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Author Topic: Question abt blue florescent readouts  (Read 2383 times)
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WA2SQQ
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« on: September 14, 2018, 10:57:47 AM »

Found an old Leader freq counter (LDC-823S) in the trash at work, with a note attached, "not working after move to new lab". The display is dead, but everything else shows signs of life with my scope.

The blue florescent display, ITRON FG913, shows two pins labeled F1 & F2. They go back to the power transformer and appear to be the equivalent of a filament connection. Should I be able to measure some resistance across these, like a vacuum tube? It's reading open. Not so familiar with these florescent readouts.

I'm thinking it was dropped and something in the display is physically broken, hence no display. Found a new display, but this isn't worth the $45 they want for it.
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w4bfs
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more inpoot often yields more outpoot


« Reply #1 on: September 15, 2018, 09:23:19 AM »

Found an old Leader freq counter (LDC-823S) in the trash at work, with a note attached, "not working after move to new lab". The display is dead, but everything else shows signs of life with my scope.

The blue florescent display, ITRON FG913, shows two pins labeled F1 & F2. They go back to the power transformer and appear to be the equivalent of a filament connection. Should I be able to measure some resistance across these, like a vacuum tube? It's reading open. Not so familiar with these florescent readouts.

I'm thinking it was dropped and something in the display is physically broken, hence no display. Found a new display, but this isn't worth the $45 they want for it.


this is a question begging a subjective answer .... to fix or not to fix Huh

well I seem to have the same jones when it comes to hp test equipment .... the quality of construction is beautiful to my eye and so I want it to have another chance at usefulness ... so I buy it when I can and delite in it when working ....

a jones is a jones is a jones ..... at least the law dos'nt care about thisun .....ENJOY

n.b.   offer them less than $45 .... they just might accept it  Tongue 
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to see ourselves as others see us.
It would from many blunders free us.         Robert Burns
PA0NVD
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« Reply #2 on: September 15, 2018, 06:15:07 PM »

Indeed a filament. You should measure a resistance. These filaments are mostly 1,6 V at 50 mA or so, so take care
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WA2SQQ
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« Reply #3 on: September 17, 2018, 08:53:02 AM »

So this one reads open. The note on the device stated, "worked before moving ..." I suspect it was dropped and the tube was damaged. I can find a new readout tube on EBAY, but it's not worth the ~$60 it would cost me. I'll salvage the transformer and 10mhz reference oscillator. The rest goes in the trash - too bad it was built very well.
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Detroit47
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« Reply #4 on: September 17, 2018, 11:10:27 AM »

I had  one of those. I would fix it. Originally I had the counter and scope  matching units.  I still have  the scope. The counter was killed ina HV mishapp .

John
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PA0NVD
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« Reply #5 on: September 17, 2018, 12:52:24 PM »

It is some work, but measure the signal driving the grids (segmants) Perhaps you can add 7 small Mos Fet's like 2N7000 and a few digit drivers to drive a LED display
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