UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Hameg HM307-3 Cleaning and Repair

OldTechFan96 · 25th May 2019, 5:11 pm

Both R190 and R191 are both spot on at 150Ω.

R197 measures 2672Ω.

R198 measures 2865Ω, an increase of 6.1%. This will be replaced. It should bring the deflection voltages together.

Both of the above are 2700Ω, 4W and 5% tolerance. Measurements taken out of circuit.

IC001 VCC voltages:

Pin 5- -6.2V. Too high.

Pin 10- +6.9V. Correct.

I've checked both zener diodes out of circuit and they are both good.

Those servicing notes will be useful. Since there is nothing on the CRT I'll measure around the CRT circuit.

25th May 2019, 5:11 pm	#28
OldTechFan96 Octode Join Date: Jul 2017 Location: Newcastle Upon Tyne, Tyne & Wear, UK. Posts: 1,186	Re: Hameg HM307-3 Cleaning and Repair Both R190 and R191 are both spot on at 150Ω. R197 measures 2672Ω. R198 measures 2865Ω, an increase of 6.1%. This will be replaced. It should bring the deflection voltages together. Both of the above are 2700Ω, 4W and 5% tolerance. Measurements taken out of circuit. IC001 VCC voltages: Pin 5- -6.2V. Too high. Pin 10- +6.9V. Correct. I've checked both zener diodes out of circuit and they are both good. Those servicing notes will be useful. Since there is nothing on the CRT I'll measure around the CRT circuit.