hybridfree/eevblog-posts huggingface dataset:
ALFA AWU036H repair - Page 1
Forum section: electronics / repair

author: papabol_24
author_rank: Contributor
timestamp: November 12, 2014, 10:01:38 am
content: Hello, i have two alfa awu036h usb wireless adapters which suddenly became dead for no apparent reason, opened them up and did some basic checks and found out that "FB3" was busted, i tried to replace both on my alfa's but yay magic smoke came, again did some multimeter checks and the ouput of the power supply section which contains the FB3 goes to the rf power amp section, i removed the rf amp chip (U5) no more shorts, no more smoke hehehe, the problem is i cant figure the part number of the chip, the marking on the chip is 1046, google search yields no sure results, i was wondering if any of you guys are familiar with this chip or a known direct replacement for it.Thanks in advance.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 12, 2014, 03:42:47 pm
content: Is FB a ferrite bead?

author: papabol_24
author_rank: Contributor
timestamp: November 12, 2014, 04:06:01 pm
content: Oh yes, im sorry, it is a ferrite bead, I thought those are fuses.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 12, 2014, 11:32:18 pm
content: Quote from: papabol_24 on November 12, 2014, 10:01:38 amSearching for1046 16-qfnyields thishttp://www.admiral-microwaves.co.uk/pdf/rfic/AP1046.pdfI don't know if this the right part, but at least you have a pinout and a circuit diagram for comparison?

author: papabol_24
author_rank: Contributor
timestamp: November 13, 2014, 05:13:36 am
content: Thank you very much sir, checked the diagram and the actual pcb layout on my alfas, this is the exact part, including the pin count and package on google search is a great tip that I have learned from you sir, Thank you.

author: papabol_24
author_rank: Contributor
timestamp: April 16, 2015, 06:53:47 am
content: Hello, I just bought those ap 1046 rf ic from alibaba and after a couple of hot air soldering attempts both of my alfa's are now working, special thanks to retiredcaps for providing the datasheet..
PWM Switch Replacement (Switched Mode PSU) - Page 1
Forum section: electronics / repair

author: Dipski
author_rank: Contributor
timestamp: April 16, 2015, 02:08:22 pm
content: Hi Folks, I've got some power supplies I'm repairing that have faulty PWM switches (TOP202YAI). Replacements weren't readily available and I was recommended TOP224YN as better replacements in this PSU. I have found the TOP224YN's to be failing so I thought I'd see if I've been recommended the wrong IC as I'm not familiar with PWM switches and the specifications are different between the two switch series.Reading the data sheets the TOP202YAI has an output power range of 15-30 watts (Flyback) and 30-75 watts (PFC/Boost), while the TOP224YAI lists 45 watts output.Is the 45 watt rating for the TOP224YAI its maximum PFC/Boost rating or its maximum Flyback rating (or both)?Could anyone recommend a suitable modern day replacement for the TOP202YAI?

author: wraper
author_rank: Unknown
timestamp: April 16, 2015, 05:05:57 pm
content: Should work. Probably something else failed. Maybe snubber circuit across transformer primary winding. Does it work for some time at all? If not at all, could be shorted diode on secondary side too.

author: Dipski
author_rank: Contributor
timestamp: April 16, 2015, 05:37:24 pm
content: Yes, it did work - first instance was in a known working PSU and the TOP224YN ruptured and shorted after 5 minutes of operation. This machine originally had a TOP202YAI suspect of causing under supply at high temperature, >70 degCI installed another into another known working PSU which seems to run fine on the workbench - I monitored temperature on the chip and it doesn't overheat or get hot, around 40 degC was the highest temperature measured.Third install of a TOP224YN has resulted in a PSU failure - I'm awaiting return of the unit to inspect. This PSU originally had a TOP202YAI failing at >50 degC and after replacing with TOP224YN was working and tested at 60 degC for 10 minutes.

author: wraper
author_rank: Unknown
timestamp: April 16, 2015, 05:49:42 pm
content: Where have you bought those TOP224YN?
Canon CA-920 batery charger/DC power supply repair - Page 1
Forum section: electronics / repair

author: salamander
author_rank: Contributor
timestamp: April 14, 2015, 02:04:10 pm
content: Hi, today I plugged in a borrowed Canon CA-920 (from Canon XM2 camera) and there was nothing ... I checked the input wiring etc. but nothing wrong. (The adapter worked a few days ago)So, I disassembled the unit, but I am unable to find anything wrong with it. There is a large text about replacing the fuses ... but for me (I am really not an electrical engineer) there aren't any (at least obvious).I checked the lines, and there seems to be no power at all on the secondary side.Please help me, what can be wrong? I am quite desperate, because I have to return the camera in a few weeks and the guy will be pissed off if the adapter will not be working(Yeah, and I need the camera for my project)

author: Grapsus
author_rank: Regular Contributor
timestamp: April 14, 2015, 02:54:42 pm
content: The fuse is the black cylinder near the mains input socket with "Bel T2A 250V" written on it. Check the fuse for continuity. Maybe you shouldn't be touching this PSU if you're not sure about it. That big 400V capacitor could hurt you badly if not discharged properly.

author: salamander
author_rank: Contributor
timestamp: April 14, 2015, 03:11:44 pm
content: Main fuse seems to be OK, there is voltage on he primary side, I measured ~300V DC behind that rectifier, but there is literally nothing on the secondary.

author: Grapsus
author_rank: Regular Contributor
timestamp: April 14, 2015, 03:32:05 pm
content: The rectified 300V DC should then be switched into the primary at around 40 kHz by a chunky MOSFET. It must be the three-legged component attached to the heatsink near the big capacitor. If this mosfet is not running it's either because it's dead or it receives a wrong feedback. Again, be careful with the mains capacitor.Edit: picture with the location of the mosfet that switches the primary.

