We are check the VRM Section when after on the power no display Generating Mother Board, CPU not Heat, so we are check VRM Section’s
- Check logic on TP1 point, received the logic on TP1 point but CPU is not normal heat proper, and then capacitor faulty of TP2 point or CPU faulty.
- If not receive the logic on TP1 point, and then check the input supply coming. On I gate mosfet drain point (P1to p.3.5v, P iv-12v). +ve supply on drain point, then check +ve signal or logic on mosfet gate. Logic is received but not received logic on IP1 point. Then check I gate, B gate mosfet for open.
- If +ve signal or logic not received on mosfet gate then +5volt supply check on Vrm Ic Vcc Pin. If supply is not coming then check the 0Ω resistance for open condition. If resistance open again and again then vrm Ic is faualty.
- +ve supply received on vcc pin and signal is not coming on I gate & B gate mosfet. So after that check shut down opposite signal on shutdown pin, high signal check on soft start pin, high enable signal check on enable pin, if low single received on SS(soft start) then check capacitor for shorting connect on this pin. After that shut down opposite signal is not received on shut down pin, so we are check in P-3 mother k Ω resistance, and in P.4 mother board check CPU section.
- If shut down signal, enable signal, SS soft start signal is ok, but signal not received on I gate and B gate pin, so after that in this condition Vrmc chip is faulty.
- After power on received the display, but CPU is hang. Check coil for short condition on IP1 point. Coil is ok then CPU is faulty.
Note: Any computer hand problem of virus, hardware, software, so in this condition , we are disconnect the hard disk with mother board, if after disconnect the hard disk with mother board, already CPU is hand, the problem is CPU or VM section. If after disconnect the hard disk CPU is not hang. Then problem is operating system, virus and bad sector in hard disk.
- After power on is received the display and system restart again and again, then change the capacitor for shorting on TP2 point.
Note: Restart problem is generate of virus or capacitor.
- System on-off again and again the start. So we are check capacitor on TP2 point.
- Mother board working with ATx SMPs but we are connect Apower supply of mother board display is not coming, and replace the capacitor of I gate mosfet drain point.
The working of this section is receive the supply 3.3v from SMPS, 2.5v from VRM section and working 14.318MHz crystal after that provide to CPU free clock pulse of CPU. In this section use the clock generator IC. And 14.318MHz crystal of create the section. Clock generator IC coming many types of company’s. example: ICS, Max, window RI1, VIA etc.
Clock generator IC is a programmable IC. It is provide CPU free clock pulse to CPU according to received Bingryon Fs0to Fs2 pin.
Received the the supply clock generator and then IC osclliator section on received the +ve/-ve supply and provide to CPU free clock pulse to CPU. CPU is received the supply from VRM section and received the clock pulse from clock generator section, after that CPU is on and generate the reset signal for all mother board. It’s procedure is working of this types
- Diagram of rest Sections:
- Block Diagram of clock generator Section:
- Description of clock generator block diagram:
1st clock generator IC received the +ve supply 3.3v from SMPS 2.5v from VRM section and –ve supply received from Gnd.
After that bingry received on Fs0 to Fs2 pin (frecouncy select pin) of clock gererator IC pins. It is working with 14.318MHz crystal and on. Start the working and provide the CPU free clock pulse according to CPU, provide the 29MHz to 75MHz. Clock pulse of RAM, 24.57MHz, 27MHz clock pulse of IEEE1394 section, 27 MHz, 48MHz of USBI.0, 2.0, 66.6 MHZ clock pulse of Pc I express slot, 66,100, 133MHz clock pulse of HDD/CDROM, 8MHz, 16MHz, clock pulse of ISA slot, 33.3MHz clock pulse of PCI slot, 54.54MHz & 74.17MHz clock pulse of N I SC/PAL/Encoder, 66MHz & 54MHz clock pulse of MPEG2, decoder, 66.6 MHz clock pulse of ICH and system control IC.
- Testing and faultfinding of clock generator section:
We are check of this section when use on the power, no display in mother board and reset signal not received from CPU. CPU is not normal heat and then we are check clock generator sections:
- If reset signal is not coming but VRM section, CPU is ok then we are check free clock pulse on clock generator free clock pulse on pins, clock pulse is received but reset signal is not coming. Then clean CPU socket or change the CPU sockets.
