hybridfree/eevblog-posts huggingface dataset:
What potentiometer to substitute with please? - Page 1
Forum section: electronics / repair

author: peteb2
author_rank: Regular Contributor
timestamp: January 25, 2018, 04:46:12 am
content: So i've all but completed a resto on an early 80s era basic well-loved stereo amp... Yamaha A-460. It's been a full recap, bulb indicators changed to LED, a full clean of the filthy PCB with every join desoldered and resoldered with fresh, new interconnects direct to the pcb, rebuilt power-supply with rear mount fuse and ever remounted the output transistors with better heatsink coupling.So the last thing is the Volume. The pot is working fine without any induced scratching crash sounds of dirty wiper on track but it's mechanically really worn and rotates way too easily. A slight brush against the big alloy volume knob and the sound would go full volume.... all too easy.So the pot is a 70k dual log and it seems unobtainable. Could i use a 50k or 100k dual ganged log? These appear to be the only values easily obtained where i live.My concern is any possible Zload issue reflected back to the RIAA phono amp stage or to the tone control's input stage causing any marked change to the sound the owner might notice. Presently the amp is OK for a good 45Wrms output into 8ohms and is running fairly flat 20Hz to 20kHz response all tone controls at unity.The project has received work classifiable as over kill but then it was an exercise in seeing just what kind of result is possible.The schematics might help.... (appreciate your advice).

author: james_s
author_rank: Super Contributor
timestamp: January 25, 2018, 06:36:07 am
content: I don't know how well a sub will work but you could try, it might make little difference.You might try cleaning the shaft and lubricating with some thick grease though, that may smooth it out and stop it from spinning so freely.

author: amspire
author_rank: Super Contributor
timestamp: January 25, 2018, 06:42:35 am
content: If you are worries by the impedance, use the 100K pots and put a 300K resistor across it. That makes it 75K.I am sure it will be fine.
AIS Receiver - Page 1
Forum section: electronics / repair

author: tombi
author_rank: Regular Contributor
timestamp: January 25, 2018, 03:12:13 am
content: Hello,Trying to fix this AIS receiver for a friend.Powers up on 12V but not on USB.The thing has a million PTCs on it. I figure out the upper one (marked C) goes open circuit when I power it up off USB.I think the chip marked ZE below is a DC-DC converter. it is just above the microcontroller.For the life of me I can't identify the damn thing from the marking codes. I've tried the marking code books, lots of google searches etc. I think the sideways 27t is some sort of batch/voltage marking code and it might be on-semi but I have no idea.I know people probably hate these posts and someone will find it on their first google search but I am stuffed if I can.Tom
Sony PS-4300 record player motor not turning - Page 1
Forum section: electronics / repair

author: AndyMacSteve
author_rank: Newbie
timestamp: January 24, 2018, 02:37:08 am
content: My Sony PS-4300 record player has a problem that when I press play the turntable motor doesn't spin by itself when I press playWhat is the problem?Could it be the motor? A fuse? Connection problem, or a capacitor or circuit board problem?

author: zvonex66x
author_rank: Contributor
timestamp: January 24, 2018, 06:25:59 pm
content: Quote from: AndyMacSteve on January 24, 2018, 02:37:08 amYou should take measurements.... It can be any problem...

author: coromonadalix
author_rank: Super Contributor
timestamp: January 25, 2018, 02:37:49 am
content: this is a direct drive motor, check the ac selector switch if there is one, powersupply capacitors etcservice manual :https://elektrotanya.com/sony_ps-4300_turntable.pdf/download.htmlwhait for the get manualor this one :https://www.vinylengine.com/library/sony/ps-4300.shtmlpublicity loll :http://www.gammaelectronics.xyz/audio_03-1977_sony-ps-4300.html
$10000 Flir Camera broke out of the blue - would appreciate help diagnosing/fix! - Page 1
Forum section: electronics / repair

author: Dan44
author_rank: Newbie
timestamp: January 24, 2018, 05:13:14 pm
content: I went and plugged the camera in using the OEM charger. I plugged the charger directly into the battery while it was in the camera, as opposed to charging it on the cradle. When I came back to unplug it the screen was on but was completely black (no gui or anything). I unplugged the battery to reset the camera. Now when I go to turn the camera on the power lights goes green and I hear the lens focusing but nothing shows up on the screen or monocle, I also can't get the power light to turn off without unplugging the battery. I believe the charger may have put to much power through the camera once the battery was charged? I could use some guidance -thanks!

