Regularly at whatever point electronic gear don't work or work, we would promptly think a defective switch mode power supply. In any case, do you have any idea that blemished or shorted parts in the motherboard or primary board could cause the power supply to quit working as well?
Switch mode power supply (SMPS) are planned productively to the point that at whatever point there is any short out happen in the principal board the power supply would stop itself and thoroughly quit working. Assuming you have no insight about investigating switch mode power supply, you might feel that the power supply have issue where as a matter of fact the primary board is the genuine reason for no power issue delta dps-200pb-185 b.
Switch mode power supply have an ongoing sense circuit (on the off chance that you take a gander at UC3842 PWM IC pin 3, it expressed I-sense which mean current sense) and assuming there is short out in the optional side (either in optional diodes or primary board), the ongoing drawn would be increment and this will lead the PWM IC to quit producing result to the power fet and consequently the power supply would close down. This occur in a split of seconds and you couldn't get the opportunity to say whether there are yield voltages at the optional side.
Some more established plan of SMPS power supply don't utilize the PWM IC, yet it really do have the circuit to recognize over current drawn and shut itself down at whatever point it distinguishes a shorted part in the optional side. One genuine model was the power supply utilized in printer. Printers ordinarily have two sheets; one was the power supply while the other was primary board. On the off chance that there is any short out in the principal board, the power supply wouldn't work. To separate at where the issue is, one should eliminate the connector from the power supply board. When the supply connector to the fundamental board was eliminated, you can now turn on the printer and check assuming there is any voltages present at the power supply connector.
In the event that there are zero voltages estimated across all the supply (VCC) pins we can reason that the power supply have issue and you can place your entire focus in this power supply board. Imagine a scenario in which there are voltages estimated across the connector. This implies that the fundamental board is making the no power issue most presumably due a few shorted parts in the principal board.
For your data, spot network printers generally expected two voltages to work. One is the 5 Volts (for rationale IC, eeprom and CPU) and the other is 30+ volts for the engines. The inquiry currently is how can we say whether the principal board is the primary driver that closing down the power supply? Extremely basic, simply utilize your simple multimeter set to X 1 Ohm and measure between the supply pin (say 5 volts pin) and the fundamental load up ground and afterward switch the tests. A decent board shouldn't show two comparative perusing and in the event that you get two comparable ohms perusing, this implies that the 5 volts line had shorted to ground through a few defective parts.
In the event that you have affirmed that the 5 volts line have issue, how would we figure out the guilty party since there are such countless parts associated with this line? TTL Ic's, CPU, EEPROM, semiconductors, diodes and, surprisingly, little channel capacitors are completely associated with the 5 volts line. Both of these parts shorted could make no power the printer. You might eliminate every parts lead (5 volt supply) in the fundamental board and trust that the short out will be no more. Expecting assuming you end up eliminating one of the channel capacitor pin and the short out is gone then we can say that the genuine guilty party is the channel capacitor.
The genuine issue is imagine a scenario in which the load up has a large number on it and this will consume bunches of your chance to seclude the issue by eliminating each pin in turn. It isn't not difficult to recognize the supply 5 volts pin to a bug IC that has 100 pins or more. Numerous insect IC's have more than one 5 volts supply pin. Some even have 4 and some have 6 to 8 supply pins. Does this mean you need to check each stick in turn until you at last find the shortcoming? Not just that, to eliminate the supply pin from the insect IC's and check for any short out between the grounds required an excellent expertise as well. On the off chance that you wrecked out the circuit board track, the fundamental board can be considered hopeless. Despite the fact that you can fix the messed up circuit track, this doesn't mean you have tackled the genuine shortcoming!
Do you see the additional issue emerge when you attempt to figure out the shortcoming? There should be a workable better method for handling this sort of issue. Indeed the facts really confirm that one can utilize ESR meter to gradually track to the wellspring of the short out You can use the ESR meter to find shortcircuits on electronic sheets by really taking a look at the genuine track obstruction. One test interfaces with the ground and the other to the circuit line and assuming the estimation ascends as you test further along the track, you realize that you are making a beeline for a misguided course! In the event that the ESR esteem diminishes as you move along the track, you are in the correct heading. The issue is consider the possibility that the principal board has twofold layers, 4 or even 8 layers. You might be burning through loads of your valuable time attempting to track to the genuine shortcoming utilizing the ESR meter strategy! Subsequent to making sense of such a great amount about the issues, right now is an ideal opportunity that you are sitting tight for to find the solution on the most proficient method to settle this sort of shortcoming quick.
Do you have at least some idea that the DC directed power supply other than utilizing it to power up electronic circuit it can likewise be use to investigate and figure out a shorted part in a motherboard? Expecting you have affirmed that the VCC supply lines shorted to ground through a few broken parts, you can undoubtedly distinguish it with the utilization of a variable computerized DC managed power supply. In the event that you don't have the computerized one you can continuously utilize one with the simple board meter which is less expensive.
Presently interface the crocodile cut from the positive result supply to the 5 volts VCC pin in the principal board and the negative result to the primary board ground as displayed from the image. Whenever everything was finished, now is the right time to turn on the dc directed power supply. Gradually shift the handle clockwise and see the voltage increment. Simultaneously the ongoing draw should be visible from the ongoing computerized meter readout. From experienced, in the event that there is a short out in the principal board, at whatever point the voltage is increment, the ongoing will rise decisively and if no short out there would be less current draw.
OK back to this issue, assuming that you see that the current drawn additionally increment (quickly) as extent to the ascent in voltage setting, you are presently without a doubt that there is part shorted in the principal board. What's the significance here? It is an uplifting news to us, since, supposing that the current drawn an excess of we can realize the guilty party by addressing the most sweltering parts in the principal board. Utilizing your finger you can address any parts that are extremely hot. Address the Ic's, diodes, semiconductors, capacitors and so forth. When you found that only one part that is incredibly hot to contact then that was the offender! That is the genuine reason that you are attempting to find! I've utilized this strategy to tackled bunches of primary board issue and typically the guilty party ended up being a deficient entryway exhibit and slam IC.
For what reason don't I promptly divert the result voltage from the dc managed power supply to 5 volts since the deficient primary board is likewise utilizing 5 volts to run? On the off chance that I do this and assuming the flawed parts turned hot excessively quick, I'm apprehensive this will lead the broken part to open circuit. Assuming the defective part open circuit, the ongoing draw will drop and the main sign that you need to distinguish the offender has been annihilated! In the event that this thing happens then you might not have a higher rate to fix the board. Obviously you actually can by supplanting individually the SMD insect IC's nevertheless this will unquestionably gobble up heaps of your maintenance time.