author: salamander
author_rank: Contributor
timestamp: April 14, 2015, 04:09:24 pm
content: Well, I will leave this to someone who knows what he's doing, I don't really feel safe probing this thing.Thanks for the advice anyway

author: SeanB
author_rank: Super Contributor
timestamp: April 14, 2015, 06:57:17 pm
content: R4, R5 or R13 are open circuit. They are under the large brown capacitor on the mains side. Most likely the value is 470k 0.25W. They are the start up resistors for the power supply.
I need schematics from a old mixer (Inkel MX 880 E) - Page 1
Forum section: electronics / repair

author: RobertoLG
author_rank: Frequent Contributor
timestamp: April 11, 2015, 10:39:54 pm
content: just got it for free, but it needs to be repaired, so if somebody can help, thanks

author: Pillager
author_rank: Unknown
timestamp: April 12, 2015, 05:03:51 pm
content: I'd tell you to google it, but instead I'll just post this Link:http://freeservicemanuals.info/servicemanuals/download/Miscellaneous/mx-880.pdfHappy fixing!

author: RobertoLG
author_rank: Frequent Contributor
timestamp: April 12, 2015, 08:43:30 pm
content: Quote from: Pillager on April 12, 2015, 05:03:51 pmDankeI did google it, but couldn't find a working link, let's see if I can get this thing working hehe
Trying to identify connector type and crimp - Page 1
Forum section: electronics / repair

author: Light Bulb
author_rank: Contributor
timestamp: April 16, 2015, 11:00:58 pm
content: Hi all,I'm trying to repair the fan on a 10Gb network card, and I need to re-crimp one of the fan wires. Unfortunately, I have no idea what type the connector is, nor can I find the right sized crimp. I found something that _might_ be appropriate from digikey, but at $39 postage to NZ for a 7c crimp, I wasn't convinced.The pin pitch of the connector is 1mm, and the actual crimp itself appears to be about 1.1mm wide at the connecting end. The connector's overall width is 5mm.Any information that anyone can provide would be most appreciated.Thanks all

author: mariush
author_rank: Super Contributor
timestamp: April 16, 2015, 11:17:34 pm
content: Sorry, don't know the connector.May be obvious but wouldn't it be easier to just desolder the header and solder three wires directly on the 3 pads on the pcb? They're reasonably spaced apart and they're long enough to make it easy for you to solder 3 wires with no effort.It would look ugly but it wouldn't cost a penny.

author: Falcon69
author_rank: Super Contributor
timestamp: April 17, 2015, 01:00:39 am
content: jst connector. plenty of them on ebay

author: Light Bulb
author_rank: Contributor
timestamp: April 17, 2015, 01:22:26 am
content: Quote from: Falcon69 on April 17, 2015, 01:00:39 amI'm having trouble finding one that looks identical to this, with the 1mm pitch.

author: Mr.B
author_rank: Unknown
timestamp: April 17, 2015, 01:54:55 am
content: Measure it carefully to make sure it is not a 1.25mm pitch. 1.25mm is more common.1.0mm pitchhttp://www.ebay.com/itm/10-sets-Micro-JST-SH-1-0mm-3-Pin-Female-Connector-with-Wire-and-Male-Connector-/251553090335?pt=LH_DefaultDomain_0&hash=item3a91bb8b1f1.25mm pitchhttp://www.ebay.com/itm/Micro-JST-1-25mm-3-pin-Connector-Plug-with-Wire-x-10-sets-/151348093628?pt=LH_DefaultDomain_0&hash=item233d0ca2bc

author: Light Bulb
author_rank: Contributor
timestamp: April 17, 2015, 04:00:26 am
content: Thanks heaps for providing that.Definitely 1mm pitch. Width of the 3 pin connector is 5mm exactly, so fits the diagram provided on Ebay.

author: Monkeh
author_rank: Super Contributor
timestamp: April 17, 2015, 05:36:18 pm
content: It does not appear to be a JST part.You could replace the whole thing, or as suggested just solder it.
HP 6114A PS disassembly - how do I remove the precision current knob? - Page 1
Forum section: electronics / repair

author: motocoder
author_rank: Unknown
timestamp: April 08, 2015, 09:08:00 pm
content: Sometime back I purchased an HP 6114A Power Supply. The supply had apparently been dropped on the front panel, as the shaft on both front panel potentiometers are bent. It seems the 20 ohm pot is unobtanium, so I purchased a broken 6114A and salvaged a replacement voltage assembly from that. However, the current control knob is a simple 1K 10-turn unit from Bourns. I purchased a replacement from DigiKey, and also a replacement turns counter. They should be here later this week, and once swapped out this thing should be back in tip-top shape.However, I am not sure how to remove the turns counter on the current control. I can remove the outer knob by loosening the two set screws in the knob. However, I don't see how that inner portion that counts the turns is removed. Can someone more familiar with this unit tell me how that's done?Thanks

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 09, 2015, 02:32:34 am
content: I gotta say I'm not sure what you're describing, a turns counting dial is one unit. What are you removing? Pics please.

author: robrenz
author_rank: Super Contributor
timestamp: April 09, 2015, 02:40:48 am
content: I think there is a small face spanner nut holding the main body on. Fine tip needle nose can make do as a spanner wrench.

author: motocoder
author_rank: Unknown
timestamp: April 10, 2015, 04:15:26 am
content: Quote from: robrenz on April 09, 2015, 02:40:48 amThanks, robrenz. It was indeed a spanner nut, and the needle nose pliers worked fine to remove.Unfortunately, I wasn't able to adapt the replacement turns counter easily. It would have required drilling the face plate, and I didn't want to take the risk of assing it up. However, I did swap out the potentiometer and lubricate the existing turns counter, and that seems to have been good enough.I love this power supply. Wish I had a 6115A to go with it.