author: stojke
author_rank: Regular Contributor
timestamp: January 24, 2018, 09:04:42 pm
content: Shouldn't have happened from charging the battery, maybe the camera had other problems the seller did not report.Try leaving it with out any power for some time. Hold the power button a minute or two while the battery and power adapter are disconnected.

author: EHT
author_rank: Frequent Contributor
timestamp: January 24, 2018, 09:19:24 pm
content: RTM or Google for how to fully reset it; perhaps that is what you have already done. If that doesn't work and a) you are not experienced at repair of such devices and b) you cannot risk a mistake that would completely destroy it, then you have no option but to take it to be professionally repaired. Maybe others could opine on where to take it if you say what city you're in. Try the manufacturer.

author: amyk
author_rank: Super Contributor
timestamp: January 25, 2018, 01:43:27 am
content: Did you know we have a forum specifically for thermal cameras?https://www.eevblog.com/forum/thermal-imaging/

author: Dan44
author_rank: Newbie
timestamp: January 25, 2018, 03:38:51 am
content: I don't get what happened. I got it working again though I unplugged both batteries (internal, normal battery) and lens for a few minutes and got it working.

author: Rasz
author_rank: Super Contributor
timestamp: January 25, 2018, 03:02:58 pm
content: one of the power rails died = partially working
FeelTech FY-6600 Corrupted Flash Repair - Page 1
Forum section: electronics / repair

author: rhb
author_rank: Super Contributor
timestamp: January 24, 2018, 06:41:44 pm
content: This thread summarizes information related the threads in T&M. The V 3.0 and V 3.1 units have a defect which corrupts memory to the point of being inoperable. This is an attempt to correct the problem. FeelTech appears to be unwilling provide any support for owners of defective product. Many promises of "lifetime warranty" have been made, but no actual repair or replacements are known. It is *believed* that V 3.2 and later are OK, but there is little data to confirm that.Abbreviations:FP - front panelRP - rear panelSB - signal boardPS - power supplyConnectors:SB J8 <--> PS connector [ -11.4 V | 11.4 V | Gnd | Gnd | 5.0 V | 5.0 V ]FP FS1 <--> 8 bit FP-SB bus [ ? | Gnd | ? | ? | CS/SS | CLK | MISO | MOSI ] 3.5 V CMOSFP J1 <--> 4 bit FP-SB/RP bus [ 5 V | Gnd | Txd | Rxd ] RS-232Major Devices:FP MCU STM32F103C8T6 [ LQFP48 | 128 KB flash | 20 KB RAM | -40 - 85 C ]www.st.com/resource/en/datasheet/stm32f103tb.pdfSB FPGA Altera Cyclone IV EP4CE6 [ 6272 LEs | 270 Kbit memory | 15 - 18 x 18 multipliers | 2 PLLs | 10 Global clock networks | 8 user I/O banks | 179 max I/O ]https://www.altera.com/en_US/pdfs/literature/hb/cyclone-iv/cyiv-51001.pdfAs more data becomes available I shall update this post.
Garmin GPS Car Cable (micro/mini USB pinout) - Page 1
Forum section: electronics / repair

author: metrologist
author_rank: Super Contributor
timestamp: January 25, 2018, 07:56:13 pm
content: I have a 1450 and 2450 and both of them have lost the original car cables. I tried using a regular USB cable and external battery to power the units and they power up into USB Data mode. Even after powering up to the map, if applying USB power they switch to USB Data mode and cannot be used.Does anyone know the secret recipe - perhaps there is a resistor or something else in the Garmin car cable? (they both plug in via a regular looking USB port)

author: metrologist
author_rank: Super Contributor
timestamp: January 26, 2018, 01:25:38 am
content: OK, the Garmins are not broken and after adding resistor to my searches I discovered that there is a resistor between pins 4-5, 15 to 22k or something else depending on model...I tried to delete the post, but it wasn't having it...

