hybridfree/eevblog-posts huggingface dataset:
Solar light fault - Page 1
Forum section: electronics / repair

author: veedub565
author_rank: Frequent Contributor
timestamp: August 27, 2016, 07:48:21 pm
content: I was asked to repair a solar light for someone. Yes I know, buy a new one, but anyway.I found that the on/off switch was corroded and intermitant, I managed to order a replacement from China and fitted it today. However the lights now no longer turn on and off automatically, they just go on and off with the switch regardless of whether it is dark or not.I don't get it, there isn't anything to it. A solar panel, an on/off switch, a resistor, a 4 legged package of some kind (diode pack?) 2 LED's and a battery. That's it! I just don't get itOnly thing I thought of was that the battery was charged with an external charger, so it's at a level beyond which the solar panel would normally charge it to, so it's not operating correctly. Running the battery down a bit may restore it's equilibrium.

author: mikerj
author_rank: Super Contributor
timestamp: August 27, 2016, 08:25:15 pm
content: Is the solar panel itself working correctly, and have the devices on the PCB suffered from any corrosion? Both faults are extremely common on the cheap solar garden lights. The solar panel not only charges the cell, but triggers the light to switch on when it gets dark so if there's no output it will behave in the way you are seeing.

author: Cyberdragon
author_rank: Super Contributor
timestamp: August 27, 2016, 09:08:15 pm
content: That "resistor" is probably an inductor. The chip is a voltage cotrolled switch with a boost converter to generate around 3V for the LEDs. Sometimes these can be messed up by too much voltage, they will sometimes dump both the solar panal and battery into the light if the battery voltage is too high (I.E. it won't turn off).

author: tronde
author_rank: Frequent Contributor
timestamp: August 28, 2016, 03:38:40 am
content: Some readinghttps://ez.analog.com/community/university-program/blog/2014/11/14/hacking-an-led-solar-garden-lightmaybe not the same IC, but probably quite similar circuit.

author: veedub565
author_rank: Frequent Contributor
timestamp: August 28, 2016, 07:44:44 am
content: Thanks guysThe first circuit in that link looks just like it.As far as I can tell the solar panel is working, it used to switch on and off automatically before the on/off switch went kaput. Devices on the PCB don't look corroded.Interesting about the boost controller becoming messed up, I'll wait and see if it starts to work all by itself once the battery runs down a bit. Although I seem to remember testing it with a 1.5v alkaline and the lights switched on and off automatically when the panel was covered/uncovered
Flex ALR 512 - Page 1
Forum section: electronics / repair

author: boonkerz
author_rank: Newbie
timestamp: August 27, 2016, 09:45:23 pm
content: Hello,Anyone knows where i can find any circuit help to repair this product?The thing does not turn on.http://ektoxeftis.com.gr/products_documents/doc_189_2be39816321165bf64251fdf3882c858_ALR_512_accessoires.pdfregards
Rainbow vertical lines on display - Page 1
Forum section: electronics / repair

author: Kopernik
author_rank: Contributor
timestamp: August 29, 2016, 08:58:14 am
content: Hi!I have problem with operational panel.It have a mixed rainbow vertical lines on display that is connected thru LVDS connection.. if I connect external monitor thru VGA, the screen is OK.. I changed S3 VIA twister bga chip, but the problem is the same.. the motherboard is PCM-9371..Any suggestions?

author: wraper
author_rank: Unknown
timestamp: August 29, 2016, 09:18:01 am
content: Have you changed actual LCD panel because is sounds exactly like faulty panel? Also a picture is welcome.

author: Kopernik
author_rank: Contributor
timestamp: August 29, 2016, 09:46:40 am
content: No, I didn't change display, because I'm not 100% sure what's wrong..here's a picture of display.

author: Kilrah
author_rank: Unknown
timestamp: August 29, 2016, 10:01:14 am
content: The display panel itself or TCON would be the most likely culprits. Trying another panel would be the first thing to do.

author: Kopernik
author_rank: Contributor
timestamp: August 29, 2016, 10:06:12 am
content: I have another panel, but it have different connector.. I'll try to connect it...Thanks

author: wraper
author_rank: Unknown
timestamp: August 29, 2016, 10:32:13 am
content: Quote from: Kopernik on August 29, 2016, 09:46:40 amWell, changing BGA as first measure when you are not sure...Yep, looks like faulty panel. Of course not guaranteed, but probability is very high.Quote from: Kilrah on August 29, 2016, 10:01:14 amIn this case T-CON most likely is part of the LCD panel and is not exchangeable.

author: Kopernik
author_rank: Contributor
timestamp: August 29, 2016, 11:25:33 am
content: Yes.. t-con is a part of display..What if i try to change main chip on display?It's AUO072.It cost 2$ from china..

author: jkf1000
author_rank: Regular Contributor
timestamp: August 29, 2016, 12:24:40 pm
content: Not familiar with the LVDS, but that display looks to be exactly the same issue as a machine I have on the bench at the moment. The one I have is missing its HSYNC/VSYNC signals from the main video processing chip due to corrupted data or faulty MPU.. Karl

author: bktemp
author_rank: Super Contributor
timestamp: August 29, 2016, 01:59:19 pm
content: Quote from: jkf1000 on August 29, 2016, 12:24:40 pmThat would be my guess too.So before changing the T-con check if the input signal is ok.
Velleman PS3005d fan doesn't spin - Page 1
Forum section: electronics / repair

author: Burgija
author_rank: Newbie
timestamp: August 23, 2016, 09:43:45 am
content: Does anybody knows why my cooling fan is not spinning? I have checked it outside of the case and it works fine, but when inside - heatsink get very hot but fan stays off.Others have problem with a noisy fan but I wish mine worked anyhow.Any suggestions?