- If not received clock on clock generator IC free clock pins, then check 2.5v, 3.5v unk Vcc pulse. VDD pins, if +ve supply is not coming from VRM, SMPS sections, then check the VRM and SMPS.
- If +ve and –ve supply is coming but received clock pulse on CPU free clock pins, then change the 14.318MHz crystal. If crystal is ok then clock IC is faulty.
Note: (i) any clock generator IC of CPU free clocks pins is in Last four pins in one pins of free clock pulse. (ii) In this section if 14.318MHz crystal body is connect with Gnd. It is very important, if body not connect with Gnd. And then clock Generate section is not working. (iii) Clock generator IC sold on mother board, before sold check brand name of IC, number of IC, and access time of IC is same. After that you are sold IC on mother board.
Bios – Section.
Description: Bios is? Basic input output system it is enable the all hardware of mother board when we on the power, on the power Bios program configuration is loading main memory and check the all hardware device and then the all hardware on booting time boot from operating system its bios program store in ROM IC. IC is mount or connect in socket on mother board. And start the working. It ROM IC is mainly PLCC 32 pin. In each computer this bios program is different types of companies. But normally bios are AMI award, Phoenix Company. The all companies sale bios source of code different distributor.
- Bios is order to operating system how your computer are boot and the all hardware load, what is load, and what is condition of CPU and RAM for identifying the working of bios is the computer is not working without bios.
The working of this section is after on the power provide post signal to CPU. Then CPU is on and all device start the working bios is? Software and this software write the different types of companies according to mother board. This bios program is written according I/o controller. If I/o controller is support to mother board or not. AMI, award, phoenix companies are write the software in chipset mother board and the direct company write the software in original mother board. Example: Intel company write the bios in intel original mother board it’s software store in ROM IC and ROM IC sold on mother board, and run the program from CPU. ROM IC is storey device, it is different capacity. Example: 5MB, 1MB, 2MB,…… The manufactory of this IC is different. Example: window, Intel, Dell AT, Max, ATMEL, etc.
Bios program is programmed on PROM, EPROM, EEPROM, Flash, ROOM. We are known to this IC called bios chip. If we are called normally it’s name is bios chip. It is a famous name.
CMOS: Complementary metal oxide semi conductor: it is semi-conductor technique it is use minimum power in generate minimum temperature. Decrease of this IC components working on two junctions and it is working on semi conductor technique. Types of ROM IC: 1. PROM, 2. EPROM, 3. EEPROM, 4. Flash ROM, 5. Firmware
- PROM: (Programmable ROM): This type of IC is identify once time read only memory. It is program once time after that we are not erase the duty this IC lock the byt IC of this IC. It is cancel circuit fuse name and this fuse work as a antifuse. it is operate on 12volt to 21 volt. It is identify the number print this IC.
- EP. ROM (erasable programmable ROM): This type of IC is 10 time program and erase the store program is in IC for erase remove the sticker on IC and set the gloys window down on ultra vilot tube, if it’s wave length is 235 nevo meter on the tube and set down on the tube 8 to 10 hours, after heat able data erased, after then reconnect the sticker on the Glass window of IC and store program IC from universal program. This IC identify the glass window.
- 3. EE-PROM: (electric erasable programmable ROM): This type of IC is program time is 2 to 3 minute we are identify this of his number.
AT 27 C. 01 – 70
W 29 C 02 – 70
- Flash ROM: This type of IC life time program and erased. It’s program and erase time is 2 to 3 second. It programmed by clock pulse. The store data in the IC secure the after 120% pepro. It’s identifying number on this IC.
W 49 LF 004 70
SST 49 F 008 90
- Firmware: It is under class in memory. It is working a ROM IC when the power is fail. It is looking according to hardware and software. Use in Intel mother board flash ROM, we are called firmware.
Testing and faulty finding of Bios-Section:
We are check of this section when on the power and receive the reset signal from CPU. If mother board is no display then check this section:
- 1stly check the +3.3volt on VDD pin of Bios IC. If the supply is not coming. Then check for open the supply circuit it is coming form VRM/SMPS section.
- If +ve supply received of IC, then check reset and clock signal on IC reset & clock pins. If reset and clock signal is not coming then check clock generator section or CPU section.
- reset and clock signal is coming, then check the data of bios IC data pin DQ0 to DQ7). If data is not coming, then faulty of store program in bios, we are reprogram of this bios.
