hybridfree/eevblog-posts huggingface dataset:
Arrow Industries and Capital Bingo Board Premiere Flashboard - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 15, 2016, 10:11:51 pm
content: I am helping someone fix a Bingo Console and flash Board.The console and flashboard don't match.There is a convertor box but it seems to be wildly expensive.Any one have schematics on these units?
ATLAS PEAK LCR 40 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: December 06, 2016, 06:49:12 pm
content: Good evening; I am trying to calibrate my ATLAS PEAK LCR40; Someone would know the procedure to follow to calibrate itThank you for your help!

author: lionelkjh
author_rank: Frequent Contributor
timestamp: December 07, 2016, 06:33:14 pm
content: sniff!

author: stj
author_rank: Super Contributor
timestamp: December 07, 2016, 11:40:32 pm
content: did you contact the maker?http://www.peakelec.co.uk/acatalog/lcr_support.html

author: lionelkjh
author_rank: Frequent Contributor
timestamp: December 08, 2016, 11:27:30 am
content: Hello; Yes, already contacted, but no answer: he must reserve the right to reply, it remains to send by post; But I do not care because the distance is great, and the loss or deterioration is inevitable! That's why I use this forum to help me .....

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: December 10, 2016, 02:14:19 pm
content: I found the manual for it, it's talking about the self test which is kind of self callibration, look it up, may be helpful.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: December 14, 2016, 04:57:58 pm
content: Good evening; Thank you for the documentation. Too bad that nothing indicates how to calibrate it .....

author: Falkra
author_rank: Regular Contributor
timestamp: December 14, 2016, 08:22:25 pm
content: Hi, I have one, but I thnnk calibration is done within the firmware or a programmed chip.If you open it, there are no adjustable components, but there (I think) is a 4 pin programming interface).See pictures here (exposed PCB on both sides) :http://www.mikrocontroller.net/topic/215095Hires pictures :http://www.mikrocontroller.net/attachment/106697/edt_PeakAtlasLCR40_6.jpghttp://www.mikrocontroller.net/attachment/106696/edt_PeakAtlasLCR40_4.jpg

author: lionelkjh
author_rank: Frequent Contributor
timestamp: December 15, 2016, 04:54:37 pm
content: Thanks!
fixing undervoltage protection on unknown pure sine wave inverter  ZXB-800WC 24V - Page 1
Forum section: electronics / repair

author: marc22
author_rank: Newbie
timestamp: December 14, 2016, 08:55:13 pm
content: Hello,I'm looking for help in fixing pure sine wave inverter 230V (on case there is no model) on board ZXB-800WC.I believe it's a 24V volt inverter, but internal circuitry cut off battery on 10.x V and sound alarm ad 11V so it's looking like 12V inverter.But at 12V it's not possible to get 800W using built fuses, also fan's are 24V, and last sine wave inverter module it's not working at 12V (tiny inverter board, is feed by 7815) - only on 24V.Main IC on low voltage side (i believe there is a problem)PWM driver - KA7500Bop-amp - AS324P-e1Could someone shine light where is voltage sense for cut off?What might be wrong?I don't know story behind this unit, i got is "as is" - not working.Maybe in factory someone fitted wrong resistors and set unit low voltage op-amp for 12V system?Here is my video showing problem:Here are pictures of low voltage part of board:http://imgur.com/a/ujVRsAny ideas are welcome!Regards

author: pyroesp
author_rank: Regular Contributor
timestamp: December 15, 2016, 04:53:35 pm
content: The buzzer activates when the voltage is too low, maybe the same signal (or derived from it) is used to disable the output?Or maybe tracing the optocoupler to see what's driving it and see what circuit can disable it as to not generate the output sine wave.Your input caps are 35V, so I would agree with you that the input is not 12V. If it were 12V the caps would have a lower voltage.

author: Seekonk
author_rank: Super Contributor
timestamp: December 15, 2016, 05:02:09 pm
content: I would guess that decision is made in the 324. What I would try first is look at the 4 output pins of it and vary a power supply to see which one transitions at a suspect voltage. That would give you the section. Does this look new or shows use.
Laptop does not start - Page 1
Forum section: electronics / repair

author: Jane
author_rank: Frequent Contributor
timestamp: December 14, 2016, 08:49:26 pm
content: Laptop(Asus model F5RL) does not start(although it is connected to mains),if there is a battery inserted.If battery is removed (laptop also connected to mains), the laptop starts.Any clue where can be a problem?Thanks

author: dcac
author_rank: Frequent Contributor
timestamp: December 14, 2016, 09:05:47 pm
content: It could be a fault in the battery, have you tried with another battery?

author: brainwash
author_rank: Frequent Contributor
timestamp: December 14, 2016, 10:40:25 pm
content: Have you tried inserting the battery while booted the BIOS? It might tell you if the battery needs replacement. At least that's what the some Dells and Lenovos do. They won't start with a dead or missing battery.Anyway, I wouldn't go out buying a new battery, an Atom convertible has just as much (or more, on the GPU side) grunt as a Core2Duo T and costs as much as a replacement battery.

author: Wilksey
author_rank: Super Contributor
timestamp: December 14, 2016, 10:45:02 pm
content: I had a HP that wouldn't start with the battery in, replaced the battery, worked a treat!

author: Jane
author_rank: Frequent Contributor
timestamp: December 15, 2016, 06:27:51 am
content: Battery is good besides the laptop was tested with different batteries.The same problem.If I remove battery then Asus F5RL starts.If I insert the battery after BIOS started, then laptops works OKAny idea where is a problem?Thanks

author: CJay
author_rank: Super Contributor
timestamp: December 15, 2016, 08:24:31 am
content: Does the system report battery presence and state after you start it and insert the battery?

