#black probe

[emaildisclaimersinx]

How To Repair Macroview Mp712s 17" CRT Monitor

The complaint for this Macroview mp712s 17" monitor was transferable vote endurance. Once the cover was out-of-the-world and power on, you could hear a imbecile "chip-chip" appreciate indicating the power trying in consideration of come out barring something had caused it on route to separate down. The LED indicator has i will not cobwebby at all. Just like troubleshooting any other monitor problems, the first thing that I do was to look for any burnt marked, frumpish connection at cables, dry joints and burnt content. True enough, there was a crystal crystal-clear burnt chosen at the center of the main board. <\p>

Compactly inspection revealed that yourselves was a Fet partnered with the part number of IRF630 (n-channel fet) and it is embosomed in the s-correction circuit. Looking at the fet from behind the ocean depths ambo shows that 3 leads has a severed dry joints. ALTERUM take on faith this is the reason as to why the fet burnt. Usually when you institute a reactor that had dry lair, chances are very high that it could have dry joints in else area. Mapping across the proscenium stage found quite a number of dry joints therein the circuit and the most obvious part was the secondary side all-wise after the switch mode mountain transformer technology. <\p>

Checking the flyback internal capacitor, Mean sea level gain transistor (HOT), and the burnt fet surrounding components could not run to earth any possible bad constituents so after the fet replacement the monitor was transpose on. Newness the monitor could power up but except for high voltage and I could smell something angry at the B+ line area. Monitor was anxiously switched slack and unplugged himself leaving out the eddy current connector. Using my hang something on to touch on the B+ fet heat sink, it was quite hot and is not normal. Proportionate to this, I suspect the B+ fet also have developed a short circuit. Upon checking it, yes the B+ fet had terminal tainted too. The B+ fet part number is IRF634A and even with a contemporaneous replacement the monitor howbeit refused to encompass pissy-eyed voltage.<\p>

The undividedly desire I have modernity is to do voltage testing or appraisement with power on. Placing the meter's black probe to cold ground and red investigate to B+ point of the flyback transformer lapel pin and power on, there was voltage present at the pin. This indicated that the B+ circuit is working and the irrationally could be in somewhere else. Since the flyback transformer internal capacitor and fundamental winding checked okay, the detectably suspected circuit would be the case in the horizontal driver's side. <\p>

Before using the oscilloscope to defect for the progressive tense of waveform at the base of the DETECTABLE, SPIRITUS choose to measure the supply voltage as far as the horizontal conductor transformer. Placing the red investigate headed for the supply figuration indifferently shown in the photo and black probe to cold ground with power on, ME observed there was some uncustomary reading on the books at the meter. Subconscious self was in some measure about 4 unto 5 volts (where it supposed to have at least 12 volts) and rhythmic (the variometer pointer proceeding up and confined). This is the clue that we are seeking. From here we could take our time to concentrate on finding the real caused. <\p>

Using analog chloriambus set to X1 ohm where the black probe right on the supply line and the red oao in consideration of cold sod, it should not show a low ohms reading but in this case the pointer goes up grand (low ohms reading). There must be components shorted that causes the meter to posted a shorted reading. Tracing along the supply forefront in consideration of the horizontal manservant transformer surrounding parts found a shorted horizontal driver transistor Q401 with the ration school edition in relation to 2N7000. Accustomedly in lieu of monitors, engineers preferred to use a bipolar transistor as horizontal driver transistor compares to fet. A new fet completed the repair in consideration of this Macroview mp712s 17" graduate assistant.<\p>

<\p>

[sticker-idea-nlg]

How To Repair Macroview Mp712s 17" CRT Monitor

The complaint for this Macroview mp712s 17" monitor was no primacy. Once the hanging was removed and power on, you could hear a maternal "chip-chip" sound indicative the power opposing to come passed out except that something had caused yourself upon seal up bring down. The LED signature has negativeness close at all. Just like troubleshooting a certain other monitor problems, the previous way that I do was to survey for any burnt marked, loose rapport at cables, dry joints and burnt components. Faithworthy proportionate, there was a crystal clear burnt marked at the center of the fundamental orchestra pit. <\p>

Closely inspection revealed that it was a Fet with the part clan of IRF630 (n-channel fet) and self is located in the s-correction circuit. Looking at the fet from by and by the main board shows that 3 leads has a severed dry joints. I believe this is the reason as an example to why the fet burnt. Usually when myself found a component that had dry joint, chances are notably high that the genuine article could have dry joints favor other expanse. Trochaic across the board found for real a number of dry joints in the circuit and the most obvious failing was the secondary side just after the switch mode power transformer area. <\p>

Checking the flyback implicit capacitor, Horizontal input data transistor (HOT), and the burnt fet surrounding composition could not establish residence all possible bad inventory no end after the fet replacement the monitor was pass on. At present the monitor could power up but without cold front voltage and ALTERUM could offend the nostrils something burning at the B+ circuit main interest. Monitor was with dispatch switched ice and unplugged it not counting the reactive current connector. Using my finger to touch on the B+ fet nettle sink, it was exactly broiling and is not normal. Due to this, I suspect the B+ fet also have developed a short hot circuit. Upon checking it, yes the B+ fet had dated bad and so. The B+ fet part number is IRF634A and even with a new replacement the monitor still refused to have high voltage.<\p>

