Help with supreme 599

This tube tester wont work to test tubes or center the needle but works on DC volts. I checked the line adjust rhehostat and it measures 270ohm. Schematic calls for 1000ohms. I dont really see when it connects to the rest of the circuit in the schematic. Where should I start tracing?

• schematic (1512 KB)

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Apparently there is  a not so cleverly placed text in the schematic. The line adjust rheostat is labeled as 300 ohms and is connected between the 100 V and 133 V taps of the mains transformer's primary winding at the top of the schematic.

The rheostat which is labeled as 1000 ohms at the bottom of the schematic, is probably used for zeroing the ohms range etc and just happens to be drawn adjacent to the text "LINE ADJ." which relates to the circuit selector switch.

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Still cant get machine or line adjust to work. The 80

Tube is only getting 3.9vac. Not sure why schematic

Shows 133vac on the line adjust but the transformer

Is just getting line voltage of 116vav with no

Resistance.

• Voltage (1286 KB)

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The 133 V tap will give correct secondary voltages if the transformer is supplied with 133 V from the mains at that tap. As well as if it would be supplied with 100 V to the 100 V tap.

Are you sure that the mains transformer is in good order, no shorted turns or so?  Does it draw a reasonable idle current from the mains and does not get hot when running without load?

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Its only pulling 10 watts and its cool. My mains is 116vac. Trying

To figure out which lug on the transformer is 133. How can i figure

That out? Hightest resistance coil on the secondary side?

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The easiest way is to measure the voltage from each of the 100 and 133 V tap to the neutral tap of the primary winding (other lead in the mains cord). The tap which currently has the lowest voltage to neutral, is the 100 V tap, the 133 V tap should have an about 33 % higher voltage to neutral.

Of course you can also make a resistance measurement from each of those taps to neutral, the tap which shows the higher resistance will be the 133 V tap.

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I got the transforner voltage and the 80 tube at 5vac but the

Only way i can get the needle to move is with the quality rehostat 0-100?

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