Tuesday, June 30, 2015

LITTMANN STETHOSCOPE How to remove and assemble the Diagram

 How to remove and assemble the Diagram _ LITTMANN STETHOSCOPE
The stethoscope is most often used to listen to heart sounds and breathing. There are two basic types of stethoscopes for respiration system diagnostics of the human body. 
Acoustic Stethoscope
Acoustic stethoscopes are familiar to most people. Acoustic stethoscopes maintain their popularity and trust among doctors due to their longstanding use in the medical profession. Although it is taking digital stethoscopes time to catch up, they are rapidly gaining in popularity. However, acoustic stethoscopes are the most commonly used.
Electronic Stethoscope
Electronic stethoscopes function in a similar way as acoustic stethoscopes, but the sound is converted to electrical signals which can then be amplified and processed for optimal listening. Because the sounds are transmitted electronically, an electronic stethoscope can be a wireless device, can be a recording device, and can provide noise reduction, signal enhancement, and both visual and audio output.
ADVANTAGES & DISADVANTAGES
> In Digital stethoscope Amplifiers are used which amplifies the low level signal.
> Data can be stored for further analysis and consultation.
> Heart signal is displayed on the LCD screen.
> In digital stethoscope battery replacement can be tedious.
> They are expensive.
> They suffer from interference when other electronic instruments like cell phones are around.
PRINCIPLE OF OPERATION
The stethoscope is composed of three major parts. The first part is the chest piece, tubes and headset. It consists of a shallow, bell-shaped piece and a clear, stiff diaphragm, which is connected to the metal earpieces by a flexible tube. The bell is used to pick up lower frequency sounds, and the diaphragm is used for higher frequency sounds. When the chest piece is placed on the skin, vibrations within in the body are amplified by either the bell or diaphragm. These acoustic pressure waves then travel up through the tubing to the earpieces and into the listener’s ears. Digital stethoscopes offer new opportunities for computerized analysis of heart sounds. In cardiac auscultation, an examiner uses a stethoscope to listen to these sounds, which provide important information about the body condition. When the heart sounds are displayed graphically, the methodology is known as phonocardiography. As heart sounds are non-stationary signals, it is important to study both their temporal and frequency contents. Recently, with the rapid development of computer hardware and digital signal processing, heart sounds could be recorded and analyzed easily. The majority of these researchers mainly emphasize on the characteristic extraction by frequency-analysis method. Others concern on how to extract the heart rate from a weeping infant through the heart sound signals, and improve signal-to-noise ratio by adaptive filtering way.
Removing the Diaphragm and Cleaning the Chest-piece.
With the diaphragm side up, grasp the rim with the thumbs and index fingers of both hands and roll the rim off the edge of the chest-piece.
Remove the diaphragm from the rim and clean the parts in soapy water or wipe with alcohol. Chest-piece surfaces can be wiped with alcohol or soapy water.
Dry all parts and surfaces thoroughly before reassembly.
Assembly and Replacement of the Tunable Diaphragm
Using your fingertip, apply a small amount of talcum powder to the inside surface of the flexible edge of the diaphragm.
This will facilitate assembly and maintain smooth and quiet low/high frequency alternation.
Snap the diaphragm with your fingers to remove excess talc.
Insert the flexible edge of the diaphragm into the groove of the rim. This is best accomplished by starting with the rim positioned above the legible side of the diaphragm.
Visually examine the ring to ensure that the flexible edge is smoothly engaged inside the rim. If necessary, flex the assembly by pinching the outer rim edge. between the thumb and fingers.
Repeat this flexing procedure after rotating the assembly one quarter.
To attach the rim/diaphragm assembly to the chest-piece, engage the groove of the rim (with the diaphragm attached) around the chest-piece at one point and hold it in place with your thumbs.
Slowly roll the rim around and over the chest-piece edge using both thumbs, moving in opposite directions around the chest-piece.
Visually inspect the edge where the diaphragm engages the rim for uniform containment.
Minor adjustments may be made by slightly pulling and rolling the rim away from the diaphragm, allowing the diaphragm to slip into position.
Avoid extreme heat, cold, solvents, and oils.
Do not immerse your stethoscope in any liquid or subject it to steam sterilization. If disinfection is required, the stethoscope may be wiped with a 70% isopropyl alcohol solution. Wipe and clean with alcohol or soap water.

