hybridfree/eevblog-posts huggingface dataset:
What does "jumping out" a circuit mean? - Page 1
Forum section: electronics / repair

author: komatsu
author_rank: Contributor
timestamp: January 31, 2015, 12:03:41 am
content: I've often heard the phrase "jumping out a circuit" in electronics - but what does it mean?

author: IanB
author_rank: Super Contributor
timestamp: January 31, 2015, 12:05:17 am
content: I think it is actually "jumpering out a circuit"; that is to say using "jumpers" or link wires to bypass a bit of a circuit or to change its configuration.

author: komatsu
author_rank: Contributor
timestamp: January 31, 2015, 12:06:57 am
content: You're right it is "jumpering out a circuit"

author: IanB
author_rank: Super Contributor
timestamp: January 31, 2015, 12:15:33 am
content: FYI, a "jumper" is so named because it can jump across a gap, or jump from one place to another.

author: tautech
author_rank: Super Contributor
timestamp: January 31, 2015, 12:18:25 am
content: Sometimes equipment can be powered by other means and a removable jumper is there for this purpose.

author: komatsu
author_rank: Contributor
timestamp: January 31, 2015, 12:26:44 am
content: On a damaged board, when would "jumpering out" be use? examples?

author: tautech
author_rank: Super Contributor
timestamp: January 31, 2015, 12:33:08 am
content: Quote from: komatsu on January 31, 2015, 12:26:44 amFor an external PSU.Output stages to an external amp for example.Damaged? One would need to know what part if the circuit was damaged.

author: komatsu
author_rank: Contributor
timestamp: January 31, 2015, 12:56:12 am
content: tautech, if for example diodes were damaged?

author: tautech
author_rank: Super Contributor
timestamp: January 31, 2015, 10:19:09 am
content: Quote from: komatsu on January 31, 2015, 12:56:12 amMore info needed.Post a schematic or photo and more explanation of what you are trying to do?

author: kolbep
author_rank: Frequent Contributor
timestamp: January 31, 2015, 10:50:14 am
content: Sometimes if you put caps or led's backwards, they literally Jump Out of the circuitStill haven't found some of them...
DMM Continuity Beeper Stuck On... - Page 1
Forum section: electronics / repair

author: OilsFan
author_rank: Regular Contributor
timestamp: January 04, 2015, 04:25:16 am
content: I have a Klein Tools CL200 Clamp Meter I use at work and it gets loaned out a lot. It was recently returned to me with a malfunction in the continuity test. When I turn the dial and set it for continuity the beeper just sounds continuously. It happens whether test leads are attached or not. It's not uncommon to test continuity of light fixtures at work then be required to check mains voltages of up to 240. I wonder if someone burned something out by having it set wrong? Nothing on the circuit board looks bad. What should I be looking/testing for? Thanks

author: SeanB
author_rank: Super Contributor
timestamp: January 04, 2015, 05:30:01 am
content: Probably arced over inside the switch, or it has a shorted protection diode or MOV on the input. Use another meter to see if the input leads have a voltage on then in continuity mode, depending on the meter it will be between 200mV and 2V. If nothing use the other meter to measure the resistance of the input.

author: OilsFan
author_rank: Regular Contributor
timestamp: January 08, 2015, 12:21:07 am
content: I have just acquired a new Extech EX330 so I'll give a poke around and see what I find. Guess this is why it's a good idea to have more than one meter.

author: whipman
author_rank: Contributor
timestamp: January 08, 2015, 02:43:37 am
content: Or not loan your tools out!

author: OilsFan
author_rank: Regular Contributor
timestamp: January 31, 2015, 07:03:38 am
content: Just wanted to follow up and say that I did not continue to look for a fix for this unit. Upon further inspection I noticed that some plastic hold downs in the case were so worn they were no longer holding the circuit board, and thus the LCD and buttons, in place. Even if I fixed it, it would still not be 100% so I deemed it not worth the effort. I got an EX330 and EX430 both at very reasonable prices. Really like the 430 actually. It was only $3 more than the 330 and is TRMS.
Replacing LED display when original replacement part no longer avail. - Page 1
Forum section: electronics / repair

author: gooseEL34
author_rank: Regular Contributor
timestamp: January 29, 2015, 05:16:57 pm
content: Ok. Here is the image of what I am working with. Unit is a guitar processor from the late 80s.sgx_midbyhondaca77, on FlickrUnit has a rotary data knob and there is a 3 digit LED that shows the patch number 1-128 in the window. The repair part is no longer available from ART. Is this something that I could attempt to fix with a generic part? I know nothing of how these counters work, but I am handy with a soldering iron, Fluke meter and a Scope if need be.I notice I can get a three digit 7 segment LED display on ebay cheap. What parameters should I watch out for?ThanksTim

author: wraper
author_rank: Unknown
timestamp: January 29, 2015, 05:25:11 pm
content: You can stick any led displays (seems to be 3 of them) with the same pinout and right configuration (common cathode or anode), likely will be brighter than old ones. Why do you think it is faulty? I would expect driving circuit to be dead unless it is just one failed segment.

author: gooseEL34
author_rank: Regular Contributor
timestamp: January 29, 2015, 05:32:09 pm
content: When it should read 001 I only get the bottom segement of the digits plus the lower left leg segement of the 1st digit

author: SeanB
author_rank: Super Contributor
timestamp: January 29, 2015, 06:26:40 pm
content: That looks more like dead driver transistors, or an open circuit in a connection to the display, likely broken PCB tracks, dry joints or a cracked DIL resistor array for the one set of drives. Might just be very dirty display sockets as well.

