3V/5V, buffered/unbuffered, EDO/FPM DIMM modules. The Sync DIMMCHECK 144 supporst all popular SDRAM/EDO/FPM 144-pin S.O. DIMM modules. The Sync DIMMCHECK 100 supporst all popular SDRAM/EDO/FPM 100-pin S.O. DIMM modules which are typically used by Laser printers.

The Sync DIMMCHECK is conveniently installed in the 90-pin expansion slot, and is automatically recognized by SIMCHECK II. It comes with a high quality test socket for easy insertion and removal of DIMMs, suitable for high volume testing.


This adapter connects to SIMCHECK II via the expansion slot.

CAUTION: Plug this adapter into the expansion slot only when SIMCHECK II is OFF! Failure to turn SIMCHECK II OFF when connecting or disconnecting the Sync DIMMCHECK may result in damage to the internal PAL chip of the SYNC DIMMCHECK!


INSERTION: The Sync DIMMCHECK uses a vertically mounted high quality test socket with two ejectors that need to be opened prior to insertion. Carefully insert the DIMM into the socket, pushing it evenly along its top. When the DIMM is properly inserted, the ejectors will snap onto the semi-circular notches on each side of the module.

REMOVAL: The DIMM is easily released from the socket by pulling both ejectors sideways.

NOTE: DIMM insertion and removal should be done only when SIMCHECK II is in STANDBY Mode.


Turn SIMCHECK II ON once the SYNC DIMMCHECK is installed in the expansion slot and insert the first DIMM module. THERE IS NO NEED TO SETUP SIMCHECK II, as it automatically recognizes this tester. When SIMCHECK II enters the STANDBY mode, the display will reflect the presence of the SYNC DIMMCHECK 168.

The Sync DIMMCHECK 144 is recognized with the following graphics:

Sync 144 Standby Mode Screen
NOTE: Do not have a module inserted in the Sync DIMMCHECK upon initial turn on, as this may load certain signals that are necessary when SIMCHECK II performs its initial locking functions to the adapter.

The Sync DIMMCHECK test procedure is initiated by pressing the F1 key.

Note that the Sync DIMMCHECK will automatically recognize and test a DIMM, regardless if it is an SDRAM device, or an EDO or FPM device. For SDRAM DIMMs (left screen above), the speed is displayed in the form of the module's fastest functional frequency rate, and size is displayed in specific JEDEC notation. An SDRAM message at the bottom line clearly indicates the type of module tested. The right screen above serves as a quick demonstration on how different the BASIC test screen for FPM/EDO modules is when compared to the SDRAM test screen.

In Version 1.44 we have added a module type indicator during SDRAM tests. The message "UBF" is used for UNBUFFERED and "REG" is used for REGISTERED modules. This indicator appears near the 3V marker at the right corner of the third display line. You can toggle this indicator OFF and ON (default) using the SETUP - CONFIG - SDRAM - REG/UBF.

SIMCHECK performs numerous timing tests at the start of the BASIC test in order to determine the frequency of the SDRAM module. We have published two online Application Notes to further explain SIMCHECK's speed detemination process:

Once the frequency is determined, SIMCHECK will commence to test the entire memory module at the selected frequency. If a problem is encountered, SIMCHECK will automatically reduce the frequency (in the order of 133MHz, 125MHz, 112MHz, 100MHz, 83MHz, 75MHz, and 66MHz), unless you have setup SIMCHECK to test at a fixed frequency by either Setup or the Change-on-the-fly feature. If the tester behaves erratically, with subsequent tests of the same modules giving widely differing frequencies, the problem may be a bad locking of SIMCHECK II and the Sync DIMMCHECK. Simply remove the module, reset SIMCHECK by turning it ON and OFF and then try to test again.

During the BASIC test, the screen will inform you of the voltage used to test the module, and display a constant change of patterns used to test it. As we use complex test patterns, only the first pattern is shown. There are two LEDs on the Sync DIMMCHECK adapter. You will note that the SDRAM LED indicator will glow when an SDRAM module is detected, and as the test procedure continues, you will see the Page Burst LED flash as memory patterns are bursted into the device at real clock rates.

After the BASIC test, SIMCHECK II will display our familiar message indicating a successful test, plus additional information on whether the module is a 2 or 4 clock device.

The BASIC TEST OK message is followed by a series of summary screens detailing speed and structure information. Please keep in mind that all speed and structure information is automatically recorded into the Test Log, which is accessible by pressing F4 from standby after the test. The information is retained in the Test Log until a new test is initiated.

Please note that if you want to reach the summary screens quickly, even before the end of the Basic Test, simply abort the test by pressing F5 during the Basic Test.

The following is an example of the first summary screen on SIMCHECK following the end of the Basic Test of a PC-100 module.

The determination of the PC-100 compliance appears on the second line of the screen, and it has the header "TEST=" followed by "PC-100" if SIMCHECK determines that the module is PC-100. The third line indicates "PAGE BURST=100MHz"; it indicates that the maximum page burst of the tested module was 100MHz. The fourth line in this example indicates "SPD=INTEL PC-100", which indicates that the data in the SPD claims the module to be a PC-100. More examples are shown in Application Note INN-8558-APN14.

If SIMCHECK determines that the module is PC-66, the message "TEST=PC-66" will appear. If a module's SPD is marked for PC-66 while the module timing parameters are measured within the PC-100 range, you will see the message "TEST=PC-100 RANGE".