author: coromonadalix
author_rank: Super Contributor
timestamp: January 26, 2018, 02:03:44 am
content: there are some usb cables who dont have the data pins wired, i have one cable like this to power up my garmin ... dont recall where i found it

author: cdev
author_rank: Super Contributor
timestamp: January 26, 2018, 04:03:51 am
content: Are you looking for special traffic features? I know the traffic radio for rerports is embedded in the power cable

author: metrologist
author_rank: Super Contributor
timestamp: January 26, 2018, 02:32:21 pm
content: No, I just wanted to use it for navigation - although I do have an older mount and cable for a Nuvi 765. That has a traffic receiver in the cable, but a proprietary plug (someone stole that GPS and left the cable lol). I may cut the end off and try to figure out the wiring.The 2450 has a mount with a mini-USB plug, but it does nothing with the GPS. The internals of that look fine so I'mIt charges with the micro-USB on the unit though and I have been able to fool that one into booting up into nav mode on occasion, but it's finicky.
Agilent/Keysight N9310A repair hints solicited - Page 1
Forum section: electronics / repair

author: bernroth
author_rank: Regular Contributor
timestamp: January 21, 2018, 12:46:02 pm
content: Hello folks!I have a Keysight N9310A on my bench which needs to be repaired. It powers on normally, passes all self tests.It is a unit from 2008 so a bit aged.Problem: Some buttons are not working (e.g. "RF on") and the "Information" screen, which should normally show firmware version, options etc., has black pixels all around and misplaced fonts.I will post a screenshot tomorrow. It looks quite funny.All other screens and menus I tested are showing correctly.I have checked all supply rails with DMM & scope (glitches). Nothing unusual, all voltages are there.The caps in the PSU show no signs of bulging.When probing the keyboard flat flex connection to the board, most buttons show sharp transitions high/low when pressing.Except the RF button (and others in the row like "Trigger"):When pressing, the "edges" are like the curve of a charging capacitor (RC), very slow.I suspect two things:First: Possibly the keyboard, inparticular the RF-ON button has a bad contact or is dirty. This could be the button which is used most.Second: The weird pixels and misplaced fonts all over the place in the "Information" screen might be due to bad memory maybe or a bad regulator on the digital board.Maybe someone has a similar issue in the pastI keep you posted, thank you!Cheers,Bernhard

author: Samogon
author_rank: Frequent Contributor
timestamp: January 21, 2018, 06:28:47 pm
content: For the button i would check multiplexer. As for the artifacts on the oarticular screen points to the firmware corruption

author: bernroth
author_rank: Regular Contributor
timestamp: January 22, 2018, 05:41:01 am
content: Update:Attached the broken "information" screen.I cleaned the keyboard but no change for RF-button.Only once removing and re-inserting the CPU board helped to make the RF-Button work again.Maybe there was a bad contact. Strange... all gold plated contacts. Hmm.The only and last non-working button is "Trigger". Possibly inactive due to missing license?I took apart the CPU board and found an empy BR2032 battery (BR... looks to be the industrial battery type with an extended temperature range and longer shelf life)But what I've found: Micron memory dated week 54 2005I had in the past dead Cisco Switches with failing memory (guess what: Micron)I wonder if the power on self-test should detect bad memory.The information screen let me think the memory being bad.Voltages (1.8 + 3.3V) on the CPU board are fine.I will continue searching

author: Samogon
author_rank: Frequent Contributor
timestamp: January 22, 2018, 03:52:09 pm
content: Well self test may check checksum of firmware and should flag it as bad.Try to update firmware it wont hurt.

author: bernroth
author_rank: Regular Contributor
timestamp: January 24, 2018, 07:28:06 pm
content: A firmware update was performed successfully but the error is still present.I suspect the memory (Micron - see other post) and I ordered some replacement parts.I keep you guys posted.
Soldering station Yihua 899D+ blown R4 and fuse - Page 1
Forum section: electronics / repair

