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Hardware I.P.B. 4036 11th September 1990 (JS)
Department Category Implementation
Hardware Hardware Advisory
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SIMMs and the Plating Material of their Edge Contacts

Apricot has recently changed from SIMM modules with tinned edge contacts to gold edge contacts. This change was implemented after research in the USA indicated that there was a small improved long-term reliability factor in poor environments (see note below) when using edge contacts and connectors manufactured from the same material, e.g. TIN with TIN or GOLD with GOLD; however this may not be possible in all cases.

With Apricot Computers' continued move to increase system reliability, all supplies of SIMM modules and connectors have been changed to GOLD and the end user documentation has also been changed to reflect this policy.

We do not expect the above policy change to affect the installed system base in the normal life time of the product, although unreliable systems should be checked for fretting when SIMM modules and connectors are of dissimilar materials. Where system reliability is a concern the following points must also be taken into account:

  1. Speed of the SIMM parts used.
  2. Only use approved manufacturers of SIMM modules, where speed, memory, and even thickness of the module can vary.

SIMM Product Codes

The following product codes will now enable the newer GOLD and older TINNED systems to be upgraded to the above policy:

SIMMs for Qi, VX1000 and VX FT products. Speed = 80 nS
Gold Tinned
1MB SIMMs 4 x 256K = XB41706 XB46388
4MB SIMMs 4 x 1MB = XB41708 XB46387
8MB SIMMs 4 x 2MB = XB41709
SIMMs for VX1000, XEN-i386/45 or 50 or 100, Tower Products. Speed = 100nS
Gold Tinned
1MB SIMMs 4 x 256K = XB8893 XB46389
4MB SIMMs 4 x 1MB = XB8894 XB46390
SIMMs for HyperRam Card
4MB = XB45677
16MB = XB45678

Identification

To identify if a system is fitted with GOLD or TINNED connectors a visual inspection is required.

Note: Poor environment - where low insertion force connectors were used. Apricot only use high insertion force connectors.

 

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Computing for a Connected World