author: jlmoon
author_rank: Unknown
timestamp: January 29, 2015, 06:39:11 pm
content: Quote from: gooseEL34 on January 29, 2015, 05:16:57 pmThose look very much like "Monsanto MAN-7" (were made both in common anode and common cathode flavors) led displays. They are kind of rare but still can be obtained if needed. What are the heights of the segments? If you look on the side of their bodies you might find a manufacturers part number, should help you tremendously.Hope this helps,JM

author: wraper
author_rank: Unknown
timestamp: January 29, 2015, 08:06:56 pm
content: Quote from: gooseEL34 on January 29, 2015, 05:32:09 pmSome dead electronics, VERY unlikely to be faulty display.

author: lowimpedance
author_rank: Super Contributor
timestamp: January 30, 2015, 02:26:09 am
content: As others have said its much more likely to be whats driving the display than the display itself.Some photo's of the inside where the display pcb and connections etc are could be useful.
Real dificul power supply for me - Page 1
Forum section: electronics / repair

author: stoica adrian
author_rank: Contributor
timestamp: January 29, 2015, 10:23:04 pm
content: Hi, there is someone who can't help me with some suggestion about this power supply ,, Power One 17,5A 45V,,.The problem that i have with this is that when i power it sink from mains 8A and it blows the internal fuse. i use a autotransformer so ya i have a large inrush current at the start. I measure all the diode, transistor, bridge rectifier, cap.. nothing at all. I dont have a schematic for this, so i wonder if there is someone with some experience in this model too give me a start point. sorry i not remove the 2 controller for a better view, no time at this moment. The power supply start at 60 -70 V then when the relay is on it sinks a large current and it blow the fuse.

author: tautech
author_rank: Super Contributor
timestamp: January 29, 2015, 10:33:00 pm
content: Identify the SMPS controller IC, get the dataheet and you might find the typical applications listed have the same PSU as yours.
Motorola SJE-1461 Datasheet - Page 1
Forum section: electronics / repair

author: jlmoon
author_rank: Unknown
timestamp: January 29, 2015, 02:45:20 pm
content: I am looking for valid datasheet on a Moto SJE-1461 BJT, from what I can tell, the package type is SOT-32. Would anyone have a older Motorola data book laying around that has this part within? The application is a flyback style inverter supply and I am looking for a suitable (actually better part) for replacement. These are run in pairs in my application.Thank youJM
-12V on tiny ATX power supply is way off - Page 1
Forum section: electronics / repair

author: dentaku
author_rank: Frequent Contributor
timestamp: January 28, 2015, 07:34:06 pm
content: I have a small FSP270-50SNV ATX power supply that has a -12V output that's way off, it measures around -10V.http://www.aerocooler.com/images/PWSP5SNVS_m.jpgAll the other rails seem fine. I know it's not much information to work from but nothing seems burned or bulged and it's so cramped in there that it's impossible to read the writing on any of the parts.QUESTION: Is there anything obvious I should look for to try and figure out why the -12V is messed up but the +3.3V, +5V and +12V seem fine?

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 28, 2015, 08:11:05 pm
content: The -12V rail is considered legacy and unimportant by all modern ATX PSU manufacturers (source: am in the ATX PSU industry). They'll typically use a really shitty inverting boost circuit off the +5V rail. The ATX12V spec allows +/-10% voltage and up to 120mVpk-pkripple, but it's not uncommon to see +/-20% and 200-250mV, even on $100+ PSUs, because no one cares. The only thing -12V is used for in a modern PC is the RS232 port, and most motherboards and serial I/O cards will have their own power supply for it. It also used to be used as the negative op-amp supply rail in some cheap sound cards about 10-15 years ago, but they stopped doing that specifically because the -12V rail was usually so noisy.-12V is expected to be removed from the ATX12V spec in the next major revision, the way the -5V rail was removed in 2003. The only thing that kept it on there so far is that the PCI bus specified a -12V rail. But now that PCI is largely obsolete, and PCIe requires only +12V and +3.3V, the -12V is gonna be up for the chopping block soon.The PSU is probably fine.

author: dentaku
author_rank: Frequent Contributor
timestamp: January 28, 2015, 09:57:36 pm
content: Quote from: Phaedrus on January 28, 2015, 08:11:05 pmI was wondering what the -12V rail was for and why this PSU didn't have a -5V pin.
C&K microswitch Dremel 4000 - Page 1
Forum section: electronics / repair

author: Yago
author_rank: Frequent Contributor
timestamp: January 26, 2015, 01:41:52 pm
content: Trying to find this microswitch for a dremel 4000.It is a C&K LC 6 250VAC, might be my lame Google-Fu, but I can't find one in UK.Cheers.

author: nanofrog
author_rank: Super Contributor
timestamp: January 26, 2015, 06:00:14 pm
content: LC series =Subminiature Precision Snap-acting Switches, and there's a lot of information missing to get the same exact switch (check the downloadable catalog pages to see what I mean). Actual PN is on the long side, such asLCS06A060P00WC(not sure of what you need exactly, just the only LC series I located on Newark).Not seeing C&K offered on the UK site though (Farnell).But if you figure out the actual PN, there's a competitor cross reference link page on C&K's site that could direct you to a suitable replacement you can get in the UK.Convoluted, but if it gets your Dremel operational again, worth the effort IMHO.

