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Everything posted by Sukhbinder

  1. any one having the service manual for the pioneer DEH-1590UB CD Receiver. thanks in advance.
  2. Looking for the service manual for pioneer MVH-1490UB. thanks in advance
  3. I use a PC SMPS for all my high current projects that need a 5V supply at a high current rating. The SMPS rails are shortcircuit protected at each voltage, there can be some high frequency ripple but you can use additional filter caps for it (by the way the maximum ripple stipulated by the design specs is 1% of full voltage; i measured a ripple of 3-4mV in a 5V supply) to switch on a PC smps just connect the power On wire (green wire) to ground (black wire). the supply is in standby and when the green wire is open or connected to +5V.
  4. Thanks for the help audioguru. I found the explanation for the 3 1/2 system and i've observed that it applies to all DMM with 1999 counts, it says that the first digit is a 0 or 1 because if we have a range of 0.999 then next range will be 9.999 and to measure 1.042, 0.999 is not adequate and in the 9.999 range the resolution is too bad and 1.042 cna be approximated as 1.03 or 1.05 but by using a half digit (0 or 1) the range is 1.999 and the next range is 19.99 so 1.042 can be satisfactorily measured in 1.999. however i can't seem to make out the logic behind the 3 3/4 digits as i have 3 DMMs all with 3 3/4 digits but counts 3260, 3999 and 5999. Still looking for the 3 3/4 logic. got one DMM with 79999 counts but no mention of 4 1/2 or 4 3/4 ??? thanks alot anyway
  5. Some one asked me about the 3 1/2 , 3 3/4 specs for a DMM, i explained it as i found it in a book but i'm myself not completely satisfied with the explanation. Do any of you guys have a good explanation for the above. I do understand the digits specs like 1999, 3999, 5999, 79999 (as i have them on my DMMs) Thanks in advance
  6. I'm looking for the part number for the SMD component with the code 31-OQ written on it (the O and Q have a minus sign on top of them). Its a 6 pin device in a SOT 26-3 or SOT 363 package (not sure of the dimensions). it is used in the power supply section of a MP3 player circuit (seems like some kind of a switching supply regulator circuit). In the circuit this components keeps over heating and the battery drain increases considerably which reduces the operating time. Any idea what it could be. Any link or website where i can look for SMD codes? thanks in advance
  7. thanks for the alternate circuit. I seemed to have a 5V DC supply also from the same transformer (the windings are different) and i will use a ICL7660 to generate a -5 for the negative bias of LM317
  8. Thanks for the inputs, The transformer that was in the supply earlier has taps: 0-9.5v: i'll use for the negative bias for bringing the o/p of LM317 to 0V 0-10.5v: use with a 7805 for 5V supply 0-11.5v: not used till yet (could use for supply for a panel meter) 16-0-16: use with 7815/7915 for +/- 15v 0-32v: planning to use for LM317 variable supply. I could use a lower winding but then the 0-32v goes un-utilized and there are no taps in it. thanks again ;)
  9. We needed some variable power supplies back at my college where i teach and came across some old multi voltage supplies which were dead but the transformers were fine. I planned to make a variable supply using the LM317 but the transformer has a winding of 32Vrms that i plane to use but 32Vrms means about 45V max. Can i use the LM317T for a variable supply, variable from 0V to say 30V. the data sheet specifies the max input-output differential as 40V for the LM317T? I was planning to use two LM317T's in series. the first can drop the voltage from say 45V to 35V along with a series pass transistor for the current boosting and then the second LM317T can work as the variable regulator. The currents needed are max 1A (using it as a lab supply for basic electronics experiments) There is the LM317HV that supports 0-60V but that is a bit more expensive and lower availability version here. Any suggestions for the supply design. I would like to keep the circuitry simple and small. thanks in advance ;)
  10. If you can change the amp ICs being used, you could use the TDA8510J from philips. It is an amp designed for 2.1 speakers and is usually used in Creative 2.1 speakers. The amp has the specs of a 26W BTL + 2x 13W stereo channels. Here's what the data sheet says: The TDA8510J is an integrated class-B output amplifier in a 17-lead single-in-line (SIL) power package. It contains a 26 W Bridge-Tied Load (BTL) amplifier and 2 x 13 W Single-Ended (SE) amplifiers. The device is primarily developed for multi-media applications and active speaker systems (stereo with subwoofer).so it simplifies the design part a lot. works from single supply rails of 15V with maximum 18 V and has a number of protection features like over heating, short circuiting to name a few. supports impedance to 4ohm for subwoofer and 4-2ohm for stereo. refer to the datasheet enclosed for more. but you will need an active crossover for the subwoofer (try googling for linkwitz riley crossover). TDA8510J.pdf
  11. Hi Guys, i have been using a 25W Solderon soldering iron for the past 15 years. i used a fine chisel tip with it, earlier i have been working with normal PCBs, but now since most of the PCB now have become more of SMD type and are much smaller in size, i am planning to get a new temperature controlled soldering iron. We have a distributor of goot products here. I tried finding about weller but no body stock them here due to high prices and less users for such quality tools. Actually there are a lot of cheap Chinese products available here at much lower prices. I found three models from goot, one is Mini-Soldering Stations/ Soldering Controllers PX-501, PX-601 with a power of 80W and temperature range 250-450C (i'll go for the PX-501 as the only additional feature in PX-601 is that the temperature control knob is covered with a protective cover and it has facility to measure leakage current and insulation resistance but i can do without these). both these models are available in antistatic versions The second is a Temperature Controlled Soldering Iron PX-201 with a power of 70W and temperature range 250-450C with a ceramic heater. the temperature setting knob is on the soldering iron itself. however it is not an antistatic product. The third is a Precision Assembly Soldering Iron PX-251AS with specs same as the second one but is an antistatic version and does not have the temperature control on the Iron but in a separate supply as the first PX-501 and PX-601. Although my trusty old 25W solderon iron still works and i have a hot air analog ( the air flow rate and heater can be set by knobs but no digital display) soldering/desoldering station also, if i buy a new temperature controlled soldering iron, which would you guys recommend from the above three choices and is it worth paying the extra for antistatic products?
