hybridfree/eevblog-posts huggingface dataset:
Dell ultrasharp u2711, open ? - Page 1
Forum section: electronics / repair

author: onesixright
author_rank: Frequent Contributor
timestamp: September 26, 2015, 09:57:33 am
content: Hey Guys,How do you open a Dell U2711? I have the feet off, but thats as far as it goes. Do you need to pry open the case ?I googled a few Dells, but this model i couldn't find it.I would appreciate some directives!Thanks!

author: wraper
author_rank: Unknown
timestamp: September 26, 2015, 10:16:22 am
content: Quote from: onesixright on September 26, 2015, 09:57:33 amLike every modern monitor. You can use some old credit card or something similar if don't have any special tools.
Syncmaster 943nw(19 inch lcd wide) - Page 1
Forum section: electronics / repair

author: rounsmith
author_rank: Contributor
timestamp: September 25, 2015, 05:47:13 pm
content: Hello to all,got this monitor from recycling i got it on and i saw that was working... i left it there with only power and then plugged vga cable to it and after 3 seconds gone black... So i took the decision to take it apart.Took it apart and didn't saw any bulging caps or such. So i went to test it again to see if it working (did a full teardown plugged and unplugged all cables).After i got it back ,it went first on and after black but i could see image with a flashlight with a high pitch noise coming from the upper right corner(ccfl lamp section).Left it there for 10 minutes and tried it again...now it comes on and i can see the screen is on with a little backlight (i can see but...) and that high pitch noise again.Propably after got it dissambled i tore it? Or is something like transformer fuse or etc?:s

author: retiredcaps
author_rank: Super Contributor
timestamp: September 25, 2015, 09:14:29 pm
content: Quote from: rounsmith on September 25, 2015, 05:47:13 pmSounds like you possibly have a frayed or suspect high voltage connection problem on the ccfl bulb and its wiring.Seehttp://s807.photobucket.com/user/budm/library/Bad%20backlight%20lamp?sort=3&page=1for examples.

author: Rasz
author_rank: Super Contributor
timestamp: September 26, 2015, 03:43:09 am
content: Quote from: rounsmith on September 25, 2015, 05:47:13 pmdoesnt mean they are fine

author: Towger
author_rank: Super Contributor
timestamp: September 26, 2015, 06:24:05 am
content: Caps.

author: rounsmith
author_rank: Contributor
timestamp: September 26, 2015, 08:15:19 am
content: Quote from: Towger on September 26, 2015, 06:24:05 amPropably , will go to my aunt that has esr meter to measure them before taking them apart for no reasonNow i have another problem.Got some other monitor (generic brand, big store in my country brings them rebrands them and sells them). Wasn't turning on , the monitor led that has for turning on was blinking, so i took the decision to take it apart to see for bad caps. I dc'd everything and then i didn't connect that ccfl lamps to inverter and had a hissing sound. Took it 2nd time apart to see that problem. Connected everything and voila everything went working good as normal(monitor was working with no signal then connected to pc for 10 minutes worked no problems at all).The question is now... is that i saw when i was plugging the vga-dvi connector with vga cable on it to the monitor that connector was making some little sparkles...got a bit afraid to be honest. I plugged the monitor with a dvi cable to my pc had same problems.Sparkles maybe be some bad connections , some sort to ground or? Should i investigate further? (I will connect that monitor to my workshop pc so i want everything to be good...).
Help Identify Chip Marked as DE-KOB (Vreg) & SiGE 5004L 430DV (5.8GHz Amplifier) - Page 1
Forum section: electronics / repair

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 25, 2015, 05:10:58 pm
content: this circuit doesnt power up, or shorting out the PSU, so need repair. i'm guessing DE-KOB marked chip is a voltage regulator for 5.8GHz band FM transmitter RTC6705. and marked SiGE 5004L 430DV is the power amplifier... i need datasheet for both but cant find what chip are they, (i only got datasheet for RTC6705). please if you a familiar tell me what chips are those two? thanks.

author: krish2487
author_rank: Frequent Contributor
timestamp: September 25, 2015, 08:57:35 pm
content: Could not find anything on the SOT device.Here you go for the SiGE 5004L

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 25, 2015, 11:55:12 pm
content: thanks thats super 90% helpful as thats the damaged chip Vrail shorted to GND. the other voltage regulator still working 3.3V out.
Whistler ws1080 scanner repaired USB wasn't working - Page 1
Forum section: electronics / repair

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: September 25, 2015, 12:59:45 am
content: Complaint was USB wasn't working, or batteries won't charge. USB port was almost ripped out as radio was dropped. Was able to repair it.Old broken oneNew USB mini B jack fitted to board
How to repair something with a power problem? - Page 1
Forum section: electronics / repair

author: grueni
author_rank: Newbie
timestamp: September 23, 2015, 04:21:32 am
content: I'm a complete noob and watched  all Episodes of Dave... He always mentions "Check your power rails first!".Now I have a problem with a sound system: I've got a Creative: 7.1-Speaker System like this:http://www.chip.de/ii/37708092_7e6bcc0c63.jpgIn the second I power it on, I hear a loud *THUMP* - and the fuse is gone.I opened it and looked at the caps - all caps look quite normal.... Everything looks normal.So now I'm stuck. What are the primary options, if there is a big short in a circuit? Is there a typical way how to debug this thing?The only idea I had would be to build a 50 Hz 5V/AC powersupply and use it instead of the mains to power the thing - to be able to find the short without breaking a fuse.... But this sounds so silly.So what would your next steps be?