author: Yago
author_rank: Frequent Contributor
timestamp: January 26, 2015, 07:11:07 pm
content: Thanks Nano, I'll give that a shot.I do have the full part number, will have another punt in the direction advised.Thanks again
How to JUMPER the G-TAB 2 (GT-P5110) - Page 1
Forum section: electronics / repair

author: WGenius
author_rank: Contributor
timestamp: January 26, 2015, 03:58:57 pm
content: Hi friendsI have a Galaxy TAB 2 10.1 (GT-P5110) which has a broken power button (Key FPCB-Power Volume ASSY - Part Number: GH59-12148A), the flex cable of that button (ASSY) was cut, anyway; my question is:How to turn ON this TAB from the logic board, in other words: which PINs needs to be jumpered to power on the TAB, thanks in advanceNB: I have the service manual (Schematic, PCB Diagrams ...).

author: Monkeh
author_rank: Super Contributor
timestamp: January 26, 2015, 04:10:36 pm
content: Quote from: WGenius on January 26, 2015, 03:58:57 pmHave you considered the ones going to the power button?

author: WGenius
author_rank: Contributor
timestamp: January 26, 2015, 04:16:15 pm
content: No, I wouldn't be asking if I did

author: Monkeh
author_rank: Super Contributor
timestamp: January 26, 2015, 04:18:30 pm
content: Quote from: WGenius on January 26, 2015, 04:16:15 pmYou have the device, you have the schematic, you have PCB diagrams.. why are you not just operating the power button?You have all the cards here, and you're not letting anyone else see them..

author: WGenius
author_rank: Contributor
timestamp: January 26, 2015, 04:25:05 pm
content: Well, the service manual is available online @ cpkb.orgplus, I don't fully understand the schematici'll post some pictures.

author: WGenius
author_rank: Contributor
timestamp: January 26, 2015, 04:27:34 pm
content: Power & Volume Key schematic

author: WGenius
author_rank: Contributor
timestamp: January 26, 2015, 04:31:26 pm
content: That's the power&volume button

author: Monkeh
author_rank: Super Contributor
timestamp: January 26, 2015, 04:40:46 pm
content: Short pins 1 and 2 of HDC500. It may be easier to go for the appropriate pads of C517 and ZD500.Try to get those right or you'll break things. I can't tell from those files which side of the components to go for.

author: WGenius
author_rank: Contributor
timestamp: January 26, 2015, 05:16:53 pm
content: Quote from: Monkeh on January 26, 2015, 04:40:46 pmThank you Monkeh these are the right pins (1 & 2), at first I want to try these two pins but I asked to be sure, thanks again, you're the man
crt tube for oscilloscope leader lbo-315 - Page 1
Forum section: electronics / repair

author: ayante505
author_rank: Newbie
timestamp: January 23, 2015, 08:18:38 pm
content: I live in Guatemala an extremely poor country, I have a oscilloscopio brand leader buy on ebay but the tube CRT damage during transport need to get in touch with someone who sells me monitor this in the united states of america, really do not want pull the oscilloscope, is a great machine and deserves many more years of use.Monitor numbers are1g and 3e180044md541locate the parts on ebay but can not find it and I've searched the web. please,

author: HighVoltage
author_rank: Super Contributor
timestamp: January 25, 2015, 04:05:10 pm
content: It will probably be very difficult to find a CRT replacement for this scope.I have one of them and it always works perfectly. Usually something else will fail, before the tube goes bad.Leader has stopped a long time ago to supply parts for these scopes.

author: oldway
author_rank: Super Contributor
timestamp: January 26, 2015, 03:04:59 pm
content: QuoteIt does not seem to be a valid type number of a CRT.Without the correct type number, you will never find a replacement CRT.Look better on glass of the broken parts or look after a schematic or a repair manual.It's perhaps a 150CTB31 Toshiba, but I am not sure of it.http://tubedata.tubes.se/
Agilent Power Supply 5 Band Color Coded Fuses? - Page 1
Forum section: electronics / repair

author: AB2ZI
author_rank: Newbie
timestamp: January 22, 2015, 12:39:42 pm
content: I'm posting this for a fellow ham on the Yahoo Amatuer Repair forum:---------------------------------------- His Message ----------------------------Guys,I found an issue with my Agilent PS. The ciruit board has two fuses and they are both open for sure. Both are placed close to each other and are identical in markings. I am not able to identify the rating of these two fuses. The fuses look similar to 1/2W carbon resistors and are color coded Brown, Black, Gold, Gold and White. I could not find such fuses in "LittelFuse" catalog. What could they be? Any suggestion?73AB3EH----------------------------------------end of message---------------------------Anyone have any information I can pass along?Thanks,Kevin AB2ZI

author: VK5RC
author_rank: Unknown
timestamp: January 22, 2015, 07:58:50 pm
content: I was recently repairing my old 6644 (~2000 MY), could they be zero ohm resistors? In my PSU the fuses are green. IF it is a 66xx or 65xx series PSU note that the schematic has parts for most models on the one diagram, you need to refer to the 'parts list' and 'correct ' the schematic. Even then there are differences!What model and any photos?

author: AB2ZI
author_rank: Newbie
timestamp: January 22, 2015, 10:21:50 pm
content: Quote from: VK5RC on January 22, 2015, 07:58:50 pmlab grade power supply model E3633AKevin AB2ZI

author: AB2ZI
author_rank: Newbie
timestamp: January 23, 2015, 03:01:12 pm
content: Quote from: VK5RC on January 22, 2015, 07:58:50 pmHere's a photo of the unit and the specific parts circled...

author: wraper
author_rank: Unknown
timestamp: January 23, 2015, 03:13:22 pm
content: They are fusible resistors. They do not have current rating, only resistance and power in Watts. Therefore you should read the resistance according to the color bands. Considering size they should be 1W or maybe 2W.

