UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Leon Crampin · 10th Aug 2009, 6:38 pm

An easier way to check mark/space ratio is to use an AVO on resistance range. Zero the AVO on Ohms x 1 with the dial switch in circuit. Run the dial and take a reading (a degree of estimation is required) using the 0 - 100 linear scale. The percentage "dwell" is indicated directly.

For anyone with an old petrol engined car, the AVO can be similarly used as a dwell meter. This time, zero the Ohms x 1 range to "90" on the 0 - 100 scale. Crank the engine and read the dwell directly.

Useful instruments.

Leon.

10th Aug 2009, 6:38 pm	#9
Leon Crampin Octode Join Date: Nov 2005 Location: Surrey, UK. Posts: 1,874	Re: Precise dial speed setting An easier way to check mark/space ratio is to use an AVO on resistance range. Zero the AVO on Ohms x 1 with the dial switch in circuit. Run the dial and take a reading (a degree of estimation is required) using the 0 - 100 linear scale. The percentage "dwell" is indicated directly. For anyone with an old petrol engined car, the AVO can be similarly used as a dwell meter. This time, zero the Ohms x 1 range to "90" on the 0 - 100 scale. Crank the engine and read the dwell directly. Useful instruments. Leon.