author: KhronX
author_rank: Frequent Contributor
timestamp: December 15, 2016, 10:57:29 am
content: It might be worth seeing if there are any BIOS updates available.Since laptop batteries are "smart", there's some I2C comms involved, and if something's screwy in that department, that could be your problem.

author: wraper
author_rank: Unknown
timestamp: December 15, 2016, 11:41:09 am
content: Quote from: Jane on December 15, 2016, 06:27:51 amIs battery charging in such case? Is laptop still working if you leave the battery in but disconnect the charger?
EZ Digital DS-1530 acts as 300Mhz Brick - Page 1
Forum section: electronics / repair

author: Eris
author_rank: Newbie
timestamp: December 14, 2016, 06:42:07 am
content: Hello,I've got from a friend of a friend oscilloscope (type EZ Digital DS-1530) and it doesn't work. The only symptoms it shows is backlight. It looks like boot problem.Any ideas what could be a problem ? I think it's bricked firmware.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 14, 2016, 07:19:29 am
content: Any beeps? Flashing lights on buttons? Relays clicking? Fans whirring? Does it seem like it's really powering up and just not showing the screen?Have you looked for a service manual or a teardown to compare the guts to?

author: Eris
author_rank: Newbie
timestamp: December 14, 2016, 08:40:54 am
content: Not a single beep, I didn't open it yet and googling didn't show any manuals at all. Only single pdf with the spec in Czech with nothing useful in it. I'll open it tomorrow when I have time. Will post pics.

author: Eris
author_rank: Newbie
timestamp: December 15, 2016, 07:17:09 am
content: So, I've finally managed to open that box of magic smoke (no smoke has been seen to escape). From the first look, I see nothing wrong. Smell test was ok, there wasn't any blown or inflated caps. When you power it up, the soft button works and you can hear the relay click inside and the fan turns on (i didn't hear it before ?!? it's really quiet). The buttons on the front panel light up and stay that way. They don't react to presses. The first thing I did when I opened it up was measured the outputs on the power supply. They have little labels with voltage next to header and the power supply did provide all the voltages. I don't have a scope, so I can't check the noise/ripple.The mainboard is nothing special.I still think it's a bricked firmware or boot problem.
HP 54502A Oscilloscope screen not working - Page 1
Forum section: electronics / repair

author: habibrenjie
author_rank: Newbie
timestamp: December 14, 2016, 08:58:04 am
content: My HP54502A scope has stopped working. When I turn it on I hear a relay ticking faster and faster, the screen doesn't turn on save for a few faint flashing of the "copyright hp" screen. Any advice on how to fix this or how to diagnose the problem is greatly welcomed.

author: Smith
author_rank: Frequent Contributor
timestamp: December 14, 2016, 11:30:59 am
content: Sounds like a power supply failure. These power supplies are notorious for failing.Most failures are due to bad caps. Mine had several of them. Finding them can be dificult, as many of them are put in parrallel. Thankfully the HP service manual does have an overview of the voltages and tollerances. If I remember correctly you can only adjust one voltage (5,2V).These power supplies are not a HP design, but manufactured by another 3rd party. There are some non official schematics on the interweb, but they are not 100% accurate.
Vandual - Page 1
Forum section: electronics / repair

author: lfostano
author_rank: Newbie
timestamp: December 12, 2016, 04:07:32 pm
content: Helping a friend out with his 1977 circuit board that sits behind a panel so I am told ,it has a trim pot , several resistors and a few diode so no big deal here. Was able to repair some of the blown away traces and have an item I don't know what it is. I am guessing a mosfet seeing how in 77 it most likely would be analog device. It is rectangular in shape like a 555 chip,on one edge it has a beveled edge .Its configuration is on one side has a single pin and on the other side it has 3 pins, one in center is clipped. There are several resistors and some .047 milar caps with a red band on one edge which I am assuming designates negative band a few diodes and a trim pot. This board operates a fan circuit I am told. Was not able to find any support from the web on this. Please help me here, any and all thought would be appreciated. Thanks in advance.

author: Monkeh
author_rank: Super Contributor
timestamp: December 12, 2016, 04:10:37 pm
content: Perhaps look at the markings on the part..

author: lfostano
author_rank: Newbie
timestamp: December 13, 2016, 02:00:33 pm
content: Yeah i would do that but part is pretty well cooked, nothing to see.I will post a picture here ,tried a few minutes ago but did not accept my photo, said it was too large .Will send one at a time .
Noctua NF-A6x25 FLX 60mm FAN ball-bearing noise ? - Page 1
Forum section: electronics / repair

author: onesixright
author_rank: Frequent Contributor
timestamp: December 16, 2016, 08:48:46 am
content: Hi,I have this FAN (Noctua NF-A6x25 FLX) thats part of a external disk cabinet (LaCie), to my utter frustration I hear the ball-bearing when its on.Anybody got a thought how to fix that or should i just replace it with a (different brand) fan, any tips?I checked the datasheet of the Nocutua and it should be already pretty silent. Maybe just a wanky model?Thanks!