author: wraper
author_rank: Unknown
timestamp: January 23, 2015, 03:20:02 pm
content: 1 ohm 5%. Hard to say about what last white band means, probably power rating, this however is out of standard resistor color coding. This resistor is 4 band + 1 something additional, not standard 5 band coding. In 5 band coding, third band cannot be gold or silver (multiplier).Edit: had a look into datasheets, that white band could mean nothing more than particular resistor series.http://media.digikey.com/PDF/Data%20Sheets/Yageo%20PDFs/FAE%20Series%20Spec.pdf

author: AB2ZI
author_rank: Newbie
timestamp: January 23, 2015, 04:57:31 pm
content: Ok, thanks for the information which I will pass along...All the best,Kevin AB2ZI
Xtronic x8060xts - Page 1
Forum section: electronics / repair

author: b1406
author_rank: Newbie
timestamp: January 15, 2015, 07:48:41 pm
content: HiHave a xtronic x8060xts,I put it by mistake on 220v line.I unplugged it very fast but C5 capacitor is blown and I cant see it valueCan any one help me to find its value.Thanks

author: tautech
author_rank: Super Contributor
timestamp: January 15, 2015, 10:36:24 pm
content: Quote from: b1406 on January 15, 2015, 07:48:41 pmPhoto?

author: b1406
author_rank: Newbie
timestamp: January 22, 2015, 02:11:28 pm
content: HiHave a xtronic x8060xts,I put it by mistake on 220v line.I unplugged it very fast but C5 capacitor is blown and I cant see it valueCan any one help me to find its value.ThanksHere are the pics
S.R.CAP. MPX/MKP X2 - Page 1
Forum section: electronics / repair

author: benjzet
author_rank: Contributor
timestamp: January 22, 2015, 01:36:31 am
content: Good Afternoon All,I am a bit stuck.I have to replace this cap- S.R.CAP. MPX/MKP X2 0.47uF k 280vFrom this website:http://www.sr-cap.com/en/product_view_64_188.htmlIt's the middle of the three shown (the two pin one).I am seeking a suitable replacement, I have checkedwww.jaycar.com.au& I don't mind buying via the internet.Any suggestions?.Thank You.

author: wraper
author_rank: Unknown
timestamp: January 22, 2015, 08:41:52 am
content: Just buy ~275V or 305V X2 rated capacitor with right terminal spacing. 280V is not common at all.
Why volatge is changing? Fixing power supply. - Page 1
Forum section: electronics / repair

author: nadona
author_rank: Regular Contributor
timestamp: January 21, 2015, 12:48:25 am
content: I am fixing the power supply of LeCroy LC584AL oscilloscope.It is a switch mode power supply which outputs several voltages.The problem is -15V output is changing to -21V in about 5 minutes and and keep going lower about 1mV per 10 seconds. I turned off after 10 minutes. If the scope is turned off when it gets over -21V then I have to wait a few hours to turn on the scope again. If I turn on the power supply right after it starts a few mV below where it turned off.What component behave in the switch mode power supply this way when it goes to bad?Thank you very much in advance. Incorporated the definition of "moment" & "slowly"

author: c4757p
author_rank: Super Contributor
timestamp: January 21, 2015, 12:49:33 am
content: Define "moment" and "slowly".

author: nadona
author_rank: Regular Contributor
timestamp: January 21, 2015, 12:56:21 am
content: Quote from: c4757p on January 21, 2015, 12:49:33 amSorry.Incorporated the definition of "moment" & "slowly" into my original post.Thank you for pointing it out.
Macbook Air power supply - unreliable charging - Page 1
Forum section: electronics / repair

author: salil
author_rank: Regular Contributor
timestamp: January 24, 2015, 02:10:18 am
content: I soldered a genuine magsafe1 connector to a 15v/3A DC Toshiba power supply I had lying around in an effort to have a cheap 2nd power supply for my Macbook Air 11" 2013. I'm also using an Apple magsafe 1 > 2 adapter to make this work. I've been using it for a couple months and usually it works, butsometimes I get the message "not charging" in the OS X status bar despite the power supply being connected.Usually plugging and unplugging the power supply a couple times fixes this (sometimes I also have to unplug the power supply from the mains).The bigger problem is that sometimes I'll need to leave my Macbook plugged in and running while I'm not there, only to findthe battery is completely drained when I come back.The LED on the magsafe1 connector is erratic in behavior, it frequently doesn't shut off when I unplug it from the Macbook. I've heard of people having this same issue with the official Apple magsafe2 power supplies but I haven't run into any issues with mine. I tried cleaning all related connector contacts with no change in symptoms. Does anyone know what's going on here? Any help is greatly appreciated.

author: peter.mitchell
author_rank: Super Contributor
timestamp: January 24, 2015, 02:16:43 am
content: the macbook won't charge unless it's less that 96% charged, also, if there is excessive ripple or voltage sag it won't either.

author: salil
author_rank: Regular Contributor
timestamp: January 24, 2015, 02:28:02 am
content: Quote from: peter.mitchell on January 24, 2015, 02:16:43 amThanks, I've encountered this problem at a variety of charge levels. Last time I did it was around 20% charge. I haven't checked the power supply for ripple or sag as I don't have an oscilloscope handy, but the Toshiba power supply was originally for a (different) laptop, so I would think it would provide clean enough power?

