hybridfree/eevblog-posts huggingface dataset:
Fluke 8010A without NiCad Batteries - Page 1
Forum section: electronics / repair

author: gmilliorn
author_rank: Contributor
timestamp: September 13, 2014, 09:52:24 pm
content: While working on my HP counter, my Fluke 8010A died. I had to dust off the Simpson260. Anyway, unlike most Fluke failures it is not the display, but the battery. I'vealready replaced it once, and it is a waste of money since it never leaves the bench.But, the manual specifically says not to operate it without a battery.I did anyway, briefly, to check that the batteries were the problem. Seems to work OK.However, the circuitry seems to be a standard constant current using an LM317.Instead of replacing the battery again, it seems like I could just reconfigure theLM317 to provide ~2.4V, since that is the fully-charged battery voltage, by addingthe appropriate values from pins 1-3 and 3-gnd. Anyone ever tried that?

author: Skimask
author_rank: Super Contributor
timestamp: September 13, 2014, 10:02:47 pm
content: 2 fully charged NiCad's would be more around ~2.8v.Google has been, and always shall be, your friend.I've got 2 8012A's. Basically the same thing. Batteries shot, never leave the bench. Put a 1/2 watt 100 ohm resistor in place of the batteries. Didn't mess with the R's across the '317. Still working after X number of years. Didn't even solder in the resistor, just got it hanging there...

author: tautech
author_rank: Super Contributor
timestamp: September 13, 2014, 10:23:45 pm
content: Quote from: Skimask on September 13, 2014, 10:02:47 pm+1But if there is a tidy/elegantfor ~2.8 V that surely would be the preferred option?Plus a sticker on the outside to remind you when the memory of the mod fades.

author: gmilliorn
author_rank: Contributor
timestamp: September 13, 2014, 10:54:45 pm
content: Hmm, 100 ohms is certainly simpler, I'll try that, thanks!Incidentally, I did Google and all I found was tons of complaintsabout the display dying. I must not have used the rightwords...

author: ModemHead
author_rank: Frequent Contributor
timestamp: September 13, 2014, 10:54:59 pm
content: Quote from: gmilliorn on September 13, 2014, 09:52:24 pmI did that on an 8050A. It uses a 4-cell battery, so I reconfigured the LM317 for voltage regulation at about 5.6V. Works fine and keeps the voltage regulation within original design intent.

author: SeanB
author_rank: Super Contributor
timestamp: September 14, 2014, 05:36:47 pm
content: Mod the regulator or add 5 1N5403 in series instead of the 2 cells to drop around 3V to keep the supply happy.
Silicon Transistors Equivalent for Marantz Amplifier - Page 1
Forum section: electronics / repair

author: masster
author_rank: Regular Contributor
timestamp: September 14, 2014, 12:09:19 pm
content: HelloI am trying to bring to life a Marantz PM400 audio amplifier.The final transistors are faulty.2SA1103http://www.svntc.com/TPDF/1390.pdf2SC2578http://www.svntc.com/TPDF/2109.pdfThe problem is I can't find them where I live (Romania) and I need your help to find equivalents, preferably using the same packaging.Thank you

author: David_AVD
author_rank: Super Contributor
timestamp: September 14, 2014, 12:17:42 pm
content: How about checking the specs of the originals and then using Digikey's parametric filters to narrow down ones with similar specs. Some important specs will be Vce, Ic, gain, package.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 14, 2014, 12:19:09 pm
content: If Digikey is acceptable, maybe one of these would do,http://www.digikey.com/product-search/en?pv16=14699&pv16=12311&pv16=10331&pv16=3436&pv16=13270&FV=fff40015%2Cfff80078&k=bjt&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25like, 2SA1186 (and the complement) seems similar, though a bit faster, so maybe you'd want a ferrite bead on the base terminal just in case.But if we have no idea what counts as available...Tim

author: masster
author_rank: Regular Contributor
timestamp: September 14, 2014, 03:30:43 pm
content: Thank you for replies.The biggest supplier for parts in my area ishttp://www.tme.eu/en/

author: masster
author_rank: Regular Contributor
timestamp: September 14, 2014, 04:12:55 pm
content: I have found these 2 transistors:2STC5242http://www.tme.eu/en/Document/53cf3b34ff283c6f437e3abc346921b3/6398412.pdf2STA1962http://www.tme.eu/en/Document/3adb6a03ac4f78bad4e0d1e4a60c67cb/7832268.pdfDo you see any incompatible parameters ?My other problem is they have to be paired for hFE, but I don't see that happening when I order online...

author: KJDS
author_rank: Super Contributor
timestamp: September 14, 2014, 04:49:56 pm
content: buy ten of each and match them yourself.

author: dannyf
author_rank: Super Contributor
timestamp: September 14, 2014, 05:01:19 pm
content: Motorolla if you don't have money;5200/1943 if you don't have lots of money;Sankens if you have lots of money.
DS1102 Power switch - Page 1
Forum section: electronics / repair

author: rexxar
author_rank: Frequent Contributor
timestamp: September 21, 2014, 03:39:43 pm
content: The power switch in my DS1102 gave it up the other day. It will latch in and out, but the power stays on. Anyone know what part I can replace it with?

author: tautech
author_rank: Super Contributor
timestamp: September 22, 2014, 08:32:34 am
content: Quote from: rexxar on September 21, 2014, 03:39:43 pmIs it really too hard to post a photo?