SAMSUNG UN32D5500RF UN40D5500RF LED TV No-Power Troubleshooting

No-Power Troubleshooting_Samsung UN32D5500RF _  UN40D5500RF LED TV  Fault symptom & checks
NO POWER
> The LEDs on the front panel do not work when connecting the power cord.
> The SMPS relay does not work when connecting the power cord.
> The units appear to be dead.
The IP relay or the LEDs on the front panel does not work when connecting the power cord if the cables are improperly connected or the Main Board or SMPS is not functioning.  In this case, check the following
>> Check the internal cable connection status inside the unit.
>> Check the fuses of each part.
>> Check the output voltage of SMPS.
>> Replace the Main Board.
Detail Factory Option
If you replace the main board with new one, please change the factory option as well. The options you must change are “Type”.
Main board & T’Con board

Saturday, June 27, 2015

SONY KDL-32BX350 KDL-40BX450 SERVICE MODE - LED BLINKING CODES

How to enter Service Mode - Self Diagnostic Mode - LED blinking codes - Sony KDL-32BX350 KDL-40BX450 LCD TV.
The units in this manual contain a self-diagnostic function. If an error occurs, the STANDBY LED will automatically begin to flash.
The number of times the LED flashes translates to a probable source of the problem.
A definition of the STANDBY LED flash indicators is listed in the instruction manual for the user’s knowledge and reference.
If an error symptom cannot be reproduced, the remote commander can be used to review the failure occurrence data stored in memory to reveal past problems and how often these problems occur.
 DIAGNOSTIC TEST INDICATORS
When an error occurs, the STANDBY LED will flash a set number of times to indicate the possible cause of the problem.
If there is more than one error, the LED will identify the first of the problem areas.
Result for all of the following diagnostic items are displayed on screen.  If the screen displays a “0”, no error has occurred .
DISPLAY OF STANDBY LED FLASH COUNT
LED blinking codes
For errors with symptoms such as “power sometimes shuts off” or “screen sometimes goes out” that cannot be confirmed, it is possible to bring up past occurrences of failure for confirmation on the screen:
To Bring Up Screen Test
In standby mode, press buttons on the remote commander sequentially in rapid succession:
INFO => CHANNEL-5 => VOLUME (--) => TV POWER
SELF DIAGNOSTIC SCREEN DISPLAY
Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic screen.
After you have completed the repairs, clear the result display to “0”.
Clearing the Self Check Diagnostic List
1. Error history and Error count : Press the Channel 8 => Channel 0 .
2. Panel operation time : Press the Channel 7 => Channel 0 .

CLICK ON THE PICTURES TO MAGNIFY

AOC LE22H158 LED TV POWER and LED DRIVER SCHEMATIC

SMPS and LED DRIVER STAGE CIRCUIT - AOC LE22H158 - 22 inch LED TV
SMPS & LED DRIVER SCHEMATIC
CLICK ON THE SCHEMATICS TO ZOOM IN

