Transistor driver, ada yang pernah mengalami waktu diukur sepertinya tidak ada masalah tapi ketika dipasang lagi hot tetap panas bahkan langsung rusak, begitu. Here in this video i am showing how to test and trouble shoot television circuit. I just got done working on a early 90s color tv which needed a bit of work on it including the replacement of a horizontal output transistor. Understanding a single transistor flyback transformer driver. The damper diodes conduction path prevents reverse breakdown current in the horizontal output transistor resulting in. How to test horizontal driver transformer electronics. If you mean the vertical and horizontal transformers, then your referring to the scanning system used by older tv systems, the beam on a tv is scanned from left.
Jika keadaan driver horizontal tidak normal maka tv akan cacat tampilan, yaitu timbul gerigi pada layar arah vertikal. Component failures in the horizontal output stage or flyback secondary, such as a flyback shorted turn, leaky filter capacitor, or an excessive load on a. I dont recommend using horizontal output transistors hots from those crt tvsmonitors as they dont work correctly in similar circuits such as this one. Ultra simple single transistor flyback driver circuit. This circuit, also incorrectly known as the 2n3055 flyback driver, bears. Understanding the ha2500 horizontal output load test. Kemungkinan driver lemah, ini sangat mungkin akan membuat panas berlebihan di horizontal output. The horizontal driver transformer primary winding is not as high as the smps transformer thus. A lot of these devices h output transistors are pretty much interchangeable. Slow turnon in a deflection circuit thomson consumer. This circuit isnt precisely the 2n3055 driver you have seen on other websites, as the two highwattage resistors used in those schematics are replaced here with a single one youve guessed it right, with a classic incandescent.
Because the this is a power transistor, a current drive signal is needed. The term flyback pulse probably refers to the wellknown problem that flyback smpss have when switching not all the energy takenin by the primary can be released to the secondary and this creates a backemf that needs to be snubbed out else the output transistor may fail. A flyback transformer fbt, also called a line output transformer lopt, is a special type of electrical transformer. You have just replaced an obviously blown shorted horizontal output transistor hot and an hour or a minute later the same symptoms appear. Another important difference, as shown in the block diagram of figure 179, is that the television horizontal deflection circuit output stage is used to provide the anode voltage for the picture. In modern applications, it is used extensively in switchedmode power supplies for both low 3 v and high voltage over 10 kv supplies. It provides a path for current to flow through the flyback s primary winding and horizontal yoke as shown in figure 2. Gejala driver horizontal tidak bekerja, biasanya ditandai dengan tidak bekerja nya flyback. I have a ctc197ak2 horizontal output transistor keeps blowing, and i could really use some help i have already replaced the flyback transformer, with part number 237506 and r14704 which was 82k plus r12709 which was 27k i also checked c14710 which is a. Hal yang sering terjadi kerusakan pada blog driver horizontal yaitu transistor. To check horizontal yoke coil if it is good or bad with flyback tester.
Horizontal output in all but the smaller tvs is a large discrete power transistor, most. How to completely check the high voltage circuit in crt. Will a tv turn on even if the horizontal output transistor. The schematic has been updated to include basic transistor protection in the form of a capacitor and diode. The major one is the much higher horizontal frequency. When drive is selected, the fluorescent display shows the ha2500s horizontal test frequency and the dcv at the chassis horizontal output transistor collector or drain.
Flyback transformer drivers the 555 driver basic flyback transformers are found in monitors, tvs or anything with a crt, and are sometimes known as line output transformers, or just lopt. Utilizing a flyback isolated control topology, this reference design provides isolation compliant to iec618005, and generates power rails for all three arms of the 3phase inverter from a single transformer. The testing method is the same as when you test on the smps transformer. It will now quickly exceed the transistors limited collector current, whatever it was, and mechanism a will complete the switchoff. Bu508 circuits transistor driver of horizontal output transistor bu508 814001 814002 flyback transforme list used for tda power amplifier circuit. So far, i have dealt with several powerful flyback drivers such as zvs and 555 timer. Basically, a flyback is a high voltage line output transformer lopt, which powers cathode ray tube crt filaments basically, powering all those televisions and computer monitors. This makes a lot of difference to the circuitry used by the horizontal oscillator and amplifier. Equivalence transistor ha11423mp transistor 415 horizontal driver transistor rlu 210 hitachi power transistor driver rj27 r101 hitachi ha text. Horizontal output, vertical output transistor on a tv board home. I dont recommend using horizontal output transistors hots from those.
The zvs flyback driver either using bjts or mosfets have been used in high voltage devices such as tesla coils, marx generators, ion experiments, and ccfls. Since this would be during the flyback time, the voltage on the collector of the transistor 24 could be, for example, 150 volts. Horizontal output transistor testing hindi urdu youtube. Or, you notice that the new hot is hotter than expected.