author: Shock
author_rank: Super Contributor
timestamp: September 22, 2014, 02:42:55 pm
content: I've no idea if that scope power switch is controlling mains voltage so you tell me. But have you tested to ensure it's the switch. e.g. switched it on, then disconnect from the mains or switch off at the mains, then reapply power. Have you seen if the switch can be cleaned?

author: kjn4685
author_rank: Regular Contributor
timestamp: September 22, 2014, 09:12:04 pm
content: Where is the pic.

author: rexxar
author_rank: Frequent Contributor
timestamp: September 29, 2014, 04:53:30 am
content: Sorry I took so long to reply-- a ton of shit happened all at once, and I just now found the time to open up my scope.The switch is on mains; it's a nice clunkin' power switch as Dave would say. It looked like it'd be easy to open up and adjust the contacts. Turns out that the actuator brokeI superglued it for now, until I can get a new switch in.The contacts are open when the actuator is out, so I'm not sure if that's NO or NC? The head where the cap fits is 3mm^2 by 8mm long. It's kind of hard to see the markings, but I think the model number is PS5? It's rated for 8A/250VAnyone have any ideas?

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: September 29, 2014, 10:25:44 am
content: If I had to wager a guess, it's probably normally-open (NO).

author: ruffy91
author_rank: Regular Contributor
timestamp: September 29, 2014, 02:03:20 pm
content: Look in this datasheet to get the correct part number:http://www.solteam.com.tw/solteam/pdf/10/05_PS-5.pdf
Soldering station not reaching temperature - Page 1
Forum section: electronics / repair

author: Erwin Ried
author_rank: Regular Contributor
timestamp: September 12, 2014, 04:03:45 pm
content: Hello, I have a cheap ATTEN 8586 (I think is quite nice) but lately I noticed how the temperature shown in the screen is different than the one in the soldering iron tip.I have a tip thermometer (the temperature was spot on months ago) and now is like off 100°C, so I need about 470°C to start to melt temp (356°C in the tip). The calibration screw is on maximum.Do I need a new soldering iron handle, or it might be a problem in the station?That coil seems to be related with the temp sensor

author: tautech
author_rank: Super Contributor
timestamp: September 12, 2014, 08:22:48 pm
content: The coil is for GND connection to the tip to minimize ESD.Normally the base station has a trimmer for temp calibration. If it is an open frame type the wiper may have a poor connection.Some units they can be accessed externally, adjust it slightly and it may come right.Replacement 8586 elements and pencils are available on eBay.

author: Erwin Ried
author_rank: Regular Contributor
timestamp: September 12, 2014, 11:31:28 pm
content: I see, I applied some thermal paste and it worked, it seems the base of the ceramic element cracked so the presure against the tip probably is not optimal.The regulation pot in the base is topped max (is accesable externally)

author: GEuser
author_rank: Frequent Contributor
timestamp: September 13, 2014, 03:00:13 am
content: Also check to see if the tip actually goes all the way on or down , mine had a 5mm further to go , it was that spacer tube it was too long .I too tried graphite powder to aid thermal transfer and also to make sure the tip would come off easily as I swap them about a bit .

author: sleemanj
author_rank: Super Contributor
timestamp: September 13, 2014, 03:28:06 am
content: I'd stick in a new element, the thermocouple in it may be dicky.Of course, catch 22, you need a soldering iron to solder the element into your soldering iron :-)Here's a seller on Aliexpress, 5 elements for $8.42, free postage.http://www.aliexpress.com/item/5-pcs-lot-ATTEN-Original-Replacement-Ceramic-Heating-Element-4-Core-Heater-Part-for-AT936b-8586/1907036724.htmlCan't go to far wrong with that.

author: Erwin Ried
author_rank: Regular Contributor
timestamp: September 13, 2014, 04:19:23 pm
content: Quote from: sleemanj on September 13, 2014, 03:28:06 amhahaha so cheap! thanks

author: mij59
author_rank: Frequent Contributor
timestamp: September 13, 2014, 05:00:41 pm
content: Also check the base unit for bad solder joints, my new hot air unit had a broken triac solder joint.
replacing bad ADJ pot on UDB1000 DDS function generator  - Page 1
Forum section: electronics / repair

author: dentaku
author_rank: Frequent Contributor
timestamp: September 13, 2014, 11:36:31 pm
content: The ADJ pot on my little UDB1000 DDS function generator is really scratchy and is unreliable.http://i1247.photobucket.com/albums/gg624/nyplatform1/Module/UDB1005S-MS-SM_zpse616b884.jpgIt looks like one of the outside legs is connected to the wiper and the other isn't. If I measure it I get 1K so I'm assuming it's a 102 even though it doesn't look like it's labeled at all.Question:I rarely unsolder stuff other than to salvage parts from old dead electronics. If I carefully remove this little pot (I'm afraid the two tabs connected to ground might be difficult) can I replace it with a full sized 1K pot connected with wires instead of replacing it with another one of those tiny trimpots. I have some pots that are exactly the same type but I don't have anything smaller than a 103 so my only alternative is to use a full sized 1K pot.OR, what if I use one of my little 10K pots that should fit fine on the board and put 1.1K of resistance across it to give me a non-linear 1K pot?
Member near Bethalto Illinois needs Help with scope - Page 1
Forum section: electronics / repair

author: tautech
author_rank: Super Contributor
timestamp: September 12, 2014, 09:50:52 pm
content: We've been trying to sort this CRO that displays only the RH side of the CRT.https://www.eevblog.com/forum/repair/have-a-screen-help/msg491297/#msg491297Need to check the sweep waveform and Lou (kjn4685) does not have another scope.Any members or not close to him that could assist?Bethalto Illinois about 30 northwest of St Louis ,Missouri
Rattling BLDC fan when used with low voltage? Delta AFB0712VHD - Page 1
Forum section: electronics / repair