author: teksturi
author_rank: Regular Contributor
timestamp: September 23, 2015, 04:31:49 am
content: Ohms lawIf fuse blows, you might want to measure resistance between rail. If there is resistance below what you expect try to find what is causing that. It is usally easy to find what is causing fuse to blow, so this hopefully be fun repair.

author: ez24
author_rank: Super Contributor
timestamp: September 23, 2015, 04:37:18 am
content: Have you tried Youtube? If you do and find something let us know. Also maybe you could make a repair video yourself.

author: PTR_1275
author_rank: Frequent Contributor
timestamp: September 23, 2015, 04:44:04 am
content: Does it have a transformer or is it a switch mode power supply? If you can take a photo of the board, transformer (if fitted) and another photo of the area around where the mains goes in if it is switch mode so we can start pointing out possible failed components for you to test.I've seen many switch mode power supplies where the switching transistors have shorted causing the fuse to blow. Quite often the fuse will blow before the components blow their case so everything looks ok.

author: drussell
author_rank: Super Contributor
timestamp: September 23, 2015, 04:47:31 am
content: Quote from: grueni on September 23, 2015, 04:21:32 amThere are probably shorted transistors in one or more amplifiers but if you can disconnect the amplifiers from the power supply you could check for both positive and negative voltage rails to be sure they are both present and at the proper voltage without the amps connected.Unfortunately we can't give you more specific instructions without knowing what make and model the unit is and/or having clear pictures of the guts of the unit and the circuit boards, etc.

author: JacobPilsen
author_rank: Regular Contributor
timestamp: September 24, 2015, 03:41:49 pm
content: Quote from: grueni on September 23, 2015, 04:21:32 amRather use lighting bulb (filament lamp) (with approximately same current rating) in place of fuse.It will not break, just light...
TV Telefunken TS32D761L5 (17MB25-3 V1) will not start, LED blinks [SOLVED] - Page 1
Forum section: electronics / repair

author: dorus68
author_rank: Newbie
timestamp: September 24, 2015, 01:47:33 pm
content: Hi, I have this TV Telefunken TS32D761L5 (Chassis 17MB25-3 V1) won,t turn on. Only blinking blue LED.I changed almost all the defective (17PW26) source especially electrolytic capacitors. Tensions are correct.I tested the source in OKI TV, and doing very well.Now, I have ridden the source in the TV Telefunken, and alone worked in mode: PC, analog TV. and AUX inputs.DTT shows black screen, and no access MENU. I changed in the MAIN board SMD electrolytic C520 and C600 47Mf,around the tuner, that were wrong and TDT has started. The TV worked two months and now returns to the blue LED flashes.I checked all of the MAIN SMD electrolytic plate and I changed any more. The symptom is the same as before, which had commented.But, if I turn off the TV with the remote control, does not restart, and the LED flashes.I disconnected the keypad and remains unchanged.I checked: tension-all good, the inverter ok.My question is on the flash U132: MX25L1605 , and eeprom U103 : 24C64 that are not corrupt.Someone could send me the dumps if any have? I have not found any respect for any information forum. Thanks!I measured with the oscilloscope, the input signal CVBS_3 pin45 of U138 (MST9WB6GQ-LF), and was upset. The MPEG decoder U104 (CT216T) as not working.Trouble: The 1V8_VCC voltage is too low (1,05V). The U121 controller: LM1117 is defective. Change also: C543 output of U121(100Mf/16V)The EEPROM-s are good. I am going to go up if someone is interested.U132-MX25L1605DM2I(Telefunken TS32D761L5) - Mediafire linkU103-24C64W(Telefunken TS32D761L5) - Mediafire link
HP ZR24W on power-up shows test colors, flickers and turns off - Page 1
Forum section: electronics / repair

author: yutronic
author_rank: Newbie
timestamp: September 24, 2015, 10:32:37 am
content: Hi,my HP ZR24W monitor hes this problem:After I turn it on it shows test colors for a moment and then starts flickering and turns off. I think it burned my graphic card.Any ideas? Please help.
Rigol DM3051 multimeter backlight failure - Page 1
Forum section: electronics / repair

author: matt6ft9
author_rank: Contributor
timestamp: September 22, 2015, 09:03:25 pm
content: I have a Rigol DM3000 series multimeter where the backlight seems to have failed. Without the backlight, the LCD is very difficult to see. But, I am able to go into the menu to the area that turns up and down the backlight intensity, no luck. The contrast (in the same menu area) adjusts well.I took the meter apart and pulled out the LCD module. There are two markings along the edge of the PCB: “A” and “K”. I assume this is the anode and cathode marking for the backlight. Also, there are two beefy (2R2) resistors RB1 and RB2 going to the “K”.I put my handheld meter to the diode setting and then held the probes to the A and K pins. (this will light a typical white LED very faintly) The backlight does not turn on. I considered taking the black bezel off, but I have never had luck with getting zebra strips back on 100% operational. Oh, if you look between the black bezel and the PCB, there is a marking on what I think is the backlight: “GX-LB11230WS-B” Google does not get any hits on that.So, at this point, I’m not really sure what else to try. I’d hate to lose a nice meter due to defective backlight.Matt

author: Macbeth
author_rank: Super Contributor
timestamp: September 22, 2015, 10:05:15 pm
content: Have you actually measured the voltage going to the backlight? If something sensible is there then it would look like replacing the whole LCD panel is in order.Looks like a jellybean part rather than a custom display made just for Rigol. It looks the same as the DM3058/68 displays in which case have a look for a 256*64 LCD.