author: singapol
author_rank: Frequent Contributor
timestamp: August 23, 2016, 10:58:01 am
content: Download the schematics and unzip them. Wait for "Processing" to change to "Get manual".Looks like there may be fault at U12 (switching ,see fan signal) or the relays.See the main schematic.http://elektrotanya.com/korad_ka3005p_velleman_labps3005d_power_supply.zip/download.html

author: Burgija
author_rank: Newbie
timestamp: August 23, 2016, 07:37:53 pm
content: It was the fan.But on the picture attached you can see two resistors on main board that are not in schematic.One of the resistors is slightly beat up and the pcb underneath is little bit burnt.It seems like the fan coils got shorted and as a result was drawing more current.Thank you singapol
TDA2003 Audio White noise fix (Qixiang/Quanzhou PCB's) - Page 1
Forum section: electronics / repair

author: GEuser
author_rank: Frequent Contributor
timestamp: August 23, 2016, 01:40:31 pm
content: Q

author: CJay
author_rank: Super Contributor
timestamp: August 23, 2016, 05:23:20 pm
content: Quote from: GEuser on August 23, 2016, 01:40:31 pmAll those Qixiang radios suffer roughly similar problems.They are a lot of radio for the money though and with a mod or two they can work really well.
B&O Audio Monitor AM1 restoration - Page 1
Forum section: electronics / repair

author: cheeseit
author_rank: Regular Contributor
timestamp: August 30, 2016, 08:14:26 pm
content: Got this audio monitor as part of a score and it works. Cosmetically it is in kinda bad condition with the paint flaking off but the meter looks as new, perhaps it has been replaced during the units life. Judging from date codes on two LM301's it is from 1980.It is a combined stereo wattmeter, AC voltmeter and measuring amplifier with 9 ranges. As a wattmeter from 10nW to 140W, with 2x100W/1x200W continuous and 2x140W/1x280W for up to 5 minutes. Selectable impedance is 2x8R, 2x4R, 1x2R and 1x16R. On the back is a DIN connector for an external 2x1KW/1x2KW load. I had a hard time believing that when I read it, seeing those puny wires leading to the connector. That seems a bit.. ambitious. I don't see how those thin wires can carry up to 2KW on a DIN connector where only two of the pins are used for the signal?Full specs and schematichere(in danish).Inside I found the aluminium heat sink for the LM386 had fallen of but had luckily wedged itself under a few wires. A few of the Roederstein electrolytics looks bad with a black smudge near the '+' sign on top of them, and one of them even has small bulge on the top. I think I'll replace those that looks bad, or should I just replace all of them? I don't have an ESR meter yet but I would like to keep it as original as possible so I will keep them and test them when I get one, and/or try to find some NOS at some point in the future.Those blue Philips has some oxidation on the positive terminal too so I'll replace them also.I plan to restore the case by sandblasting and painting the case, in as close as possible to the original colors but I'm not quite sure how to restore the front. I'm thinking that I have to measure everything, or perhaps scan, the front and create an image from which I can have a stencil cut? Toner transfer maybe, how would enamal paint react to the required heat? I would imagine that I have to apply lacquer on top of the toner if that is an option? Advice and ideas are appreciated.This will take some time and it is not on top of my pile so don't expect updates anytime soon.Last image shows a 1kHz sine on a Yamaha M-35 amp specced at 57W dynamic power into 8R, which is what the meter shows precisely, right before clipping.
looking to use an ultrasonic cleaner - Page 1
Forum section: electronics / repair

author: wiseold
author_rank: Newbie
timestamp: August 22, 2016, 11:35:11 pm
content: Hi,I am looking for somebody with a large ultrasonic cleaner to help me clean a large mac motherboard, hopefully around the Sydney CBD/inner west.Board is around 270x350mm, that said I really only need to clean one corner of the thing.cheers all..
2445a Connector O-ring - Page 1
Forum section: electronics / repair

author: kaldj
author_rank: Newbie
timestamp: August 13, 2016, 05:35:03 am
content: Hi,Everyone, I just picked up an 2445a an it works well but I noticed it" missing a white (teflon?) o-ring around the first probe connector like pictured below (not mine).Can I use anything or any type of o-ring? Or where can I get one? I was thing about just putting a colored probe ring on it.Thanks in advance!

author: LazyJack
author_rank: Frequent Contributor
timestamp: August 13, 2016, 06:02:07 am
content: That should be the insulation between the BNC ground and the probe identification contact (the large metal ring around the BNC). This whole connector should be one assembly, I don't really see how that could be missing. Maybe post a picture of your scope.Does it properly identify the type of the probe on that channel? 10X etc.?

author: kaldj
author_rank: Newbie
timestamp: August 13, 2016, 08:04:35 am
content: Thanks for the help, I'll get a picture tomorrow and post it up.

author: kaldj
author_rank: Newbie
timestamp: August 14, 2016, 05:02:12 am
content: This is mine.You can see the difference between the two connectors. The appears to be a o-ring that sits flush but none protruding like the rest of the connectors.

author: kaldj
author_rank: Newbie
timestamp: August 14, 2016, 05:05:26 am
content: It appears to be working fine. But admittedly this is my first scope so I'm inexperienced at best with it.

author: iXod
author_rank: Frequent Contributor
timestamp: August 14, 2016, 05:54:19 am
content: Nice scope!

author: LazyJack
author_rank: Frequent Contributor
timestamp: August 22, 2016, 01:32:15 pm
content: Quote from: kaldj on August 14, 2016, 05:05:26 amIt is probably fine then. Maybe the CH1 connector was replaced previously or something like that. That metal ring round the connector ground is used for sensing the probe attenuation. Compatible probes (those on the photos are not) have a small pin protruding from the connector and making contact to that large ring. Bases on the resistance between GND and the ring, the scope can figure out the probe attenuation and adjust the V/div display accordingly. I think a 11k resistor will make it sense as a 10X probe. You can try it by connecting a resistor to it and see what happens. Connecting directly to ground is the probe ident function. Compatible probes have a button on them and the scope will identify which channel it is connected to, when you press the button.