author: robrenz
author_rank: Super Contributor
timestamp: April 10, 2015, 11:31:48 am
content: I have a spare 6115A that is working but needs a output jack replaced and total cleaning. PM me if you are interested.
Samsung T240 (Touch of Color) monitor - Page 1
Forum section: electronics / repair

author: mofoq
author_rank: Newbie
timestamp: April 08, 2015, 10:31:35 pm
content: I've got a T240 monitor which was exhibiting the dreaded 2-second blanking issue.I swapped out the inverter transformer and it stopped doing the 2-second blanking issue but was stuck in some infinite loop diagnostic mode (it would display gradient in red, then one in green, then in blue, then go to greys, then it would blank out and repeat).The low voltages check out just fine and no visibly bad caps so I figured the processing board was also fubarred (I've repaired plenty of monitors and other devices with those).I picked up a replacement board on e**y and plugged it in.Now the power button assembly doesn't even bother to light up and I can't even turn it on to see if the new board is good or not good.Anyone have a way to trick/force it to turn on? (note, I did check to make sure there weren't any obvious breaks or shorts in the traces for the touch sensor assembly all the way back to the processing board, aka "Key1", "Key2", "LED", "+3.3V", "GND" etc. and the old processing board does have a short on the regular "+3.3V"; "+3.3V_IP" is ok though)
Old Psu Konstanter 34 K 32 R 4 - Page 1
Forum section: electronics / repair

author: DarkZero
author_rank: Regular Contributor
timestamp: April 08, 2015, 07:22:45 am
content: Hello All!I'm trying to repair this thing for quite some time and i checked everything on this board and i suspect that MC1466 is broken.now i found this articlehttp://www.radiomuseum.org/r/gossen_konstanter_34_k_32_r434k3.htmlit mentioned that MC1466 can be replaced with couple of components but links are broken and i don't understand german.Anyone have some ideas ?

author: Guni
author_rank: Regular Contributor
timestamp: April 08, 2015, 08:32:05 am
content: MC1466 is still possible to findhttp://www.ebay.com/itm/1pcs-MC1466L-MC1466-PRECISION-WIDE-RANGE-VOLTAGE-AND-CURRENT-REGULATOR-/181039901431

author: DarkZero
author_rank: Regular Contributor
timestamp: April 08, 2015, 05:16:21 pm
content: Hello!i don't have ways to buy outside my country. is it possible to emulate this circuit in anyway ?

author: Guni
author_rank: Regular Contributor
timestamp: April 08, 2015, 09:10:15 pm
content: Yes, it's possible.Ask tefkan, he build emulator. Check this tread:https://www.eevblog.com/forum/chat/restoring-the-lambda-lq-532v-power-supply-**end-of-project**/msg42513/#msg42513http://s1138.photobucket.com/user/tekscopes/media/MC1466replacement.jpg.html?t=1300195263Advanced, miniaturized version:http://tubetime.us/?p=237
QRD60-1.5 Sorensen PSU - Page 1
Forum section: electronics / repair

author: backd00r
author_rank: Contributor
timestamp: April 08, 2015, 03:15:25 pm
content: A friend of mine gave me a QRD60-1.5 Sorensen PSU that he got very cheap from a thrift shop that is not working. The sticker on it reads open internal circuit. It seems as someone tried to repair it or something. Does any one know what would that be hinting to? also I can't find the user manual for this thing on the net.Thanks

author: merox
author_rank: Regular Contributor
timestamp: April 08, 2015, 08:12:31 pm
content: I think i've got an QRD 40-.75 sitting somewhere in the basement, together with the (service?) manual. I think your PSU belongs to the same series as mine, so the schematics for yours might also be in the manual i've got. Could you please upload a picture of your PSU? If it looks reasonably close to mine, i'll try to dig up that manual to take pictures of the schematic.I've attached a Datasheet of the series for others to see what it might look like.
Re-lacquering PCB's for outside usage? - Page 1
Forum section: electronics / repair

author: Chris Wilson
author_rank: Super Contributor
timestamp: April 07, 2015, 11:33:58 am
content: I have some expensive outside radio linked PIR sensors and 2 have suffered water ingress. I eventually found the reason they were intermittently faulty was the coating on the PCB's had become slightly conductive and op-amps were doing "funny things". I soaked and washed the boards after dismantling the devices in isopropyl alcohol and dried them slowly. I have found some coatings go soft and are removed by IPA, and some are unaffected. This stuff came off in minutes. They now work fine but I fear usage in an outdoor environment may cause PCB track degradation. I would like to re-coat them with a water proof varnish of some kind. has anyone any experience as to what to coat them with please? Thanks!

author: android
author_rank: Regular Contributor
timestamp: April 07, 2015, 11:44:27 am
content: You could tryElectrolube DCA SCC3 Conformal Coating. I bought a 200ml spray can recently, but have to admit to not actually using it yet. You can solder through it later if you need to. Pricey though.

author: tautech
author_rank: Super Contributor
timestamp: April 07, 2015, 11:47:24 am
content: Here's a local one for you:http://uk.rs-online.com/web/p/electronics-varnishes-lacquers/0569290/I use similar one all the time in our humid climate, even on new home etched PCB's before soldering.Good for touch ups after rework too.

author: Chris Wilson
author_rank: Super Contributor
timestamp: April 07, 2015, 12:00:00 pm
content: Excellent, RS are convenient as I need some other stuff that I can add on to get free P&P. Thanks for that!

author: madires
author_rank: Super Contributor
timestamp: April 07, 2015, 12:32:23 pm
content: CRC's SK10 works fine for me. SK10 is flux and lacquer in one, but it's not a conformal coating. I got old home automation stuff I made over 20 years ago and the PCBs still look like new (some mounted in a moisty environment).