author: peter.mitchell
author_rank: Super Contributor
timestamp: January 24, 2015, 03:15:57 am
content: yeah, should be clean enough, they are fairly tolerant, i'd double check your soldering.
New (2nd Hand) Car Radio with Strange LCD Problem - Page 1
Forum section: electronics / repair

author: kolbep
author_rank: Frequent Contributor
timestamp: January 14, 2015, 04:44:45 pm
content: Hi Guys.I scored a car radio off a South African Auction Site, for R250.00...Only after I received the radio (Today) did I realise what a score this indeed was. The Radio itself has built in DVD Player, Bluetooth, GPS, MP3 Player, Movie Player, Clock, Reversing Camera Input, Canbus Interface, etc etc etc and (of course) a Radio.There was1 problem listed by the seller, that the screen randomly goes off.I played with the radio a bit, and it is indeed random that the screen goes off,but it is not predictable. What is even stranger, is that if I put a DVD in, or choose a Mode,the screen will show "DVD" or whatever in the corner, then will start fading out (or something like that), changing mode, or doing something again, and it does the same again.Now that I have screwed it into the dash, this problem is almost completely persistant.Here is a video of what the screen is doing (I remember something else doing this once, but I cannot remember what)http://youtu.be/BWmYT25YPM8Can anybody throw me some suggestions

author: JVR
author_rank: Regular Contributor
timestamp: January 14, 2015, 08:29:38 pm
content: That looks like whatever is driving the LCD resetting. Open it up and look for obvious problems, as well as stuff getting hot. IIRC they have a ribbon that goes to the LCD that gets damaged easily if care is not taken on install.

author: Wilksey
author_rank: Super Contributor
timestamp: January 14, 2015, 09:25:14 pm
content: Maybe a load issue or unwanted feedback?Check the caps etc first

author: kolbep
author_rank: Frequent Contributor
timestamp: January 15, 2015, 07:06:44 pm
content: Pity, it is a lot of SMD Electrolytic caps inside.Will need to order some before I continue with that.I did replace the 4700uF cap on the input though. No differenceThe strange thing is that if I press the NAV button, that part works the whole time, and I can access the menu, settings,etc. But then when I press the DVD/Radio/Etc buttons, it does the switch over, flashes the text overlay in the top corner, and then does the funny screen thing (most of the time).But then when it does come right(by itself), it works fine for a long time.All the connectors were seated fine.Oh well, what can i expect for that price..p

author: tibimakai
author_rank: Contributor
timestamp: January 16, 2015, 07:49:21 pm
content: Maybe, you have a bad solder joint somewhere, use a hair drier, freeze spray to locate the problem area/component.
car stereo not turning on - Page 1
Forum section: electronics / repair

author: Porto
author_rank: Contributor
timestamp: January 15, 2015, 02:24:39 am
content: Hello,For 2 years already I have here a car stereo laying around which won't turn on anymore.It's a 1-din, China made no-name thingy with a 7" foldable touch display, which in whole worked quite good!The standby LED is lit when on 12v power but it won't go out of standby.The switch itself is working.Is this a classic case of a malfunctioned cap you think?Thanks in advance.

author: wraper
author_rank: Unknown
timestamp: January 15, 2015, 03:10:06 am
content: Rather dead flex. Capacitors do not die very often in such situation, this is not PC monitor. And not with such kind of defect.

author: Porto
author_rank: Contributor
timestamp: January 16, 2015, 04:55:49 am
content: Thanks for the reply.I haven't check the flex yet so I'll do that.

author: aargee
author_rank: Frequent Contributor
timestamp: January 16, 2015, 05:14:22 am
content: I know this is an obvious question but you do have both the main 12V (IGN) and the Acc 12V connected to 12V?

author: Psi
author_rank: Super Contributor
timestamp: January 16, 2015, 06:19:14 am
content: Bad caps would definitely be something i would suspect.I've seen brand new PC motherboards where all of the caps have leaked after being sit on the shelf for 6 months. (zero use, just sitting on the shelf).Really bad electrolytics will swell up and leak from ambient temp!!

author: Falcon69
author_rank: Super Contributor
timestamp: January 16, 2015, 06:31:08 am
content: if it is an older model, you may need to connect the emergency brake wire. The older models would not turn on the displays (for fear of operating a dvd movie in drivers view) in the US unless that wire was connected. I can't remember if that wire needed to be grounded or a shift from ground o +12 volt pull-up, or just connected to +12v pull-up. need to check the install instructions.

author: Porto
author_rank: Contributor
timestamp: January 16, 2015, 02:32:22 pm
content: Hi,yes, both constant 12v and ignition 12v are connected. It didn't work one day in the car where it did work the day before.After that I tried on the workbench with a 13.8v power supply but it just stays on standby.It is not only the display which is not turning on, it's the whole radio.Maybe the current is first supplying the display, via the flex, and than the tuner itself, so it already blocks at thedisplay not getting power?!There are no eletrolytics in there, only SMD. It's not a very old radio, it has navi, BT, DVD etcI just found a brandname, it's a Meos MC701B, year 2008... never heard of it though.
Fluke 87-3 goes crazy when backlight is turned on - Page 1
Forum section: electronics / repair

author: commerou
author_rank: Contributor
timestamp: January 12, 2015, 11:16:25 pm
content: HiSo the titel describes it pretty well.Have any of you guys had the same problem and know what might cause this phenomenon.Sometimes it freezes with no segement lighted in the display.Furthermore, the battery warning shows up when the backlight is turned on and it does not f*ck up. I have checked the battery.Here is a video that will show a bit of the problem:Best regardsCommerou

author: retiredcaps
author_rank: Super Contributor
timestamp: January 13, 2015, 12:19:55 am
content: Questions.1) What is the current draw when the backlight is on? I don't have 87 III, but I suspect normal current draw should be around 25 to 35mA with the backlight on.2) Are you the original owner?3) Did this problem just start happening?

author: retiredcaps
author_rank: Super Contributor
timestamp: January 13, 2015, 01:00:53 am
content: Take a look at your rotary switch for debris and dirt. See modemhead's blog entries.http://mrmodemhead.com/blog/fluke-83-iii-rotary-switch/http://mrmodemhead.com/blog/fluke-83-dmm-repair/

author: ModemHead
author_rank: Frequent Contributor
timestamp: January 13, 2015, 01:35:53 am
content: It acts just like a battery with high internal resistance. Check the battery again, this time under load.For reference, normal current draw is around 0.81mA on VDC, 0.96mA on VAC. With backlight on, about 26.10mA.

