UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Tenma 72-6802

See_Mos · 16th Nov 2018, 3:55 pm

A friend has two of these 'scopes with brightness faults.

I have not been able to find a circuit diagram online so I will put a request in the wanted section.

Meanwhile, if anybody knows of an equivalent model or maker etc I would be pleased to hear from them.

One has reduced brightness and the other you have to turn the brightness control down to increase intensity, the trace does not bloom so I don't think the tube supply is the problem, probably resistors in the high voltage chain.

16th Nov 2018, 3:55 pm	#1
See_Mos Hexode Join Date: Nov 2003 Location: Ossett, West Yorkshire, UK. Posts: 482	Tenma 72-6802 A friend has two of these 'scopes with brightness faults. I have not been able to find a circuit diagram online so I will put a request in the wanted section. Meanwhile, if anybody knows of an equivalent model or maker etc I would be pleased to hear from them. One has reduced brightness and the other you have to turn the brightness control down to increase intensity, the trace does not bloom so I don't think the tube supply is the problem, probably resistors in the high voltage chain.