author: SeanB
author_rank: Super Contributor
timestamp: April 07, 2015, 04:04:36 pm
content: If you only have a few use some 2 part clear epoxy after cleaning the board to coat the boards on each side. Cover all components and wiring so that moisture does not get to the copper.

author: wagon
author_rank: Frequent Contributor
timestamp: April 08, 2015, 01:49:00 pm
content: If you are really tight for funds you can use a clear 'enamel' paint in a pressure pack can. Do a couple coats. Works OK, and is good considering you can buy a can of it for about $5.

author: Chris Wilson
author_rank: Super Contributor
timestamp: April 08, 2015, 02:03:19 pm
content: Got the RS branded spray coming as per tautech's link, hopefully it will do the job, with luck they'll last another 14 years thenThanks everyone!
Repair broken HP knobs - Page 1
Forum section: electronics / repair

author: Guni
author_rank: Regular Contributor
timestamp: April 08, 2015, 12:12:58 am
content: I'm working on restoration of early HP1707B.My scope is generally in very good condition. Knobs are complete but some of them are broken. Still in one pieces but broken.I can not clean and degrease splits very good what is required for epoxy glue (best solution imho). So think about some aggressive plastic glue on acetone or similar base. But I'm not sure what is the best.Do you have any experiences with this? What is the best type of glue for repairing?It looks like common problem on vintage HP measurement devices. HP used the same type of knobs for decades.

author: xrunner
author_rank: Super Contributor
timestamp: April 08, 2015, 12:25:52 am
content: Quote from: Guni on April 08, 2015, 12:12:58 amYes.QuoteMEK (Methyl Ethyl Ketone). It will weld the plastic real good.

author: GreyWoolfe
author_rank: Unknown
timestamp: April 08, 2015, 01:42:44 am
content: I remember Plastruct from my military modeling days in the 70's and 80's. Good Stuff. You bond 2 pieces of plastic with it and you will never get them apart.

author: cncjerry
author_rank: Unknown
timestamp: April 08, 2015, 01:52:11 am
content: I've not found glue that will hold them together though I haven't tried ME. I make molds and recast the plastic know over the aluminum insert. I've had great luck, they are hard and with just a little dye the colors are near perfect. I bought all the chems at Tap plastics.

author: Guni
author_rank: Regular Contributor
timestamp: April 08, 2015, 08:18:05 am
content: Thx for all advices. MEK seems to be the best solution.I'v tested glue on methyl acetate base but it is a gel. It melt plastic a little but it's hard to apply because of consistency and not good penetrate split.
Weller 921Z Soldering Station - Page 1
Forum section: electronics / repair

author: vette54
author_rank: Newbie
timestamp: April 05, 2015, 11:54:19 pm
content: Does anyone know where I can buy tips for my Weller 921Z? Or is the complete removable iron and cord available?

author: LA7SJA
author_rank: Regular Contributor
timestamp: April 06, 2015, 10:56:49 am
content: I have not found any information about that model, but here are som general info from Weller.Weller® SolderingBroschure Soldering TipsWeller_Soldering_TipsJohan-Fredrik

author: ciccio
author_rank: Frequent Contributor
timestamp: April 06, 2015, 04:08:19 pm
content: Your model was sold only in the America market.For what I see from the (not many) photos I've found in the net, the iron seems the same of the WES station.There were some offers on e-bay.I cannot guarantee this, but you can contact Weller USA.

author: miguelvp
author_rank: Super Contributor
timestamp: April 07, 2015, 08:29:29 am
content: they are discontinued but this site at least has the part numbers if it helps you look for some:http://www.testequipmentdepot.com/weller/tips/9000seriestips.htmand this doc:http://datasheet.octopart.com/9011-Cooper-datasheet-59580.pdfThey seem to be very hard to find, so good luck!
MASTECH MS8229 - Blown resistor - Page 1
Forum section: electronics / repair

author: vagfou
author_rank: Newbie
timestamp: April 07, 2015, 10:35:31 am
content: Hi,I have a MASTECH MS8229 multimeter and after an unfortunate frequency measurement it seems to have some mulfuctions.After opening the multimeter I saw a blown resistor. It is the R33 on the main circuit board.Can anyone (who has the MS8229) open his multimeter and tell me the Ohms of that resistor? (or anyone who has the circuit schematic)

author: 1xrtt
author_rank: Regular Contributor
timestamp: April 07, 2015, 05:37:18 pm
content: It has the inscription 01D (same as R13, close by). I'm not sure what it means, but it measures ~100K in-circuit.

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 07, 2015, 06:44:11 pm
content: Quote from: 1xrtt on April 07, 2015, 05:37:18 pmEIA-96 codet 1% resistor, that is 01 (100) multiplied by D (1000) so 100K seems abut right.

author: vagfou
author_rank: Newbie
timestamp: April 08, 2015, 09:44:55 pm
content: Thank you very much guys... you really helped me.I fixed it!
Quick Refurbishing of HP 5381A - Page 1
Forum section: electronics / repair

author: VK5RC
author_rank: Unknown
timestamp: April 04, 2015, 02:59:28 am
content: A bargain off ebay (USD 20) for an 'as is' HP 5381A.A few stickers, a few funny LED segments (fixed by cleaning off some old flux and a re-solder or two) but no major catastrophes.Techniques, general cleaning melamine sponge and IPA, Mothers Back to Black for front panel.Before 1st Three pictures, After is the last one

author: xrunner
author_rank: Super Contributor
timestamp: April 04, 2015, 03:17:22 am
content: Yea I saw those on eBay. Good cleaning job.

author: VK5RC
author_rank: Unknown
timestamp: April 04, 2015, 07:49:28 am
content: Thanks, inspired by yours and Robrenz et al efforts.I am a bit of a red LED fan.
PCB Connector - Page 1
Forum section: electronics / repair

author: wchafe
author_rank: Newbie
timestamp: March 28, 2015, 11:58:34 pm
content: Hello all.Can anyone tell me what type of connector would match up with the solder points based on this picture? The gap between pins is 1.5mm.