author: w2aew
author_rank: Super Contributor
timestamp: August 22, 2016, 02:00:33 pm
content: Quote from: kaldj on August 14, 2016, 05:02:12 amI have several Tek scopes - and have both types of connectors. Some have the protruding white insulating ring, others have the flush gray colored ring (and some are white but flush). Looks like one of your connectors was replaced at some point, but nothing to worry about.
LG Plasma 60PK750 repair - Eay60968901 PSU - Page 1
Forum section: electronics / repair

author: Jbates58
author_rank: Regular Contributor
timestamp: August 22, 2016, 11:23:46 am
content: Hello all,i have a LG plasma that is exhibiting the clicking relay symptoms.it will fire up for about 10min when cold, then it will suddenly turn off, i will describe the sequence:plug in and power on from coldfires up and functions perfectl for 10-15minafter 10-15 min it turns off suddenly and relays click (indicating shutdown as per normal)i press power on againstandby light changes colour, relays click and then it instantly shuts downtv wont turn back on until its been off for a period of time (i havent yet determined the minimum)from what i can gather, it is the power supply. but i havent found anything wrong with a visual inspection, and i have tried a few repairs mentioned online, to no avail.all the test point voltages are spot on when the unit is functioning, so i dont think that a mis-setting is the issue.from what i can find online there are a few "repair" kits available, and they offer these componentsIC701R108R109R110R111R112R113R296R297R298i have removed each of these components from the PSU and tested them. they are also spot on, or very close to. the only thing i cant test (because i dont know how) is the IC. from what i can tell, the ic is a "F4316MSF17"can anyone assist me in repairing my plasma? i have a multimeter and am good at soldering. but no oscilloscope to test things. hopefully i wont need one. but i have been looking at getting one, so if i have to then i will.cheersJason

author: Srbel
author_rank: Frequent Contributor
timestamp: August 22, 2016, 12:52:19 pm
content: Try changing the electrolytic capacitor next to the F4316MSF17 chip. The cap between the +V and GND pins. Usually about 10uF 50V, or something like that.
Tektronix TDS 684A monitor having a really bad day - Page 1
Forum section: electronics / repair

author: magnehh
author_rank: Contributor
timestamp: May 30, 2016, 06:47:00 am
content: Hey, guys! I finally got around to posting this. A few weeks ago, I was searching for old test equipment "trash" in the electronics waste bins, and found this beautiful beast of a scope. Took it with me, powered it up and WAH WAH WAH!As you can see from the attached pictures, the monitor is in some sort of gooey state. It looks sort of like silicone smudged out behind the front glass, but I have no idea how it would have gotten there.Has anybody seen this before? Or do you have any idea of what it might be, and perhaps a fix for it? Any help is appreciated!Magne

author: tautech
author_rank: Super Contributor
timestamp: May 30, 2016, 07:47:53 am
content: Welcome to the forum.My guess is water under the screen protector overlay.Well you did say you got it out of a electronics waste bin......

author: nctnico
author_rank: Super Contributor
timestamp: May 30, 2016, 08:29:00 am
content: This is easy to fix but messy. There is silicone gel between the LCD shutter and the CRT screen. You can cut the assembly open and remove the gel. This guy wrote how to do that:http://jvgavila.com/tds524a.htm

author: magnehh
author_rank: Contributor
timestamp: August 22, 2016, 05:01:43 am
content: Wow nctnico, that's exactly what I was looking for! Thanks very much!

author: Jwalling
author_rank: Unknown
timestamp: August 22, 2016, 09:21:59 am
content: Quote from: nctnico on May 30, 2016, 08:29:00 amAlways wondered why Tek did this, in later models, there was no gel. It's like 5 ounces of gooey snot. After scraping most of the gel away with a plastic scraper, I've found that "Goo Gone" does a pretty good job of removing the remaining stuff.

author: MosherIV
author_rank: Super Contributor
timestamp: August 22, 2016, 11:38:58 am
content: My GUESS would be either crt shatter protection.See this thread on similar note:https://www.eevblog.com/forum/chat/vintage-crt-safety-lense-removal-and-cleaning/I asked a colleague of mine at TNMOC.org and he thinks removing the bonding is a bad idea since you loose the protection but putting back proper glass bonded blast protection is a real problem.Or could be extra protection from x-rays.I am only speculating
Wavetek DM23XT not meausring - Page 1
Forum section: electronics / repair

author: blueagle91
author_rank: Newbie
timestamp: August 21, 2016, 01:06:29 pm
content: HelloSo i have this old Wavetek andi used it a lot. Excelent DMM, not autorange but fast reliable, well reliable thats a question mark there isnt itSo bout a month ago, i just turned it on wanted to do some measurments, and well it wont measure. It stuck, it changes all the ranges, displays correct units, moves the decimal point, turns on off, changes AC DC, but it wont measure nothing.For an example if i put it in diode/continuity check, its stuck at .220 and thats all. If i put it in MegaOhm range, it counts up like its charging a capacitor.Volts are zero all the time. Anyone had this problem, fuses are ok, inputs do have nice clean contacts, probes are good.I just hope its not something big, cause i really like it, i have other DMM`s, but i really love this one.Thanks all the best

author: retiredcaps
author_rank: Super Contributor
timestamp: August 21, 2016, 04:19:25 pm
content: Quote from: blueagle91 on August 21, 2016, 01:06:29 pmCan you post clear focused pictures of the pcb (both sides) so we can see the inside? You may have a problem with one or more of the input protection components?