author: ebclr
author_rank: Super Contributor
timestamp: December 16, 2016, 09:00:20 am
content: I use Noctua NF-F12 PWM and is zero noise, it's extremelly quite, In your case i would replace the unit for another Noctua the product is good , extremelly good,

author: cdev
author_rank: Super Contributor
timestamp: December 16, 2016, 08:54:56 pm
content: is it possible to put one drop of light machine oil on the bearing?I have a Noctua and its been very quiet for me. I've never had to lubricate anything.But on other fans often that makes them quieter. Just one drop per bearing, never more.
HP54512B - Page 1
Forum section: electronics / repair

author: femtohertz15
author_rank: Contributor
timestamp: December 07, 2016, 09:54:51 am
content: Hi all,I just got myself an HP54512B from the bay. Self tests pass and firmware cal goes smoothly. 4 channels of 1.2ns risetime goodness! But, it dumps cal after each power cycle. I think I see the cal ram battery looking straight down between the CRT and the CRT driver board on the left, held in by a clip reaching over the top of the battery.What kind of battery could I use to replace it? And, any chance I can pull it and replace using long forceps, or will I need to remove the motherboard to do the replacement?

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 07, 2016, 12:16:15 pm
content: Out of SWIMBOs and mine own painful experience:And, any chance I can pull it and replace using long forceps, or will I need to remove the motherboard to do the replacement?If you ask this about any mechanical process, the answer is NO. Better safe and sorry. I was fast once when trying to repair a DPO, and had to buy another one.

author: wn1fju
author_rank: Frequent Contributor
timestamp: December 07, 2016, 12:25:11 pm
content: I had to pull the motherboard for my somewhat similar HP 54522A. But then I removed the battery and ran 2 wires out through the back panel which attached to a cheap plastic battery holder (attached to the panel) containing 2 AA-cells. That way, 1) I can keep an eye on the battery life, 2) I never have to pull the motherboard again to replace the battery, and 3) when they eventually leak (as all batteries in test equipment seem to do), they will leak on the outside of the unit, not the inside!

author: femtohertz15
author_rank: Contributor
timestamp: December 12, 2016, 02:59:32 am
content: The battery had welded-on terminals, designed to be soldered into a board, which they were. I just clipped the leads and ran jumpers to a new battery. Cals fine now.
rca tv rlded5078a - Page 1
Forum section: electronics / repair

author: jonboy
author_rank: Newbie
timestamp: December 13, 2016, 02:55:14 pm
content: hello all and thanks in advance if you can help (or if you cannot)our tv appears to be stuck in a color test mode. comes on normally then cycles through all colors of the rainbow. none of the buttons work. have tried various combinations of button pushing found online but so far none have been effective. sure wont be sending it to a repair shop as it would cost the same as buying a new one but would rather not add it to a landfill. I dont know if this has anything to do with anything but the standby button on the tv itself seems to be recessed ...dont know if it always was or not.thanks again!

author: jonboy
author_rank: Newbie
timestamp: December 15, 2016, 07:20:37 am
content: nobody?
lpl psu repair require sockets and plugs - Page 1
Forum section: electronics / repair

author: mdronic
author_rank: Contributor
timestamp: December 11, 2016, 09:15:42 am
content: Hi, I lost my lpl psu for my enlarger. I bought a replacement psu however the sockets and plugs are different. On my enlarger the psu only supplies the lamp a 24v 200w and the leadhas a five sided connector. The fan plugs directly. However on the replacement paying the connection is via a round three pin type that supplies both the lamp and fan.If possible I prefer at this stage not to be too drastic and keep each as they are. I was thinking of. Just getting the suitable replacement plug and socket and some lead and making a joining lead. However I haven't been able to find any of the right plugs or sockets. I have tried the repair department for the enlarger and they do not have any or know where I might find them. Have included some pictures of the psi and lead to the lamp . Hopefully that someone may have some ideas. It has been suggested to convert to iec connections. ?..

author: JFJ
author_rank: Regular Contributor
timestamp: December 11, 2016, 05:14:05 pm
content: A standard 3-pin XLR plug would fit the round connector. They're available from sellers on eBay or from most electronic component suppliers, e.g:http://www.futurlec.com/XLR-3Pin.shtmlThe 2-pin connector looks similar to polarized Molex connectors:http://www.ebay.com/itm/Molex-2-Pin-Connector-Kit-0-093-3-Sets-/321658244477but they might not be compatible.If you cannot find a suitable 2-pin connector, and do not want to chop off the existing connector, then one option might be to fit an XLR plug to a new length of cable and wire the other end of the cable directly into the enlarger. That way, the original cable would still be available and intact, should you wish to reverse the modification. Presumably, there will be screw terminals for the cable within the enlarger, as the connections to the halogen lamp are likely to be made with high temperature cable.
Please help ID Passive - Page 1
Forum section: electronics / repair

author: Rjc987
author_rank: Contributor
timestamp: December 11, 2016, 08:38:12 pm
content: Hi, so I have a hard drive that got wet and fried - there are no obvious failures, nothing let the smoke out but I was just checking components with a meter and there's a small white ceramic surface mount component the size of a normal resistor -- it has 2 terminals, and had D over the number 6 written on it. The board labels it vr3 and it has 2 small traces leading to it, not connected to the ground plane. When I test resistance, it's completely open circuit. I think that might be my culprit but I have no clue what it is. Any ideas?Sent from my iPhone using Tapatalk

author: tatus1969
author_rank: Super Contributor
timestamp: December 11, 2016, 09:18:44 pm
content: i would look for a used drive of the exact same type and swap the electronics. that way you might be able to recovet the data on the discs.