Thursday, June 25, 2015

TRANSISTORIZED SMPS POWER SUPPLY TROUBLESHOOTING – PART2

Now, let’s come to the COLD side [secondary side] of the SMPS power supply.  Please refer the previous post here for more details.  
The secondary side has the output voltages to main board components.
There are 6 voltage outputs:
+14VDC > to audio output IC.
+5VDC > to CPU side of the syscon chroma IC
An other +5VDC > to tuner stage
+B110VDC > to line output transformer [LOT] section.
+27VDC > to vertical scan output IC
+8VDC > to syscon-chroma IC, pins 17 & 49 of IC8873
Let’s discuss all these supply voltages in detail.
+B110VDC:  this voltage should be there all the time when the set is powered ON; provided there is no fault to primary [HOT] side of the SMPS.
+27VDC:  this voltage too will be there all the time when the set is powered ON; provided there is no fault to primary {HOT] side of the SMPS
+14VDC: this voltage too will be there, when the set is powered ON.
Then comes +5VDC [CPU]:  this voltage is the output from a voltage regulator IC; 78L05.  It too will be, and should be there, as the input to this regulator IC will be present when the set is powered ON.  Refer to the circuit diagram.  Input voltage to this regulator IC comes from pin-14 of the SMPS transformer [after rectification].
The +8VDC 7 +5VDC< {the voltage goes to pin36}are switched type, means these tow voltages will be absent when the set it powered On.  These voltages will be present only after we press either the power button on the remote control handset or at the front pane control of the TV set.  Here more description is needed I thinks.
Take the case of these two voltages only.
Refer the circuit diagram.
Consider all these 3 voltages [+5V CPU, +5VDC, +8VDC]
The source of all these voltages are generated by pin-14 of the SMPS transformer, and then rectified by (D604-FR104).  The rectified voltage is then fed to input of the regulator IC 67L05, which in turn outputs +5VDC CPU.  It will be present all the time, because this voltage is needed to CPU section circuit inside the syscon-chroma IC.  Without this voltage, the CPU section circuit within the IC wont work and there by the set too will not response to any external or remote commands.  In short, the set will be dead.  This voltage is not switched type.  Means it will always be present.  The rectified voltage is also fed to collector of a NPN transistor [V507-C8080] and the collector of another NPN transistor [V508-C8050]; switches the +5VDC.  Refer the circuit diagram and try to understand what happens when we Switch ON the set first, after it is plugged to AC mains, and then we press the power button; either at the remote control, or at the front panel of the TV set.
When we first Switch ON on the set:
+B110VDC is OK - present
+27VDC is OK – present
+5VDC (CPU) is OK – present.
+14VDC is OK – present.
But; there will be no 8VDC & 5VDC. Both these voltages are by-passed by transistors V607 & V508 respectively.
Why?  Here comes the point.
Note the circuit with NPN transistor V507-C8080.
Its base terminal is pulled down to 8.7VDC by using a Zener diode [VD8].  By no means the voltage at this pont will go up, than the break-down voltage of this zener diode; ie 8.7V.
But, from where this voltage comes from?
There is 3.3KOms resistor connected to the cathode of this Zener diode; from the 27VDC voltage output. 
Now what happens?
When we press Power  button either on the remote control or at the front panel  control of the set; to Power On; there should be 8VDC to the base terminals of transistor V507 .  But, it won’t be there now.
Why?
Refer the circuit diagram once again.
  The base of this transistor is connected to [Power On] pin-64 of the syscon IC.  The voltage level of this pin will be hight [=H]; when we switch On the set.  Just see, this high voltage is fed to the base of a NPN transistor [Q210-2SC1815].  The collector voltage to this transistor is fed from (+5V CPU), via a serial resistor CR292, and then a LED (power indicator) and an other resistor R291.
As we know, when the base bias of an NPN transistor is at high [H] level, it will conduct and its collector voltage will drop considerably due to load.  Here the emitter of this transistor is grounded.  So, when its base voltage is high [H], its collector voltage sill be low.
  In fact, when we switch On the set by its AC main Power Switch, the system control section voltages to the IC will be present, the voltage at pin number 64 of IC8873 will be high[H], and the voltage at the collector of Q210 will be low, and in turn the base voltage of +8V regulator transistor too will be low.  So this transistor won’t conduct, and there will be no +8V.
Let it be.
  Now come over to the base of V508; the 5VDC controller transistor C8050.
Refer the circuit diagram again.
 Its collector terminal get voltage from the cathode of D604 itself; through resistors R572 & R571.  The base of this transistor is pulled down to 5V by using a 5V6 zener diode, and the base bias comes from the emitter of V507 [+8VDC].
It is clear that the base bias voltage to this transistor will be present only after the +8VDC has been bypassed by V507.  In short, there will be no +5VDc without +8VDC.
When +8VDC is present, +5VDC too will be there, and should be.
In short; the Main Switching Point to these tow voltages are of pin-64 of the system control IC.
  When the voltage level of this pin is high [H], there will be no +8VDC & +5VDC.  When we press the power button, the voltage at pin-64 of the IC will go low[L], the collector terminal voltage of Q210 will go up; and the base voltage of V507 too.
  Now the transistor V507 will conduct (bypass) +8VDC.  The base bias of V508 will go up and it too will start to bypass the +5VDc.
This is the main switching process takes place, when we press the Power button on the remote control.
Please do not mind my language.  I’m not a person belongs to an English speaking country.  Please try to understand the idea I’ve tried to express.
Any comments? Any suggestions?  Please respond.  I'm here waiting.    google.com/+GopakumarGopalan

