Dataman Forum

Hello

my S3 will quite happily programme EPROMs that require 12.5V programming voltage but not those that require 21V. If I put a scope on the programming voltage pin it never gets higher than 12.5V even when a 21V device is selected.

Is there any test mode available that will allow me to permanently enable the programming voltage to make it easier to track down the fault as trying to test it by selecting BURN and then having it fail due to insufficient voltage only gives you a fraction of a second to make the measurement.

I note that there is an adjustment pot by the switch mode regulator, could you also tell me what this sets up, where the measuring point is and what it should be set at?

many thanks

regards

James Williams

Hello James,

This is a difficult one as we have not supported the S3 for many years now. The engineer that worked on S3 is not longer with us and as such the knowledge is no longer with us.

I am sorry that we cannot be of more help.

Neil

Ok, well thanks for responding anyway.

As it happens after some further investigation I was able to resolve the problem and in case anyone else experiences the same this is what I found.

1. Some algorithms do not stop even if there isn't an EPROM present in the ZIF socket, this seems more prevalent in the algorithms for the smaller chips. Selecting these algorithms allowed me to monitor Vpp for a minute or more before having to restart the S3 burn.

2. Testing the 100uF capacitors around the 8 pin step up regulator chip revealed some to be faulty, these were replaced.

3. Some solder joints appeared to be dry around the voltage regulators, the inductor, large diode and capacitors. The solder was removed and the joints remade.

I can now achieve all the relevant Vpp voltages and my S3 works as it should.

Regards

James Williams