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: January 13, 2015, 09:14:24 pm
content: Quote from: commerou on January 12, 2015, 11:16:25 pmYou spelled "title" wrong, no excuses for bad spelling on a computer.
I need help identifying the value of a resistor that has lost it's magic smoke - Page 1
Forum section: electronics / repair

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: January 13, 2015, 06:16:30 pm
content: My dad got one of those rechargeable USB battery packs and it recently failed, on opening it I found a charred resistor that was hard to read. I managed to make out 1R but the number after the R was hard to read, it looked like it could be either 1R5 or 1R9. I tried to use a soft brush to make it easier to read but that just made it worse, any guesses as to the value?The link is a pic of the resistor after the brush attempt :

author: Skimask
author_rank: Super Contributor
timestamp: January 13, 2015, 06:47:49 pm
content: What might help is if you posted the make/model/identifying information of the unit you're playing with.Somebody else has the same thing, maybe they'd be good to ya, crack it open, and see what their non-charred resistor reads...

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: January 13, 2015, 07:39:02 pm
content: Quote from: Skimask on January 13, 2015, 06:47:49 pmIt was a freebie so i don't have the model# but the make appears to be "Brookstone", Here are some pics of the casing of the unit, ignore the "north american td seminars" bit, that was the event that my Dad got it at:if someone has one and is willing to take it apart the clear plastic part comes off with a spudger, and then there are 4 #0 phillips screws under the label on the end with the USB ports to remove the black piece.
DVD player Troubleshooting (what to do next?) - Page 1
Forum section: electronics / repair

author: lightray03
author_rank: Newbie
timestamp: January 12, 2015, 01:57:58 pm
content: hello im a newbie troubleshooter for electronics, and an ECE student,we have a dvd player in house, and when my parents tell me that our player is turning on its on/off state,i try to repair itat first i discharged the filter capacitor and replace it with a new one,and test it actual but i forgot something the output of the powersupplyit has wrong inputs to the board next to it, pls refer below (sorry if i have no screenshots/picture)+5v gnd +12v -12v (INPUT supply to the board-12v +12v +5v +5v (Output from the power supply)before that i noticed the FR diodes are broken and emits a smoke, i replace all the FR diodes,but still nothing, it has supply, but what makes me think is that rather than 5v and 12v it outputs 15 and 20vbut when i tip the probe to the board and the power supply, it output 5v and 20vwhen i tried to replace 431 transistor still nothing happens it does have supply but does not turning on,(sorry for my bad english) please help me in what to do nextUPDATE:I've checked all the diodes on the main board and the transistors as well, and they are all good, i've fixed the supply andsupplied the board with the correct voltage,now the problem is, it plays and turn ON but when the movie plays or the inserted disk plays, it suddenly pause and leave the LED display on but having no power on the DVD/CD DriverModify message

author: pedroteck
author_rank: Contributor
timestamp: January 12, 2015, 10:11:43 pm
content: Hi .The easiest thing i would do is first check the mechanical system of the drive .If everything good try tracking back the drive's motor supply from the psu output and check if the components are good .
power supply BK1550 - Page 1
Forum section: electronics / repair

author: J4e8a16n
author_rank: Regular Contributor
timestamp: January 08, 2015, 12:14:58 pm
content: Hi,The Current Limiting feature does not work anymore on my 2 years old BK1550 Precision power supply. I paid 160$ on Digikey and I wonder if it woth the effort.I am looking at the schematic helplessly.Thank for your attention,Jean Pierre

author: mij59
author_rank: Frequent Contributor
timestamp: January 08, 2015, 01:43:22 pm
content: Hi,Of course its worth the effort.Start by opening the power supply and look for clue's e.g. bad solder joints, lose connectors, burned components etc.Please post some photo's of the pcb's .Check the supply voltages e.g. 9V+, 9V-, VCC, VREF .The opamp U3A and the opto coupler PC2 are part of the current limit function .Got page 2 of the schematic ?

author: J4e8a16n
author_rank: Regular Contributor
timestamp: January 08, 2015, 09:20:46 pm
content: >Check the supply voltages e.g. 9V+, 9V-, VCC, VREFFor the lm358?Unfortunately I have open the PS for photographs.If you dont need more photographs, I will put the parts in place to take the readinds.JP

author: mij59
author_rank: Frequent Contributor
timestamp: January 09, 2015, 06:53:49 am
content: Quote from: J4e8a16n on January 08, 2015, 09:20:46 pmWhy is this a problem ?Did you measure the supply voltages 9V+, 9V-, VCC, VREF ?

author: J4e8a16n
author_rank: Regular Contributor
timestamp: January 11, 2015, 06:07:07 pm
content: Here are the voltages.The main output voltage vary under load. For example 2.9 volts & .03A on a 12 V light goes to 1.6V.A better photograp of the board.JP

author: mij59
author_rank: Frequent Contributor
timestamp: January 12, 2015, 12:13:37 pm
content: Quote from: J4e8a16n on January 11, 2015, 06:07:07 pmSo there's also a problem with the output voltage of the power supply.Sorry, but no relevant information is presented, non of my questions are answered.Can not proceed this way.