author: alexanderbrevig
author_rank: Frequent Contributor
timestamp: March 29, 2015, 12:25:09 am
content: My guess would be some kind of JSTMeasure the pin pitch and try to search for a connector with that pitch and pin count.Good luck!

author: SL4P
author_rank: Super Contributor
timestamp: March 29, 2015, 01:10:47 am
content: The SMD solder mounting points may help identify the connector variant as well...

author: wchafe
author_rank: Newbie
timestamp: April 03, 2015, 02:42:32 am
content: I found one at Digikey. Thanks for the help!
Need help identify microchip on macbook air charger magsafe2 85w - Page 1
Forum section: electronics / repair

author: TUAREG
author_rank: Newbie
timestamp: March 31, 2015, 08:54:25 pm
content: Hello, today i was charging my mac book air and suddenly the charger litterally exploted.After opening it, i realized the microchip marked on red was completely destroyed, i unsoldered it, the board it is ok, no missing pads by the explosion....could anyone give me the reference??thanks in advance and excuse my english

author: BlueBill
author_rank: Regular Contributor
timestamp: March 31, 2015, 09:11:24 pm
content: Is that a fake Magsafe2 charger?

author: TUAREG
author_rank: Newbie
timestamp: March 31, 2015, 09:40:34 pm
content: No, It is an original Apple charger

author: TUAREG
author_rank: Newbie
timestamp: April 02, 2015, 02:12:46 pm
content: Nobody can help me on this?

author: BlueBill
author_rank: Regular Contributor
timestamp: April 02, 2015, 08:22:51 pm
content: There's a good chance it's a custom Apple IC, plus something blew it up so replacing it might just blow up the new part.Those magsafe connectors don't last, might be prudent just to buy another charger or if you have AppleCare try taking it to an Apple store.How are you sure that's a genuine Apple charger? Can you post more photos?
Garrison Fan - Page 1
Forum section: electronics / repair

author: Ginette
author_rank: Newbie
timestamp: April 07, 2015, 10:04:46 pm
content: I have a Garrison, "Oscillating Pedestal Fan, model.: # 043-5641-2.After dismantling and reassembling the fan to clean it, the "Safety Stop Touch Senser" does not work anymore ....
HP E3631 Readback problems - Page 1
Forum section: electronics / repair

author: dundee
author_rank: Regular Contributor
timestamp: February 26, 2015, 09:39:46 pm
content: Hi Guys!I bought a faulty E3631 Power supply here in the forum - Thanks to Peter! Very fast deliveryhttps://www.eevblog.com/forum/buysellwanted/uk-fs-hpagilent-e3631a-triple-output-dc-power-supply/This device has some problems with it's readback voltages and currents.I measured around the ADC and found R5 that was open.After replacing with a 30K resistor the +-25V Ranges were working perfectly.But the 6V range is still wrong. I made a little Video:Sometimes the display shows values over 100V...Any suggestions, where i have to look?Steffen

author: free_electron
author_rank: Super Contributor
timestamp: February 26, 2015, 10:55:22 pm
content: check the main board circuitry around the optoisolators.

author: dundee
author_rank: Regular Contributor
timestamp: February 27, 2015, 02:40:16 pm
content: You're right. The two left optoisolators are wrong...Do you know where i can get these? Or an equivalent?

author: rolycat
author_rank: Super Contributor
timestamp: February 27, 2015, 03:48:40 pm
content: HCNR200 optoisolators are still readily available, although not cheap.For example, Farnell have them in stock:http://uk.farnell.com/avago-technologies/hcnr200-300e/optocoupler-smd-analog/dp/8549710

author: dundee
author_rank: Regular Contributor
timestamp: February 27, 2015, 05:54:14 pm
content: Quote from: rolycat on February 27, 2015, 03:48:40 pmIs the HP2211 the same as HCPL2211?I think the pinout of the HCNR200 is not the same.

author: rolycat
author_rank: Super Contributor
timestamp: April 02, 2015, 01:21:31 pm
content: Quote from: dundee on February 27, 2015, 05:54:14 pmNo, the HCNR200 is the other optoisolator on that board which is often a source of problems.I believe the HCPL2211isthe same as the HP part HP2211 -this Taiwanese websitesuggests that this is the case.How is the repair going?P.S. Sorry about the long delay in replying - was hoping a more knowledgeable forum member would answer your query.
LCD EW162B1YLY Datasheet required - Page 1
Forum section: electronics / repair

author: TSL
author_rank: Regular Contributor
timestamp: March 31, 2015, 09:06:24 am
content: Hi all,I'm having a hard time finding any info on this LCD.Any information on this device greatly appreciated.thanksTim

author: bktemp
author_rank: Super Contributor
timestamp: March 31, 2015, 10:04:46 am
content: Looks like a standard 2x16 HD44780 compatible LCD, manufactured by EDT in 2001.http://www.edtc.com/Datasheet for this series:http://www.alldatasheet.com/view.jsp?Searchword=EW162BThe difference in partname are most likely a different backlight, viewing angle or other minor details.
Repairing Hitachi V-212 - Page 1
Forum section: electronics / repair

author: dlane
author_rank: Newbie
timestamp: March 27, 2015, 12:20:05 pm
content: Hello,I recently won a V-212 oscilloscope on eBay with a damaged knob and switch. Other than those problems the scope shows a trace and the other controls appear to be fully functional.I bought the 'scope for the express purpose of learning, so I'd like to take a shot at repairing it if possible.The parts in question (front panel pic attached):INT/TRIG switchVOLTS/DIV knob (x5 gain knob appears to have snapped off)I've searched the forum and tried Googling part numbers from the V-212 service manual but no luck.Any suggestions on where replacement parts might be found?Thanks in advance!

