Improved Dim Bulb Tester Current Limiting Test Fixture w/ Bulb Preheat Feature for Sale

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Improved Dim Bulb Tester Current Limiting Test Fixture w/ Bulb Preheat Feature For Sale

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Improved Dim Bulb Tester Current Limiting Test Fixture w/ Bulb Preheat Feature :
$179.95

I list shipping as 3 days just in case I get more than one order on the same day or if I ever have a problem getting to the post office quickly, but I almost always ship the next day.This Dim Bulb (Dimbulb) Guitar Amp Current Limiting Test Fixture is now available in 3 models and each model comes with an 11 watt incandescent starter bulb (a low power 11 watt bulb is helpful for reforming capacitors in amps that haven't been powered up for 6 months or longer), a 53 or 60 watt (depending on availability) medium power incandescent bulb, and a 200 watt high power incandescent bulb. The video included with the pictures shows the 3 amp box - the 5 amp box works identical to the 3 amp box (except it can handle more current) but in most cases, unless you have a very high power amp, the 3 amp meter will give better resolution since most amps don't draw more than 3 amps. A Dimbulb Current Limiting Test Fixture is a helpful tool during testing of guitar amplifiers and other electronic equipment by safely powering up the equipment by limiting the current through an incandescent light bulb (the bulb must be an incandescent, LED and other bulb types will not work properly) This box is available in a 3 amp version, a 5 amp version, and a dual range (1 & 5 amp); the 3 amp version has a 3 amp meter and a 3 amp circuit breaker, the 5 amp version has a 5 amp meter and a 5 amp circuit breaker, and the dual range comes with a 5 amp circuit breaker. On the dual range model the 1 amp meter is protected by the current limiting of the low power bulbs. These boxes takes away all the guesswork by showing you the exact voltage and current that the amplifier is receiving. The problem with most Dim Bulb Current Limiting Test Boxes is that they apply power to the amp while the bulb is cold while the bulb has a very low resistance which allows a huge current flow, which pretty much completely eliminates the entire point of the Dim Bulb box; the bulb must be hot for the device to limit current properly. I also sell an economy Dim Bulb Current Limiting Test Cable that is just two bulbs, which is better than nothing (one person bought one just to take to test amps at yard sales!), and as good as any dim bulb box that doesn't have a Preheat Bulb feature, but to get full protection and have the Dim Bulb circuit limit current as intended there needs to be a bulb preheat feature. Once it has been determined that there is no dead short in the amp (a bright light indicates a short and the amp needs to be repaired, a dim light indicates all systems normal) the bulb limiting feature can be switched out (to DIRECT/BYPASS) so that the amp gets full direct voltage while the current can be monitored on the meter. The current meter is on at all times and even measures the current of the bulb while in PREHEAT mode. The boxes have a cover on the back and come with a standard power cord and 3 bulbs: a low power 11 watt incandescent bulb to use as a low current starter bulb to reform filter capacitors that haven't been powered on for 6 months or longer, a medium power 53 or 60 watt incandescent bulb, and a 150 or 200 watt high power incandescent bulb. The box is 9.5" wide x 5" tall (without bulb (or bulbs)) x 3" deep. All wiring and soldered by hand.

Reforming Filter Capacitors with the Dimbulb Tester:
NOTE: A DimbulbTester *ONLY* works with an INCANDESCENT bulb.

Using the single bulb unit: With the DimbulbTester OFF, insert an 11 watt bulb and set the middle toggle switch:BULB LIMITING / DIRECT/BYPASS to the up position to BULB LIMITING andset the TEST AMP / PREHEAT BULB on the right toggle switch to thedown position to PREHEAT BULB. Plug the amp being testedinto the output of the Dimbulb Tester box and turn the amp on; if theamp has a standby switch don’t use it – leave the amp turnedon.Verify that the amp is turned on, the box is in BULBLIMITING (middle toggle switch up), and PREHEAT BULB mode (righttoggle switch down).Turn on the Dimbulb box – the bulbwill glow full brightness (an 11 watt incandescent bulb isn’t verybright). The middle toggle switch stays up in the BULBLIMITING position until the end of the test.Switch theright toggle switch up from PREHEAT BULB to TEST AMP. The rightmeter AMPLIFIER VOLTAGE should bump up a hair – continue eitherway, but always pay attention to both meters.The 11 wattbulb will limit the current to the amp so the voltage going to theamp will be low, the AMPLIFIER VOLTAGE meter will typically readaround 10 volts. Starting with a bulb with a wattage as low as 11watts is extremely helpful if an amp has been unpowered for a longperiod of time; it allows the filter caps to reform gently without ahuge current spike.Turn off the DB box, change the bulbfrom 11 watts to the 53 or 60 watt bulb, and repeat: Verify that the amp is turnedon, the box is in BULB LIMITING (middle toggle switch up), andPREHEAT BULB mode (right toggle switch down). Switch the righttoggle switch up from PREHEAT BULB to TEST AMP. The right meterAMPLIFIER VOLTAGE should bump up a hair – continue either way, butalways pay attention to both meters.As you increase thewattage of the bulb the voltage going to the amp should continuegoing up – if the AMPLIFIER VOLTAGE stays near zero and theAMPLIFIER CURRENT is moving above zero then the amp has a problemthat would ordinarily blow the fuse. If desired an amp can be tested withas many incandescent bulbs as you want to: 11 watt, 25,watt, 40watt, 60 watt, 100 watt, 200 watt, just start with the lowest wattageand work your way up. If you are using the new dual range box then the two left bulb sockets that run through the 1 amp meter should not be used with higher than a 100 watt bulb, but the high power bulb socket can accommodate any bulb up to 600 watts.I list shipping as 3 days just in case I ever have a problem getting to the post office quickly, but I almost always ship the next day.