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 11, 2014, 02:59:32 pm
content: I'm trying to put a second fan inside my Korad to cool the transformer as it is getting quite hot. The fan i'm using is a Delta AFB0712VHD, voltage range 5v-13.2v The Korad's fan controller outputs 6v idle 12.03v full power. But i noticed that the Delta fan rattles when it idles at 6v, any idea why is that? It works perfectly when the fan speeds go up and when it drops down to idle it rattles. It shouldn't be vibration as the fan does not physically rattle, it just makes a rattling sound.The stock fan that came with the Korad doesn't have this problem.When i power the Delta fan with the Korad's output it spins as low as 4.3v before it stalls.

author: Rufus
author_rank: Super Contributor
timestamp: September 11, 2014, 03:32:55 pm
content: Quote from: cybertronicify on September 11, 2014, 02:59:32 pmProbably because when you say it idles at 6v it is actually idling at 12v applied half (or less) of the time. The 12v pulses create an audible mechanical impulse. It probably depends on where the motor armature is in relation to the poles at the time of the pulse which makes it sound like a random rattle rather than a continuous buzz.

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 11, 2014, 03:43:06 pm
content: Ahh i see, so a cap won't help?

author: wraper
author_rank: Unknown
timestamp: September 11, 2014, 04:03:56 pm
content: Quote from: cybertronicify on September 11, 2014, 03:43:06 pmIt depends on fan and control circuit. Try it.

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 11, 2014, 04:08:11 pm
content: nope added a 16v 1000u cap. didnt do a thing

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 12, 2014, 02:05:03 am
content: Ok i tried to put a inline resistor with the Delta fan and it seems to be fine. Not sure why is that.
Broken tablet microUSB socket - Page 1
Forum section: electronics / repair

author: Rihards Veips
author_rank: Contributor
timestamp: September 09, 2014, 02:17:50 pm
content: 3 Months ago my tablets microusb socket broke and took all the pads with it except the 5volt and ground - i fixed it with 2 wires and a computer floppy drive plug because i didnt have the microusb socket available in my local electronics store.. yesterday the ground wire broke off with the pad and I was wondering, can I connect the ground directly to the battery ground?

author: madworm
author_rank: Frequent Contributor
timestamp: September 09, 2014, 03:31:34 pm
content: You could use a DMM to measure resistance between the connector GND and battery GND. If it is essentially zero in both directions, it might be ok.

author: wraper
author_rank: Unknown
timestamp: September 09, 2014, 11:45:27 pm
content: Connect to the ground closest to the broken connector. There should be plenty around the pads where connector was soldered. I even fixed mobile phones with all pads taken off. Scraped off PCB to expose next inner layer of copper where to solder connector body (there usually is a ground under the pads where connector body was soldered) and connected all pins with thin wires to the smd components which where connected to the broken pads. If some were connected directly to BGA and no exposed place available, just scrped off pcb material to expose track in the inner layer. Of course that is some kind of masochism and reacquired microscope and a lot of time but proved to be pretty rugged solution.

author: wraper
author_rank: Unknown
timestamp: September 10, 2014, 12:03:42 am
content: Here are some photos

author: wraper
author_rank: Unknown
timestamp: September 10, 2014, 12:04:16 am
content: one more

author: orion242
author_rank: Unknown
timestamp: September 10, 2014, 12:07:38 am
content: Quote from: wraper on September 09, 2014, 11:45:27 pmJust did the same on a kindle fire. There is a ground plane under the socket nicely exposed if the mounting tabs rip off the top layer. Scraped off the mask, cleaned, and got the replacement jack on pretty well without issue.

author: orion242
author_rank: Unknown
timestamp: September 10, 2014, 12:10:38 am
content: Wow, mine wasn't that bad. That looks like it took a good chunk of two layers.Nice kapton work!

author: wraper
author_rank: Unknown
timestamp: September 10, 2014, 12:26:39 am
content: That one was real PITA. 3 traces go directly to BGA and that vibra motor in the back which is pretty massive, so all wires unsoldered when soldering it back it with a hot air. So end up with high board preheat and heating that vibra on top with soldering iron.

author: Rasz
author_rank: Super Contributor
timestamp: September 10, 2014, 10:53:32 am
content: wow that is nasty

author: Rihards Veips
author_rank: Contributor
timestamp: September 11, 2014, 12:28:36 pm
content: Thank you for the help everyoneI fixed it
Samsung 216BW Monitor  - Page 1
Forum section: electronics / repair

author: FastFeet
author_rank: Newbie
timestamp: September 07, 2014, 01:30:31 pm
content: I have a Samsung 216BW Monitor which the screen turns off after 2 or 3 seconds after being turned on. Monitor is powered, but the screen goes black. I turned it off and back on again... same thing screen goes black after 2 or 3 seconds.I was thinking it appeared to be an issue with the Capacitors on the power board; so I replaced each of the 9 Cap's on the power board. Power Board model: IP-43130A. After replacing the Cap's there is no change with the monitor.Would you have a suggestion to what else I could check/replace?Sincerely,FF

author: mariush
author_rank: Super Contributor
timestamp: September 07, 2014, 03:20:33 pm
content: If one of the fluorescent tubes (there's probably 4, in two pairs of 2) is bad or one of the wires going to it is loose (wire can desolder due to heat and electric arch) then the circuit powering the lamps will stop everything for protection.Grab a flashlight and start the monitor, get the flashlight very close to the screen. If you see some image on the screen in those 2-3 seconds then the backlight circuit is a problem, not the power supply. Carefully inspect the wires going to the fluorescent tubes (top and bottom) on the panel. See if one is loose or burnt up.A fluorescent tube is bad if it becomes yellowish, or pink or has black spots at the ends. This is relatively rare, so if the power supply is good, loose wires is a good bet. Less often, it's a faulty mosfet or broken transformer in that inverter circuit that powers the fluorescent tubes.Be careful, don't play with the fluorescent wires while monitor is plugged in, there's 700-1500v going to those tubes and it can shock you (or kill you).