author: matt6ft9
author_rank: Contributor
timestamp: September 23, 2015, 08:31:36 pm
content: Ok, finally got back to it. There is an LM324 quad opamp on the LCD PCB. I used pin 11 as the common connection for the readings. The Anode side of the backlight measures 24V and the cathode side of the backlight is at 0V.The LCD does not seem to be a standard, off the shelf product. (that I could find)To me, it looks like there are LED strips on each end of the display. My next plan is to use a Dremel tool to cut the black metal bezel off the end of the display. I should then be able to bend down the PCB that contains the white LED’s. (I thought about bending down the black metal, but I thought that would put too much pressure on the LCD itself)

author: wraper
author_rank: Unknown
timestamp: September 23, 2015, 11:38:27 pm
content: Quote from: matt6ft9 on September 23, 2015, 08:31:36 pmAre you crazy? Why do you need to destroy the display with dremel? Just bend the metal hooks holding the bezel into straight position, then remove it. You will have an access to the LCD and after removing it, to the backlight. If you destroy the bezel, LCD won't be properly pressed down to the conductive rubber strips and PCB anymore, therefore you'll need to figure out how to undo the damage done (if you won't completely destroy the display in the cutting process).Anyway, you won't be able to remove the backlight without removing the LCD itself first.
Not really a Repair question HP53131A but a question - Page 1
Forum section: electronics / repair

author: smgvbest
author_rank: Unknown
timestamp: September 22, 2015, 01:29:12 am
content: I was wondering if anyone has looked at being able to upgrade a 53131A to a 53132A?I was looking at the schematics and it's really a Xilinx FPGA and 2 ADC's plus discrete's and the 53132A ROMs. the FPGA doesn't appear to be hooked up to any memory itself to load it so image in it's programmed via a micro at boot.Has anyone given it any thought to doing this? Or know it's not possible?on a side topic, there's a foot print for a math coproccessor. anything know if just adding one does anything worthwhile?
Pace MBT 301 with very faint LCD - Page 1
Forum section: electronics / repair

author: Rutger
author_rank: Regular Contributor
timestamp: September 21, 2015, 09:10:25 pm
content: Hi, any tips are welcome. Got a very faint display on a Pace MBT 301 desolder station, tried to change the contrast & backlight but didn't improve much.Is there a simple led replacement that needs to take place?

author: crispy_tofu
author_rank: Super Contributor
timestamp: September 22, 2015, 02:28:36 am
content: It looks like the backlight isn't working ... have you tried checking voltages
Can You Identify This Xbox 360 Controller Potentiometer? - Page 1
Forum section: electronics / repair

author: seancsnm
author_rank: Regular Contributor
timestamp: September 19, 2015, 08:35:43 pm
content: I'm trying to replace the potentiometers on the analog sticks of an Xbox 360 controller, but I am not sure what kind of pot they use. It looks like a $0.50 part but I just can't seem to find similar pots on Digikey or Google in general. I can purchase full analog stick replacements, but that seems like a pretty big waste considering that the analog sticks in question work perfectly fine (mechanically).A replacement analog stick can be found here:http://www.amazon.com/gp/product/B00B7Y5XVY?psc=1&redirect=true&ref_=ox_sc_act_title_1&smid=AFIC2PTYP66NXAttached are some photos of the potentiometer I want to replace (the component on the left). As can be seen, it is a 10k pot. The problem I'm having is that the angular range over which the pot goes through its values only covers about 60% of the range of the analog stick in the controller. I have no idea why this is, but this is the case for both analog sticks. Older wireless Xbox 360 controllers actually do have the full range, but it looks like the potentiometers changed from that version to the wired version that I just purchased (they are a different color). Opening the potentiometer on the new controller up reveals that the narrower functional region seems to be intrinsic to the design of the pot itself.This is just speculation, but maybe Microsoft lost its original supplier and started making 360 controllers with a different pot without making sure the functionality was identical, or maybe I just got a dud. Either way, I like the satisfaction of fixing things myself rather than going through the hassle of RMA, but I'm not sure what to look for. Any wise insight would be appreciated.

author: picandmix
author_rank: Frequent Contributor
timestamp: September 20, 2015, 08:33:06 am
content: This Ebay unit might suit, there is a pdf on the pot lower down on the page.http://www.ebay.co.uk/itm/Xbox-360-PS2-and-PS3-Joystick-Potentiometer-10K-Thumb-Game-Repair-Replacement-/121645601430?hash=item1c52a49296

author: seancsnm
author_rank: Regular Contributor
timestamp: September 20, 2015, 07:33:48 pm
content: Thanks. It looks like it might be what I'm looking for.For my (an anyone else's) future reference, here's a few links that might be useful:http://www.polyshine.cn/ProductDetail-216.html
Repair: Samsung LED TV - Page 1
Forum section: electronics / repair

author: AnBa
author_rank: Newbie
timestamp: September 18, 2015, 03:56:34 pm
content: Hi,I have a Samsung LED TV (UE39F5300) that fell on the floor from about half a meter high. The screen went "white-ish" with a noticable "dead area" on it. I was able to fix the white hue by reseating some of the cables that go from digital board to t-con board and from there on to "two drivers" below the screen which then go directly to the panel. But the dead area remained. On a closer inspection I found that one of the flex cables that goes from that "driver pcb" to the panel had been damaged (it seems like it had also been burned) and of course this is what is causing that part of the screen to not function as it should (I think there's also a chip on that flex cable).Now I'm 99,999% sure that this is unfixable (apart from replacing the whole lcd panel), but is there any way to replace that flex cable?Pictures:http://1drv.ms/1QLUhH8http://1drv.ms/1QLUk5RIf it is unfixable (which I'm almost certain), is there anything useful I can do with the TV in this condition?