author: brainwash
author_rank: Frequent Contributor
timestamp: December 14, 2016, 02:17:48 am
content: Could be a fuse, those are USUALLY white, but capacitors CAN be white as well. Obviously swapping a cap for a fuse is a bad idea. But if you don't have anything to lose you could connect a multimeter on amps setting to the terminals.Also check what the other components marked D are. 6 might mean amps. Fuses are usually marked F on the board. Maybe someone designing SMD boards can have a better idea.

author: KhronX
author_rank: Frequent Contributor
timestamp: December 15, 2016, 11:11:41 am
content: That component description sounds familiar - some time ago (earlier this year) i tried to find some data on a similar-sounding component on a hard-drive PCB.My searches led me to some Murata datasheet or catalog page, if memory serves, describing it as some sort of shock sensor.

author: wraper
author_rank: Unknown
timestamp: December 15, 2016, 11:24:24 am
content: Such questions usually are pointless without providing a picture.

author: KhronX
author_rank: Frequent Contributor
timestamp: December 15, 2016, 06:06:00 pm
content: Is it something like this?http://www.murata.com/products/sensor/shock/consumer

author: lfostano
author_rank: Newbie
timestamp: December 15, 2016, 09:34:11 pm
content: My guess is variable resistor, vr usually stands for that but it is only a guess.
Looking for circuit diagrams of Kontron 8201 generator... - Page 1
Forum section: electronics / repair

author: carl_lab
author_rank: Frequent Contributor
timestamp: December 06, 2016, 10:52:55 am
content: Need to find circuit diagrams for this defective generator:

author: azer
author_rank: Regular Contributor
timestamp: December 06, 2016, 12:05:18 pm
content: http://sci.tech-archive.net/Archive/sci.electronics.equipment/2004-09/0129.htmlIt's old, but might be worth a shot if you haven't tried it.

author: carl_lab
author_rank: Frequent Contributor
timestamp: December 07, 2016, 11:19:27 am
content: Got it, thank you...
ASUS Zenpad C170CG Reboot Continuously and Won't Enter Recovery Mode - Page 1
Forum section: electronics / repair

author: ramadhan.saufik
author_rank: Newbie
timestamp: December 06, 2016, 01:36:00 am
content: Hi,I got a problem with my asus c170cgwhen i charge the tablet it goes to reboot again and againunfortunately the recovery mode also doesn't work, after i press power+volup button it remain still displaying android icon for long timethere was a condition that the screen remain still displaying boot icon (ASUS .Insearch of Incredible)can anyone help?before i got this problem i was open the back case (tablet) to repair my micro sim slot card which not dectect my sim card
identify component - Page 1
Forum section: electronics / repair

author: Daxxin
author_rank: Regular Contributor
timestamp: December 04, 2016, 11:48:38 am
content: help me identify this and choose equivalent replacementprinted 15SP 010

author: carl_lab
author_rank: Frequent Contributor
timestamp: December 04, 2016, 11:57:59 am
content: http://www.uei.com.tw/psp.pdfhttp://www.ebay.com/itm/10pc-NTC-Thermistor-Surge-Protection-15SP010-N15SP010-10-15mm-15mm-UEI-Taiwan-/131858976063?hash=item1eb3684d3fhttps://lmgtfy.com/?q=15SP+%20+010+varistor

author: Daxxin
author_rank: Regular Contributor
timestamp: December 04, 2016, 04:28:56 pm
content: thanks its fine working , i have problem with hp 16702 psu sparkling and clicking after swapped 2SK1531 (shortened) with IXTH15N50L2 mosfet ..it was good equivalent?any suggestion apreciated about replacement ..cannot find 2sk1531

author: carl_lab
author_rank: Frequent Contributor
timestamp: December 05, 2016, 06:19:13 pm
content: http://elektron.uw.hu/catalog/Cross-referenceMOSFET.pdfhttp://noel.feld.cvut.cz/hw/st/3650.pdf

author: dacman
author_rank: Frequent Contributor
timestamp: December 06, 2016, 12:45:47 am
content: I'd look for another problem. Possible crosses: NTE2970 and NTE2394. Your cross should have worked, although its parameters aren't identical.
Battery rant - Page 1
Forum section: electronics / repair

author: PaulAm
author_rank: Frequent Contributor
timestamp: December 05, 2016, 10:39:45 pm
content: I had a power failure this morning that put all my systems on the UPS. When my monitor told me I had 30 minutes left I started shutting down systems. This was not a big deal, normally, but all of a sudden the batteries just died.Well, I was expecting this and I had a couple of replacement batteries sitting on the shelf. Just plug them in an go, right? No, after putting them in, the UPS wouldn't start. I took them out and put in the old batteries and pried off the end covers so I could charge each of the 12V batteries in the pack separately. When I did that I found one of the battery connectors had been wired up in REVERSE! Fortunately, the two packs are put in series to get 48V ( 2 packs of 2 12V batteries) so inthis case I got 0V. Things would have gotten interesting if they were paralleledMoral: don't assume a brand new battery pack is correctly assembled without testing it first.
HP Logic Dart (died after battery leaked) any info out there? - Page 1
Forum section: electronics / repair

author: RussD
author_rank: Contributor
timestamp: September 17, 2016, 06:58:37 pm
content: HiMy Logic Dart died after battery leaked out all overI have replaced the lithium and tinned some of the through holes that looked dodgyIt now powers up but with faults and can't power down system boots and stops at about 80%This was a nice little tool in it's day and would love to resurrect it.Main problem is lack of any information, all I can find is a user manualAny info would be gratefully received.If you have one or ever used one I would be interested in that too.Hewlett Packard Logic Dart E2310A