author: alanb
author_rank: Frequent Contributor
timestamp: March 27, 2015, 02:03:05 pm
content: I have a copy. I have been trying to upload it however the size is too large to attach. As a Zip file it is approximately 8mb I have split it into a series of RAR files however this forum does not allow that file type to be uploaded.Happy to email them to you if you send me your email address by PM.Alan

author: alanb
author_rank: Frequent Contributor
timestamp: March 30, 2015, 08:18:01 am
content: Manual sent by email. Good luck with the repair.Alan

author: dlane
author_rank: Newbie
timestamp: April 01, 2015, 08:57:04 pm
content: Cheers Alan!If anyone on the board has suggestions on where to find replacement parts (knobs and switches) for the Hitachi V-212 here in the States I'd be most grateful.
TDS 5000 series - Page 1
Forum section: electronics / repair

author: boughdiri
author_rank: Newbie
timestamp: April 01, 2015, 10:46:10 am
content: HELLO everybodyCan someone help me please?I have an oscilloscope TDS 5052 I lost my emergency disk and my HDD is deadI have the two operating system restore 063-3509-04 CD's but i can't to rebuilt it. the system tells me ''this is not a tds 5052''.There is a solution for my problem.thank you for help
HP 4195A A10 schematic and parts locater needed. - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: March 31, 2015, 10:23:26 am
content: Hello all,I'm in the process of repairing an HP 4195A Network/spectrum analyzer. After getting the power supply up and running, there is another problem on the A10 Frequency generator module. I have the service info available on the web and from Keysight, but it is quite a bit different as my serial prefix 3123A. The one from Keysight dated August 1988 is for serial prefix 2738J. I'm hoping that someone may have a newer manual that they could scan the A10 schematics and parts locator.Thanks!Jay
Repairing i5-2500k - Page 1
Forum section: electronics / repair

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 26, 2015, 09:55:03 pm
content: Hi,I need a dirt cheap computer like dirt cheap. I am decent and SMT soldering and I was wondering. Is it worth my while to purchase two i5-2500k with different missing capacitors. they are being sold for £5 each. Is it worth my while to buy these and solder new capacitors on one of them for the slim chance it may work?

author: TiN
author_rank: Super Contributor
timestamp: March 27, 2015, 11:14:29 am
content: They are likely to work fine. Those are decoupling caps usually.

author: AKM
author_rank: Contributor
timestamp: March 27, 2015, 12:29:32 pm
content: I don`t think the missing capacitor is the reason why the CPU doesn`t work.

author: bdivi
author_rank: Regular Contributor
timestamp: March 27, 2015, 02:48:59 pm
content: If the CPUs do not work without the capacitors they will not work with capacitors. Someone most probably tested them the ended up with this ridiculously low price.I hear however that those CPUs can be fine keychain accessories :-)

author: van-c
author_rank: Regular Contributor
timestamp: March 27, 2015, 04:38:21 pm
content: That i5-2500K is a great CPU and may be worth dropping a small price to gamble you can get it working. I recently overclocked one in my wife's game machine to 4.7 GHz, up from the stock 3.3. But new Socket LGA 1155 motherboards are starting to get scarce.Hope it works out for you.--Van

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 27, 2015, 11:47:33 pm
content: So should I buy one instead of two?

author: van-c
author_rank: Regular Contributor
timestamp: March 28, 2015, 04:06:50 am
content: Quote from: Aodhan145 on March 27, 2015, 11:47:33 pmYou'll have to decide that for yourself. If you have (or can get at a reasonable price) a motherboard and are willing to gamble £10 (about $15 USD) you'll could luck out and have the basis of at least one working system. But I'd try to find out some history from the seller first. If they are known not to be working in their current state, I'd pass. Frankly, it's not likely they were taken from a known working system at that price.

author: Rasz
author_rank: Super Contributor
timestamp: March 28, 2015, 11:28:29 am
content: things like CPUs being sold as 'not tested' are 99.999% always broken and _tested_. One does not simply sell $200 item for $10 without testingbroken off caps mean this cpu had a life in a spare/junk box in some service center

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 28, 2015, 10:59:29 pm
content: Quote from: Rasz on March 28, 2015, 11:28:29 amGood point he is selling a lot of them. It's definitely from an old box of broken ones.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: March 30, 2015, 04:55:47 pm
content: For a good mobo, look for asrock z77 extreme motherboards. Mine can OC a non k series to 3.8ghz. The extreme4 has a debug display and cost me about 100$ used.
Replacing T5 in Solar Charging Light - Page 1
Forum section: electronics / repair

author: james2k2
author_rank: Contributor
timestamp: April 02, 2015, 11:03:46 am
content: Hi All,After seeing Dave's eev video on replacing his bathroom T4 with LED strips, I had a thought about a solar charged light I have where it uses one of those little T5 tubes and unfortunately was quite poor in actual light output - even with a new tube, so I want to replace the tube with LED's. Not a problem I thought! Remove the starter electronics and take a direct feed with some voltage dropping for the white LED's.I *think* the solar panel has died. I can't get a voltage at all from the DC plug on it and I can't open up the panel without damaging it as it's a fully enclosed waterproof one designed to go on an outdoor wall or shed roof as it's original purpose was an emergency light.Can anybody give me any pointers on testing small solar panels like these? If it helps, I think the reverse protection diode has failed as instead of infinite reverse resistance, it has somewhere in the realms of 500K and then around 6K forward. Hmm.So, if I want to go ahead with this project, I guess the first thing would be to replace that diode. Then the panel if required. As for charging, at the moment the PCB simply links the solar panel output directly to the battery terminals - what cheap improvements could be made here?You're all probably thinking "Why would he continue with this if it's this far gone?" I like the chassis of the thing as a whole. It has mounting holes on the back and is big enough to fit extra stuff in if required and I like the diffuser too. The thing as a whole only cost me £5 so it's worth it just keeping the casing.
Apple PowerMac G5 Repair Advice - Page 1
Forum section: electronics / repair

author: acdcflyonthewall
author_rank: Newbie
timestamp: March 26, 2015, 12:54:16 am
content: Hello everyone! I'm new here and I have a power mac g5 that I garbage picked and it needs a new logic board or at least a re-flow I guess... I have looked up tons of info on this problem and i'm very pissed about what happened with this computer as it one of the best built ones I have ever seen! My question is there are alot of sites that have used logic boards and "reconditioned" boards but do they really fix the problem or just sell used boards? what would be the best site to get a board from?