I/0 Controller Section
The working of this section control the keyboard, mouse IRDA parallel port, comport, FDD port, ACPI interface section, and monitoring interfacing sections. Input output chip use in this section I/o controller IC is 28 pins. It is product by ITE, window SMBC Company. Explanation of internal sections of I/O controller IC:
- FDC Interface Section: The working this section is control the 34 pin floppy drive and synchronization the data in serial way of. Floppy. In this section on/off of spindle motor. Pin detail of this section:
Pin-1-This pin is output pin of density select the density select of drive a of this pin density=data transfers select.
Pin -2- This pin is multi function input/output pin of this IC. B-drive density select from this pin. This pin is data input/output pin of input /output port B of bits 6.
Pin-3- This pin is index # input pin floppy drive head index file input information coming this pin this index file read.
Pin-4- This pin is spindle motor signal out pin of floppy drive A:. This pin is on of spindle motor.
Pin-5- This pin is output pin of floppy drive A:. This pin is select of A drive. This pin is disable a drive when the signal is high on this pin and this pin enable a drive when the signal is low on this pin.
Pin-6- This pin is B drive select output pin. This pin select of B drive. On this pin when the low then select and when the high then disable.
Pin-7-This pin is spindle motor output pin of drive B. This pin on the spindle motor.
Pin-8-This pin is dir output pin. This pin is move floppy drive head of step by step according to Dir command. When the high signal on this pin then floppy drive head move front side and when the signal low out his pin then floppy drive had is back.
Pin-9- This pin is output pin of slide motor single. This pin use for movement the slide motor.
Pin-10- This pin is write data output pin of this IC. This is provide writing data to floppy.
Pin-11- This pin is write enable output pin of IC. It is enable internal writing section of floppy drive.
Pin-12- This pin is tracko sense input pin of this IC. On this pin received the format command and then head is coming on tracko information provide to floppy drive.
Pin-13- This pin is write protect input pin of this IC. The floppy disk write protect condition protect signal in received on this pin. Unprotect signal on this pin. When the signal is low and in the writing condition high signal received on this pin.
Pin-14- This pin is read data input pin of this IC. The reading data received on this pin of IC.
Pin -15- This pin head select output pin of this IC. This pin select of floppy drive head side A/side B. On this pin side A select when the high on this pin, side B side when the low on this pin .
Pin -16- This pin is disk change input pin of this IC. The disk change message received on this pin, when the disk change in floppy and then index file read of new disk. In high condition disk in. In low condition disk out message received on this pin.
Testing and fault finding floppy drive controllers:-
Check this section when connect floppy drive but floppy drive not detect and fdd enable & floppy disk drive is ok, then check this section of these types:
1st:- 1stly enable the A, B drive 1.44MB floppy drive in Cmose setup.. if the Cmos setting is ok. Then check the low signal on floppy drive select pin if high received on this pin, then check low on DSA of input/output IC. If low received on DSA pin. Then check track open in between input/output controller IC and floppy disk drive.
2nd:- If high received on DSA pin of input/output IC. But floppy drive is not detect, then input/output controller IC is faulty or replace the input/output controller IC.
3rd:- Any disk connect in computer on the writing time and received the write protect message screen. Then check the high on wp pin. If low received: then check network resistance for open. It received high on this pin but wp message received then change the I/0 controller IC.
- Keyboard interfacing section
The main working of this section control the normal and PS2 keyboard and mouse and syncrozise the data. Pin detail of this section:
Pin-58- This pin is keyboard lock signal input of this IC. Received the keyboard of lock signal form front panel on this pin. It is used in branded PC. In assembled PC. This is pinisfix for unlock.
Pin-59- This pin is output pin of A-29 gate of this IC. It pin is received data from KBC interface section provide to ICH.
Pin=60- This pin is keyboard reset signal output pin of this IC. It is reset of the keyboard.
Pin-62- This pin is keyboard clock signal output of this IC. It is provide operating clock pulse of keyboard.
Pin-63-This pin is keyboard data input pin of this IC. Received the data from keyboard on this pin.
Pin-65-This pin is PS2 mouse clock signal output pin of this IC. It pin is provide operating clock pulse to PS2 mouse.
