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

Billy T · 14th Dec 2008, 8:52 am

I started in electronics as an apprentice 44 years ago and have serviced all kinds of appliances from the usual toasters, heaters & shavers etc, TRF valve radios (from elderly customers) valve TVs, radios and radio telephones of the slightly more modern era, through to all solid-state colour TV, radios, radiotelephones etc. Next to a good multimeter the most useful instrument I ever had was a small battery operated high voltage insulation tester.

In my opinion their value and usefulness is highly under-rated. I still use one regularly and with a choice of 250, 500 and 1000 volt outputs it is surprising how much it can tell you about a lot of components that a multimeter can't. I am not overly fussy about the maximum rated operating voltages for various components either, if they can't stand a test voltage 100 volts or so in excess of their rated working voltage then they are not going to be reliable in service. I recently bought some NOS oil-filled .1uF 1000 volt caps which checked out perfectly with a multimeter but they all leaked a little at 250 volts and a lot at 1kV.

I too prefer an analog multimeter for most servicing and although I own several AVOs of various marks, my meter of choice for general servicing is a Hioki AS100D 100,000 ohms per volt sensitivity and 22 volts at the probes for high-ohms testing. It is a good compromise between the higher loading of a 20k-ohms/V AVO on low voltage ranges and the very high input impedance of digital meters and has a large and very clear scale.

For my business I have a wide range of test equipment including several scopes, signal generators and some other fairly exotic goodies but when it comes to fixing radios, nothing much beats a comfortable seat and a good meter.

Incidentally, I am rather envious of the range of service sheets you have available, because although we did have circuits for most radiotelephones and TVs, and books of circuits that covered most Japanese transistor radios, almost all valve radio servicing was done without the benefit of a circuit, enforced experience that stands me in good stead today.

Cheers

Billy

14th Dec 2008, 8:52 am	#29
Billy T Retired Dormant Member Join Date: Feb 2008 Location: Auckland, New Zealand Posts: 631	Re: Test equipment for valve radio repair I started in electronics as an apprentice 44 years ago and have serviced all kinds of appliances from the usual toasters, heaters & shavers etc, TRF valve radios (from elderly customers) valve TVs, radios and radio telephones of the slightly more modern era, through to all solid-state colour TV, radios, radiotelephones etc. Next to a good multimeter the most useful instrument I ever had was a small battery operated high voltage insulation tester. In my opinion their value and usefulness is highly under-rated. I still use one regularly and with a choice of 250, 500 and 1000 volt outputs it is surprising how much it can tell you about a lot of components that a multimeter can't. I am not overly fussy about the maximum rated operating voltages for various components either, if they can't stand a test voltage 100 volts or so in excess of their rated working voltage then they are not going to be reliable in service. I recently bought some NOS oil-filled .1uF 1000 volt caps which checked out perfectly with a multimeter but they all leaked a little at 250 volts and a lot at 1kV. I too prefer an analog multimeter for most servicing and although I own several AVOs of various marks, my meter of choice for general servicing is a Hioki AS100D 100,000 ohms per volt sensitivity and 22 volts at the probes for high-ohms testing. It is a good compromise between the higher loading of a 20k-ohms/V AVO on low voltage ranges and the very high input impedance of digital meters and has a large and very clear scale. For my business I have a wide range of test equipment including several scopes, signal generators and some other fairly exotic goodies but when it comes to fixing radios, nothing much beats a comfortable seat and a good meter. Incidentally, I am rather envious of the range of service sheets you have available, because although we did have circuits for most radiotelephones and TVs, and books of circuits that covered most Japanese transistor radios, almost all valve radio servicing was done without the benefit of a circuit, enforced experience that stands me in good stead today. Cheers Billy