"Trouble-Shooting" memory is often related to knowing a few simple facts, and they are usually only learned at the time you try to install additional memory in a PC. First, lets state some of these facts.

1. 30-pin SIMMs do not fit in 72-pin slots. And neither fit in a 168-pin DIMM slot.
2. Many people see a bargain in memory and purchase it without knowing if it will work in their PCs. Often, it must be returned to the store.
3. FPM memory was designed for PCs of the 386 and 486 motherboard styles.
4. EDO memory does not work on a 486 style motherboard.
5. SDRAM memory does not work on a 486 style motherboard.
6. Memory for 486 machines should be FPM SIMMs.
7. Memory for Pentium PCs will most often be EDO RAM, but in a few cases it may be SDRAM which is on 168-pin DIMM chips.
8. Parity memory and non-parity memory is not the same!
9. Non-parity memory will not run if you have parity enabled on your motherboard.
10. Some parity memory will run as non-parity on motherboards which are configured for non-parity memory.
11. AND MOST IMPORTANT MANY PC OWNERS DO NOT LOOK IN THEIR USER OR SYSTEM MANUAL TO DETERMINE THE TYPE OF MEMORY THEIR MACHINES WILL ACCEPT, BANKED OR NON-BANKED, ETC. PLEASE READ BEFORE PURCHASING!

To actually test memory, you may want to purchase a SIMM tester, or a DIMM tester if available.

Ok, with that in mind, lets look a little further into troubleshooting memory. The following types of problems may occur with memory:

1. Installing New Memory.

   SYMPTOM: Sometimes a new set or additional memory causes a configuration error or is not recognized when rebooting after installation.

   CAUSE/SOLUTION:

   In many cases, this caused when your BIOS does not recognize the memory. You may need to go into the CMOS (Setup) and enter the memory. This will cause the system to record it in its POST test checks.

2. SYMPTOM: Configuration Error.

   CAUSE/SOLUTION: If you are using larger capacity SIMMs and do not place them in the first memory slot, some BIOS's will not recognize the memory. Sometimes, putting memory into multiple banks without totally filling the first bank (0) before going to bank 1 causes a boot problem.

3. SYMPTOM: Screen is "blank" or black and nothing appears to happen after installing EDO memory in a 486DX 33.

   CAUSE/SOLUTION: EDO does not work even if you have 72-pin memory slots. Return it for FPM mode. Remember EDO memory is intended for 64-bit Pentium motherboards. I believe most 486 motherboards are 32 bit buses.

4. SYMPTOM: I purchased 72-pin FPM memory chips and they don't fit.

   CAUSE/SOLUTION: Some systems have proprietary memory chips. We had some GTSI 486's that would not accept the memory from other memory manufacturers. ALSO: Sometimes inexperienced persons do not know which direction the cutout on the end of the chip goes, or that you need to lay the SIMM chip at an angle to insert it before snapping the SIMM into place.

   CAUSE/SOLUTION: Sometimes it depends on the PC you have.

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   Trouble-Shooting PC's