author: RussD
author_rank: Contributor
timestamp: September 18, 2016, 07:31:06 pm
content: Some Photos of the beast

author: RussD
author_rank: Contributor
timestamp: September 18, 2016, 07:35:58 pm
content: More ShotsThe vertical lines are bad screen connectors I don't think this causes system boot errors

author: RussD
author_rank: Contributor
timestamp: September 18, 2016, 07:45:53 pm
content: As you can see in the photos power up screen banner is displayed and LED's flash in sequence and then the main screen comes up and alarm buzzer comes on (and stays on until AAA batteries are removed no other functions work

author: RussD
author_rank: Contributor
timestamp: September 18, 2016, 09:21:29 pm
content: JMI Software SystemsPageAnother example of a customer product using C EXECUTIVE is the LogicDart from Hewlett-Packard. You may note that this product was featured on the cover of Embedded Systems Programming's 1998 Buyer's Guide, the de facto reference document for the embedded systems industry. This advanced logic probe uses the 80186 version of C EXECUTIVE to provide a powerful hand-held instrument for testing new microprocessor boards and other digital logic. This product won the Test Product of the Year award for 1998 as a "clear winner". You can also read about the LogicDart in the cover story of the March, 1998, issue of PennWell's Portable Design magazine. To get the full details on this product, check out Hewlett-Packard's LogicDart announcement.

author: emptech
author_rank: Regular Contributor
timestamp: December 05, 2016, 08:00:01 pm
content: I have a brand new one in the box a friend gave me, I don't see where I would ever use it, thought about putting it on ebay, but am too lazy. Is it something that anybody is interested in?Jim emptech@surewest.net
Hameg HM5005 spectrum analyzer - Page 1
Forum section: electronics / repair

author: rodd
author_rank: Regular Contributor
timestamp: December 03, 2016, 03:09:41 pm
content: I received one of these as a gift from a friend.No trace at all so I am hopping this a power supply issue.I searched the invoice net but could not find the schematics and/or the service manual.Does anyone has a copy to share?Thank you all in advance,RogerEnviado do meu iPhone usando Tapatalk

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 03, 2016, 04:58:53 pm
content: I could not find anything free to download, but a few sites offer the document to download for $6-$10.I found the service manual for the MH5010, but I have no idea how similar or different the power supply is.http://www.ko4bb.com/manuals/92.110.177.228/Hameg_HM5010-11_Service_Manual.pdf

author: bktemp
author_rank: Super Contributor
timestamp: December 03, 2016, 05:39:20 pm
content: Can you take a photo of the power supply board?Most Hameg scopes/spectrum analysers when through several revisions. The early versions used a mains transformer + linear regulator. The later ones used a SMPS.Often scopes and spectrum analysers used identical power supply boards, so even if you can't find a service manual for the spectrum analyser maybe an identical power supply board is used in a scope.

author: rodd
author_rank: Regular Contributor
timestamp: December 04, 2016, 04:04:54 pm
content: Quote from: bktemp on December 03, 2016, 05:39:20 pmI can't take a picture of it right now but it appears to be a SMS power supply.Would you suggest other instrument I could use as a reference?Enviado do meu iPhone usando Tapatalk

author: bktemp
author_rank: Super Contributor
timestamp: December 04, 2016, 07:06:20 pm
content: Unfortunately most available service manuals only cover the older linear regulated power supplies.If you are lucky the power supply board in HM305-2 is similar.

author: rodd
author_rank: Regular Contributor
timestamp: December 05, 2016, 04:52:57 pm
content: This a photo of the power supply.Enviado do meu iPhone usando Tapatalk

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 05, 2016, 06:33:08 pm
content: that looks like a linear supply. Did you look at the link I posted earlier in this thread?

author: bktemp
author_rank: Super Contributor
timestamp: December 05, 2016, 06:56:16 pm
content: Yes, that is a linear power supply and it looks identical to the one used in HM5010.
Electronic Ballast trouble  - Page 1
Forum section: electronics / repair

author: vodka
author_rank: Frequent Contributor
timestamp: December 05, 2016, 03:44:47 pm
content: Hi , i have a trouble with an electronic ballast . At principle the breakdown seemed easy , only it was a blasted electrolithic capacitor after of the bridge diodes.When i went to test , the lamp didn't turn on. I returned to take apart and i checked transistors(It's ok), i checked the all diodes(It's ok) and i check the toroid's wire(It's ok) .Then , i injected a 60 VDC* on the fixed capacitor and after the first transistor with the goal to discover if the transitor began to oscillate . With a fail resulted: No oscillate neither it consumed current.*note(Like you have seen the board haven't fuse, the reason is that when i was checked the board ,a tip slipped and it touched a phase .This is too the reason for injecting 60 VDC because i don't want to blow more fuse and i haven't a isolator transformer ).Photos and schematic:https://drive.google.com/drive/folders/0BzVlJNeWPQJzQi1JNXFZclpJWDA?usp=sharing
Marconi 2022E - Page 1
Forum section: electronics / repair

author: electricspark
author_rank: Contributor
timestamp: December 01, 2016, 04:13:33 pm
content: Hi.I wonder if anyone out there has experience with the Marconi 2022?Mine works fine apart from the internal modulation frequency which is about 1.5% low on all three (400Hz, 1Khz & 5Khz) settings. I don’t think there is an adjustment for it, so it must be a fault.I would really appreciate any thoughts about where to look – I am assuming around IC36/a, C71/C72.I spent ages trying to fix a radio with a poor SINAD only to find it was because the 2022 1K modulation was low, causing my SINAD meter to read too high!

