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Author Topic: Headlight bulb load quickfix  (Read 1572 times)
VU2NAN
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Posts: 245




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« on: January 18, 2013, 10:54:24 AM »

Here's the link.

http://nandustips.blogspot.in/2013/01/headlight-bulb-load-quickfix.html

73,

Nandu.
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WB6BYU
Member

Posts: 13112




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« Reply #1 on: January 18, 2013, 12:13:29 PM »

If you connect the bulbs one at a time, rather than all at once, you can often
avoid this problem because the supply only sees the surge current from one
bulb at a time.
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VU2NAN
Member

Posts: 245




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« Reply #2 on: January 18, 2013, 07:50:37 PM »

Hi OM Dale,

Each bulb has 2 filaments. The PSU tripped even when one filament was connected.

Many thanks.

73,

Nandu.
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KI0BK
Member

Posts: 2




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« Reply #3 on: January 20, 2013, 09:12:22 AM »

Does this power supply have an over-voltage crowbar circuit, (astron's do).  If it does, a poor solder or loose connection made during the repair may cause the voltage to rise and trip the crowbar.   Look for loose or poor solder connections using an ohm meter (with the power supply off and caps discharged). 
Hope that helps.
Jim ki0bk

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VU2NAN
Member

Posts: 245




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« Reply #4 on: January 20, 2013, 10:19:52 AM »

Hi OM Jim,

The tripping was only on account of the bulb characteristics (very low cold filament resistance).

The quickfix was a crude method to ramp up the voltage and in turn the filament resistance.

Many thanks.

73

Nandu.
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