Wednesday, June 24, 2015

TRANSISTORZED SMPS POWER SUPPLY TROUBLESHOOTING – PART-1

Set dead. AC fuse blows up instantaneously the set is switched ON.
No DC voltage across C507 [main filter capacitor]
The type of SMPS here in discussion is composed of transistors.  This type of SMPS is used with many brand and models of TVs.  Troubleshooting to this type of SMPS is rather easy than related to STR based ones.  If you get the set for repair in dead condition; isolate the secondary +B voltage [110VDC] from the rest of the circuit by anyway.  This voltage is fed mainly to Horizontals Output and Horizontal drive stages.  Now proceed.
No DC voltage across C507 [main filter capacitor] (100 to 250MFD 450VDC)
See the circuit part.  The AC mains voltage is lead to the rectifier section circuit through a line filter choke L501 and a serial fuse.  This voltage is then rectified and converted to DC voltage, by using 4 rectifier diodes.  If any of these diodes has shorted junction, the AC fuse will blow up as soon as the set is switched ON.  Therefore if you see a blown up fuse; be sure that some short circuited component/s at its main rectifier section circuit or the rectified DC voltage line.
The best way to detect this short circuit is to measure the DC resistance across the main filter capacitor terminals.  It should not show a short circuit.  If it does, de-solder out the SMPS drive transistor and measure it again.  If there is no short circuit detected now,; be sure that the SMPS drive transistor has damaged [collector to emitter leak].  Never replace it, and power up the circuit now.  There shouldbe a reason for this damage to the transistor.  Make sure that there is no damage to other associated component/s with it.  It is best practice to replace the other two small signal transistors with new ones.
De-solder out the other two transistors.  Note their numbers and position in circuit.  One of it is PNP and the other is NPN type.  Now check the other components. Resistors, zener diodes etc:-  Unsolder up one end of each component, and measure its characteristic.  If found OK, solder it in place.  You must be patient and concentrate on work.  Hurry up does not go.
See the circuit.  The rectified DC voltage passes through the primary winding of the SMPS transformer; then to the collector terminal of SMPS drive transistor. As we have already de-soldered out this transistor from circuit, there should not be any short circuit to this votage line to ground now.  If it shows, be sure that the SMPS transformer is damaged [winding short between its primary and secondary].  But this kind of fault is very rare.  Sometimes 0.01% or so.  Can’t say never.  Might be!
Now check the DC resistance across the terminals of the main smoothing capacitor.  It should not measure any short circuit now.  Set the meter to Ohms range, and measure this. Never set it to KOhms range.  Suppose still the meter shows a short circuit.  See; there is no SMPS drive transistor in place.  Then which component/s should be suspected?.  Either the rectifier diodes or the ceraminc capacitors connected in parallel across each of it might cause this.  Check all the four diodes for reverse leak.  If any one among it shows a short circuit, replace all four of it at one time.  It will be the best.
Here one main point to recall is, the rectified DC voltage across the main filter capacitor will be higher than the AC input voltage.  If AC input voltage is 220VAC, this voltage will come around 345VDC or more; and it should be. If not, be sure that the rectifier diodes are faulty.  Replace all these four diodes along with the ceramic capacitors connected in parallel with it. Never forget to check these ceramic capacitors.  They too are likely to be faulty. All of it might be 4.7KPf 630VAC.  If all the components are found OK, plug in to aC power; after inserting a fuse of appropriate specs. 3.5Amps 250VAC.  In rare cases, when we power up the set, with degaussing coil connected, the AC fuse blow up.  If so, the degaussing posistor is short circuited, and should be replaced.
Here we can end with the troubleshooting to primary side of the SMPS circuit.  There is not much more to check with this section. 
Beware:  the primary section circuit will be always HOT, irrespective of connected AC mains phase.  So, take care when you work with this section circuit.  Use of a hand glove is recommended.
Troubleshooting the secondary section circuit will be described by the next post here.
NB: check the resistor and capacitor connected across the primary winding of the SMPS transformer; for open or loose solder terminals. (R525 &C516).  These two components are so critical.  Damage to any one among it will result in the failure (short) of SMPS drive transistor; at the instance of switch ON the set to AC mains.  So, look for any damage or loose solder terminals to these components before power up this circuit.  You won’t get any time to check this fault.  So be cautious.
                                       See the second part for more.