author: wraper
author_rank: Unknown
timestamp: September 10, 2014, 10:08:53 pm
content: Check secondary winding of both transformers. Resistance must be around 1k ohm.
Soniq QASA - Page 1
Forum section: electronics / repair

author: Mesza
author_rank: Newbie
timestamp: September 09, 2014, 08:29:45 am
content: Hi, thanks for taking time out to read my messagel have acqiured a Soniq QASA, probably 5yrs old. l would like to place this TV into my kids room, but l have found that the picture is lagging. The sound is good, but as objects of the screen move they leave a streak and if the objects finally stop, then the streak finally catches up and the object and then becomes clear, until it moves again. The colours seem out of wack as well. The only way l can discribe the colours is intense. l have tried to use the settings to turn them down without luck.lm hoping that someone can give me an idea on where to start and how to fix this problemThanks for helping

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 09, 2014, 11:31:17 am
content: Sounds like it needs a new Tcon board.

author: Rasz
author_rank: Super Contributor
timestamp: September 10, 2014, 10:54:33 am
content: check capacitors on tcon, sounds like one of them is going bad
capacitor replacement technical question - Page 1
Forum section: electronics / repair

author: Napalm2002
author_rank: Regular Contributor
timestamp: September 10, 2014, 02:12:24 am
content: I am replacing some failed electrolytic caps in a stereo receiver. I need a 50uf cap. I have two 100uf caps. I k know if I wire them in series that the capacitance drops. But what happens to the working voltage. The one I am replacing was a 50 v cap and the two 100uf are 50 each.does the working voltage stay 50 or increase or decrease. I am sorry for asking such a stupid question.

author: sacherjj
author_rank: Frequent Contributor
timestamp: September 10, 2014, 04:32:01 am
content: It isn't simple, like a resistor. It has to do with the ESR of the capacitor and the leakage current. It is possible that one cap gets a majority of the voltage. So if you are using caps that are rated as high as the replacement, then you won't have a problem.To get a high rating with serial caps, you need to parallel resistors with the caps to balance out current. These should cause a few times the leakage current of the cap.

author: AKM
author_rank: Contributor
timestamp: September 10, 2014, 07:54:39 am
content: If it is a bypass capacitor, just replace it with the 100uf one you have.

author: wraper
author_rank: Unknown
timestamp: September 10, 2014, 08:25:01 am
content: Just replace 50uF with 100uF. Will be OK in 99% of the cases. You only don't want higher capacitance if they used in the overload protection circuit time delay or need that they charge/discharge faster for some reason. I often increase capacitance intentionally to prolong it's lifetime in particular place.

author: Napalm2002
author_rank: Regular Contributor
timestamp: September 10, 2014, 10:53:53 am
content: Thank you everyone.
Toshiba LED TV 40L1353N - Page 1
Forum section: electronics / repair

author: torr032
author_rank: Regular Contributor
timestamp: September 07, 2014, 02:09:59 pm
content: Has sound but no picture, the backlight is not at all working, I can see the picture when pointing a lamp to it. I have 24V going to the LED's, all caps on the power board all are tested and good.When turning on the TV power lamp goes flashing green/red for 9 times and then turn on green and stays like that. TV is about one year old.

author: German_EE
author_rank: Super Contributor
timestamp: September 07, 2014, 02:22:34 pm
content: If you have 24V going to the LEDs then they are probably in a string along one edge and one has gone open circuit. If you are very careful then you may be able to remove the LED light but the workshop needs to be very VERY clean to avoid getting dust between the parts of the LCD panel.

author: torr032
author_rank: Regular Contributor
timestamp: September 07, 2014, 02:33:51 pm
content: On the screen jack for the backlight there are 9 contacts. Two wires goes to T-con board, the others are 4x 24V and 3 are ground.I don't have the other T-con to swap it, wonder could it be faulty?

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: September 07, 2014, 02:39:57 pm
content: Don't know about your TV specifically but on some sets there is a surface mount type fuse close to the connector on the tcon board. Maybe you'll get lucky and it's just a blown fuse.

author: torr032
author_rank: Regular Contributor
timestamp: September 07, 2014, 02:52:16 pm
content: One pin that goes to the T-con is 3.3V, the other is 0.29V must be some sort of a logic signal. Will in detailed test the T-con now.

