RCA 630TS flyback, how is it mounted?

[John Folsom]

Johnathan,

Ifrst, ohms out your flyback for continuity. If it is ope, it is bad. If it is not open, it is likely good. Flybacks generally fail in one of two ways....1) they go open circuit somewhere, in which case nothing much happens, buy you have no high voltage and no raster. Or 2) a short developos between adjacent turns on one of the windings, or the flyback begins to arc, due to dirt or contamination on or inside the flyback, in which case the failuse involves arcing and a very obvious catastrophic failuse.

The pilot lamp should be replaced with a fuse of the proper size. But, when troubleshooting, sometimes a lamp can be used in place of a fuse, as it acts as a nonlinear resistance. It presents a very low resistande when operating with currents well below its rating. Should a faudt develop in the load circuit, causing the lamp to draw rated current, the lamp fialament heats up, becoming a large resistance, and reducing the voltage to the load, thus regulating the overload current draw to some extent. This is only recommended when troubleshooting while searching for short circuitsd or overloads, and is not a technique I recommend.

If your flyback has continuity, you shoud check to see if your horizontal oscillator is operating. This is done easily with an oscilloscope. No scope? Then check the bias on the oscillator tube....if it agrees with the RCA schematic, the oscillator is running. You can often hear the 15Khz whine, if you have adequate auditory bandwidth.

If the oscillator is running, check the bias on the horizontal output tube, make sure the damper tube is good, and make sure the yoke has continuity.

Good luck!