author: mariush
author_rank: Super Contributor
timestamp: September 18, 2015, 04:35:23 pm
content: It's very hard to fix without the proper tools. It's very hard to "glue" the strip with traces to the copper/gold traces on pcb and the panel itself.I guess you would have to buy a second TV with perhaps a damaged panel (scratches, broken glass) cheaply, remove the strip and replace your strip with the strip from the other TV, but like I said, it's very hard to replace such strips.

author: OldSchoolTechCorner
author_rank: Frequent Contributor
timestamp: September 18, 2015, 05:25:18 pm
content: It not going to be repairable, without the right equipment, or new panel and isn't cost effective, as the other end goes to that IC. Best bet is to part it out, as people buy the mainboard, PSU and T-CON board and sell the parts to recover some of the loss

author: wraper
author_rank: Unknown
timestamp: September 18, 2015, 05:48:27 pm
content: There is no "right equipment" to fix this. First of all you won't get the replacement FPC with IC on it.

author: AnBa
author_rank: Newbie
timestamp: September 18, 2015, 06:30:55 pm
content: Yeah, I thought so. I'll probably just sell it for parts. Thanks for the answers.

author: Rasz
author_rank: Super Contributor
timestamp: September 19, 2015, 05:57:37 pm
content: Quote from: wraper on September 18, 2015, 05:48:27 pmwell, that snot entirely truehttp://www.diytrade.com/china/pd/10050717/TAB_Bonding_Machine_for_Repair_LCD_Screen.htmlhttp://www.amadamiyachi.com/products/systems/hot-bar-systems/emeraldand a clip:lots more in related videos
Repairing a Apex plus 2000VA inverter - Page 1
Forum section: electronics / repair

author: Lowku
author_rank: Newbie
timestamp: September 09, 2015, 06:27:45 pm
content: Hi guysI have this inverter that i am trying to rapair. Its a APEX PLUS from TESCOM 2000VA 24V to 230V DC to AC power inverter (see photos). The mains of were connected to the output of the inverter (wrong side). Initially i opened it up and all the mosfets on the (input) BATTERY side were shot, so i replaced them all. I checked all the fuses and but nothing else looked bad. When i plugged it in, it gives a continues beep and red light (meaning fault). when i plug in the AC side the inverter works as it should, but when the AC is removed there is no power anymore.If anyone can help me on figuring out if their might be a protection circuit of some kind that might have blown after the MOSFETS blew or some circuit diagrams that would be very useful.Thanks in advance

author: station240
author_rank: Unknown
timestamp: September 18, 2015, 03:15:33 pm
content: There is a connection to the battery supply to get an initial start voltage, most likely a simple resistor. Start by tracing what components besides the mosfet are fed off the battery. Should be easy enough to follow the PCB traces.
Chinese plasma cutter repair - Page 1
Forum section: electronics / repair

author: Puffie40
author_rank: Regular Contributor
timestamp: September 14, 2015, 08:54:33 pm
content: I have a Simadre CUT50DX that I bought as a non functional device on eBay. The only symptom right now is the O.C. light triggers when the torch trigger is pulled.The air solenoid activates on the trigger as well; the torch I am using is a P80.After dismantling, a visual inspection of the boards reveal no burned or damaged components. I found a shorted diode IC on the middle board, and replaced all of them with like components from DigiKey.The HF diodes on the bottom board tested okay. I have not yet tested the MOSFETs by function, but they did passed a diode test on my multimeter.I am wondering if you have any other suggestions on where to look. So far all the major components have passed testing

author: SteveH
author_rank: Contributor
timestamp: September 16, 2015, 09:06:32 am
content: O.C. light coming on with operation of torch trigger usually means at least one damaged IGBT/MOSFET. Using a diode test won't find them. I find them by using my DMM set to measure resistance. I repair these wretched things as part of my day job. Good luck!

author: Puffie40
author_rank: Regular Contributor
timestamp: September 20, 2015, 06:52:02 am
content: I desoldered the MOSFETs from the board and tested and retested them by this method:https://www.utm.edu/staff/leeb/mostest.htm. They all pass the function test. I also tested the gate resistors, and they are all good too.I searched for Over-Current light on google (What O.C. stands for in the first place), And I found this:http://www.mig-welding.co.uk/forum/threads/over-current-fault-on-cheap-chinese.5218/The guy there mentioned he unplugged a thermistor that was taped on one of the output transformers (The middle board) and the machine started working again.Since mine has a sensor there as well, I'd thought Id remove it and check it out. - turns out mine is a normally closed bimetallic switch that opens at 100 degrees, and it looks like it's stuck open.Well, time to find a replacement and test!
Escort EGC-2230 Function Generator - Page 1
Forum section: electronics / repair

author: mortent
author_rank: Newbie
timestamp: September 18, 2015, 03:58:12 pm
content: Hi,I got an defect Escort EGC-2230 Function Generator from a local school the transformer is bunt and does not output anything.If anyone has one and can measure the AC output voltages from the transformer i would be very grateful.Everything on the power supply except the transformer measures fine.Thanks in advance.