author: AKM
author_rank: Contributor
timestamp: September 07, 2014, 03:29:13 pm
content: Quote from: 4thDoctorWhoFan on September 07, 2014, 02:39:57 pmThat fuse protects the T-Con board. If it opens, you would see only the backlight (usually completely white screen on TN panels). He has completely the opposite problem.
Pioneer A109 Stereo Amp - blown R channel - Page 1
Forum section: electronics / repair

author: Driver
author_rank: Unknown
timestamp: September 07, 2014, 12:13:41 pm
content: Hi Guys.I recently acquired a Pioneer A109 stereo amplifier that failed to power on.I'm no electronics expert, but some basic visual inspection revealed a blown 800mA fuse on the pre-transformer/mains PCB, and some very toasted looking PCB board around the Right channel power mosfets on the main board. These mosfets were shorted too, so I sucked them out and replaced the fuse.Then bingo, the unit powered up and I got audio from the left channel only! So I ordered some replacement mosfets and fitted them, and everything worked fine for the 15-20mins I had it running on the workbench. During this time, I noticed the Left channel heatsinks seemed hotter than the newly replaced Right channel, so I decided I'd spend another $3 on more new Mosfets for the Left channel too.So after swapping them out, I powered the unit up and the fuse blows again. Seems the right channel Mosfets were shorted again. Once removed & fuse replaced, it powers up again, left channel only again.Any ideas as to what's going on here before I scrap the entire unit?

author: David_AVD
author_rank: Super Contributor
timestamp: September 07, 2014, 12:37:31 pm
content: You may have a bad driver transistor or bias control which is resulting is excessive bias current and thermal runaway. Sometimes the bias trim pot can go open circuit either by itself or as a result of an output stage failure.

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: September 07, 2014, 01:34:42 pm
content: You need to check the driver transistors and the 4 .22 ohm resistors. Once you know for sure the output transistors, driver transistors and four resistors are good, you will probably have to adjust the DC offset and bias if this unit has a bias adjustment.A quick check for DC offset is simple: Power the unit up with no speakers attached and the volume at minimum, then measure the DC voltage at the Right & Left speaker terminals. It should be low. It varies from unit to unit but the DC offset is typically somewhere between 5mv to 30mv.Also, make sure your speakers are okay. If they are no good, it could be blowing the amp. Another thing, don't use 4 ohm impedance speakers as your amp lowest recommended impedance is 6 ohms. Using 4 ohm speaker could also damaged the amp.
Background hissing noise from wireless headphones - Page 1
Forum section: electronics / repair

author: sspj9
author_rank: Contributor
timestamp: September 06, 2014, 10:44:21 am
content: I accidentally dropped my Sony MDR-RF855RK wireless headphones and as i plugged them in they worked fine as before though there is this annoying loud interference which is increased as volume from headphones is increased, obviously. Before I dropped it this was barely noticeable though now its really loud. Think its from the receiver circuitry. Any ideas were the fault might be?

author: Unknown
author_rank: Unknown
timestamp: September 06, 2014, 10:51:44 am
content: Those particular headphones I believe use an analog FM signal for transmission. The drop might have been enough to knock a RX tuning pot slightly out of whack.Don't turn it on, take it apart, and try to adjust the tuning (at the right tongue angle of course!)

author: sspj9
author_rank: Contributor
timestamp: September 06, 2014, 12:16:25 pm
content: There was nothing to adjust on the headphones receiver. I tried checking out the transmitter. It had 3 components to be adjusted though 2 of them were for balancing and the other was for loudness, nothing to do with the hissing. :/

author: Psi
author_rank: Super Contributor
timestamp: September 06, 2014, 12:17:53 pm
content: yep, they will have been knocked off frequency.A tune should fix it, use a plastic screwdriver or tuning stick.If it doesn't have any tune-able components in the RF section then look for air core inductors, maybe the impact has bent the coil slightly.Be very careful and adjust in really fine amounts while listening to it, if you throw it far out of tune you may not be able to find it again.

author: sunnyhighway
author_rank: Frequent Contributor
timestamp: September 06, 2014, 02:03:36 pm
content: Try change the radio frequency with the CHANNEL selector on the transmitter, then change the radio frequency to that of the transmitter with the TUNING switch on the headphones.

author: Unknown
author_rank: Unknown
timestamp: September 06, 2014, 09:18:27 pm
content: Quote from: sspj9 on September 06, 2014, 12:16:25 pmJust to confirm, you actually pulled it apart? It probably won't have fine tuning capabilities that are accessible to the user.

author: sspj9
author_rank: Contributor
timestamp: September 07, 2014, 10:13:36 am
content: Yeah, there were 4 air-core inductors in the rf reciever. Bending them made it worse lol. I just kept it as it was..
Blown Resistor Dewalt Battery Charger - Page 1
Forum section: electronics / repair

author: crxsi71
author_rank: Newbie
timestamp: September 08, 2014, 12:45:28 am
content: I have a Dewalt battery charger model dc 9310 and it has a blown resistor on the pcb I've looked for pictures and schematics attempting to acquire the correct resistor to replace the blown one with and I haven't been successful in locating the exact part for a replacement. I have however found out that it has the number 202 on it and that is the only identifying mark on it. I believe if I purchase a flat chip surface mount resistor with 202 on it, it may work but I looked around and they're seems to be many sizes and I'm not sure which one to buy. I will attach the best picture I could get with my camera. The blown resistor is in the top left corner of the picture with R7 next to it. Oh and I have a new one with a good resistor in the same spot, so this is how I know about the 202 identifier on it. Please and Thank You!