author: cosmicray
author_rank: Frequent Contributor
timestamp: March 26, 2015, 01:32:21 am
content: Is this one air-cooled or water-cooled (with the baby radiator) ?

author: sdev2004
author_rank: Contributor
timestamp: March 28, 2015, 01:16:40 am
content: Hi, what is the problem with the G5? does it post? you said that the logic board needs a re-flow but on which chip?

author: Rasz
author_rank: Super Contributor
timestamp: March 28, 2015, 11:31:09 am
content: YT clip suggests one/both chipsets

author: sdev2004
author_rank: Contributor
timestamp: March 28, 2015, 01:12:33 pm
content: If you are going to source a new board then your old board is as good as dead, do you have any liquid flux? try putting liquid flux around the chips and using a heat gun heat them for around 15-30 seconds using a 700w gun, the issue could be cracked solder joints on the PCB under the chip, its a temporary fix but if it sorts the issue then you can apply some decent thermal paste and run some tests.

author: Rasz
author_rank: Super Contributor
timestamp: March 28, 2015, 10:37:33 pm
content: Quote from: sdev2004 on March 28, 2015, 01:12:33 pmyesQuote from: sdev2004 on March 28, 2015, 01:12:33 pmnooo, thermal shock will kill chips, not to mention burn a hole in pcboven is nicer because its gentle

author: sdev2004
author_rank: Contributor
timestamp: March 28, 2015, 11:25:13 pm
content: That's true mate! however i don't like the oven as it can burn the plastic connectors if your not very careful lol (from experience haha)

author: tooki
author_rank: Super Contributor
timestamp: March 30, 2015, 02:43:43 pm
content: You can probably buy an entire working Power Mac G5 on eBay for less than the cost of a logic board. Those machines are indeed beautifully engineered*, but so hopelessly obsolete for any real computing purpose. It'd almost make more sense to use its PSU and enclosure to build some new project, rather than invest in resurrecting a dinosaur. Remember that the G5 machines are extremely power-hungry, and thus have massive, high-quality power supplies one could have lots of fun with. (Some G5 models were so greedy that they needed more power than a standard C13 power connector could handle, so they had the C19 connectors instead, normally seen only on bigger servers.)* In my Mac technician days a decade ago, I installed several dozen new Power Mac G5 machines, and oh, they were glorious for their time!
help identify smd component - Page 1
Forum section: electronics / repair

author: Daxxin
author_rank: Regular Contributor
timestamp: April 02, 2015, 06:09:19 pm
content: hi i have problem with NL3224AC35 nec lcd 5.5' panel look like this component low ohm beetwen pins but cant recognize it , connected to out of tl1451 pwm controllerit has 5 pins .. complex npn-pnp? mark is E5 ..thanks for helping.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 02, 2015, 06:27:00 pm
content: cmos inverter TC7S04FUhttp://www.datasheetcatalog.com/datasheets_pdf/T/C/7/S/TC7S04FU.shtml
32" Samsung LCD no backlights! - Page 1
Forum section: electronics / repair

author: sdev2004
author_rank: Contributor
timestamp: March 28, 2015, 06:37:58 pm
content: Hi all, need some help please repairing a 32"LCD there are no backlights, image can be seen with the good old torch trick. Thanks

author: tautech
author_rank: Super Contributor
timestamp: March 28, 2015, 07:30:25 pm
content: Check you are getting "clean" DC to the backlight inverter.Indentify the inverter controller IC and get the datasheet.Some inverters have Over Current shutdown protection, disabling it is a common fix, recommended?Inverter operation can be confirmed just with a scope probe used like a "near field" probe. (no connection)That should get you started.

author: Prime73
author_rank: Regular Contributor
timestamp: March 28, 2015, 07:34:47 pm
content: have you checked for bulged caps in the power supply?
Problem about Hantek DSO5202B - Page 1
Forum section: electronics / repair

author: beauty2003tt
author_rank: Contributor
timestamp: March 30, 2015, 01:58:03 am
content: Hello everybody.I have one Hantek DSO5202B from one year agao.It works well until last month.I powered it on but it kept restarted again and again.I have asked the after-sales service of Hantek but it hasn't been fixed until now although they seemed to help actively.Can anybody give me some help here?Or does anybody meet this problem also?Thanks.
Advantest R6551 DMM - Page 1
Forum section: electronics / repair

author: radhaz
author_rank: Regular Contributor
timestamp: March 27, 2015, 03:57:08 am
content: Hi guys.I have an Advantest R6551 DMM bought off of Ebay. It mostly works OK, but the AC functions are pretty much dead (ACI, ACV). Using my DMMCheck I get no response on ACV or ACI), DC stuff and ohms are good.There is not a service manual to be found anywhere. Any ideas about where to begin looking? This DMM is from around the late 1980s early 1990s.