author: Hydrawerk
author_rank: Super Contributor
timestamp: September 18, 2015, 04:03:23 pm
content: Check the voltage rating of capacitors. If there is a 2200uF 16V, then there should be a 12V transformer for example. Is there a integrated voltage stabiliser like 7812 in TO220 package?

author: mortent
author_rank: Newbie
timestamp: September 18, 2015, 04:16:26 pm
content: there is two taps on the transformer each one goes to four diode for rectification one has a 16v cap and the other one three 25v caps.there is two regulators on the board one ha17805 5V and one ha17815 15V.

author: Hydrawerk
author_rank: Super Contributor
timestamp: September 18, 2015, 05:13:59 pm
content: So it might be 8V and 18V on the mains transformer... Or 2×9V.
Help identifying these old SMD compponents, Lexicon PCM80 repair. - Page 1
Forum section: electronics / repair

author: mckenzie
author_rank: Newbie
timestamp: September 13, 2015, 02:07:59 pm
content: Newb to this forum so hello, nice to be here!Hoping someone is good with SMD component identification. My Lexicon PCM80 Digital Effects Processor (made in 1995) VFD display has failed due to a bad cap leaking everywhere. The unit still works but with no display. I've cleaned things up & buzzed out the tracks which miraculously are all ok. Problem im having now is identifying the SMD components that test bad.ZD1 - has the identifier '30' printed on it, obviously some kind of zener but what value?D1 - some kind of diode, it has D3 printed on it ?Also Q1 could be iffy, this has just got LG as an identifier on top?Q2 looks like some kind of regulator & im going to assume its ok. This just has M Y printed on top?There are no schematics for this module hence the guess work. Also finding & fitting a new display module would be very difficult/costly.Thanks for any help

author: Kjelt
author_rank: Super Contributor
timestamp: September 13, 2015, 06:50:26 pm
content: Did you look here?http://www.marsport.org.uk/smd/mainframe.htmThere are many more smd code sources, just have to see which package it is match the code, download the datasheet and check if the connections are right.For zeners double check the voltage with a small current on lab psu and take the highest wattage available in that package if there are more versions available.

author: Len
author_rank: Frequent Contributor
timestamp: September 13, 2015, 08:41:34 pm
content: Quote from: mckenzie on September 13, 2015, 02:07:59 pmIt looks to me like Q2 is a MOSFET for the switching power supply. A regulator would properly be labeled "U" not "Q".

author: mckenzie
author_rank: Newbie
timestamp: September 14, 2015, 02:25:10 pm
content: Thanks for the replies & thanks for correcting my mistakes. I was a bit lazy initially with this as i didn't bother to try to understand how the circuit functions as my knowledge is very limited (obviously!) , I thought i'd just try to replace the components that were bad. So anyway yes, after having a closer look at VFD's in general this part of the circuit looks like a switching power supply for the VFD with Q2 doing the pulsing.The components are all SOT23 apart from Q2. I think I can be fairly sure ZD1 is a 30v zener. D3 looks to be a switching diode (1SS187). Q1 is tricky to identify though, some sources say its a voltage detector (RT9819) & others say it's a standard BJT ? If Q1 was a voltage detector pin 3 would be VDD which is connected to the smd fuse & V+. If it were a transistor pin 3 would be it's base.Sorry for my poor understanding of this, this post should probably be in the beginners section.Thanks

author: marshallh
author_rank: Unknown
timestamp: September 15, 2015, 07:35:36 pm
content: Some more pics herehttps://www.usbid.com/parts/M202SD01H
Laptop lcd 17 inch to a 15inch laptop with CCFL - Page 1
Forum section: electronics / repair

author: rounsmith
author_rank: Contributor
timestamp: September 13, 2015, 07:50:39 am
content: Hello to all,i am a longtime fan of Dave,and i love his Dumpster dive videos(MOAR DAVE PLEASE).So i acquired a nice laptop from work(fried motherboard) so i parted it out 2nd time(someone got ram/hard disk before me).I got the lcd and i didn;t saw any cracks on it and i put it on the shelf along with my other computer pats. Since i was going to purchase a lcd controller board(so i can make it my 2nd monitor) i thought i could connect this lcd to a old laptop my father uses that has same technology(ccfl but 15'inch).I connected it screen comes on backlight is ok(even i didn;'t connect the 17inch inverter but the 15inch one to the 17inch lcd) but screen comes a little reddish.So my question is. This redish color is because the cable is not correct to drive the 17inch lcd or because it;s maybe screen is broke?I just want to know before i buy a lcd controller board and connect it and have a red monitor forever

author: amyk
author_rank: Super Contributor
timestamp: September 13, 2015, 01:16:08 pm
content: "reddish" as in slightly tinted, or is the whole blue channel missing? You can try some test images to determine that:http://www.lagom.nl/lcd-test/If it's just a slight red tint, the CCFL could be worn out, or not receiving enough current since you're not using the original inverter for it.