author: wraper
author_rank: Unknown
timestamp: September 08, 2014, 01:07:14 am
content: 202 is 2k ohm, size likely is 0603 or maybe 0805. You can determine it by measuring dimensions. 0603 means 6/100 inch x 3/100 inch (length x width). However unfortunately I don't think that resistor is the only fault, likely it is consequence of something else gone bad.
Front panel problem with LeCroy WaveSurfer 6030A - Page 1
Forum section: electronics / repair

author: gicho
author_rank: Newbie
timestamp: September 05, 2014, 10:34:02 am
content: This scope has been at repair at service center (while in warranty) but either they didn't fix the issue or it appeared again later. Also, this same unit had some issues with touchscreen - not sure if I understood right but it may be that the intended repair was to fix the touch issue but when it was returned it had additional problems with the buttons.The problem is that the front panel buttons make random actions - switching trigger type, enable/disable some channels. As far as I could trace down the schematic, those (buttons and leds) are controlled by I2C expander (or more than one). It does not seem to be affected by twisting/pushing the panel or connectors. But still only some buttons are affected, so it is not totally random. For example channel enable/disable happens only on channel 1 (or at least most of the time, I have not seen it on other channels).So I am looking for help to bring back to usable state this 350Mhz, 4 channel, WinXP device. Is it possible to find a service manual (schematic level)? Or, any hints from other "pacients" of similar type?As far as I can tell, the problem comes from the buttons. No matter that I see random "lights" on the panel, I think that this is expected reaction, when channel gets randomly disabled I see both the led on the panel and the GUI on the screen to act in sync - both acting like there was a button pressed.So, most reasonable conculsion is that there is an electrical problem with rubber buttons on the panel. But cleaning and careful inspection does not reveal a reason.

author: tautech
author_rank: Super Contributor
timestamp: September 05, 2014, 10:50:19 am
content: Loose/broken front panel connector cable headers/plugs/sockets?Gnd strap missing/loose?Cracked component and/or solder joint or track around a heavier/larger component?Take the time to look, look and look to find the unusual/easily missed.Does it play up immediately from a cold boot?Latest Firmware installed?Silly simple stuff I know, but it is always where I look first.

author: gicho
author_rank: Newbie
timestamp: September 05, 2014, 11:00:22 am
content: Firmware is the latest one. The problem appears when the oscilloscope GUI is loaded, not related to heating.Thanks for reply, I will look again and again.

author: Rasz
author_rank: Super Contributor
timestamp: September 06, 2014, 03:10:45 am
content: > It does not seem to be affected by twisting/pushing the panel or connectorshow about little percussive maintenance?make some pictures so we can see what you are talking about
HP iPAQ H5450 & H5550 dead (battery flat) - any ideas?  - Page 1
Forum section: electronics / repair

author: h1386343
author_rank: Regular Contributor
timestamp: September 03, 2014, 06:58:58 pm
content: Hello folksI have just procured two lovely condition HP iPAQ PDAs, with a small issue on each. The batteries are Li-Po and are *totally flat* - I assume they were in storage for years, probably. Anyway, I have:~ Put them on charge on the cradle, direct 5VDC, 2A connection as per specs.~ Taken one apart, measured the plug-in backup battery which reads 0.6V (I'm sure these batts are rechargeable, but I didn't jump start it, just in case).~ Disconnected the backup battery, put the main battery in.~ "Jump started" the main Li-Po battery by applying 5VDC (0.8A) to the battery terminals for 15 secs.At some random point during today, the H5550 booted up to the digitiser calibration setup screen, but shortly died again right before I could tap the final crosshair (there are 5 - one centre, four corners). This happened 4 more times, then since then, nothing.If anyone with some iPAQ experience could give me some tips as regards this frustrating issue, that would be much appreciated. I have also done all the recommended hard/soft resets HP say to carry out, but to no avail.thank you all

author: Rasz
author_rank: Super Contributor
timestamp: September 04, 2014, 01:45:36 am
content: start by giving it proper powerfrom lab supply for example

author: h1386343
author_rank: Regular Contributor
timestamp: September 04, 2014, 01:56:50 am
content: Quote from: Rasz on September 04, 2014, 01:45:36 amI have no lab supply. This shouldn't need that - I have LOTS of proper 5VDC PSUs, and a lab supply isn't going to magically make it work. I am not buying a lab supply for a purchase that cost me £10thanks for your reply anyway

author: Napalm2002
author_rank: Regular Contributor
timestamp: September 04, 2014, 03:02:21 am
content: I am pretty sure that he meant power it up from a suitable power supply. Ie a adjustable power supply that most of us have on our benches. If u have a walwart or a cell phone charger with enough beef that should work.

author: LektroiD
author_rank: Frequent Contributor
timestamp: September 04, 2014, 07:02:49 am
content: Of course the battery is flat, what shape did you expect it to be?

author: h1386343
author_rank: Regular Contributor
timestamp: September 04, 2014, 01:46:03 pm
content: Quote from: LektroiD on September 04, 2014, 07:02:49 amSquare? Round? Any shape imaginable?Sorry if I've killed your "joke"

author: h1386343
author_rank: Regular Contributor
timestamp: September 04, 2014, 01:47:07 pm
content: Thank you - I've done that and no help.
Identify a capacitor - Page 1
Forum section: electronics / repair

author: Jaxmoto
author_rank: Contributor
timestamp: August 30, 2014, 10:36:24 pm
content: Weekend warrior, I'm not great with the terminology... looks like what I call a vertical surface mount aluminium cap.The markings are (in this order and shape):54 (maybe 5 4)2206s (the s is underlined)Here is a picture of one of the good caps that are next to it (I can read everything on the bad one so I know it is the same).Also, I have a huge inventory of thru-hole regular caps, would it be ok to use one (with proper specs) in place to test the board?