The horizontal driver transformer primary winding is not as high as the smps transformer thus you cannot expect it to show many led bar from the test. For best results, use a horizontal output transistor, the original fbt primary winding and a 160vdc offline supply warning. Flyback driver circuits high voltage with a television flyback transformer. Troubleshooting horizontal deflection circuit oktora service. During a transition interval that follows a standby mode of operation, the duty cycle of the oscillator output signal is reduced relative to when a run. The flyback vertical portion of the sawtooth wave can be a potential problem to the flyback transformer if the energy has nowhere to go. Protection circuit for a horizontal scanning circuit and. I use electronic workbench to simulate the circuit which can generate about 20khz with 90% duty cycle and i come out with this. A flyback transformer fbt, also called a line output transformer lopt, is a special type of.
It was initially designed to generate high voltage sawtooth signals at a relatively high frequency. If the set performed normally until it died, there are other possible causes. In this video there is step by step procedure of making flyback driver with using one transistor. The nominal output current of flybacks are usually a few ma at most, but arc. Line output transformer lopt flyback fbt peter vis. Loneoceans laboratories flyback driver circuits gao guangyan. Utilized on electrohome g07, sanyo 20ez, wells gardner and many other monitors. If you have the flyback tester then it would be easy for you to test the horizontal driver transformer. This causes the inductance to drop, which increases the rate of rise of primary current dramatically. Horizontal output transistors are located near the flyback transformer or yoke connector plug on the circuit board.
This single transistor flyback driver topology was created in response to achieve higher efficiency and higher output voltages from ordinary crt television flybacks diode split flybacks, for experiments such as xrays or ionic lifters, without having to make any external hv multipliers. A flyback is a special transformer which in conjunction with the horizontal output transistordeflection circuits boosts the low voltage power supply to the 10 to. The step 9 page going further now includes a way to measure these illustrious voltage spikes with a regular volt meter. Hence, it is an extremely critical component playing a. Allowing for the higher powers needed for bigger tubes. If the drive signal at terminal 10 were to be disrupted during the flyback pulse retrace, the driver transistor 14 would normally cause the horizontal output transistor 24 to conduct.
Adjustable duty cycle allows adjustable output, while a proper drive circuit and switchmode transistor power the flyback transformer efficiently and powerfully. I think it has to do with the amplification h21e factor or base current. The transistor inside the set wwas a d1555, in order to test the set while i got the part i put in a d2499 was a bit worried as it has. Dry joints in nearby area yes, dry joints in the hot leads, flyback transformer, horizontal driver circuits could cause hot to blow. The primary purpose of this transformer was to produce the high voltages necessary for the operation of the crt. Bu508 circuits transistor driver of horizontal output transistor bu508 814001 814002 flyback transforme list used for tda power amplifier circuit diagram text. A damper diode parallels the horizontal output transistor. At a wild guess,if you can use a 2n3055,a more rugged device would be almost any bjt used as a horizontal output transistor in a tv set. Electronics projects, simple flyback driver circuit mosfet power electronic projects, simple circuit projects, date 20140621 circuit quite simple but quite high voltage flyback transformer of placing the television or monitor eht transformer typically used in this poje song writer seems to. The original version of this circuit used 2 transistors. Tida00182 reinforced isolated igbt gate drive flyback. The hot is switched on and off by a signal applied to the base. Horizontal output transistors keep blowing or excessively. Most of the people in the 4hv community use the mazilli driver to make flyback transformers also known as line output transformers lopt from tvs and computer monitors.
I will show you the way how to test a horizontal output transistor. To be honest i m more interested in a simpler but powerful flyback driver, so i researched about drivers that utilise only one. A flyback transformer, sometimes called a line output transformer, are used in. Testing flyback transformerhow to test and when to replace it. I came across lots of hot failure due to shorted primary winding in flyback transformer. Why horizontal output transistor in crt monitor get. This part is a substitute for the 2sd870 and has a higher amperage rating. The squeal you heard was the high voltage trying to come up for the picture tube. Cheap horizontal output transistors antique radios.
A lineoutput transformer lopt, also known as a flyback transformer fbt is an electronic component used in television receiver sets and visual display units vdu that employ a cathode ray tube crt to display an image. Driver test or sub drive pushbutton outputs drive to the chassis horizontal output transistor and is. It provides a path for current to flow through the flybacks primary winding and horizontal yoke as shown in figure 2. I try to fix up the frequency and duty cycle with help from simulation software. This horizontal drive signalwaveform comes from the horizontalvertical oscillator ic and to the base pin of horizontal output transistor hot after went through the horizontal.
Hence, an oscillator circuit usually created the necessary voltages to drive the primary winding of this type of transformer. A horizontal oscillator, responsive to an onoff control signal, generates an output signal that is coupled via a driver stage to a control terminal of a horizontal deflection output transistor. The reason why ive put the 2n3055 driver in quotation marks is simple. Horizontal output, vertical output transistor on a tv. They are used for generating high voltage for the crt, which is needed to create an electric field, which in turn accelerates electrons towards the screen. Television horizontal deflection circuit horizontal. Creating the flyback driver 20khz with 90% duty cycle thanks to jonathan filippi for the idea.