author: rounsmith
author_rank: Contributor
timestamp: September 13, 2015, 03:18:39 pm
content: Quote from: amyk on September 13, 2015, 01:16:08 pmhmm i will try it out ty for help !
UC10A counter repair - Page 1
Forum section: electronics / repair

author: texane
author_rank: Regular Contributor
timestamp: September 27, 2015, 10:49:37 am
content: Hi,I recently retrieved a malfunctioning uc10a frequency counter. Iopened it and tracked the issue to the icm7226a chipset. This chipsetimplements the core frequency counting and display. I am using thefollowing datasheet:http://www.intersil.com/content/dam/Intersil/documents/icm7/icm7226a-b.pdfThe IC is powered correctly, but I noticed that there is no signal atpin 38 (buf osc out). Thus, I suspect the main oscillator stage to bedefective.When looking at the datasheet p.13, I see that the Pierce oscillatorcaps (39pF) are connected to VDD, not GND. On the actual device, theyare connected to GND. Do you think there is a mistake in the datasheet ?Thanks for your help !

author: SeanB
author_rank: Super Contributor
timestamp: September 27, 2015, 12:38:46 pm
content: Makes no real difference, it just is the load capacitors are just required across the crystal, so where the midpoint is connected makes no difference from the loading point. As a quick test of the crystal unsolder it and solder it back in with the leads swapped. This often does work with old crystals to help them start up and work again. If it does work then you can either leave it in, and it will work for a few years again, or get a replacement one and solder it in.

author: texane
author_rank: Regular Contributor
timestamp: September 27, 2015, 04:11:06 pm
content: Hi,Thanks for the answer and tip. I tried to rewire the quartz but it did not help. Also, I tried with another new one, changed caps, built an external oscillator ... nothing worked. I guess the chipset is dead :/Cheers,
Rigol DS1074Z signal faulty channel 2.  - Page 1
Forum section: electronics / repair

author: newbie_electron
author_rank: Newbie
timestamp: September 10, 2015, 12:59:29 pm
content: Hello everyone, sorry for my bad English. I bought a DS1074Z for about two years now and its out of warranty and i haven't been using much lately. Today after i turned it on, I hooked it up to my function generator, first i thought it was my function generator but after i changed the channel 1 or channel 3 or channel 4, the sine signal is perfectly okay. does anyone ever have any problem like this? I have no idea :/. The channel 2 stills detecting the signal except the trigger is completely fail and the voltage display seems to be jumping all the time.

author: Shock
author_rank: Super Contributor
timestamp: September 10, 2015, 01:22:45 pm
content: Check the warranty isn't it got 3 years?

author: newbie_electron
author_rank: Newbie
timestamp: September 11, 2015, 09:23:01 am
content: So do I have to send them back to the seller or I send them back to rigol company? i bought it from ebay therefore its a little hard to send them back.

author: Karel
author_rank: Super Contributor
timestamp: September 11, 2015, 09:33:45 am
content: Are you sure it's not the probe?

author: newbie_electron
author_rank: Newbie
timestamp: September 11, 2015, 01:07:18 pm
content: I am sure it is not the prob. So and i kinda not trust people by sending it back to Hong Kong to get fixed. :/
Motorola GPN6101A  - Page 1
Forum section: electronics / repair

author: jonshaw
author_rank: Newbie
timestamp: September 10, 2015, 09:36:20 pm
content: please help I need a repair manual, schematic, or parts list to help me identify burnt and o/c resistors. a test sequence would also be useful.Thanks to EEVblog members I was able to obtain information for a previous project.
schematic of unit in question audio Capacitor debate. - Page 1
Forum section: electronics / repair

author: retrotubeguy
author_rank: Contributor
timestamp: September 10, 2015, 08:20:16 am
content: I have attached a schematic of the unit I am blabbing about. I tried this in the original post but the file was too big. The caps of most concern are circled in green , yellow, & purple.Thanks
Repair service for PC/104 CPU module? - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: September 10, 2015, 01:13:49 am
content: Hi all-Does anyone know of a repair service for an old PC/104 CPU module? It's part of some obsolete gear I want to keep running. It won't boot, and gives BIOS beeps but I can't find any info on what the beeps might mean. Part number is Kontron/JumpTEC 1028-0000-30-2. Thank you.-CarlChicago

author: amyk
author_rank: Super Contributor
timestamp: September 10, 2015, 01:51:27 am
content: Is it a BIOS from one of the big companies (Award, AMI, Phoenix)? The beep codes for those are widely available online.

author: plesa
author_rank: Frequent Contributor
timestamp: September 10, 2015, 02:47:15 am
content: Check if the ChipDisk is OK ( readable ). If not replace it with some industrial grade CF card and IDE44 adaptor.Check RAM with Memtest. Measure the 3V battery.Did you tried to contact Kontron?For example Kontron MOPSlcdLX platform is still available.
Testing Driver Chips - Page 1
Forum section: electronics / repair

author: Matt R
author_rank: Newbie
timestamp: September 09, 2015, 06:13:52 am
content: Hello!I often find myself having to test and replace the NJM3773D2 chip. It's also fairly common that I need to replace the NJM3775D2, PBL3775/1N as well as the NJM3771D2 chips.These are used in old stage lights which are no longer being built. Normally, I can repair these rather rapidly. However, I've recently been sent a large case of the logic boards to be repaired. Generally I cannibalize a known working stage light, install the "dead" logic board, and run tests to find which motors don't fire up. However, that's no longer possible.I'm not very good with circuit design and I was wondering if I could get some help here. I want to make a simple circuit where I can fire up one of these chips and test it to know that it works. I do have an Arduino available if that helps any. I also have stepper motors available that match the type used in our stage lights.Any bit of assistance would be so much appreciated as I don't even know where to begin. Circuitry really isn't my thing! I just know how to replace the bad chips.

