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Old 20 March 2011, 03:17   #17
Stunt Car Racer Vet
Eamoe's Avatar
Join Date: Mar 2006
Location: Vevey/Switzerland
Age: 39
Posts: 134
Originally Posted by cpiac64 View Post
you need insert a switch or jumper for use the ram (3 pin near ON)
and my reply is

Originally Posted by Eamoe View Post
The switch was soldered directly onto the board and looked really bad (bent, dirty and greasy). Continuity test showed it was ON in both positions. Removed it, cleaned the gooey mess and soldered temporary leads for testing.
But cipiac64, thanks for the very instructive picture, it tells me a lot about this expansion: it can work without any other component but the RAM chips and one capacitor. Testing will now be way, way easier.

Looks like this "Issue 3" was made for the A500+ which didn't need any clock as it already had its own, while my version "Issue 2" was built to give the regular A500 a clock (and apparently nearly any component on the expansion PCB is there to enable this clock function).

Despite this, removing these resistors and caps wasn't a waste all the way, because it helped me to better clean the board. Thanks for your advice folks, I have learnt a few things here!

Does anyone know what the three narrow black components are?
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