Pin-66- This pin is PS2 mouse data input pin of this IC. It pin provide data to PS2 mouse.
Keyboard controller testing and fault finding:
We are check section when on the power and generate the display but keyboard or mouse is not working properly:
1st :- If keyboard is not work then check keyboard connector for open or loose. If connector is ok then check +5v. VCC supply on connector pin no. 5. If supply is not received then check open the jumper connect in supply line. If jumper connect in pin 2 ,3 then connect jumper in between pin no. 1 and 2 after between that complete this work , supply is not coming then clock the fuse in path of pin no. 2 for open. If fuse is ok then check the coil. After the supply is received, check the Gnd. On lindpin ,of connector. If it is ok. But KB is not working. Check the 4.5volt supply on data and clock pin. If supply is received but KB is not work and the fault is input output controller IC and replace this IC.
LPC Interface section: The working of this section is control the all section of I/o controller IC. Then I/0 controller IC is start the working. Pin detail of this sections:
Pin-18- This pin is clock pulse input pin of this IC. On this pin input 24 MHz to 48 MHz clock pulse input pin of this IC. On this pin input 24 MHz to 48 MHz clock pulse in normally condition 24 MHz clock pulse in on this pin.
Pin-19- This pin is output of power management section signal f this IC. It is control the pwn section .
Pin-20- This pin is volt source to source pin of all internal section of this IC. It pin is Gnd.
Pin-21- Its pin is PCI clock input pin of this IC. On this pin provide PCI clock pulse from clock generator IC.
Pin-22- Its is output pin of encode DMA request signal pine of this IC. It pin is control the DMA of any device internal IC.
DMA: – Direct Memory Access:
His the meaning of synchronize the data of any storage device without CPU used.
Pin-23- Its pin is serial I & Q input/output pin of this IC. It is control the input section of this IC.
Pin-24, 25, 26, 27:- Its pin is address and data input/output pins of IPC. Interface section.
Pin -28- Its pin +ve input supply pin of LPC section +3.3volt provide on this pin.
Pin-29- Its pin is clock pulse enable indicate input pin of this IC. On this pin provide clock generator IC on information.
Pin-30- Its pin is reset input pin of CPU section (internal section) of this IC. It is reset the IPC section.
Multi mode parallel port:- The main working of this section is syncronization the data from parallel device and connect on parallel port. The meaning of multi function parallel port synchronize the date multifunction of serial ports. Parallel and serial devices are connect on parallel port. But only parallel devices is connect on parallel port. In use P-1 to P-3 mother board normal parallel port, and in P-4 mother board use the multifunction parallel port. The pin detail of this section is here.
Pin-31- Its pin is input pin of printer mode floppy of this IC. It pin is select parallel device and serial port. On this pin in low condition select parallel device and in high condition select. Serial device.
Pin-32- It pin is working paper end in printer mode. On this pin in the high condition on paper end time and it pin is working write data out for external floppy drive.
Pin 33- It pin is printer is not ready signal dip pin in printer mode. The printer is not reply when printing command time, then, receive the message printer is not reply.
Pin-36- It pin is PD-6 data I/o pin in printer mode and it is working start the spindle motor of internal floppy drive.
Pin -37- It pin is PD-5 data I/o pin in printer mode.
Pin-38- It pin is PD-4 data input output pins in printer mode and it is working change the disk of external floppy drive.
Pin-39- It pin is PD3 data input output pin in printer mode. It is working for external floppy drive of data recalled input.
Pin-40- It pin is working for external floppy drive of write product work.
Pin-41- It pin is in printer mode of PD.1 data input/output pins and it is tracko input pin for external floppy drive.
Pin-42- It pin is PDO data input/output pin in printer mode and it is index signal input pin for external floppy device.
Pin-43- It pin is mode select input pin in printer mode the print online or off line message received on this pin form printer and it is working Dir for external floppy drive.
Pin-44- It pin is input pin of printer mode insulation pin after reply the printer provide ready signal +0 system and it is working Dir for external floppy drive.
Pin -45- It pin is error detection input pin in printer mode. On this pin on printing command time printing data is not ok according to printer then out the printing error message in low wsy and it is work head select for external floppy drive.
Pin-46- It pin is paper auto feed or manual feed pin in printer mode. On this pin in loc condition auto feed and in high condition. Manual feed message received and it is drive A drive B select output of external floppy drive.