author: tautech
author_rank: Super Contributor
timestamp: September 09, 2015, 08:35:05 am
content: Welcome to the forum.Not that I could be of much help, but maybe advice.Knock up a block diagram so all watching can understand.Provide a link to any device datasheets.Maybe pics?What diagnostic and repair tools do you have?What are the motors for, pan and tilt?

author: Shock
author_rank: Super Contributor
timestamp: September 09, 2015, 12:25:33 pm
content: Datasheets typically have example circuits in them. That is where you need to start. But ideally you want to get a proper test environment, charge them accordingly so you can afford to buy one to guarantee the quality of your work or get a loaner. This is quite a common occurrence in repair.
fixing a tec 314 scope - Page 1
Forum section: electronics / repair

author: deth502
author_rank: Frequent Contributor
timestamp: September 17, 2015, 10:06:44 pm
content: cant figure this one out, and i know the knowledge on this site is just scary, so im hoping someone can point me in the right direction.i have a tec 314 (manual:http://eternal.sk/hamphoto/TEK_314_SM.pdf)it works fine in the upper timebases, but when you drop below 10mS, i get NOTHING. loses the trace. blank screen.this has been setting in the corner for over a year now. last time i had it out, (reference page 129 in the linked manual) i checked c363 *in circuit* and it seemed a bit out. i thought (hoped) eureka!! this MUST be the problem. once i desoldered it, it tested fine out of circuit, but i continued to switch it out with the new one anyway. no change, didnt help. after that i got frustrated and stacked it in a far off corner.i recently brought it back out and STILL cannot see why the slower timebases are not working. as far as i can tell, anything that would kill it at the slower timebases and not affect it elsewhere should be whatever is connected to contacts 12 and 15, yes?? again, c363 was replaced. c349 checks out close (202nF) *in circuit* but my lcr meter is saying 11-12 ohms (again IN CIRCUIT) i know thats high for an electrolytic, but i dont know if thats bad for this cap. (its a small blue rectangle, not sure if its a dipped ceramic or poly, markings are "ITW 224K 50V") and i dont want to do too much soldering on the board and invite problems if i dont need to.any one have any clue? know somewhere else i should be looking?? something else i should be testing??eta: i HAVE checked the mechanical contacts of the switch and they are working properly (on 11,12,14, and 15 anyway, didnt check them all)

author: BFX
author_rank: Frequent Contributor
timestamp: September 17, 2015, 11:27:39 pm
content: deth502: hi this is my web from where you have SMI have also one of this guy to repair but now I haven't time for that, I hope it will be soonIn my case is lot of bad caps in power supply, but disassembly of this unit is not so easy

author: AF6LJ
author_rank: Unknown
timestamp: September 17, 2015, 11:44:35 pm
content: Are the switches working properly This looks like one of the camsswitch arrangements like in a Tek 465 series scope. Can you verify that the proper switch closures take place?

author: deth502
author_rank: Frequent Contributor
timestamp: September 18, 2015, 01:06:17 am
content: Quote from: AF6LJ on September 17, 2015, 11:44:35 pmyes, i have checked, cleaned, and rechecked the switch, and everything is as it should be. its all actually very clean inside, so the contacts were very clean and tarnish free to start with.
Leader LSG 221B signal Generator Help Needed - Page 1
Forum section: electronics / repair

author: AF6LJ
author_rank: Unknown
timestamp: September 05, 2015, 03:33:10 pm
content: About a year ago I picked up this Leader LSG 221B for cheap. I know the person I bought it from he said "it works but it has this problem"..Well it does have a problem excessive phase noise on the carrier.I have an idea what is going on but need a manual or at least a schematic. I have looked on the net but haven't seen one. I am hoping someone has one stuck back somewhere and ether has a copy or wants to part with it.

author: HighVoltage
author_rank: Super Contributor
timestamp: September 06, 2015, 07:38:42 am
content: Send a request for service manual and schematics to Leader directly. I was lucky before that way but with an older instrument.

author: AF6LJ
author_rank: Unknown
timestamp: September 06, 2015, 01:36:05 pm
content: Quote from: HighVoltage on September 06, 2015, 07:38:42 amLooks like I will have to do that.
replacing dead cordless phone battery.  Can I drop from a 550mAh to a 300? - Page 1
Forum section: electronics / repair

author: gooseEL34
author_rank: Regular Contributor
timestamp: September 06, 2015, 06:01:20 am
content: Hey all.I have an older cordless home phone that has a battery that will no longer recharge. My original battery is marked 2.4v 550 mAh Ni-MH. The new battery is marked Ni-MH 2.4v 300 mHa. the physical size is identical as is the pigtail connector (which makes polarity correct).so basic question.....I know that because the voltage, polarity and type are the same, it should power the phone handset. Since this is being used for a home phone, what will I notice if I drop from 550 mHa battery to a 300 mHa? is there any reason not to use these replacements?phone handset is a SL82318 AT&T and replacements are marked Radio Shack 2302357 and the back does say Fits "many AT&T CL, EL, SL AND TL series phones"I am just assuming I will get less talk time per charge but since these are generally returned to the charging cradles after the call ends (as opposed to staying on the coffee table), I don't think there will be a problem, right???thanksTim