author: Andy Watson
author_rank: Super Contributor
timestamp: December 01, 2016, 04:36:45 pm
content: The internal modulation is provided by an RC-Wein oscillator. Tweaking either R or C should bring the frequency within range.If frequency is the problem, why not use the external mod input? However, whichever source you use, the modulation signal is digitised to 8 bits - I think this will limit your SINAD measurements.

author: electricspark
author_rank: Contributor
timestamp: December 05, 2016, 02:46:14 pm
content: Thanks for the response.It seems I was a little pre-emptive – The 2022E spec says the mod frequency is +/- 5% or +/- 50Hz at 1Khz. So mine being 15Hz low was well within spec. The problem was with my SINAD meter – I made the filter a tad narrow with only a 14Hz passband.I added a trimmer across the R in the 2022E oscillator and now the it starts at 998Hz cold and drifts upto 1001Hz once warmed up.I had only recently acquired the 2022 and didn’t realise the mod freq. spec. was so wide.Live & learn!
Motorola Xoom 10.1 inch Android Tablet (v1) power button not working? - Page 1
Forum section: electronics / repair

author: Lee Newsum
author_rank: Newbie
timestamp: December 02, 2016, 05:00:18 pm
content: power switch not working.1) the switch on the bolt feels like it is working. it clicks.2) the plastic button on the back plate moves but has no spring it.3) wen it is put back together the button dues not work or mover.so that do I need to fix?

author: retiredcaps
author_rank: Super Contributor
timestamp: December 02, 2016, 06:08:27 pm
content: Quote from: Lee Newsum on December 02, 2016, 05:00:18 pmIf pressing the above switch turns tablet on, then seefor possible solution to plastic button?

author: brainwash
author_rank: Frequent Contributor
timestamp: December 05, 2016, 11:44:29 am
content: It might also be that the plastic button is misaligned or presses too much (continuously) on the flex button. The only way to know for sure is to test the flex button itself first.If the flex button is broken and it's difficult to replace then in the past I've taken the metal dome off, cleaned the contacts and surface beneath it reapplied it. It requires a bit of finesse and steady hands.Unsoldering those buttons without melting them is almost impossible. Usually the best course of action is to replace the entire assembly (like shown in the video).
Tektronix DSA602A No Screen No Work Diagnostics Succesfully Complete: SOLVED - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 08, 2016, 07:33:06 pm
content: OK, so I really shouldn't be starting a new project just yet but I couldn't resist.I bought a DSA602A for parts to have on hand, fans, boards, CRT, etc.When I picked unit up I found it was newer and in much better condition than my DSA602 that I use every day.Turning it on I got a Dmx Pipeline 4 error and after pressing screen to exit diagnostics mode the unit locks up and screen goes blank.Did some research and consensus was poor wave soldering on heavy backplanes.So I heated the #1 and #24 pins on each Ram chip of Pipeline 4.Error corrected.Restart machine and after diagnostics sequence screen goes blank and locks up.Both Fine button LEDs are lit alongside Vertical and Horizontal knobs.So I restart and force machine to halt during diagnostics, by the way, I have clear crisp display during diagnostics including working touchscreen and ability to run all tests manually.Unit passes every test.When exiting diagnostics and in the blank state the calibrator functions, fans run.However, the Touchscreen Panel light is set to off and the Fine control lights are lit on both knobs.All other LEDs are normalDo not have control of front panel buttons or plug-ins.Any Ideas or experience with this?I am following service manual but not much help when tests pass.I am leaning towards a problem in the display controller board A16This boards function is consistent with display of traces and grids

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 10, 2016, 04:43:20 pm
content: After fixing the memory error by resoldering pipeline #4.Unit would stall after completion of self test.SolutionMore reading, more reading, service manual, then Tektronix website.Question:Someone in our group turned the DSA off while it was running the complete self test. Now each time we turn the instrument on it never finishes the self test and the instrumentcannot be used.Answer:In the users manual under the heading of Initialization, page two of that discussion tell you how to erase the nonvolatile RAM. Hold down the WAVEFORM and TRIGGER menu buttons as you turn on the power. When the LEDs next to the menu lights stop blinking, release the buttons. When the instrument completes self test, a message"should be displayed that says "Teksecure Erase Memory Status: erased." All volatile RAM will be erased, including waveform and settings memory. The instrument will be set to a factory default condition.After applying reset unit ran complete diagnostics and initialized oscilloscope and plugins (took about 10 minutes).Hey Hey Merry Christmas!!
Samsung HDD HD204UI logic board - TVS diode blown - Page 1
Forum section: electronics / repair

author: quad
author_rank: Regular Contributor
timestamp: December 03, 2016, 12:49:56 pm
content: Hi,On my Samsung HDD - HD204UI - 2TB - the TVS diode on the top left (circled in light green) cracked, let out the magic smoke, and went short circuit on me.The 0 ohm resistor next to it went open circuit.The other TVS diode next to it on the right is not short circuited.What I've tried:I desoldered the TVS diode and left it open circuit (yes, no protection)I desoldered the 0 ohm resistor and replaced with a blob of solderNow when I try it, the hard drive tries to power up, I can hear a "whirr" for about 5 seconds then stops, then tries again for about 5 seconds with the "whirr" and it keeps looping like this.Tried a different known working power supply - same result.I'm running out of ideas - anyone can offer some suggestions?Additional info:The TVS diodes - the left says "ON pA01 LG" the right says "6V8A". Not sure which is 12V which is 5V, but I'm deducing from the identifiers the one on the left is the 12V.I've been using this as a guide:http://www.users.on.net/~fzabkar/HDD/TVS_diode_FAQ.html

author: wraper
author_rank: Unknown
timestamp: December 03, 2016, 01:00:20 pm
content: Quiet likely motor driver IC was damaged because of overvoltage too as it is directly powered, without any regulators in between. Therefore while heads move ("whirr") while trying read the plates, motor does not spin-up.AliexepressYou will need hot air gun to replace it, as center pad is soldered to the PCB.