author: Jacek_Paw
author_rank: Contributor
timestamp: August 22, 2016, 07:16:44 am
content: I saw similar problem with Wavetek multimeter and it was caused by one of the traces under the knob. The material was to soft and it got pounded on the pcb and made a short with another trace. As far as I remember one of the traces was responsible for the reset and while it got shorted uC wasn't able to work.
Samsung LED Smart TV UA48J6300AKXXA - Page 1
Forum section: electronics / repair

author: valia
author_rank: Newbie
timestamp: August 23, 2016, 08:41:14 am
content: I have a Samsung LED Smart TV UA48J6300AKXXA bought in South Africa which is now in Cuba, country where there is no Samsung service. It was working fine until recently but now when you start reaches the 4th screen tv signal : Antenna or HDMI or Display box . At this point it stops and does not pass the following. No matter which option is chosen. the signal will not enter either Antenna or box or just use it as a monitor.TV technician tells me that those tv lose their memory programming.How can memory be reprogrammed for these tv?Also they say to me that I must reset main POB. ¿ How to do it?Others advise to change main boardWhat you advise me?¿Where I can find technical manual of this Samsung LED Smart TV UA48J6300AKXXA?thank you

author: wraper
author_rank: Unknown
timestamp: August 23, 2016, 09:22:24 am
content: Have you flashed firmware update and reset the settings from menu?http://www.samsung.com/za/support/model/UA48J6300AKXXA/

author: wraper
author_rank: Unknown
timestamp: August 23, 2016, 09:24:10 am
content: BTW starting 2 identical threads is not good at all.

author: Simon
author_rank: Unknown
timestamp: August 23, 2016, 04:47:14 pm
content: Please don't double post, it is extremely annoying.
1500w Strobe Tube Trigger Wire - Page 1
Forum section: electronics / repair

author: kolbep
author_rank: Frequent Contributor
timestamp: August 21, 2016, 06:52:33 am
content: HiBusy working on a 1500w Strobe Light (for club use)I see that the Trigger wire that is wrapped around the tube, was broken halfway along. (The trigger supply hooks up to this wire at one side.You can hear the trigger pulse. But the strobe does not flash.If I put a piece of copper wire across the piece where the Trigger wire is broken, then the system starts working (This thing is bright.)Now, how to repair this. What type of wire do they use for the outer trigger, is it anything special,or can I just rewind the whole thing with Copper wire. Or can I just stretch the trigger wire pieces together, and twist them?And, after working on this, should I clean the tube? If so, should I use Surgical Spirits, or Methalted Spirits, or something else (that can be obtained at a drug store)?ThanksP

author: SeanB
author_rank: Super Contributor
timestamp: August 21, 2016, 07:34:09 am
content: Wire is nothing too special, just a stainless steel wire as it does not corrode easily. clean the tube with surgical spirits, so there is no residue left like in meths. Best is isopropyl alcohol, or pure methanol.
HELP I'm stuck! Fixing halogen 12v dimmer.  - Page 1
Forum section: electronics / repair

author: ElectroCamillowski
author_rank: Newbie
timestamp: August 20, 2016, 06:00:52 pm
content: Well hello gentleman,I have a problem. After bringing a standing lamp home from friend it turned out that small lamp is not working.I decided to take a challenge and try to fix it.It's a lamp with double dimmer. One for 200W halogen bulb ,and other for a small 12v halogen tiny bulb.Thing is, upper big lamp is working perfectly, but small one is not working at all. I turn knob and nothing happens.I disassembled it and checked two bronze wires, which go directly from dimmer unit to a bulb with tester and it shows 0V.I want to repair it and learn something from that experience. Thing is I have no clue what is broken or how to check it. I have multimeter, soldering iron and other necessary tools.Description for photos:-Lower dimmer is not working-Brand of dimmer is Guang Hao CHZ-4100Data of dimmer:-Input AC230V-50Hz-Output1(Big) AC230V, MAX 300W, MIN 50W-Output2(Small, broken one) AC12V, MAX 50W, MIN 20W.Please guide me how to check what's wrong and how to fix it.Thanks!

author: IanB
author_rank: Super Contributor
timestamp: August 20, 2016, 06:40:38 pm
content: First things first. Did you check the fuse?

author: ElectroCamillowski
author_rank: Newbie
timestamp: August 20, 2016, 09:06:09 pm
content: Yes. Fuse was checked at the beginning.It's good.Its a two dimmers in one device kind of thing. Big bulb is operating. Only small is not.
KEPCO BOP replacement voltage/current limit pots - Page 1
Forum section: electronics / repair

author: siggi
author_rank: Regular Contributor
timestamp: August 05, 2016, 11:06:58 am
content: Hey y'all,I wonder if anyone here has a suitable part number for replacement pots for the limit controls on Kepko BOP power supplies?My Kepco BOP 100-1 is missing a couple of the locking nuts for the voltage/current limit pots. This is driving me to distraction, though other than my OCD this isn't a real problem.I'm looking at thishttp://www.digikey.com/product-detail/en/precision-electronics-corporation/RV6LAYSA102A/RV6L102C-ND/222818on DigiKey as a likely candidate.It'd be nice to get the right value pot as insurance against the day when one dies, but unfortunately I don't know what it is. Kepco do make the service manuals available (seehttp://www.kepcopower.com/bopbuy2.htm#man), but my OCD doesn't quite stretch to $200.Im hoping someone here with access to the service manual could supply the part number of the replacement or at least the value of the pot...Siggi

author: siggi
author_rank: Regular Contributor
timestamp: August 20, 2016, 09:02:09 pm
content: I dropped a couple of those pots in a DigiKey order, and the locking nuts fit like a charm. OCD daemon will find something else to focus on now.
A Better Thermal Pad for Power devices - Page 1
Forum section: electronics / repair