Pin -47- It pin is +ve input pin f multi function parallel port (internal section) of this IC +3.3volt provide on this pin.
Pin-47- It pin is printer store signal input pin of this IC. Printer connect information received on this pin when low signal on this pin.
Testing and fault finding of parallel port:
We are check of this section when we are connect parallel device on parallel port, and the parallel device is not working then we are of this section.
1st:- 1stly we are enter in Cmos setup and enable the parallel device and then check parallel port mode for EPP+ECP.
If auto function in Cmos setup then set this option for auto.
2nd :- If Cmos setting is ok, then check low signal on PNFpin of IC. If high received on PNF pin, and parallel port, printer cable or printer is faulty.
3rd:- If low received on PNF pin, then check logic on PD0 to PP7. If logic is ok then parallel device generate fault, I/o contgroller IC is faulty.
Communication interface section:- The working of this section control the serial communication device and syneronization of the data. Pin 49,78 This pins is input pin of clear to send information of this IC. On this pins after complete the send command received the information from communication device on this pins.
Introduction of this IC. On this pins after complete the send command received the information from communication device on this pins.
Pins-50,79- This pins is input pin f data set to ready signal pin of this IC. Transfer data ready information received on this pins. On this pins in low condition received data set ready information.
Pin -51,80- It pins is output pin of request to send of this IC. It pins is data send to request message send from communication device.
Pin-52,81- It pins is input pin of data terminal ready of this IC. On this pins in low condition data send and receive from communication device.
Pin-53,82- It pins is input pin of serial data of this IC. The serial data receive from communication device on this pins.
Pin-54,83- It pins is output of serial data of this IC. It pins is syneronize the data from communication device.
Pin-55- It pinis –ve supply pin of communication section, and it is Gnd. Pin.
Pin-56,84- It pins is careerdefect input pins of this IC. On this pin received data career frequency connect information received from communication device.
Pin-57,85- It pins is input pin of rigton intecat of this IC. On this pin is received communication device connect with network connectivity information.
ACPI- Advance control power interface. The working of the section is control the stand by section. (Internal section of I/o controller). +5v provide from I/o wire of SMPS to on this section. This section is working start when the system is non condition or the system is shut down. Pin detail of this section is here:-
Pin-67- It pins power signal output of this IC. It is provide signal of SMPS green wire.
Pin-68- It pin is output pin of power signal. On this pin provide power on signal from power trigger switch.
Pin-74- It pins is battery volt input pin of this IC. The sample volt provide to the system received from UPS of this IC. Then system is display the backup time according to UPS battery backup time. The battery volt provide on this pin by through pass 10Ω to IC0 Ω ¼ watt or 1/8 watt resistance. It pin used in Branded PC, not in assembled PC-
Pin-76- It pin input pin of system cover open of this IC. System cover open in high condition received the information when the system cover is open of this IC. It pin used in branded PC only.
Testing and faulting of ACPI section:-
We are check of this section, when on the power and system is restart or press the power trigger switch but SMPS is not start but SMPS and VRM is ok then check this section:-
1st:- If direct on the main power system is restart then clear Cmos from pumper and again system restart directly then check NPN transistor for shorting, it is connect on I/o controller signal output pin. If transistor is ok or not command here, then I/o controller IC is faulty. Replace this IC.
2nd:- If press the power trigger switch but SMPS is not on then short green and black wire and green display is coming check RTC section for on condition. If RTC is ok then check I/o controller internal section standby section. On VCC pin +5v. if +5v is not coming then check oΩ resis. For open condition.
3rd:- If +5v received on standby section but again press power trigger switch and loot on the system. The I/0 controller IC I faulty.
Hardware monitoring interface section pins details :
Pin 94, 95, 96, 98:- It pins in analog 0/T input sense pin of this IC. The -12v, +12v, -5v, +3.3v, provide from SMPS and sense input volt. After sensing display from ICH.
Pin- 99, 100:- It pins is V core A, V core B input sense pin of this IC. The V core A pin sense the CPU core volt, and grenate the display and V core B pin is sense system controller IC. Volt and generate the display.
Pin-101- It pin is reference volt output pin. On this received volts provide volt to thermal device.
Pin-102, 103, 104:- It pin is temperature sensor 1, or 2, or 3 input pins. This pin is input the CPU socket temperature CPU slot temperature, system temperature.