author: rastro
author_rank: Frequent Contributor
timestamp: March 27, 2015, 09:09:25 pm
content: Advantest doesn't seem to have much information available on most of their test gear.FWIW some principals of operation are in the back of the user manual.http://exodus.poly.edu/~kurt/manuals/manuals/Other/ADV%20R6551,%20R6551EMC%20%20Operation.pdfSince it's all A/C functionality not working you may want to look for a relay that routes the input's for the A/C path from the banana jacks. Perhaps DC is the default path?It might be worthwhile to post a few pictures of the insides.
LHC - electrical short in Large Hadron Collider  - Page 1
Forum section: electronics / repair

author: coderAndHackerNW
author_rank: Newbie
timestamp: March 28, 2015, 05:47:24 pm
content: Hi, Dave:Would you do a video on debugging and repairing a short circuit in the largest machine on Earth?A tear-down would be nice; but I don't think they're finished with it yet. :-)Physicists narrow in on electrical short in Large Hadron Collider -http://news.sciencemag.org/europe/2015/03/physicists-narrow-electrical-short-large-hadron-colliderLHC Report: X-rays probe for cause of short circuit -http://home.web.cern.ch/scientists/updates/2015/03/lhc-report-x-rays-probe-cause-short-circuitThanks, Bob
Semi-Open Fuse? - Page 1
Forum section: electronics / repair

author: wn1fju
author_rank: Frequent Contributor
timestamp: March 28, 2015, 01:29:24 pm
content: I was fixing a generic Chinese function generator (Instek GFG-8020H) and after replacing the shorted transistor in the output amplifier, I hooked it up to the scope with an unterminated BNC cable and everything looked reasonable. When I properly terminated the cable with 50 ohms at the scope, the output vanished. I turned the unit off and put an ohmmeter across the output jack. Expecting to see 50 ohms, I was a bit surprised to measure ~400K. The culprit was the protective fuse in the output circuit which measured 400K after I pulled it. It is a standard glass 200 ma fuse (and looks intact). Didn't know that fuses can pop partially open. Guess I learned something today.

author: SeanB
author_rank: Super Contributor
timestamp: March 28, 2015, 02:26:47 pm
content: The fuse can fail as nearly open, as the wire breaks or oxidises at the crimp or at a break at the end, and while it will break down at mains voltage and work again at low voltage it is an insulator. Also you can get poor contact at the connections to the holder, which can be hard to trace as the slightest touch ( like picking the equipment up) makes it work again.
BK Precision 2120 rotation control - Page 1
Forum section: electronics / repair

author: Sparks
author_rank: Contributor
timestamp: March 26, 2015, 08:12:07 pm
content: I recently scored a nonfunctional BK 2120 oscilloscope from a thrift store and brought it back to life. The only problem I'm having is that the trace rotation pot is completely missing. After a quick search on the web I came across a schematic (didn't save it) which had it listed as a 5k?. Once replaced it worked, mostly. The trace is all straight, except the lower right quadrant drops down. Any advice would be appreciated.

author: tautech
author_rank: Super Contributor
timestamp: March 26, 2015, 08:20:46 pm
content: Got another scope?Might be a non-linear sweep.You'll need that schematic, better save it this time.Better still a Service manual.EditYou'll need another scope to confirm sweep.

author: Sparks
author_rank: Contributor
timestamp: March 26, 2015, 08:22:24 pm
content: Even drops if I lower the ground to the lower half of the screen

author: tautech
author_rank: Super Contributor
timestamp: March 26, 2015, 08:26:56 pm
content: Quote from: Sparks on March 26, 2015, 08:22:24 pmHappy with my faulty sweep initial diagnosis but post a photo to be sure.
Trinitron computer monitor fault? - Page 1
Forum section: electronics / repair

author: steve30
author_rank: Frequent Contributor
timestamp: March 09, 2015, 08:26:23 am
content: I have a Dell P790 monitor, with a 17" Trinitron tube, dating from 1999. I've haven't used it much sine 2008 when I changed to a bigger monitor, but it has always been quite reliable.However, I went to fix some problems with a computer yesterday, and required the use of this monitor, and it started behaving weird. The image was shrinking horizontally, the brightness was changing, and it was flashing on and off. I made a 3 minute video of the problem here:Does anyone have any idea what the problem could be? I haven't had chance to take the monitor apart and inspect it yet. Might do that later.Many thanks.Stephen Coates

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 09, 2015, 03:37:08 pm
content: Weeeeird!Your problem may be similar to what I had;http://seventransistorlabs.com/Monitor/index.htmlTake off the back cover and see what's inside. Also, try to find the service manual if you can. Likely, you'll have a main deflection board, or something like that. The board contains voltages from 100V to 1500V, so... probe very carefully, with as insulating a stick as you can find!The pincushion changing makes me think it's possibly a broken solder joint or SMT component near the horizontal drive (as was my case) or pincushion or S-correction circuits. The failing intensity may be the same (i.e., video cutoff under weak horizontal conditions, to protect the tube). Or it may be something completely unrelated (e.g., ~100V supply to the video amps going intermittent?).Good luck!Tim

author: steve30
author_rank: Frequent Contributor
timestamp: March 10, 2015, 04:29:54 pm
content: Thanks for the link. I'll have a detailed look inside the monitor when I get chance.What is the best way to discharge the capacitors in a monitor?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 10, 2015, 05:32:37 pm
content: A 10-100 ohm resistor will do fine, or a screwdriver if you're lazy... the HV you should probably leave alone, since you don't need to remove it.Tim

author: steve30
author_rank: Frequent Contributor
timestamp: March 28, 2015, 06:48:59 pm
content: Well, I took the monitor apart, and cleaned out 15 years worth of dust.Unfortunately I couldn't see anything bad inside it.The fault still seems a little bit intermittent. And today, the tube kept turning off (with the power light blinking fast). So I switched it off and left it to cool down, and now it is back to all the flickering as shown in the video.