author: Mosaic
author_rank: Regular Contributor
timestamp: August 19, 2016, 08:52:41 pm
content: Hi guys:This is something I've made for myself and it works quite well so I took it to Tindie.I hope the admin will permit me to post this here.It basically beats the best out there due to the 0.5mil dimension thickness which allows a 0.1°C-in²/W thermal impedance when thermal paste is used.The caveat is lower voltage (200V tested) apps. Its material dielectric specs look to be better than double that though, but I haven't had to use it in that range.http://usa.dupontteijinfilms.com/informationcenter/downloads/Electrical_Properties.pdfFor us DIY, vintage & repair gear folks, cheaper & better when repairing/restoring is always a good thing. So if you use To220,To3 or To247 devices as I do.....have a look:https://www.tindie.com/products/Protofabtt/mylar-05mil-thermal-pads-to220--to247218-to-3/thxAncel
Yihua 853D 2A problem - Page 1
Forum section: electronics / repair

author: Patrick kelly
author_rank: Newbie
timestamp: August 17, 2016, 09:15:33 pm
content: HII have a YIHUA 853D 2A 3in1 HOT AIR GUN REWORK SOLDERING STATION I have only using it for a few hours when the soldering iron led went from 350 to 008.When I looked at the iron tip it was glowing orange I turned it off let it cool down when I switch it back on the led showed 5-E.When I checked the ceramic heat element it was cracked and broke when i opened the unit up one of the wires was off what I think is a termostate for the fan. I checked online and I think it might be the TB137 600b triac if anybody has had a similer problem and came to the same conclusion and fixed it.I would appreciate any help.I attached some pics.

author: jitter
author_rank: Frequent Contributor
timestamp: August 19, 2016, 04:38:29 am
content: I do not have this unit, so I have no experience with it, but I think that the switch that I know as a "clixon" is not for the fan. It sits very close to the TO-3 package, and that would seem a bit big for a fan.More likely, it is a failsafe to cut out power if the heatsink gets too hot (e.g. if the fan has failed). Or does the fan only run when the heatsink gets hot?In my mind it's more likely that the thermal sensor in the tip failed and that the station kept putting power into the heating element as a result. This resulted in overheating and cracking it. The loose wire on the clixon may not be related to your problem at all. A loose wire would be the same as a clixon going open when its specified temperature has been reached (it's how in e.g. a coffeemaker the temp of the hot plate is regulated).But I may be totally wrong, here...

author: Patrick kelly
author_rank: Newbie
timestamp: August 19, 2016, 08:19:50 am
content: Thanks for the information I ordered a new soldering iron handle complete the heating element was almost the same price.Wheh I get it with any luck you will be right and I won't have to touch the station itself.
A2 Display replacement for HP 8590 Spectrum Analyzer - Page 1
Forum section: electronics / repair

author: deepskyridge
author_rank: Regular Contributor
timestamp: August 18, 2016, 07:55:49 pm
content: I just replaced the A2 Display unit in my 8591E analyzer and the new one works great. If anyone wants one here is the ebay listing.http://www.ebay.com/itm/351781522402I have no association with the seller in any way. I paid $50 for the one I got and it was new.Gary
Samsung ue40es5500 - Page 1
Forum section: electronics / repair

author: Kopernik
author_rank: Contributor
timestamp: August 18, 2016, 09:27:08 am
content: Hi..I have a problem with lcd tv.There is no sound on speakers.. I cannot find a datasheet of audio IC NTP 7412, so I don't now how locate the problem.. any suggestions?

author: Srbel
author_rank: Frequent Contributor
timestamp: August 18, 2016, 10:02:05 am
content: This?http://pdf1.alldatasheet.com/datasheet-pdf/view/301416/SILAN/SA7412.html

author: wraper
author_rank: Unknown
timestamp: August 18, 2016, 10:22:07 am
content: Quote from: Srbel on August 18, 2016, 10:02:05 amThat's completely different IC.If you cannot find schematic for your TV, there should be others with this particular IC. Try searching from that end instead of searching for datasheet.
HP6633A DC PSU heatsink power dissipation + quiet fan choice - Page 1
Forum section: electronics / repair

author: Pat Pending
author_rank: Regular Contributor
timestamp: April 19, 2016, 07:56:30 am
content: I recently acquired a HP6633A PSU (50V 2A) that was also missing its fan.It been talked about here on the forum that an nice upgrade would be a quieter fanbut I don't see that being a good option for low voltage high amp loads.If for example, I draw 1V@2A or 2W then by reason more than 98W is dissipated in the heat sink.I don't see a quiet fan upgrade being possible/safe with these HP PSUs. Am I wrong?

author: starphot
author_rank: Contributor
timestamp: April 19, 2016, 09:24:08 am
content: Just as long as the quieter fan has or exceeds the CFM rating of the original. Today, the fans are quieter and push more air than the original when the unit was introduced. 12v fan according to the manual. Unit has a thermal shutdown feature anyway. Just keep it safe.Joe

author: pigrew
author_rank: Frequent Contributor
timestamp: August 19, 2016, 03:39:10 pm
content: I just bought this model (6633A rev 3004A, from 1990 or so), and finally found where it listed its fan as 25 CFM. The OEM fan is "Fan-Tubeaxial 12-VDC 6100-RPM 23.5-CFM 35dB(A) 60X60X25.4mm Plastic", made by Papst in West Germany. The modern replacement (according to the Keysight site) is the Mineba (NMB) 2410ML-04W-B60.After cleaning my unit's fan, it is much quieter, but I think I'll still order a new fan. I might also order a thermal controller, though I'm not sure about the easiest way to mount the thermometer to the heat sink.ADDENDUM: I'm thinking about a cheap fan controller, likehttps://www.amazon.com/Qianson-Automatic-Temperature-Controller-Governor/dp/B01KH2U2XK/ref=sr_1_3?ie=UTF8&qid=1471622356&sr=8-3&keywords=automatic+cpu+fan+controller+12v+case. My only worry is that it would introduce too much noise on the 12V rail, but the fan is on its own regualator, so it'd probably be OK.-Nathan