author: tautech
author_rank: Super Contributor
timestamp: August 30, 2014, 10:59:27 pm
content: Electrolytic 220uF 6V.Sure, anything similar will do for a quick check

author: Jaxmoto
author_rank: Contributor
timestamp: August 30, 2014, 11:06:15 pm
content: Quote from: tautech on August 30, 2014, 10:59:27 pmThanks. Normally I'm pretty good at finding this stuff myself but I couldn't find any reference to a "6s" cap.

author: mariush
author_rank: Super Contributor
timestamp: August 30, 2014, 11:37:48 pm
content: It's not 6v ... or it's unlikely to be 6v.TheSmay be a code representing the voltage rating (but the code varies from manufacturer to manufacturer), or the 4 in "5 4" may tell you the voltage (4V). The numeric voltage ratings are somewhat standardized and the most common ones are 2.5v, 4v, 6.3v, 10v, 16v, 25v etcOtherwise, I'm fairly sure it's a 220uF.. usually when there is enough room on the capacitor, the actual value is printed. When the cap is very small, they often use the notation where the last digit is the number of zeroes .. for example 821 means 82x10 = 820uF

author: Jaxmoto
author_rank: Contributor
timestamp: August 31, 2014, 12:16:08 am
content: Quote from: mariush on August 30, 2014, 11:37:48 pmI dropped on a 220uF 25v since there was room and it did not resolve the issue I was having. It can't be much higher than that even if it isn't 6v.It's on a DLP projector that starts the startup cycle but then goes to "warning" state and stays there. There was an obviously bad cap so it was just a shot in the dark that it might get it going.

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: August 31, 2014, 12:52:03 am
content: I'm almost positive that the cap is a Panasonic and the 6 designates a 6.3V cap while the S is the actual series of caps.

author: HighVoltage
author_rank: Super Contributor
timestamp: August 31, 2014, 01:14:18 pm
content: I just bought a similar capacitorThis one has 25V, 820uF, 20% Tol.On the capacitor it is printedJ1820ECMMay be only the capacitance can be read directly, the rest has to be found in a Datasheet

author: caall99
author_rank: Regular Contributor
timestamp: September 02, 2014, 06:55:47 pm
content: Many companies remove the decimal place for 6.3V SMD caps (Nichicon says so on its SMD cap datasheets). Its definitely 6 volt 220 uf.
Sony hcd-sb100 failure - Page 1
Forum section: electronics / repair

author: m112
author_rank: Newbie
timestamp: August 26, 2014, 03:25:47 pm
content: Hi everybody!It's the first time that i post in this forum but i've been reading around for quite a bit.I'm writing to ask help from you guys that know a lot more than me ...And here's the problem:There have been a sony hcd-sb100 home theater system sitting around my house for a couple of years now, and now that i really need it I can't get it to work.When i power it on, only half of the screen actually turn onNo sound is audible from the speakers in every mode but if you plug in the earphones and turn the volume all the way up you can barely hear the actual sound.I took it apart and just by looking at it everything seems fine, the only "strange" sign is in the top metal case just above an huge cap of the power supply, where there seems to be some smokes residues, even if the cap looks alrightI really don't know what to do... All my hopes are in you guys.If you need any mor info just ask, I'll do whatever i can !

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: August 31, 2014, 10:48:33 am
content: If I had to wager a guess, I'd say the screen is a cabling issue, and the quiet sound is probably a capacitor issue, but not the one you pointed out. That's a power cap, the thing probably wouldn't turn on at all (or exhibit strange on/off issues). The residue is probably dust, it can get pretty gnarly looking if it builds up over time.

author: mij59
author_rank: Frequent Contributor
timestamp: August 31, 2014, 11:16:50 am
content: Hi,Start by checking for bad solder joints.Please post some photo's of the copper side of the power supply board.Download the service manual.

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: August 31, 2014, 12:30:29 pm
content: Give the Amp board a good visual on both sides. The Amp board is the one that has the speaker terminals.The Amp board also has the connections going to your front panel. Since you have a problem with both the display and audio, the Amp board is probably the problem. Look for bad solder joints and/or cracks on the board. If you don't see anything visually then start checking voltages on the Amp board.
[HELP] Broken Fluke Scopemeter 99 + TEARDOWN PHOTOS - Page 1
Forum section: electronics / repair

author: zitrex
author_rank: Contributor
timestamp: September 17, 2014, 02:47:51 pm
content: Hi,I just got Fluke scopemeter 99 series II. I have problem with it. This thing is quite shy and don't want to display anything on its "LCD". In short words - scopemeter don't show anything on display. It's not completely dead, because when I click auto set button I can hear relay clicks and also backlight is working. No obvious damage on PCB.Somone tried to repair contrast regulation block. I see some flux on PCB and some not very professional soldering. Here you have pics of it.LCD is driven by 6 HD66204F.Here you have service manual for Fluke 93/95/97:http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Philips/pm93_95_97_fluke_93_95_97.pdfIf someone have service manual for 99 model please, post it here.Thank you for suggestions and your time.Sorry for my english it's not my native language.

author: kc9qvl
author_rank: Regular Contributor
timestamp: September 19, 2014, 12:47:49 am
content: Did you check power? Actually measure power from plug pack and the batteries.

author: zitrex
author_rank: Contributor
timestamp: September 19, 2014, 09:27:33 am
content: Yep it was fine. I just resoldered LCD power supply and diming block, also cleaned LCD pads with IPA. It's fully working now. Lucky noob huh ?
ILPI-176 - Page 1
Forum section: electronics / repair

author: rahandford
author_rank: Regular Contributor
timestamp: August 30, 2014, 09:01:11 pm
content: Does anyone know where I can find information on a power board type ILPI-176 REV:A with a part number of 493011400100R.I can find lots of adverts to purchase replacements (from China) but can not find any schematics.As always your help will be much appreciated.

