Author Topic: (...) in finding components for fluorescent inverter board  (Read 222 times)
Solanaceae
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(...) in finding components for fluorescent inverter board « on: May 22, 2017, 06:09:15 PM » Author: Solanaceae
Just got this today, but unfortunately the caps are probably bad and are what I suspect to have taken out the transistor. The trans doesn't have any legible markings. Could anyone help determining the proper replacement components im in search of? Thanks in advance.

Pix of components in question:
http://www.lighting-gallery.net/gallery/displayimage.php?album=lastup&cat=0&pos=0&pid=134100 
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Ash
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Re: (...) in finding components for fluorescent inverter board « Reply #1 on: May 23, 2017, 01:07:24 AM » Author: Ash
Most of those early single transistor circuits are blocking oscillator type

http://www.lighting-gallery.net/gallery/displayimage.php?album=2942&pos=10&pid=57299

Maybe with some differences and more components in the feedback and supply, which would make it better than the basic 3 component version

We gotta know what are the inputs/outputs on the transformer (coil sets, taps, roughly how many turns) and the battery voltage
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tolivac
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Re: (...) in finding components for fluorescent inverter board « Reply #2 on: May 23, 2017, 10:50:03 PM » Author: tolivac
Can you just replace this "ballast" with a another one?May be easier than trying to rebuild this old one.Esp if the component types are unknown.
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Re: (...) in finding components for fluorescent inverter board « Reply #3 on: May 24, 2017, 01:36:10 AM » Author: Ash
The transformer can be guessed just from looking at it and at the circuit

The rest is not that critical - The transistor with the long flexible tab is really old, like from the 70s, it may not be possible to find an identical one. But you dont have to. I think it would work ok with anything like a 3055 or a TIP41C
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Re: (...) in finding components for fluorescent inverter board « Reply #4 on: May 24, 2017, 03:13:21 AM » Author: Medved
The thing is, with most of the blocking oscillator ballasts the component parameters have to match together. So when using different transistor type, you may need to readjust the base bias resistor (to adopt for the different transistor current gain) and even the timing capacitor (to maintain the time constant close to the original) for the circuit to work properly.
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