IMPORTANT NOTE: The BASIC Test is the only test used by SIMCHECK II to determine PC-100 compliance. It provides an information summary that gives specific information if the module is PC-100 compliant. Other frequencies are used throughout the Extensive Test to create additional conditions for the test. Therefore, if a module finishes BASIC Test as PC-100, the fact that it may run at 83MHz during Extensive Test or AUTO LOOP does not mean that the module is not a PC-100.

The first speed summary screen is followed by the Tac measurement screen as in the following examples:

The screen shows the measurements of Tac (access time from clock) for CAS latency 2 and 3. Please refer to Application Note INN-8558-APN13 for further details about these important measurements.

Following this screen will be the module's explicit structure information.

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It shows the size of the module, its type, number of the module's banks (not to be mistaken by the individual SDRAM banks), the use of the -S control lines, and the size of the individual chips used in the module. The above example shows an unbuffered 16Mx64 SDRAM module with two banks, using control lines S0, S1, S2, and S3, and employing 4x2Mx8 chips.

The size of each individual chip of the module is shown in the format of [number of banks] x [each chip bank's size in Meg] x [bus width in bits]. The following examples show some typical chip sizes: 2x1Mx8 - a 16Mbit chip with overall size of 2Mx8; 4x2Mx8 - a 64Mbit chips with overall size of 8Mx8; 4x4Mx4 - a 64Mbit chip with overall size of 16Mx4; 2x2Mx4 - a 16Mbit chip with overall size of 4Mx4; 4x1Mx16 - a 64Mbit chip with overall size of 4Mx16.


Most SDRAM modules employ an SPD device. The final structure screen allows you to view the SPD as follows:

SDRAM modules without an SPD will show a 'MISSING SPD!' message. Choosing to view the SPD will stop the test and allow you to review its information, otherwise, the test procedure will continue and currently skip the Extensive Test into the Auto Loop test. We will release the Extensive Test for SDRAM modules in the near future.

Please review our Application Note INN-8558-APN12: SPD DATA STANDARDS, which provides detailed information regarding the SDP data.

NOTE:Please refer to our detailed SPD Management manual addendum for information on viewing, saving, editing and programming the 256-byte SPD information.


The Change-On-The-Fly function is also supported with the Sync DIMMCHECK adapter. You can access it by pressing F2 during the Basic Test, then selecting either Speed or Refresh override. The SPEED override menu uses a horizontal scroll format:

Use the keys to scroll through the available frequencies: 63MHz, 75MHz, 83MHz, 100MHz, 112MHz, 125MHz and 133MHz. Pressing F1 will restart Basic Test at the selected frequency. If you select a frequency beyond the capabilities of the tested module (e.g. selecting 133MHz), the test will definitely fail. Some PC-100 modules may run at 112MHz. Some modules that are determined to be 83MHz by the automatic mode may still run at 100MHz, however SIMCHECK will still indicate that the module is a PC-66, not a PC-100.


The EXTENSIVE test is currently under development and will be released soon. The SINGLE BIT test will not be supported for SDRAM devices since individual bits have less variations in a synchronous access.


During the AUTO-LOOP test, the module is endlessly tested with different patterns of data bits, generated by different algorithms.

Some long tests like Self Refresh are incorporated into AUTO LOOP as shown in the following screen:

AUTO-LOOP is an excellent means for a burn-in procedure, as it will continue indefinitely until the user presses the Esc key.

Unsupported Modules

As there are various types of modules in the market, you may encounter some that may not be supported in the Sync DIMMCHECK test tables. SIMCHECK II will then show the following screen displays.

These displays are merely an indication that the tested module is not supported; they are NOT an indication of failure. We are currently working to resolve such compatibility problems, and they are likely to be supported in the coming new versions. Please contact us when acquiring these displays, as there may be a need to add this module to our test tables.


Standard EDO/FPM DIMM modules will test according to our regular test procedure. Please note that the LEDs will not glow when Standard DRAM DIMMs are tested. The EDO/FPM DIMM module has an internal architecture similar to the 72-pin SIMM module, but to achieve a wider data bus, the number of -CASx control lines has been doubled from four (-CAS0, 1,2,3) to eight (-CAS0,1,2,3,4,5,6,7). Also, two Write Enable control lines (-WE0 and -WE2) and two Output Enable (-OE0 and -OE2) have been added. This arrangement allows for one-bank (e.g. 1Mx72, 4Mx64, 16Mx80) or two-bank (e.g. 2Mx64, 8Mx72) embodiments. Special A0 and B0 address lines (for the first multiplexed address line) have been implemented within the DIMM 168-pin standard for optimized bank interleaving operation. The 144-pin Small Outline DIMM uses only 2 -RASx lines (-RAS0,1) and no OEx lines.

Simply press F1 to start the test! The Sync DIMMCHECK will automatically test a Standard EDO/FPM DIMM without setup. After the BASIC test, SIMCHECK II will provide explicit structure information on the module tested.

SIMCHECK II also provides the PRD settings as well as the ID settings of the DUT.

If SIMCHECK II detects the use of an SPD EEPROM chip, a summary screen will appear giving you the option of entering the SPD Management Mode.

IMPORTANT NOTE: This is the second version of the manual addendum. Many additional functions are currently being developed for the Sync DIMMCHECK, so we recommend updating your SIMCHECK II firmware often.

Note: This adapter can be used only on SIMCHECK II or SIMCHECK II se. It cannot be supported by our previous generation of SIMCHECK PLUS.

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