Tuesday, June 23, 2015

TDA8873 SYSCON-CHORMA IC – CIRCUIT TROUBLESHOOTING

Some Faults that can occur due to defects to this IC are:
Power does not switch ON.
TV/AV selection is not possible.
Picture lacks black level.
Tuner does not work.
No EHT.
Horizontal Output Transistor fails frequently.
Audio problems.
Out of synchronized picture.
Displaced picture [horizontally]
Before proceed to troubleshoot, make sure that the SMPS section circuit is woking properly and all the secondary voltages generated are present.  Check the +5VDC & +8VDC.  These two voltages are the supply voltages to TDA8873.  If all these voltages are present, and still the IC do not work, we can assume that the IC is defective.  Check the main supply voltage; 8VDC at pin-17.  The 8VDC is supplied to this pin only.  No other pins receives this voltage.  Check this voltage first.
If it is OK, proceed.
If not, check V507-2SC8080 transistor and associated components at the SMPS section circuit. 
Assuming that this voltage is OK;
Check the voltages at these pins; 3,9,36 & 55.  At all these pins, the voltage should be 5VDC.  If absent, check the 5V voltage regulator IC used at SMPS section, IC607-78L05 & transistor V505-C8050 and related components.
Here one point to note is, with the SMPS circuit used here with this circuit; if there is no 8VDC; the 5VDC too will be absent. 
Assuming that all the voltages stated above are Ok; but the IC do not function:
If so; the first check should be concentrated toward the soldering terminals of the IC.  There are 64 pins.  If any of these pins have loose solder, erratic symptoms will be the result.  So; first make sure that these solder terminals are OK; and have no dry solder points.  Normally it will be too difficult to detect a dry solder terminal, as it will be too microscopic for normal vision.  So it will be the best practice to re-solder all these 64 pins; by applying a little more fresh solder to each terminals, without making any solder-bridge short in between adjacent terminals.  Be sure not to apply too much heat for long time, at these termilas, as it might damage the IC.  The soldering should be done as fast as possible; and should be clean.
Now check all the other pin voltages. 
Measure the voltages at SCL & SDA [Serial Clock & Serial Data] pins; 58 & 57 respectively.  Both of this should be around 2.8VDC.  if any of these voltages are either too low or high; the IC is defective.
No repair.  Replacement is the only remedy.
Next check the Power-ON signal voltage present at pin 64.  When you press the Power On button on the remote control, this voltage should be vary to High/Low [4.8VDC.0.5VDc.]
If not; the IC is defective. The system control section inside it does not work properly.
Check the voltage at pin-5.  This is the Reset voltage to IC and should come around 3.2VDC.  if absent; check Q203-A1015 and Zener diode VD201, connected to its base terminal.
Assuming that all the above voltages are normal:
Measure the voltage at pin-13 [horizontal out signal].  It should be about 0.4 to 0.7VDC.  will have an oscillating frequency of ~ 15.625KHz.  if your meter is capable of measuring frequency; you can measure this frequency directly from this point. If this frequency and the voltage at these terminals is abnormal, the IC is defective.
In most cases; measuring the voltages said above will reveal the condition of this IC; whether defective or good.
Click on the schematic to zoom in