Pin-105:- This pin is over shut down temperature signal output pin of this IC. This pin auto shut down the system when the CPU temperature is up to 70°C.
Pin-106, 107, 108, 109, 110:- This pin VID0 to VIDy binary output pin of this IC. It pins is provide VID binary to VRM section.
Pin-111, 112, 113:- This pin is CPU fan speed control output types of this IC. This pin is control the CPU fan, system fan, and cabinet fan speed. This pin is sense the all fans speed.
Pin – 115, 116:- This pins is fan PWN control output pins. This pins is control the fan pulse width.
Pin- 118:- This pin is system beep signal output pin of this IC. The system speaker connect on this pin and received the beep signal.
Testing and fault finding:- We are check of this section when we on the power display is come, but system is hang on post screen or show the overheat message on screen and restart again and again. We are checking this section.
1st:- If power on time system is hang on post screen, then press Cmos enter key before post screen is coming. After that system also hang in Cmos setup, then CPU or VRM section is faulty.
2nd:- If system is not hand in Cmos setup, then fault in mother board or thermal diode connecting CPU internally then thermal diode is change for shorting.
Note:- If thermal diode short then system is hang on post screen. If it is not hang in Cmos setup, then Cmos monitoring utility disable in Cmos setup, and display is ok.
Game port Joystick port Midi port:-
Pin-119 – This pin is midi port bit, data input section of serial data input pin. It is used in green purpose for input/output port 2 bit data use input.
Pin-120- This pin is serial data output pin of midi port, and it is out of the interrupt signal.
Pin-121- This pin is command input of joystick A switch 2. Pin and it is input of port 1 bit y.
Pin – 122- This pin is input pin of joystick switch 2 command pin and it is input pin of port 1 bit 6.
Pin – 123- This pin is input pin of joystick A, y position sense. Pin and it is input pin of port 1 bit 5.
Pin – 124 – This pin is input pin of joystick B of y position sense pin and it is input of port 1 bit 4 pin.
Pin – 125 – This pin is input pin of joystick A of y position sense and it is input pin of port 1 bit 3 pin.
Pin – 126 – This pin is input pin of joystick A of y position sense pin and it is port 1 bit 2 input pin.
Pin – 127- This pin is command input pin of joystick A of switch 1 pin. It is input pin of port 1 bi to pin.
Note:- The pin no. 121 to 128 is used for the data input and output.
General purpose I / O port:-
Pin – 64 – This pin is suspend L.E.D. out pin of this IC. The suspend indication on this pin, when system is in suspend mode.
Pin – 69- This pin is infrared receipt data output pin of this IC. On this pin the information infrared diode of convert in digital information and receive in as a IR data.
Pin – 70- This pin is output pin of reset signal of this IC and the system is restart of this signal.
Pin – 72 – This pin is power ok signal output pin of this IC and SMPS continue on of this signal.
Pin – 73 – This pin is chip set suspend signal pin of this IC.
Pin – 87 – This pin is infer Txfr. Signal output pin of this IC. On this pin is connect infrared diode and transfer the infrared signal.
Pin – 88 – This pin is IR receipt signal input pin of this IC. On this pin is out the IR TxR single.
Pin – 89 – This pin is watch, doc time output pin of this IC. The system is going in standby from this IC.
Pin – 90 – This pin is power led indicate output pin of this IC. The power led connect on this pin.
Pin – 91 – This pin is port 1 of bit 1 input/output pin of this IC. This pin is serial clock pulse in input.
Pin – 92 – This pin is port 2 of bit 2. I/O pin of this IC. This pin is providing clock pulse in a input and this pin is used in +17 port mother board.
Power division section:
Pin – 12, 48, 77, 114 – This pin is +ve supply pin of digital section (internal section of this IC) input pins of this IC +5v provide on this pins.
Pin – 61 – This pin is +ve supply pin of standby section SMPS provide the standby (+5v violet wire) voltage of this pin. This is n when power on but system is shut down condition.
Pin – 28 – This pin is input supply pin of host transfer section (int. section of this IC). +3.3volt provide on this pin.
Pin – 97 – This pin is +ve supply pin of analog section of this IC +5v providing of this pin.
Pin -20, 55, 86, 117 – This pins is –ve supply input pins of all internal sections of this.