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Light Bulb Limiter

Started by J M Fahey, March 17, 2011, 12:23:04 AM

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Bill Moore

I can't seem to add a pic, I'll try a link to my "spare parts" limiter.


The biggest lightbulb I can find is 140W. I am trying to test a Solid State Amp (Jamo) when I connect to Amp via the light build it glows slightly then when I press the ON button the the amp it glows REALY bright (doesn't blow) and the amp turn off.
Is this indicating that I need a bigger light build or indicating a direct short in the power supply.
Interestingly if a plug the amp straight into the mains the amp now works some of the time.
There are 4 10000uf caps in the power supply, perhaps this phenomina is just the caps trying to charge ? and thus a bigger build is needed perhaps.
With the amp running it is drawing 0.14 amps without speakers attached so not a big load.
Any assistance for this newbe would appreciated.


The light bulb is not supposed to blow. It is just a visual indicator of an issue if one is there and yours says yes there is a problem.
The direct short could be in the power supply or elsewhere.  Do you have a schematic or exact model number?



Yes I have a schematic, attached


If the unit is working then there is very little need for the light bulb.
This is a very complex circuit with many potential points to check.
The most likely issue would be all those circuit breakers.
Check "AVR power board" and the relay board for clues.

With a wooden stick gently probe around all the relay circuits to see if you can find which one is causing the problem.


Thanks of your input. Taking a root-cause-analysis approach I started with the light build box and found that inside of it the power plug receptacle had blown black gunk out of the vent hole in the bottom this was why it would start up without the light bulb device but with the lightbulb in series it was limiting the power available to start up properly. Using your suggestion I found that the main power relay continued 'chattering' after the amp off power switch was replaced so that is the next replacement but probably also indicating that there is some ghost voltage flowing to the relay, perhaps the diode across the relay may also be faulty, will replace for good measure.


Here's my 5 minute limiter...


Yep,, that is all you need,, saves lotsa headaches. :tu:


Here is the one I made.
I made a shorting plug as well, figured it would be easier to check to make sure the bulbs were good. Not much use if you have bad bulbs in it.

Only thing I purchased were the bulbs.


Quote from: teemuk on November 19, 2011, 10:41:34 AM
Someone also instigated a rebellious act to sell those light bulbs as "heat balls" ...or something in that manner. Really a genious idea to get around the loopholes.

I'm all for protecting environment and saving energy but I don't support total ban of something that in the end is just a drop in the ocean when considering the big picture. The electricity consumed by my house's light bulbs is peanuts compared to street lights not to mention some industrial plants that alone may draw as much as electricity as mid-sized towns.

I couldn't agree with you more. Compared with illegalizing incandescent tungsten bulbs, why don't ban the over-updating of intelligent products like phones and computers? New models of phones and laptops continuously fountain up in electronics shops and lots of old(but still well-performing and even powerful!!!) ones floods down to trashcans and landfills. Huge enterprises like Apple ban the re-using of second-hand IT products by blocking kernel authorizations(like jailbreaking and rooting) and applying activation locks intentionally.  That trashes many tons of chips which need huge amount of energy to produce.

Also, when it comes to so-called energy-saving illumination devices, do they really cost less energy and cause less pollution than traditional ones? Mentioning that some companies intentionally overloads LED elements in order to limit their lifespan and therefore to force customers to replace elements more frequently, it really drives me crazy. That's the REAL CRIME TO THE EARTH, even more guilty than producing tungsten bulbs.