Tuesday, 13 October 2015

Teardown: Vintage Solartron LM1619 Volt Meter

In this teardown i take a look at a vintage Solartron LM1619 Digital Volt Meter. This is a UK made product which dates from around the early 1970s.

Full Teardown Video:

The LM1619 is a 1999 count volt meter only with DC ranges of 200mV, 2V, 20V, 200V and 1kV. AC ranges are 2V, 20V, 200V and 750V.

The unit weighs about 5Kg and is housed in an extruded aluminium chassis with vinyl covered steel covers. The front panel is a thin layer of beige Formica with cutouts attached to the chassis. Has integral tilting bale.

Connections are provided on the front with three banana jacks, HI, LO & CHASSIS.

The display consists of three Mullard ZM1080 Nixie Tubes. Decimal places, polarity indication and the 1000 count indication are provided by discrete neon lamps.

Inside there are three main areas:

DVM Board
which contains most of the electronics for the voltage measurement. This includes two vacuum tubes, a Mullard CV4003 valve and a Mullard 83A1 which is the voltage reference.

Display Board
This contains the components to drive the three nixie tubes and consists mainly of descrete transistors on a hinged PCB for easy maintenance.

Front End
Located within a shielded can this houses the voltage dividers and trimmers along with a Weston cell and what appears to be a battery connection. Although the battery was missing from my unit i am insure what the battery was for.

View from the top:

View from the bottom.