author: edpalmer42
author_rank: Super Contributor
timestamp: August 20, 2016, 03:53:23 am
content: I'm not familiar with the 6633A, but most decent linear power supplies use a transformer with multiple voltage taps. They select the tap that will allow them to provide the required output voltage while minimizing the wasted power. Does the main transformer look like it has a ridiculous number of connections? If so, it probably uses that kind of switching.If you can measure AC current, you can also compare the input and output power levels to see how much power is being dissipated internally.Ed
Yamaha RX-V1075 / RX-A1030 help - Page 1
Forum section: electronics / repair

author: Raff
author_rank: Regular Contributor
timestamp: August 14, 2016, 04:17:14 am
content: Hi all,I'm trying to repair yet another Yamaha receiver I scored cheap.This one has audio fine but no video.Built in diags pass ok until I get to the digital video parts. Analog through works fine.I'm suspecting the HDMI transmitters at this point as all communication tests pass as do ram and rom tests.None of the HDMI loop tests pass. Nor does the GUI test work.Anyone have any experience with these receivers?Thanks,Raff

author: Raff
author_rank: Regular Contributor
timestamp: August 17, 2016, 01:29:20 am
content: Update:I found on Element 14's web site a bulletin from Texas Instruments regarding premature aging problems in a series of their chips.You guessed it, the DSP chip in both the RX-V2071 and the RX-V1075 Yamaha receivers I'm trying to fix have the affected chips.I have bought the replacement module for the RX-V20171 and that fixed it, but I have this time contacted Yamaha Australia to see what they say about the second receivers problem.Seems to me they should be repaired for free, or at least a good discount as its a known problem with that series of chips.
ohaus scale GT2100 - Page 1
Forum section: electronics / repair

author: EMUD
author_rank: Regular Contributor
timestamp: August 14, 2016, 03:35:14 pm
content: Hello,I have a GT2100 scale made in USA. It was dropped and some of the mechanical components (flexures) are broken. The scale was produced to 1996, and now there are no spare parts avaiable any more.The spares of GT2100,GT4100 and GT4800 seemed to be compatible. Is there someone who has a ohaus with a broken electronic?Best RegardsEMUD

author: kleblanc
author_rank: Unknown
timestamp: August 16, 2016, 03:37:08 pm
content: I'm going to guess that the load cell/strain gauge is damaged as well. Unfortunately it is probably cost prohibitive to repair and recal.
Potentiometer D-spindle oddity - Page 1
Forum section: electronics / repair

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 15, 2016, 05:46:52 am
content: Recently I found a Fender 100W guitar amplifier left for dead on the kerb. I dried it out and it works well apart from the missing speaker.9 of the 12 knobs were missing and I had to replace a couple of pots. I ordered some knobs with grub screw fixing, but then realised that the flat on the original pot spindles is at the top (12 o'clock) when the pots are at mid-travel. This does not suit knobs with grub screws as the screw is at the bottom so that it is not visible. I had a look in my 'pot box' and the D-spindle type all have the flat at the bottom.Are the pots unique to Fender/music equipment or have I just not noticed in many years of meddling that there are 2 configurations?Regards, BT

author: MosherIV
author_rank: Super Contributor
timestamp: August 15, 2016, 08:35:30 am
content: QuoteQuoteAre you sure it is the potentiometer or is it the plastic knob that is non standard?I know Marshall make their own knobs for their amplifiers. No idea if they are inverted or not, should have taken up the offer from a friend years ago for some reject knobs from MarhsalGood luck

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 15, 2016, 12:23:13 pm
content: It's definitely the pots that are non-standard (at least to all my other stock of pots).Of course the knobs are the same too ! They have a skirt with numerals and a round hole with two small radial 'ribs' that allow for the flat of the spindle.The pots have alloy spindles and the wiper is carried on a clear plastic disc. The disc is fixed to the spindle by a 'staking' process that spreads the alloy.The pots look completely standard. Sorry no pics.I just thought it strange that they were different for no apparent reason or advantage.A pity that you didn't snaffle the Marshall original knobs- they are such a price new.Looking at the Chinese replacements that come (conveniently) in packs of 10 or 12, the quality is atrocious. The printed numerals are all over the place, and the sellers don't even select well moulded examples for their photos. This is why I ordered grub screw knobs but I may have been better off with 'collet' type- I'm not bothered about keeping the amp original, in fact I have only a sheet of green Tolex to re-cover the case with !BT

author: CJay
author_rank: Super Contributor
timestamp: August 16, 2016, 09:43:26 am
content: Work out where the grubscrew needs to be (screw it down on the shaft and see where it marks) then drill a shallow hole or file a shallow notch for it to sit in.
AGILENT/HP - Page 1
Forum section: electronics / repair

author: GEuser
author_rank: Frequent Contributor
timestamp: July 03, 2016, 03:24:42 am
content: Q

author: chihaxinh
author_rank: Regular Contributor
timestamp: July 25, 2016, 03:37:14 am
content: Hi GEuserI Have one osc like you . But can runing user cal allway fail , and when mearsurement frequency wong.Sigen 100Hz ==> OSC Display 150HzSigen 1Khz ==> OSC Display 1.5KHzSigen 1MHz ==> OSC Display 1.5MHzSigen 10MHz ==> OSC Display 10.5MHzIt's allway multiple 1.5I dont know way to check and fix ...