  12. You cannot add a memory card inplace of the memory chip. the chip you marked is a flash memory chip which readily connects directly with the microcontroller (the other small square chip in the pic). try looking for the data sheet for the microcontroller and see if it supports other storage media (and to what capacity).
  13. You cannot connect a USB drive on a microSD card slot. The specifications and format for a microSD card and USB interface are totally different from each other. A USB has just 2 pairs of terminals, one for the power (the two outer ones) and one for the data (the two inner ones). A USB drive has an inbuilt interface chip with its own clock generating crystal and a flash memory chip. while a microSD card is just a flash memory without any supporting hardware. The supporting hardware for the memory card is on the host side. USB slots are more popular in devices because of the robustness of the devices and the USB protol and standard is a free to use platform while incorporating an memeory card interface will need licensing from its developers.
  14. lab power supplies base on an SMPS donot have much of a surge rating for the current. if you drive a motor (especially a motor from a power tool) , the motor will appear as a short circuit for the supply and most of the time the supply goes into the current limiting mode. To drive heavy inductive loads like motors u need an old fashioned transformer based linear suppl but they are expensive than the SMPS types. some times SMPS based supplies can work as a low cost alternative. in my case i needed a high current supply for my digital projects (voltages of 5V for logic and 12V for relays, etc.) so i used a extra computer 400W SMPS that i had lying around (they are quite cheap these days). so now i have 5V at 30A and 12V at 25A. ;)
  15. We use a CRT setup as a part of our experiment for our students to calculate the e/m ratio of the electron. The experiment is usually referred to as finding e/m ratio using magnetic focusing. The supply to the CRT seems to have some problems and the setup is quite old and no circuit diagrams included. the setup uses a HITACHI oscilloscope CRT. the only thing mentioned on the CRT is TYPE no:95CB31. I was planning to repair the setup but need the CRT pinouts and specs like the heater voltage, current. Any one having any idea about this. could not find any thing on google. ;)
  16. Thanks HtG for the reply. I knew about the fast recovery diodes and their use but was a bit confused about the general purpose rectifier and high efficiency rectifier. May be the high efficiency rectifiers are more preferred in high frequency rectifiers (may be in a switched supply or so). Schottky diodes surely have a lower drop out voltage than silicon diodes. (germanium diodes had lower drops of 0.3V but could not handle high currents like silicon diodes and had a larger reverse leakage current than Si diodes. Also the Germanium devices could not be used at high temperatures or high powers, Si devices work easily at 80C with breakdown till 150C)
  17. what's the difference between 1N5402, HER502, and FR502 diodes? The 1N5402 is a 3A 100V general purpose rectifier diode. The HER502 is a 3A 100V high efficiency rectifier diode. The FR502 is a 3A fast recovery diode. The fast recovery diode is used for damping the reverse EMF in relays or other inductive devices like motors, chokes, etc. The HER502 and 1N5402 are rectifier diodes but i can't seem to understand the difference between the a general purpose rectifier and a high efficiency rectifier. can one use the high efficiency rectifier as a fast recovery diode? what are schottky diodes used for? need some light on these features. thanx :D
  18. Hi guys, I hold a B.Sc.(Hons) and M.Sc. degree in Electronics from the University of Delhi, INDIA. Currently I'm pursuing my Ph.D degree in electronics from the same. I'v been working on conducting polymers based devices specifically solar cells for my doctoral thesis for the past 3.5 years and plan to complete it in 6-8months. This site is of great help to all hobbyists, amateurs and professionals in electronics, and is a great resource for all. ;)
  19. I agree with Ante, the green colour is most probable of Copper. All leads in diodes are made from copper with a tin coating on them to allow for easier soldering. You can try evapourating the blue water as Ante suggested if if its copper you'll find greenish blue crystals of copper sulfate
  20. I tried Google for the service manual but all i could get were payed links. no free downloads. any help here guys ???
  21. In Need of Sony KV-LS21M80 21" CTV service Manual. please post if any one has it. Thanks in advance ;)
  22. Sure you can download it at http://www.audiotester.de/aowv22.exe as an exe file or as a zip file at http://www.audiotester.de/aowv22.zip. These are the demo versions. ;)
  23. heres part2 and part3 AudioTester_v2.2a.b10.part2.rar AudioTester_v2.2a.b10.part3.rar
  24. Spectrum analyzer, Oscilloscope and Wave Generator with the help of a sound card and the audio tester. Just found a piece of software on the internet which i think is worth sharing with you Guys. With the help of a high quality sound card your PC will be an audio lab. You measure frequency responses of loudspeakers crossovers, distortion of any audio equipment and impulse responses of loudspeaker systems. great for audio persons. check out the web page http://www.audiotester.de/mainE.htm. By the way i found a rigged version of the software along with its crack. just check out the attached file. tell your response about the software. ;) AudioTester_v2.2a.b10.part1.rar
  25. Any one having the service manual for the Sony CDX-757MX 10 CD changer with MP3 support. Thanks in advance ;)
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