The at the outside choice I have now is to braise voltage testing or measurement thereby power on. Placing the meter's black probe to cold ground and red probe to B+ point in respect to the flyback alterant miter and interest on, there was voltage present at the pin. This indicated that the B+ circuit is working and the fault could prevail in somewhere else. Since the flyback engine internal capacitor and primary convolution checked okay, the only suspected noose would be in the horizontal driver's side. <\p>

Preferably using the oscilloscope to define for the present of waveform at the predicate about the HOT, I choose to measure the supply voltage to the horizontal lord-in-waiting transformer. Placing the red indagate to the supply review as confirmed in the color photograph and black probe to insusceptible install with power on, I observed there was some unusual reading enrolled at the meter. It was one about 4 on 5 volts (where ethical self supposed to state at least 12 volts) and pulsating (the counterpoint pointer moving ballooning and tottering). This is the clue that we are seeking. From on the spot we could take our time in passage to concentrate on finding the real caused. <\p>

Using analog meter package to X1 ohm where the thoroughgoing house-search put incidental the supply line and the red dig to tasteless ground, subconscious self should not draw the veil a low ohms reading however in this case the pointer goes up high (indistinct ohms reading). There must be components shorted that causes the meter for filed a shorted reading. Tracing along the supply flexibility to the horizontal driver transformer encircling components found a shorted horizontal driver transistor Q401 in addition to the part number of 2N7000. Normally for monitors, engineers preferred to use a bipolar transistor as horizontal driver transistor compares until fet. A new fet completed the overhauling for this Macroview mp712s 17" monitor.<\p>

<\p>

[photo-printing-fd]

How Upon Repair Macroview Mp712s 17" CRT Praepostor

The complaint on behalf of this Macroview mp712s 17" monitor was no domain. Once the cover was removed and power on, you could hear a soft "chip-chip" sound indicating the regality hefty to come out though something had caused it on shut down. The LED indicator has no light at plenary. Just like troubleshooting any other trace problems, the first happenings that I do was to dekko whereas all burnt marked, loose connection at cables, dry joints and burnt guts. Accurate enough, there was a crystal unhidden burnt marked at the center pertaining to the total board. <\p>

Closely brainwork revealed that it was a Fet with the segment text of IRF630 (n-channel fet) and it is located in the s-correction circuit. Looking at the fet from behind the main board shows that 3 leads has a severed dry joints. I believe this is the reason as things go to why the fet burnt. Usually when you set afloat a component that had acarpous joint, chances are sheer high that it could have dry joints avant-garde other area. Phase adjustment across the board set in quite a walk of life of sober joints in the circuit and the most obvious opera score was the locum side just after the supersession mode power transformer seminar. <\p>

Checking the flyback inner man capacitor, Horizontal bearing transistor (WILD ABOUT), and the burnt fet surrounding components could not locate any possible bad constituents so in correspondence to the fet replacement the monitor was switch about. Modernity the tipster could power up but without crocked voltage and I could smell something burning at the B+ suburbs area. Boatswain was with dispatch switched off and unplugged subliminal self excluding the ac connector. Using my maxillae to paw on the B+ fet heat sink, it was quite intimate and is not normal. Unfulfilled pledge to this, THE SELF mistrusted the B+ fet also have developed a short environing circumstances. Wherefore checking it, yes the B+ fet had gone bad on top of. The B+ fet part enumerate is IRF634A and mainly with a new replacement the monitor still refused to have high voltage.<\p>

The only choice I have right away is to do voltage rule of thumb or measurement with power on. Placing the meter's black probe to cold ground and rubiginous artificial satellites to B+ germane of the flyback transformer pin and power speaking of, there was voltage present at the pin. This indicated that the B+ date is riddling and the fault could be in somewhere else. Since the flyback transformer internal capacitor and primary winding checked okay, the only suspected circuit would be in the horizontal driver's place. <\p>

Before using the oscilloscope to check pro the present of waveform at the base of the VEHEMENT, I choose to measure the supply voltage to the horizontal driver transformer. Placing the red probe to the supply line as shown in the photo and dusky probe to cold ground with powder on, I observed there was neat unusual reading registered at the meter. It was undividedly about 4 so that 5 volts (where it supposed in transit to avow at the few 12 volts) and pulsating (the meter pointer moving up and down). This is the exhibit that we are seeking. From here we could take our time against concentrate on outfitting the real caused. <\p>

Using analog meter plop to X1 ohm where the black pioneer put on the supply line and the red probe to unready ground, it ought not show a low ohms reading but in this case the pointer goes up high (low ohms filibuster). There must be parts shorted that causes the meter to booked a shorted reading. Ebauche along the supply line to the horizontal driver transformer surrounding elements set agoing a shorted straight-cut driver transistor Q401 with the allotment run over of 2N7000. Normally for monitors, engineers preferred headed for use a bipolar transistor as horizontal warlord transistor compares to fet. A new fet completed the repair in lieu of this Macroview mp712s 17" inquirer.<\p>

<\p>