B&K 747 tester fault

[Down Under]

Hi all,

I was recently using my tester when the heater on a tube being tested went cold. Turns out now that NONE of the heaters of any of the valves I test light up. I looked for a wiring fault, but I have a horrible suspicion my tranny is open.

Has anyone seen this and know what it is?

All help appreciated.

Cheers,

Adam

[snelson903]

no iv not had any problems with mine

[bob91343]

Open it, measure the primary voltage on the transformer, then the secondary voltage. If one reads something and the other doesn't, you have a bad transformer.

Else it could be a bad connection; the line voltage adjuster on tube testers sometimes opens up. Or there might be a fuse blown somewhere.

Don't assume it's the transformer unless your testing indicates that.

If you have no voltage at any setting, maybe the primary isn't getting any voltage.

[dieseljeep]

Is this tester made for the export market, or one made for the US market?
Even when using with a step-down transformer, a unit made for 60HZ areas will have a smaller transformer and will run warmer at 50hz.
If the primary appears open, there is possibly a thermal fuse burried in the winding.

[Down Under]

Thanks guys,

I'm not sure which wires are for the pri and sec, there are oodles of wires going to the heater volts switch though! I have another one on its way (via epay), so I hope this'll be OK. Does anyone have any info on this model? The fuses I could see check OK, not sure if there's a thermal fuse in the tranny or not.

The one I have is a US version, trying to find this sort of test gear in Aust is virtually impossible. Not sure about whether 50Hz is an issue or not, my Predictas seem to handle it OK.

Cheers,

Adam