author: J4e8a16n
author_rank: Regular Contributor
timestamp: January 12, 2015, 12:35:20 pm
content: Hi,>Are not your answers about VREF VCC etc. in the pdf file uploaded?>Did you measure the supply voltages 9V+, 9V-, VCC, VREF ?Answers about the multiples vref vcc and 9 volts on the schematic in the pdf in the --Reply #4 on: January 12, 2015, 05:07:07 AM »-- .+9 -9 8.99+9 3.3vcc 12.13 12.17VREF 1.932 4.5 2.559JPD
Sola 620RM 2000VA Service data - Page 1
Forum section: electronics / repair

author: RJFreeman
author_rank: Regular Contributor
timestamp: January 12, 2015, 12:02:54 pm
content: I have a couple of Sola 620RM 2000VA UPSesthey both generate 240V from teh battery pack when I press the On button but then shut down as soon as I release it.while I have had a quick prod around and seem to be getting 5V on the CPU/controller card etc and power capacitors seem to be ok, charger is charging the battery pack ok, however with a 100V DC battery pack I am reluctant to prod around too much further without a service manual/schematic.So long shot I know, but does anyone have any service information for one of these?
HG 5502 scope repair - Page 1
Forum section: electronics / repair

author: pedroteck
author_rank: Contributor
timestamp: January 10, 2015, 11:20:06 pm
content: Hello everybody here.Just found the forum on tapatalk and decided to join in.Anyways , i have recently got an old scope from a friend .I decided to check a pwm ic output with it and i accidentally shorted some pins with test probe .Now i get this on the screen (see bellow)i checked the probe resistance and its about 400 kohms.could the problem be related to the probe ? Or worse?

author: tautech
author_rank: Super Contributor
timestamp: January 10, 2015, 11:57:55 pm
content: Welcome to the forum.What waveform does the Cal output on the scope display?

author: pedroteck
author_rank: Contributor
timestamp: January 11, 2015, 12:24:45 am
content: Hi and thanks for the quick replay , i must be lucky here .Is this the one on the picture ?Also what is the normal probe resistance please ?

author: tautech
author_rank: Super Contributor
timestamp: January 11, 2015, 08:47:43 am
content: Yes.This Cal output will produce a 1 KHz 1 V peak to peak square wave.It is used to calibrate a 10x probe only.The trimmer of the probe compensation is to be adjusted for a perfectly shaped square wave display.So adjust the vertical attenuation for close to a full vertical display and timebase for ~2 div period (0.5 mS (500 uS)) and adjust the probe trimmer.So a 200 mV/ div setting should display 5 div high for 1x probe and 20 mV/div setting will display 5 div for 10x probe.Understand all this and it will indicate if your probes are OK.

author: pedroteck
author_rank: Contributor
timestamp: January 11, 2015, 05:53:41 pm
content: Ok man.I have assembled the scope , i will check the cal signal and be back with news.

author: pedroteck
author_rank: Contributor
timestamp: January 11, 2015, 09:35:14 pm
content: Hi i have checked the 1v cal output and it actually showed up on the screen .I dont how it happened because before desassembling the scope i could not display anything.Thanks for the time man .
Whirlpool Duet GEW9250PW0 dryer no start fix - Page 1
Forum section: electronics / repair

author: reagle
author_rank: Unknown
timestamp: January 11, 2015, 03:24:26 pm
content: Just posted a writeup of a Whirpool Duet dryer repair.http://kuzyatech.com/whirlpool-duet-gew9250pw0-resurrectionCan't say I like their design methodology, but it did work for eight years before failing.Hopefully this helps others avoid buying the overpriced spare parts

author: SeanB
author_rank: Super Contributor
timestamp: January 11, 2015, 03:44:49 pm
content: So a dead LED will cause you to toss the entire board in most cases. Lovely design to save a wire or two and a half dozen diodes on the display board.

author: reagle
author_rank: Unknown
timestamp: January 11, 2015, 03:46:06 pm
content: Yep, or even two boards if the tech is in a hurry

author: IanB
author_rank: Super Contributor
timestamp: January 11, 2015, 04:15:07 pm
content: Interesting. I have similar dryer, purchased in 2004 and running fine since. Bookmarked for future reference.
Caught out by swindler on eBay? Yep! - Page 1
Forum section: electronics / repair

author: ashwobla
author_rank: Newbie
timestamp: January 09, 2015, 05:01:29 am
content: Long time fan of Dave's blog, first time user of forum. Hi guys n gals!Is there anyone out there (UK preferable due to postage costs) who can help out a chap with advanced Parkinson's disease (me!!) who has bought a 70s LED watch on eBay and discovered too late that the watch crystal is so crap that it loses 5 minutes every hour?My hands barely work well enough to type this on my iPad, so there's no chance of me de-soldering and re-soldering such a tiny component. Please help!! I left it too late to complain to eBay.I will pay postage both ways, of course, thru PayPal. I don't have a 32k crystal handy - I was hoping you could source me one?So many thanks and smiles,Blair A

author: Rigby
author_rank: Super Contributor
timestamp: January 09, 2015, 02:08:58 pm
content: Oh man someone help this guy already.

author: Yago
author_rank: Frequent Contributor
timestamp: January 09, 2015, 02:14:33 pm
content: I sent a PM to him.I am Manchester UK, with iron and some 32k crystals

author: zapta
author_rank: Super Contributor
timestamp: January 09, 2015, 02:20:55 pm
content: Quote from: ashwobla on January 09, 2015, 05:01:29 amAre you sure it has a crystal and not RC oscillator? 5 minutes per hour is very bad for a crystal.

author: Wilksey
author_rank: Super Contributor
timestamp: January 09, 2015, 04:09:51 pm
content: 5 Minutes per hour is quite a drift.Was it Ebay China per chance?

