27-04-2017, 09:42 PM
Very interesting Mel, mine is in the same condition bar for the fact that from cold the volts on neutral message can be cleared. It will stay away for a few minutes then return. Cycle the power and the message remains. Wait 20 mins and the clear spell returns.
When I first acquired the tester very few of the keyboard keys worked. This I traced to a faulty CD4052 on the keyboard PCB. As far as I remember the Neutral fault only appeared after the chip was replaced. I did remove the backup battery while working on the board so also got a message about lost settings/sequences.
The 4052 chip seems to cover the keyboard matrix, the bus to the main unit and the analogue voltage from the base unit that measures how many volts are between the neutral and earth. This voltage seems to be added to one of the bus lines and is measured when the line is at logical zero. I may be wrong here but without a schematic fault finding is a bit hit and miss. There is a bit more information here. https://www.vintage-radio.net/forum/show...p?t=130980 One point of note, the 4052 sits right beside the battery so perhaps you still have some conduction on the PCB.
I do wonder if the associated PC software package has a way of restoring the missing setup but with the neutral fault still present and the cost of the package I am not prepared to go down that path yet. Currently the tester is back on the roundtuit pile and is waiting for me to develop enough enthusiasm to have another look at it. Add to that that I already have a working PAT tester then it might be a while.
Al
When I first acquired the tester very few of the keyboard keys worked. This I traced to a faulty CD4052 on the keyboard PCB. As far as I remember the Neutral fault only appeared after the chip was replaced. I did remove the backup battery while working on the board so also got a message about lost settings/sequences.
The 4052 chip seems to cover the keyboard matrix, the bus to the main unit and the analogue voltage from the base unit that measures how many volts are between the neutral and earth. This voltage seems to be added to one of the bus lines and is measured when the line is at logical zero. I may be wrong here but without a schematic fault finding is a bit hit and miss. There is a bit more information here. https://www.vintage-radio.net/forum/show...p?t=130980 One point of note, the 4052 sits right beside the battery so perhaps you still have some conduction on the PCB.
I do wonder if the associated PC software package has a way of restoring the missing setup but with the neutral fault still present and the cost of the package I am not prepared to go down that path yet. Currently the tester is back on the roundtuit pile and is waiting for me to develop enough enthusiasm to have another look at it. Add to that that I already have a working PAT tester then it might be a while.
Al
Tuned for maximum smoke . 