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 06, 2015, 06:14:32 am
content: Yes, you will get less talk time (and listen time for that matter). But, as you say, if you are normally returning it to the charging cradle, then maybe not a big deal.There may be some slight possibility that if you are out at the limits of the operating range, the transmitter may be "starved" for power, but maybe that isn't an issue in a normal situation.

author: SeanB
author_rank: Super Contributor
timestamp: September 06, 2015, 07:04:26 am
content: No problem other than the replacement battery will probably not last as long, as it will be slightly overcharged. Other than that, and the talk time and standby time off the cradle now being roughly half ( great way to limit call length) it will work. You might want to get a spare battery in a year, as the new one will probably only do that if the phone lives on the charger and the charger is the dumb type that always charges the pack. If it is an intelligent charger ( tells you battery capacity and not just low then dead) then it will have a good life.

author: jitter
author_rank: Frequent Contributor
timestamp: September 06, 2015, 07:10:21 am
content: Agreed. Besides, the original battery will have dropped available capacity over time. It most likely already had less actual capacity for quite some time now.However, it's worth checking the manual or battery compartment for a warning. I have an old cordless Logitech rechargeable mouse. This came with 1700 mAh NiMh AA batteries. The battery compartment lid has a warning sticker that says to replace the batteries only with 1500-1900 mAh types. My guess is that it uses a less than sophisticated charge control that will leave smaller capacities overcharged and larger undercharged.
FPC (Flex Printed Circuit) tracks repair - Page 1
Forum section: electronics / repair

author: ecom.gp
author_rank: Contributor
timestamp: September 04, 2015, 09:19:10 am
content: I'm working on a button panel with some non working buttons.As you can see form the pic two tracks are clearly interrupted, but I have no idea of how to deal with this FPC stuff.I'm now considering getting some kind of silver based ink/pen. Any thoughts? Feedback?

author: dundee
author_rank: Regular Contributor
timestamp: September 04, 2015, 11:00:45 am
content: Hi!I would try it with conductive silver!

author: ecom.gp
author_rank: Contributor
timestamp: September 04, 2015, 11:07:52 am
content: Can you suggest any specific product?My main concern is for the mechanical reliability of the bridge.This is a flexible circuit not a regular PCB.If the silver tracks harden, aren't they going to break when buttons are pressed during regular operation?

author: Marc M.
author_rank: Regular Contributor
timestamp: September 06, 2015, 05:26:33 am
content: Yup, silver ink pens is the way to go for repairing flat flex cables. Done many over the years without any issues. I have a Roland U-20 I use for a MIDI controller sitting here. About 20 years ago a section of the keyboard stopped responding. Upon opening the keyboard up I found the flat flex cable that ran between the keys and the main board had several burned traces. Including the collateral damage I think I had to repair 7-8 traces. I picked up a Chemtronics silver ink pen, probably from MCM Electronics back thenSilver Ink Pen @ MCM. I used the pen and painters tape to repair the cable. 20+ years later and it's still working without any issues. But this cable is relatively static and is certainly not seeing any sort of mechanical stresses so that would be more ideal conditions for this sort of repair.Unfortunately, it appears your situation is less than ideal due to the mechanical aspect. The way I would approach it would to be repair the traces with the pen then overlay the top with PET (that nasty plastic they make clam shell packaging out of) or mylar, carefully dressing all the edges to help protect the ink and see how long it lasts. Also, be aware that there are 2 common types of conductive ink pens: Silver and Nickel bearing. I've always used silver ink so I don't know how nickel compares. It's a lot less expensive and might hold up better mechanically compared to silver.These mylar/conductive ink keyboards are some of the cheapest, nastiest designs I've seen for a keypad. In the past I've reverse-engineered them and made a replacement using a conventional PCB and Cherry MX switches. They're cheap, reliable, and I can get custom key caps made for them reasonably to boot!BTW, another really handy use for these pens is repairing automotive window heating grids (rear window defoggers here in the US). I just run down the broken grid line with my DMM set to DCV to find the break, mask it with painters tape, paint over the break with the pen. Rinse and repeat as req.
Crashed hard drive on a Bruker / Siemen SRS3000. Help! - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: September 04, 2015, 11:08:33 am
content: Hello all,I'm trying to recover a hard drive in a XP machine for a friend of mine that controls a Bruker / Siemens SRS3000 X-ray spectrometer. The drive is in a Dell Optiplex computer. So far, I've been able to recover the entire O/S to another drive and get it booting again, but it's missing a lot of files and folders in the SPECplus program files directory - here's all that is left. It looks like all the files beginning with A to S are missing. There's also references in shortcuts that point to subfolders in this directory as well. Hopefully someone out there has one of these - I know it's a long shot...Thanks!Jay

author: Jwalling
author_rank: Unknown
timestamp: September 05, 2015, 10:26:37 am
content: Crap! I made some assumptions based on the data in some of the files.This is not the instrument it goes to. Will start another thread.Jay