author: quad
author_rank: Regular Contributor
timestamp: December 04, 2016, 09:19:00 am
content: Thanks wraper
Adjustment for Uni-T UT71E - Page 1
Forum section: electronics / repair

author: jf_ED
author_rank: Newbie
timestamp: December 03, 2016, 09:14:26 am
content: Hi Everyone,I am having trouble for adjusting voltage and current values of UNI-T UT71E.Can anyone help me for this matter?AC values are out of tolerance same as well in the current.I'm searching in the internet for the schematic diagram of this UT71E, but sadly lower versions of the unit I searched.thanks for the help in Advance.

author: retiredcaps
author_rank: Super Contributor
timestamp: December 03, 2016, 05:57:05 pm
content: What reference or other meter are you comparing to that makes you think the UT71E is out of tolerance for basically every reading?Please give us examples of your readings.

author: Lightages
author_rank: Unknown
timestamp: December 03, 2016, 06:16:56 pm
content: Here are some videos to help, and all the files attached are for the UT71E. Two of them are with a filename for the rebranded version from Voltcraft. I have added another more complete calibration procedure.

author: jf_ED
author_rank: Newbie
timestamp: December 04, 2016, 07:19:05 am
content: Thanks for this. Big Help. I tried to adjust all VR's. Before the first calibration, the out of tolerance value is at micro Ampere only, but I already turn every VRs, I think I need to re-calibrate every function.Again, thanks for this.
Coto 1240 SPST relay. Where to buy? - Page 1
Forum section: electronics / repair

author: VintageNut
author_rank: Frequent Contributor
timestamp: December 03, 2016, 10:48:45 pm
content: I have a piece of Keithley gear that may need one or more of the Coto 1240-0197 reed relay. I see that there are some similar looking Coto relays.Has anyone acquired some of these and can point me to where these can be obtained?
AWA LCD TV    CL-40KDF10S SCHEMATIC - Page 1
Forum section: electronics / repair

author: geobee
author_rank: Contributor
timestamp: November 28, 2016, 06:58:32 am
content: Hi all, at a dead end trying to locate a schematic for this LCD tv set. Tried all my usual resources to no avail. Any help would be much appreciated. Regards.

author: Rasz
author_rank: Super Contributor
timestamp: December 01, 2016, 07:34:56 am
content: you dont need a schematic, it would be useless to you anyway.its either something simple like caps/bad inverter, or uneconomical like scaler chip or panel

author: geobee
author_rank: Contributor
timestamp: December 03, 2016, 12:53:12 pm
content: Hi, it has a strange fault in that it had the power led just blinking, as stuck in standby. Yes, as you say, it is just normally caps in the supply, as there were four that were bulged up. After replacing all four, now the supply is dead, no led, nothing. Double checked my work, cap values, polarity, even removed the newies and checked them on my cap meter, all good. Thought I may have misplaced a supply plug to the wrong socket or something, as there are a couple of extra sockets more than there are plugs to match, hence my request for a schematic. It has been a while since I stripped it down, so just need to make sure of a couple of things with it.
Simpson 461-2 DMM MOVs with GEW52754 part number - technical data? - Page 1
Forum section: electronics / repair

author: KJ-90
author_rank: Contributor
timestamp: December 02, 2016, 05:11:15 pm
content: I own a Simpson 461-2 DMM that has four 7mm radial disc MOVs made by General Electric. They have the part number GEW52754, and are colored red. Three MOVs are connected across the DMM's input terminals, and one protects the ohms input. The DMM's maximum AC input is 750 V, and the maximum DC input is 1000 V. I was wondering if anyone knows the technical data aboutthese MOVs. GE MOVs were taken over by Harris Semiconductor, and then Littelfuse, but there is no technical data available online about the part number. Any ideas?

author: dacman
author_rank: Frequent Contributor
timestamp: December 02, 2016, 09:50:46 pm
content: I'll guess that it is equivalent to a Littelfuse V275LA4 or V275LA4P, but only because they are marked 2754 and your's ends in 2754 and the ratings seem about right.
Broken Fluke 52 II Thermocouple Thermometer - Page 1
Forum section: electronics / repair

author: dencohe
author_rank: Newbie
timestamp: December 04, 2016, 07:44:36 pm
content: Hi Guys,I recently acquired a broken Fluke 52 II thermocouple thermometer. The symptoms include no reading from either channel (T1 or T2). I decided to go ahead and open the unit and inspect. I found a cracked ceramic capacitor but no other signs of damage. I used forum member TiN's guide athttps://www.eevblog.com/forum/testgear/fluke-5x-ii-series-thermometer-tear-down-and-hacks/to replace all the front-end components. The meter still did not read any voltage on either of the channels, so I went ahead and just replaced all the active components up until the ADC (LT2400). It now reads voltages and the open contact comparator is causing readings to happen when a voltage appears at the channel. The ADC is still not seeing the correct voltage, regardless of where the mux'es are switching.My theory so far that someone touched two exposed non grounded themocouple wires across some unknown voltage potential and destroyed most of the meter although there is no physical signs of anything wrong besides that cracked ceramic cap. I am looking for anyone who has any advice or someone who may have a better understanding of how the circuit works.Thanks,Denver
VOLTCRAFT VLP 2602 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: November 30, 2016, 06:29:31 pm
content: Good evening; I am looking for the diagram of laboratory power supply VOLTCRAFT VLP 2602. Can anyone help meThanks in advance!

