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Review of the DY294 Digital Transistor Tester-Part 1
Last week i was busy with the repair course and holiday and finally today i could review the meter. The DY294 Digital Transistor Tester is using 4 pcs of AA batteries and and this tester can be used to test on many type of components. Select to the range as shown in the photo below and you will know the total voltage of the internal batteries:
Below are the result of certain components that i have tested and i will proceed to provide more information on other components in part 2.
Voltage Regulator IC:
Just insert the IC to the respective point (point 1, 2 and 3) and press the TEST button and see the result
Insulation Test on Non Polar Cap:
There is only one range for you to select to test the non polar cap- 1000v. The 200 volt produce no result when test on non polar cap. Set to 1000v to test on non polar cap that have working voltage of 1kv and above. For a good cap, it will show approximately 1500v and if the non polar cap insulation have problem, it will show a very low voltage from 60 to about 300 volt. This test have similar function like an insulation tester.
If you need to test on non polar cap that have working voltages that is less than 1000v then you may need to add a resistor in parallel so that the insulation of the non polar would not fail when you pump in the 1000volt to the cap. As for the resistor value you have to find it on your own because the manual does not comes with it. In the photo below, i found that the resistor of 560kOhm is suitable to test on a non polar cap that have 250 volt working voltage. If you use a lower ohm value the non polar cap insulation may breakdown. From the same photo you could see that the max voltage only hit 231 volt. If this non polar cap insulation have problem, the value could be less than 100volt.
Testing on Electrolytic Capacitor:
For your information, this meter is not design to test on the ESR or the capacitance value of e-caps. It test just the same way for a non polar cap. Just insert the e-cap into the respective section and select 200 VDC as shown in the photo and press the Test button. The LCD display will show the capacitor is charging and it will charge up to 200vdc-make sure that you are testing a cap that have working voltage higher than 200 volt. The disadvantage of this test is you have to wait for the cap to charge up.
The advantage of this meter over insulation tester is that it can be used to test on e-caps that have lower working voltage like 16 volt, 25 volt, 50 volts and etc. Just make sure that when you want to test a lower voltage of capacitor, the charging voltage should not exceed the working voltage. That means if you want to test a 16 volt cap, make sure the charging voltage would not exceed 16 volt. If there is a problem with the cap, there would be no charging or the charging would just stay at one value for example it stays at 8 volt and stop.
I found that this tester consume lots of current especially testing on the capacitor. If possible get a 6 vdc (2 amp) power adapter to power up this meter. In the long run, you could save the cost of buying batteries. Another thing is that if the batteries voltage is lower than 5.7 volt, i found that the test result would not be accurate especially testing on the non polar caps. Stay tune for more testing result in Part 2.