author: chihaxinh
author_rank: Regular Contributor
timestamp: August 17, 2016, 01:52:11 am
content: Hi GeuserI Have one HP 54622D but oldest version ( square button in control pannel ) . I buy from one company bankrupt and missing Logic Probe !Can you help me research pinout and Can i diy Logic probe from IDE cable ?Many thank so much !
Castomig 250c Welder - Control Board - Page 1
Forum section: electronics / repair

author: Mad Professor
author_rank: Regular Contributor
timestamp: August 13, 2016, 01:38:50 pm
content: Hi All.I am trying to fault find and repair a control board for a Castolin Eutectic Castomig 250c Welder.The issue with the welder was that as soon as you unit was powered on, the spool feed would run at max speed.It would not matter what the speed feed was set to on the front panel.I have so far traced the fault to the main control board. in particular a BUZ10 Power Mosfet.All of the pics were showing as a dead short. after removing the BUZ10 from the PCB my DMM reads dead short across all three pins.Here is a link for theBUZ10 datasheet<Click for datasheetI normally order parts from RS Components UK, but it seems that the BUZ10 is not something they stock.Could someone please help me found a compatible replacement for the BUZ10?I am also concerned that maybe the driver circuitry for BUZ10 has been damaged.Thanks for your time.Best Regards.

author: singapol
author_rank: Frequent Contributor
timestamp: August 13, 2016, 05:40:23 pm
content: BUZ10 is obsolete. The nearest equivalent is IRFZ34 which is available from Element14 UK. Just key in IRFZ34to search, there are a few choices and price. PS it's listed in RS Electronics too.IRFZ34 datasheet-- Compare carefully with BUZ10.http://www.vishay.com/docs/91290/91290.pdf

author: Mad Professor
author_rank: Regular Contributor
timestamp: August 14, 2016, 06:56:30 pm
content: singapol: Thank you for your reply, and your suggestion to use the IRFZ34, as a compatible replacement for the BUZ10.I will have a good read of both datasheets and compare, before ordering any new parts.What would normally cause a Power MOSFET to go dead short across all three pins.Thanks again for your time.

author: tautech
author_rank: Super Contributor
timestamp: August 15, 2016, 01:47:12 am
content: Quote from: Mad Professor on August 14, 2016, 06:56:30 pmThe back EMF from an inductive load.The inbuilt free wheeling diode can often manage the back EMF but it's poor design to not add a snubber to specifically manage back EMF.
OLED part number identification/repair - Page 1
Forum section: electronics / repair

author: dermitza
author_rank: Contributor
timestamp: August 14, 2016, 01:52:33 pm
content: Hi all,I was curious what was inside my Aspire odyssey e-cig (http://www.aspirecig.com/aspire-kit/aspire-kit232.html) so I tried to take it apart.. With horrible results. These things are not meant to be disassembled after assembly (at least not without some part destruction as they are held together with glue).So I managed to rip off a couple of buttons, the USB socket for charging and the OLED.. LOL. The buttons and USB port I sourced from digikey, however the OLED is a strange one. The external (glass) dimensions measure approximately 29x9.2mm, with a viewing area of 22x6.6mm and I cannot find a part similar to this. The closest I have found is an OLED from adafruit (https://www.adafruit.com/products/931) but there the dimensions (and pinout) do not match.I was wondering if anyone could identify the OLED? Failing that, I think the best option would be to hack some enamel wire on the microvias on the flex.. fun!

author: amyk
author_rank: Super Contributor
timestamp: August 14, 2016, 10:21:49 pm
content: 29.1 x 9.2, 14 pins, not sure if resolution is correct though:http://www.buydisplay.com/default/0-84-inch-ssd1306-96x16-pixel-oled-display-manufacturer-i2c-blue-on-blackThis one is slightly smaller:http://www.buydisplay.com/default/graphic-i2c-0-69-inch-96x16-oled-display-mp3-module-white-on-blackCheck the others here too:http://www.buydisplay.com/default/oled-display
Fried Compact Flash card - what is this burnt component called? - Page 1
Forum section: electronics / repair

author: orjanh
author_rank: Newbie
timestamp: August 14, 2016, 12:36:35 pm
content: I recently bought a new Kingston 16 GB CF card with the intention of replacing the old, noisy hard drive in my old iMac G3.I popped it in a CF-to-IDE adapter I got from dx.com, turned on the power and it made a poof-sound, with some nasty smell coming off it.When opening the CF card up, I found this:Does anyone know what the blown component is called? And can I replace it?Thanks!

author: EMUD
author_rank: Regular Contributor
timestamp: August 14, 2016, 03:50:28 pm
content: Hi orjanh,this was a switched mode regulator chip. It may be that the other components (flah chips, controller) are damaged, too. Normally these regulators are proof against nearly everything.The easiest way is to g..gle the datasheet of the memory chips and look for the recomended supply voltage. Look for the power consumption, too. Then look for a chip wich has an inputof (I think 5V) wich can make this. It may cost one to 2€ . Assemble it, and try ...Good luckEMUD

author: Jwalling
author_rank: Unknown
timestamp: August 14, 2016, 04:31:24 pm
content: Quote from: orjanh on August 14, 2016, 12:36:35 pmToast.Quote from: orjanh on August 14, 2016, 12:36:35 pmLikely that there is more damage than just that.Jay

author: kony
author_rank: Regular Contributor
timestamp: August 14, 2016, 05:12:07 pm
content: Judging from the blown hole on controller package, this thing is sadly beyond repair. You can actually see soot mark on the outer shell coresponding to that spot as well.

author: tatus1969
author_rank: Super Contributor
timestamp: August 14, 2016, 05:26:10 pm
content: the only reason that I can think of why you would want to repair that CF card instead of buying a new one is that you need access to the data on it. What about trying to buy another one of the same type, and solder the flash chips to the new one?