author: ashwobla
author_rank: Newbie
timestamp: January 10, 2015, 09:22:55 am
content: Thanks to all who read my post, and especially to the local bloke (Hull) who is helping me fix the watch!! It was bought on eBay UK, and to answer the other question, I believe it is a 32,768Hz crystal (silver can, approx 3mm dia).I'd have chucked it away if it hadn't cost me £100 (it is a Bulova Comptron with exceptional LED quality despite its age).Thanks again

author: crystal
author_rank: Contributor
timestamp: January 10, 2015, 02:46:33 pm
content: Quote from: ashwobla on January 10, 2015, 09:22:55 ami can help you with that....PM sent. Regards

author: amyk
author_rank: Super Contributor
timestamp: January 10, 2015, 03:43:55 pm
content: One of these?http://www.crazywatches.pl/bulova-computron-255-drivers-n7-led-1977Looks like the crystal has a trimmer cap:http://www.crazywatches.pl/images/upload/led/bulovan7computronled8.jpg

author: wraper
author_rank: Unknown
timestamp: January 10, 2015, 04:01:04 pm
content: Quote from: amyk on January 10, 2015, 03:43:55 pmYes, but it could trim in ppm, not % range. It is impossible to trim 8% offset
Tektronix TDS1002, Screen appears backlit but otherwise blank. - Page 1
Forum section: electronics / repair

author: FivePoint0
author_rank: Contributor
timestamp: December 30, 2014, 07:13:41 pm
content: Any suggestions:-Thanks a lot.

author: tautech
author_rank: Super Contributor
timestamp: December 30, 2014, 07:25:35 pm
content: As with any repair get the Tek service manual and check the PSU voltages are to spec.You could register with Tek for it or it should be available in one of the links in the Repair Docs threadThere is a trick to get them apart, the handle must be removed to expose all the cover screws.Re-seat the LCD cables too.Keep us posted.

author: nctnico
author_rank: Super Contributor
timestamp: December 30, 2014, 10:38:54 pm
content: Do any of the leds behind the buttons light at power up? If not it could be a simple power problem.

author: FivePoint0
author_rank: Contributor
timestamp: January 09, 2015, 09:33:33 am
content: None of the leds power up.All supply voltages were good.There looked to be a SPI link active to the display, but with no data lines moving.I think it's the main board that has gone. No output from the 1KHz probe calibrator either. Which according to the tek service manual means replace the main board.I never liked the LCD scopes that much, but it is really well designed, and comes apart very nicely.

author: tautech
author_rank: Super Contributor
timestamp: January 09, 2015, 07:01:56 pm
content: Check the PCB for any corrosion, investigate any spec of dirt on IC pins.I've got a 2000 series that had a corroded pin on a 100 pin IC that prevents it from booting with the same symptoms as yours.I'd be interested if yours has the same complaint and if this is a problem with these Teks.
Hameg HM806 - Page 1
Forum section: electronics / repair

author: grumpydoc
author_rank: Super Contributor
timestamp: January 07, 2015, 01:21:25 pm
content: Anyone got a service manual or schematics for the HM806?Plenty of copies of the user manual kicking around the web but nothing with circuit diagrams that I can findTried the Hameg site, kurt, k04bb, lots of googling and a couple of other manuals collections I know about (eg elektrotanya) but with no luck.

author: madires
author_rank: Super Contributor
timestamp: January 07, 2015, 01:33:51 pm
content: Have you asked the Hameg support already? AFAIK they hand out service manuals for older scopes.

author: grumpydoc
author_rank: Super Contributor
timestamp: January 07, 2015, 01:53:39 pm
content: QuoteNot yet although it is not on their website (most of the ones that they have are available directly from the website).

author: anotherlin
author_rank: Frequent Contributor
timestamp: January 09, 2015, 01:59:35 pm
content: Quote from: grumpydoc on January 07, 2015, 01:53:39 pmSend an email. I've asked several times, they responded each time in a timely manner with service manuals.
LG42LD750 Smart TV - Page 1
Forum section: electronics / repair

author: EMUD
author_rank: Regular Contributor
timestamp: December 03, 2014, 03:53:58 pm
content: Hi,our LG TV has a problem with the mainboard. There are often white lines on the screen when the device is started.I have checked with spray and discovered, that the problem is very strong when cooling the processor (LGE3556C) or when pressing it with my fingers.This is a BGA, has anyone tried to replace or to reball and resolder it? And, did it work?The mainboard EBU60844952 of my LG is obsolete, and so I failed in buying a new or even a used one.Do you think there is a real chance to get it work again?EMUD

author: Rasz
author_rank: Super Contributor
timestamp: December 03, 2014, 11:12:35 pm
content: might be rohs solder cracking/whiskers, might be chip itselfwont hurt to reflow this chip (without reballing), jam flux around the chip, put board on preheater, wait till it gets up to ~150 and heat that chip until it floatsanother ghetto option ishttp://www.banggood.com/Universal-LCD-TV-Controller-Board-VGAHDMIAVTVUSB-Interface-p-936100.html

author: arekm
author_rank: Unknown
timestamp: January 07, 2015, 01:27:29 pm
content: Better V59 which adds usb media support in some form and doesn't cost much more:http://www.banggood.com/V59-Universal-LCD-Controller-Driver-Board-PCVGAHDMITVUSB-Interface-p-955022.html

author: wraper
author_rank: Unknown
timestamp: January 08, 2015, 06:42:01 pm
content: I can reflow it (without removing IC) for free on IR station if you pay shipping both ways. Don't guarantee anything though. Shipping back is 6.50 Eur for items below 1 Kg if any interest.