Saturday, June 20, 2015

AKAI 14CRM – TROUBLESHOOTING – From My SERVICE TABLE TODAY

Troubleshooting – Akai 14CRM, 14 inch color TV.  No picture – raster OK – no system Functions
The set switches ON, firmware loads properly, raster appears, suddenly goes to AV mode, displaying AV on the screen.  After few seconds, this AV display too will be out, and the set is irresponsive to any external commands, either by remote control or by the front control panel switches.
Powered OFF the set, unplugged it from AC mains, and re-plugged it back to AC, to check whether a hard reset will help.  No effect.  The same thing as before has happened.
IC used as system control-chroma jungle is TDA11105/PS/V3/3/AT2
System memory IC used is 24C16WP
The above mentioned symptom mainly indicates the main system control memory IC fault.  I’ve came across this type of problem, at about 6 months back, with a Panasonic 24 inch CTV.  Here I did recall it.
Anyway; I’ve to confirm the fault before replace the memory IC.  Checked the main supply voltage to 24C16.  OK. 5VDC is there.
Checked the Serial Data and Serial Clock [SCL SDA] signal voltages.  Found fine.  Shows 2.7VDC to each of these two pins.
Checked the voltage to control panel switch board.  OK.  4.87VDC.
Checked all the micro switches for its contact continuity.  3 out of the 6 of it have bad contacts detected.
Replaced all the 6 micros switches to make sure that they are OK.
Now I tried to control the set by the front panel switches.  Do not control.
Checked all the pin voltages of TDA11105; with reference to the schematic diagram.  All the voltages were found normal.
Fault to main system control memory IC 24C16WP confirmed.
Replaced it with a new one.
OK.
There was no other problem detected.
Re-tuned the set to On-Air transmission.  Fine.  Auto-search tuning is ok.  Set auto tunes, locks the channels in programs.

Friday, June 19, 2015

LG LPC-LM530A MP3 - CD CASSETTE – Circuit Diagram

SCHEMATIC DIAGRAM - LG LPC LM530
Used ICs: AN22004A – MN6627933CG – M12L16161A – LC877480 – TDA7468 – LA4663 – KIA6289 – BA3126
Power consumption > 30W
Mass > 2.75kg
External dimensions > (W x H x D) 550 x 290 x 220mm
Output Power > 7.5W x 2
Speakers > 8Ω x 2
Battery Operation DC 12V, eight “D”(R20) batteries (not supplied)
Frequency response > 100 ~18000Hz
Signal-to-noise ratio >59dB T.H.D 0.7%
Tuning Range > 65~74MHz, 87.5~108MHz or 87.5 ~108MHz
Intermediate Frequency > 10.7MHz
Antenna > Telescopic antenna
Tuning Range > 522~1611kHz or 530 ~1610kHz
Intermediate Frequency > 450kHz
Antenna Ferrite bar antenna
Recording System > 4 Tracks 2 channel stereo
Frequency Response > 125 ~8000Hz
Signal to Noise Ratio > 40/45dB (REC/PLAY)
CDP
CONTROL PANEL
TAPE DECK
POWER AMPLIFIER & EQUALIZER
EXPLODED
PWB

LG XC62 LGXCS62F – MINI STEREO SYSTEM – HOW TO RESET – EXPLODED VIEW – Troubleshooting Chart