author: dundee
author_rank: Regular Contributor
timestamp: November 30, 2016, 11:41:27 pm
content: Hi!I've schematics for the VSP 2405. Could be similar to yours?http://www.xup.in/dl,17081693/Voltcraft_VSP2405HE.pdf/

author: lionelkjh
author_rank: Frequent Contributor
timestamp: December 01, 2016, 11:28:28 am
content: Hello; Helas the schema does not match; but thanks anyway. Someone would have it

author: lionelkjh
author_rank: Frequent Contributor
timestamp: December 02, 2016, 11:41:50 am
content: sniff!
Looking for recommended terminal release/extractor tool/set... - Page 1
Forum section: electronics / repair

author: gotwood
author_rank: Contributor
timestamp: November 30, 2016, 09:10:11 pm
content: Wondering if anyone has any recommendations.in particular I need it for TE Connectivity Mini-Universal Mate-N-Lock housing plugs...But I don't mind buying a small set that lets me do additional types/manufacturers.
Metz camera flash repair - Page 1
Forum section: electronics / repair

author: trisa25
author_rank: Newbie
timestamp: November 30, 2016, 07:01:53 pm
content: Hello,my dad was using a Metz camera flash and once it just poped, screen went black and nothing happened and he just took the batteries out. When I opened it I found an blown smd diode and replaced it with 1n4007, but after that when I tried contiunity across battery terminals it was shorted and I also found out that transformer mos-fet (custom one with core on the pcb and metal shielding) was shorted and first replaced it with buz11. It worked, but buz11 got very hot (transformer is drawing less than 5A at arround 6V). then I switched to irl3803 (170A hex-fet), but ist sill gets very hot and charges capacitor very slow. Is the problem frequency of DC-DC boost converter or something else?Thanks for answer,trisa25
Yamaha MX1000 POWER AMPLIFIER - Page 1
Forum section: electronics / repair

author: geobee
author_rank: Contributor
timestamp: November 30, 2016, 08:55:06 am
content: Hi all, just wondering if anyone has repaired one of these. This has been to someone else to try and fix, but they have not use the original output device types for replacement. I note in the schematic that some of the output devices are a DC to DC convertor transistor, but they have only fitted normal audio out type devices. The repaired channel has destroyed several components and I have been left with the problem to solve. If anyone has looked at one of these and replaced the outputs, any advice would be good.

author: mzacharias
author_rank: Frequent Contributor
timestamp: November 30, 2016, 12:54:22 pm
content: This model, descended from the M-80/M-85 models, is a difficult repair even for long-time Yamaha servicers. I may be able to help with advice; maybe better to email me directly.mark_zacharias@sbcglobal.net
What's the best way to re-seat this part? - Page 1
Forum section: electronics / repair

author: Section8
author_rank: Contributor
timestamp: November 29, 2016, 11:11:53 pm
content: So i bought some cheap display modules from China. While I can't argue with the price, the assembly is a little bit sloppy.As you can see from the attached photos the displays are pretty poorly seated against the board.What's the best way to re-seat these parts? I've already tried solder wick on one side but it didn't manage to get all the solder out.Should i use a heat gun to try heating all pins at once? what's the risk of damaging the driver chip on the other side of the board?Re-flow oven? seems like it would probably melt the displays.Any other options?thanks for your time.S8.

author: sleemanj
author_rank: Super Contributor
timestamp: November 29, 2016, 11:25:43 pm
content: Err, it looks to me like the displays are plugged into machine pin sockets, so you should be able to pull the displays off, or get enough wiggle room that you can adjust alignment without soldering anything.

author: Section8
author_rank: Contributor
timestamp: November 29, 2016, 11:38:27 pm
content: well I feel silly. you're right, they were.
Fluke 731B Battery Replacement - Page 1
Forum section: electronics / repair

author: VK5RC
author_rank: Unknown
timestamp: December 09, 2016, 05:40:02 am
content: An eBay purchase of an old Fluke 731B soon showed that although it worked reasonably well (quick fire up only) and was able to charge its internal NiCad batteries, they did not hold charge for more than an hour or so. Opening it up revealed a bit of 'battery cancer' which had also wicked down the cable to the main board. An EEV blog postee ( I can't find the post now!) had had good results with routine rechargeable batteries. I had a few (well quite a few) eneloops (700mAHr) lying around. I like the retention of charge feature of eneloops.I used the technique in the Mr Carlson's Lab Youtube (making a new battery for a Tek 200 series mini-scope) to solder the batteries together. sandpaper, flux, solder quickly and have an IPA soaked rag handy to cool off rapidly after.New connectors and a good clean of the PCB.A quick current measurement showed a charging current of 18mA (~0.025C) on mains and a battery draw of 8mA when switched on but not connected to the mains.Hopefully they will last a while.

author: lowimpedance
author_rank: Super Contributor
timestamp: December 09, 2016, 06:11:44 am
content: Would that be a 731B instead of 531b ?.

author: VK5RC
author_rank: Unknown
timestamp: December 09, 2016, 06:17:39 am
content: D'oh , Thanks. 731B 731B NOT 531B,EDIT Title altered