The 16M SOJ ADAPTER enables SIMCHECK to test the surface mounted SOJ DRAM chips with 16 Megabits. It can be ordered for 400 mil (p/n INN-8448-14-4) or 300 mil (p/n INN-8448-14-3) SOJ DRAM chips. These include the 4Mx4 and the 16Mx1 configurations. 4 Megabits and smaller SOJ and PLCC DRAM chips are testable by the optional PLCC/SOJ adapter. The 16M SOJ ADAPTER tests and distinguishes between the 4K and 2K refresh modes which are now available for the 4Mx4 chips.
Connect the adapter to your SIMCHECK SIP ZIF (green) socket when SIMCHECK is either ON or OFF.
HANDLING THE SOJ CHIPS: The 16M SOJ DRAM chips are made in accordance with the standard 400 mils package. Pin 1 of the SOJ chip is typically marked with a dot. Alternatively, the short edge of the package which is near pin 1 may be slightly slanted. The left socket is for the 16Mx1 configuration, and the right socket is for the 4Mx4 configuration. Place the chip in the corresponding socket so that pin 1 points away from you. Also, make sure that the markings on the top of the chip face up (this is called "LIVE BUG" insertion). Insert the chip carefully as far as it will go. Use an IC chip extractor or a thin flat head screwdriver to remove the chip from the socket.
If you are not sure whether to use the 16Mx1 or the 4Mx4 socket, you can safely try either socket. If you have inserted a 16Mx1 into the 4Mx4 socket (or vice versa), SIMCHECK will protect your chip by immediately stopping the test with a "NO MEMORY" error.
Once the 16M SOJ chip is inserted, press F1 to start the test. The test procedure is exactly the same as our SINGLE CHIP ADAPTERS.
THE 4K REFRESH DETECTION: The 4Mx4 DRAM chips are currently available in two refresh modes, 2K and 4K. The 2K refresh mode uses 11 address lines for the row strobe and for refresh. This is the more common refresh mode as it uses only 11 multiplexed address lines for both row address and column address. Therefore 4Mx4 DRAM with 2K refresh are compatible with regular 4Meg modules. The 4K refresh uses 12 address lines for the row strobe and for the refresh and therefore the chip must use 12 multiplexed address lines (MA11 and MA12 used for row address only). This mode is less common and therefore SIMCHECK provides a detailed message indicating that the chip is 4M/4K Refresh having 12 Rows and 10 Columns.
Required EPROM Version: 2.04 or above.
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