LG XCS62F - HOW TO RESET - HOW TO DISASSEMBLE
AMPLIFIER
Output Power 30W + 30W
T.H.D 0.5%
Frequency Response 40 ~ 20000Hz
Signal-to-noise ratio 75db
SPEAKERS
Type 1Way 1Speaker
Impedance 4Ω
Frequency Response 75 ~ 17000Hz
Sound Pressure Level 83dB/W (1m)
Rated Input Power 30W
Max. Input Power 60W
Net Dimensions (WxHxD) 144 x 243 x 171mm
Net Weight (1EA) 1.47kg
HOW TO RESET
You can reset your unit to initial status if malfunction occur(button malfunction, display, etc.).
Using a pointed good conductor (such as driver), simply short the RESET jump wire on the inside of the volume knob for more than 3 seconds.
If you reset your unit, you must reenter all its settings (stations, clock, timer)
1. To operate the RESET jump wire, pull the volume rotary knob and release it.
2. If you wish to operate the RESET jump wire, it is necessary to unplug the power cord.
EXPLODED VIEWS
CD MECHANISM
TAPE DECK MECHANISM
SPEAKER BOX
TROUBLESHOOTING CHARTS
FLD DISPLAY
SMPS
MICOM PART
POWER AMPLIFIER
CLICK ON THE PICTURES TO MAGNIFY
                See the Schematics (Circuit Diagram)

Thursday, June 18, 2015

HP pavilion ZE1000 HOW TO REMOVE KEYBOARD – OPTICAL DRIVE – HARD DISK

Keyboard_SDRAM_Hard disk drive & Optical drive removal – Hp pavilion ZE1000 series notebook PCs.
To remove the keyboard and optical drive, proceed the following order:
Battery => Lion 8-cell > F3410-60911
Drive, hard disk [20MB, 9.5mm, IBM (Diablo) ATA100  > 0950-4163
SDRAM, 128mb, PC133 SODIMM(x16) > 1818-8504
SDRAM, 256mb, PC133 SODIMM(X16) > 1818-8635
KEYBOARD > F3420-60913
DVD > F3410-60917
DVD,CD-RW > F3410-60919
BATTERY REMOVAL PROCEDURE
Slide the battery’s release latch, and then pull the battery out of its compartment.
HARD DISK DRIVE
Remove both hard drive retaining screws from the bottom of the notebook.  Carefully remove the hard drive from of the notebook.
Remove all four screws from the tray and drive case, and then remove the drive from the tray.
(If you’re installing a new hard disk drive, install the factory software and O/S on the drive before loading any additional software.)
The notebook has no SDRAM built into its motherboard, but has two slots for removable SDRAM modules in a compartment on the bottom of the unit. (One of these slots contains a module installed at the factory). You can use these slots to expand your unit’s RAM. Use HP PC133 SDRAM modules only, or your notebook will not boot up.
Turn off the notebook: click Start, Turn Off Computer, Turn Off.
Unplug the AC adapter (if present) and remove the notebook’s battery.
On the bottom of the notebook, loosen the screw holding the RAM cover (the cover retains the screw), and remove the cover.
Release the two latches at the sides of the SDRAM module by pushing them gently outward  (away from the sides of the module). When you release the latches, the free edge of the module pops up.
KEYBOARD REMOVAL
Unplug the AC adapter, if present, and remove the battery.
Use the flat-blade screwdriver to carefully pry up the right end of the keyboard cover, just above the Delete key, then lift the cover off of the notebook.
Insert the tabs on the left end of the cover into the slots in the notebook’s case, and then gently press along the length of the cover to snap it into place.
Remove both retaining screws from the top of the keyboard.
Raise the top of the keyboard, then lift the keyboard up and out of the notebook, and lay it face down on the top case, forward of its normal position.
OPTICAL DRIVE REMOVAL
Remove both retaining screws from the back of the optical drive. 5. Carefully slide the optical drive out of the notebook.