Simpson model 260 series 6 Multimeter

Simpson260


Simpson model 260 series 6 Multimeter which has a 2000 ohms/volt meter movement is housed in a Bakelite case. It was given to me by  Ian Powell who had no further use for it.

I soon discovered that would not work on any of the ranges and the battery connector for the 9V battery was corroded and on opening it up that the 2 Amp fuse was missing. By checking the resistance of the meter I found that movement was functioning. The instrument worked on the AC voltage ranges when the 2Amp fuse holder was temporarily bypassed but the DC and ohms ranges showed no sign of life. A quick look at the circuit board revealed that the re were a couple of burnt out resistors that would need replacing down in the bottom left hand corner , but the value had they had been a and what was their function was not resolved until I had found the schematic diagram and component layout. Fortunately both are available on this site:http://simpson260.com  which shows that these two resistors form part of the resistance measuring circuitry (1.109KΩ and 123.57Ω) though their failure would not explain the inability of the meter to work on the DC voltage ranges. Eventually having resorted to partially removing the circuit board to reveal the tracks on the underside the culprit was revealed - a burnt out track.

I spent quite some time sorting through my resistor collection to find two that were close to the requisite values and soldered these in place and soldered a wire link across the broken track. In my tobacco tin containing metal spacers I found two brass sleeves which with aid of some aluminium packing and a conventional glass fuse completed the repair and enabled the meter to function on the DC ranges. Finally after replacing the 9V battery connector and  inserting batteries I found that the Resistance ranges worked with creditable accuracy.

        

Burnt out resistors                               Burnt out and ruptured track                  Modified fuse to fit internal fuse holder

Modified fuse installed in holder


All back together with replacement resistors

 

How old is it? The 260 range of meters were made for many years but this one probably dates from around 1974/5

For lots more information and documentatio see here: http://simpson260.com/260-6/simpson_260-6.htm