author: tautech
author_rank: Super Contributor
timestamp: August 30, 2014, 11:10:30 pm
content: Quote from: rahandford on August 30, 2014, 09:01:11 pmUnlikely you will find schematics, however identify the SMPS controller and get datasheet/s and likely you will find a very similar "typical application" schematic attached.Different manufacturers of the same device might have differing applications, so take your time to have a good hunt.Trouble shooting SMPS can be tricky, search the forum for hits.A trick that many use is to power the controller chip with an external supply to ensure start up.Be careful and do your homework.Even Google searches for the "(device) application or circuit" could well produce results.
Repairing Battery Pack - Page 1
Forum section: electronics / repair

author: baget
author_rank: Contributor
timestamp: September 01, 2014, 07:36:11 pm
content: HelloI have a cheap battery pack that does not seem to work.the PCB has USB connector for power output and microUSB connector to power inputwhen I connect a microUSB I always see a green light indicating that the battery is full...when I measure the volt on the battery I get ~0.850v when I unplug the microUSB power I see the battery volt is downing down very fast...the ICs on the PCB that I could see are:DW01 and 8025AI think the problem is with the battery, what is the best way to confirm that expect from replacing the battery?

author: amyk
author_rank: Super Contributor
timestamp: September 02, 2014, 04:52:33 am
content: QuoteThat's a pretty standard lipo protection combination. If you measure 0.85V on the cell itself then it's certainly dead, if it's after the protection then check the voltage at the cell terminals to be sure (be careful of shorts!)

author: baget
author_rank: Contributor
timestamp: September 02, 2014, 09:16:13 pm
content: Quote from: amyk on September 02, 2014, 04:52:33 am0.85v is on the battery terminals

author: amyk
author_rank: Super Contributor
timestamp: September 04, 2014, 01:10:38 pm
content: Dead cell.
metex 1280 - Page 1
Forum section: electronics / repair

author: R_G_B_
author_rank: Frequent Contributor
timestamp: August 06, 2014, 09:08:58 am
content: I have an a problem with this meter it takes around 20 minutes to measure a 1 Meg resistor. The meter does this by first displaying the highest value its capable of reading and counting backwards ( converging to the value of the resistor being measured before counting back to its maximum residence it can measure. Can anyone please explain.

author: R_G_B_
author_rank: Frequent Contributor
timestamp: August 06, 2014, 01:17:38 pm
content: intermittent connection problem

author: retiredcaps
author_rank: Super Contributor
timestamp: August 24, 2014, 10:04:27 pm
content: Quote from: R_G_B_ on August 06, 2014, 01:17:38 pmDid you get this fixed? Was the above the problem?

author: R_G_B_
author_rank: Frequent Contributor
timestamp: August 27, 2014, 07:18:21 am
content: Yes it was the 4mm sockets not allowing the 4mm plugs to fit snuggly. By the way the scope function on this thing is pants!
Trying to repair a Bosh PPW3120/01 Weight Scale - Page 1
Forum section: electronics / repair

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: August 25, 2014, 03:08:19 pm
content: Hello guys.As weird as it sounds i am trying to repair a weight scale.The problem:The scale usually turns on when pressure is being applied to its 4 legs.But when i apply pressure it wont show anything on the little lcd.I tried to change the 2 CR2032 batteries with no result.The repair process so far :I am just a beginner.I just play with circuit boards i have not studied on electronics yet and my experience does not cover the repair section of electronics.The cons of the repair :The main processor is covered by this black thingy (pictures bellow)New at repairsThe pros of the repair:My house needs a weight scale and this is about 60 USD new (40 euro)

author: mij59
author_rank: Frequent Contributor
timestamp: August 25, 2014, 04:38:32 pm
content: Hi,Maybe the scale powers on by actuating a switch, the switch could be faulty.Check for mechanical issues, lose wire etc.Got a multimeter ?Post some photo's of interior of the scale.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: August 25, 2014, 04:59:44 pm
content: Ill check the switches and since i dont have a multimeter to use the continuity test function ill have to see if the switch lights an led up ...As for the wires ill remove the metal plate and then check just to be sure there is no damaged wires beneath it.Also photos will be up soon

author: German_EE
author_rank: Super Contributor
timestamp: August 25, 2014, 05:15:51 pm
content: Make sure that the battery contacts are nice and clean. Scales like this are often used in bathrooms and the dampness tarnishes the contacts.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: August 25, 2014, 05:21:59 pm
content: Checked the battery contacts nothing there the looked like brand new i also tried scraping the metal with tweezers just to be sure it would make good contact.Also no loose / cut or damaged wires that i can see of.The switches on the other hand seem a bit complex... they are not your regular tactile button switch anatomy i have some pictures bellow.

author: mij59
author_rank: Frequent Contributor
timestamp: August 25, 2014, 05:59:11 pm
content: Quote from: ChrisGreece52 on August 25, 2014, 05:21:59 pmOn the white part of the foot is a metal ring, it could be part of the switch.Check the board on the right of the main board seems to be some gunk on it, also check the switch on the board.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: August 26, 2014, 02:57:50 pm
content: Mij59 i have to tell you a huge thanks.Not only you but all the guys here helped me a bunch.The problem was at the main board where you noticed the gunk on there.That may was a broken solder connection i tried reflowing the solder using a bit of flux then cleaning the board using an alcohol pad.So thanks to everyone here for your help.Time to learn my weight now