author: orjanh
author_rank: Newbie
timestamp: August 14, 2016, 06:56:41 pm
content: Thanks for your replies!The card was blank, so I don't need any data on it. Just thought I'd see if it was an easy fix, but if multiple things on that tiny board may need repair then I don't think I'll bother. The CF only cost me 18 euro.

author: amyk
author_rank: Super Contributor
timestamp: August 14, 2016, 10:30:24 pm
content: Buy another one to figure out what that IC was. Are you sure your adapter doesn't have the 5 and 12V rails reversed?

author: lowimpedance
author_rank: Super Contributor
timestamp: August 14, 2016, 11:47:57 pm
content: Quote from: Jwalling on August 14, 2016, 04:31:24 pm@ orjanh , if you get another CF make sure you try it in another devive to make sure it works first. And then suspect the adapter (particularly since it came from DX.com!!).

author: Rasz
author_rank: Super Contributor
timestamp: August 17, 2016, 07:37:59 am
content: Quote from: orjanh on August 14, 2016, 12:36:35 pmwrong way around Im affraidas kony said there is a burn mark on the flash controller
Small LCD module polariser repair - Page 1
Forum section: electronics / repair

author: gnif
author_rank: Unknown
timestamp: August 09, 2016, 08:31:37 am
content: Hi All,I have been asked by a friend to repair a Yamaha amplifier from '93 which has a LCD backlight by a 12V globe. The rubber grommet that held the globe in place has failed and the globe was resting on the back of the LCD, which has overheated and destroyed the polarising film. The LCD is configured to be a negative display allowing light through the active segments, so the new polariser needs to be as opaque as possible on unlit segments.I tried to use a polariser from eBay for an iPhone, but the results were terrible. I am guessing these early LCD modules used some other kind of polariser.Does anyone has any suggestions of a suitable replacement filter?

author: NottheDan
author_rank: Frequent Contributor
timestamp: August 09, 2016, 10:02:27 am
content: Huh? Don't you usually just turn the polariser around and put it on backwards to get that? Certainly always worked with watches.

author: amyk
author_rank: Super Contributor
timestamp: August 09, 2016, 10:39:21 am
content: If the module got hot enough to damage the polariser, I think the liquid crystal would've also suffered.

author: gnif
author_rank: Unknown
timestamp: August 09, 2016, 12:02:36 pm
content: Quote from: NottheDan on August 09, 2016, 10:02:27 amI have done some further research and it turns out I used the wrong polarizer, modern phones use a circular polarization where these displays used a linear polarizer.Quote from: amyk on August 09, 2016, 10:39:21 amIt was only warm enough to heat the film which causes it to lose its properties over time. Polarized film is created by carefully stretching plastic, heating it allows it to return to its prior state. The display works fine, but has a spot where it was warm/hot which is not contrasting enough and hard to read. I have confirmed the display is fine by moving the old polarizer across to an undamaged edge to test.

author: Kilrah
author_rank: Unknown
timestamp: August 09, 2016, 02:19:35 pm
content: Yup, linear polarizer and changing between "white on black" and "black on white" is done by simply rotating one of the polarizers by 90°.

author: SeanB
author_rank: Super Contributor
timestamp: August 09, 2016, 02:31:35 pm
content: Have you tried using the polariser out of an old LCD monitor? One side has the colour filter as well, but the other side will not. You just need to split the 2 thin glass plates apart and clean off the cholesterol from the surface, then see which side works best on the front, and then mark the correct darkest polarisation angle to cut along that to get a smaller glass and film to place there.

author: SeanB
author_rank: Super Contributor
timestamp: August 14, 2016, 12:37:16 pm
content: Did a quick test on Friday....Seems to work using an old scrap small LCD display as the donor for the glass and film.
One output on Rigol DP832 not delivering - Page 1
Forum section: electronics / repair

author: kentavv
author_rank: Newbie
timestamp: August 13, 2016, 07:08:56 am
content: Hi. I have a Rigol DP832 three output power supply. One output connection, while set to 24V3A came loss momentarily and there was a zap at the connection (not inside the power supply. Now that particular output, when first enabled, very slowly climbs to the desired voltage, fluctuates +/- 1V or so, never goes higher than 12V, but if any load is placed on the output, there's nothing there. Could the current sense resistor had been blown? Something else? Any point in attempting to repair it or is it best to send it off for repairs?Thank you

author: andtfoot
author_rank: Unknown
timestamp: August 13, 2016, 07:29:43 am
content: Possibly related?How old is it?

author: kentavv
author_rank: Newbie
timestamp: August 13, 2016, 07:49:22 am
content: That is freakishly similar. Thank you for finding the video. I dug out the receipt and box and it's two years old. Looks like there is a three year warranty. Stinks, but the best solution may be to send it in.
nice, broken, but repairable UPS - Page 1
Forum section: electronics / repair

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: August 12, 2016, 08:36:30 pm
content: Found one of these pure sine wave jobs for $20...https://www.amazon.com/Tripp-Lite-SU2200RTXL2UA-Rackmount-Outlets/dp/B00006B81Y/ref=sr_1_1?ie=UTF8&qid=1471033899&sr=8-1&keywords=su2200rtxl2uaFront panel corners were smacked a bit, but main problem... No Power. If you let these babies sit, they drain the batteries to zero, never to work again. New set of batteries $60Hard to get the front panel screws out they got really bent up. Once I got the panel off, swapped in the new battery set. Working great!

author: eKretz
author_rank: Frequent Contributor
timestamp: August 13, 2016, 02:07:23 am
content: Good stuff. I got one the same way but it wasn't that caliber! Amazing that people don't even try to change the batteries.