author: webgiorgio
author_rank: Regular Contributor
timestamp: January 24, 2018, 11:00:21 am
content: Hello,I have this soldering stationhttp://yihua-soldering.com/product-1-2-4-hot-air-rework-station-en/147660/Used not so often, but mains connected for about 3 years.Yesterday while I was soldering I hear an explosion from the stationary unit, which turns off. I smell the magic smoke.The fuse (6A t) was blown pretty violently (metal splatter all over the glass).There was a burn in the top-right corner of the PCB. R4, 120 kOhm, 1/8W. It burned up to the point to detach both wires from the PCB and fall on the connector below.I replaced the fuse and the unit works.Looking at the wires and PCB traces, it seems that the 120 kOhm and also the capacitor (CL 104J, 100nF 400V) are both in parallel to the mains.The red and black cables are the mains, the two red cables are in parallel to the red-black and goes to the transformer.I will replace the 120 kOhm resistor as soon as I get hold of a second soldering iron.But, what is the point of putting a 120 kOhm load across the main?Moreover, P=V²/R=230²/120000=0.44W, so the power rating of the original resistor (1/8 W =0.125W) was way too low!Engineered to fail?

author: webgiorgio
author_rank: Regular Contributor
timestamp: January 24, 2018, 11:29:02 am
content: Has anyone the schematic Yihua 899D+ solderign station?

author: Armadillo
author_rank: Super Contributor
timestamp: January 24, 2018, 11:43:28 am
content: The capacitor 100nF is 32Kohms in parallel with 120Kohms resistor, so the capacitor is taking the bunch of the load.But I doubt they are in parallel to the mains but in series to the mains as voltage reducer, otherwise is a waste of energy.

author: webgiorgio
author_rank: Regular Contributor
timestamp: January 24, 2018, 03:48:06 pm
content: Someone one else with the guilty resistor about to burn outhttps://youtu.be/E7uoLxUhwlQ?t=12m49s
Micron SDRAM memory chips manufactured between 2005 and 2010 degrade over time - Page 1
Forum section: electronics / repair

author: bernroth
author_rank: Regular Contributor
timestamp: January 23, 2018, 08:06:40 am
content: Hello folks!I think the forum is the best place to put that information.There are many Micron memory chips out there which degrade over time.These chips have been manufactured between 2005 and 2010 (according to Cisco).Here is a dedicated webpage from Cisco:https://www.cisco.com/go/memoryThey do not blame Micron but I had many of the affected Cisco products on my bench for repairAfter replacing the broken Micron memory chips, all was back to normal.I am convinced that not only Cisco is affected.Possibly there are other field notices from other manufacturers out there.Would be great to collect them here.Links & comments are welcome!Best regards,Bernhard

author: pinkman
author_rank: Regular Contributor
timestamp: January 24, 2018, 05:24:50 am
content: This is really interesting. Can you post particular part numbers of affected memory you have replaced? Is this DRAM? I wonder if the little dram caps are just becoming more leaky and discharging before the refresh, and if so, what the root cause is. This sounds like network equipment, and is probably powered on continuously, maybe even an electromigration issue?It seems that the time period in question was during the initial dramatic increase in memory density, maybe things moved too quickly and some lessons were not learned yet.

author: bernroth
author_rank: Regular Contributor
timestamp: January 24, 2018, 05:35:46 am
content: The chips I'm replacing in failed Cisco network equipment areMicron 46V32M16-6TThere might be many other model numbers affected but the industry is keeping silent.Unlike software security problems, issues with components are still not very public.I was unable to find a comprehensive list of affected products/chips form the manufacturer.

author: Jeroen3
author_rank: Super Contributor
timestamp: January 24, 2018, 06:40:18 am
content: This is known since 2015?

author: bernroth
author_rank: Regular Contributor
timestamp: January 24, 2018, 07:04:17 am
content: Cisco usually publishes informations quite quick (see Intel Atom C2000 series LPC clock failure).So yes, possibly known since 2015.Edit: As long as the device is running, it works fine.The problem is when you power-cycle it, the memory stops working.Anyone with more informations?A Micron field notice for manufacturers would be nice.
Identify manufacturer / series for motorcycle connector - Page 1
Forum section: electronics / repair

author: rbm
author_rank: Regular Contributor
timestamp: January 22, 2018, 12:10:38 am
content: I'm trying to find the manufacturer and/or product series for a connector that comes from my 1987 BMW motorcycle. Being a BMW, the same style of connector would have been used on BMW cars from the same era, such as E28 and E30. The embossed logo might give a clue but I have not had success matching it to any known connector manufacturer. Photos below:Thanks for pointers.

author: fossi
author_rank: Contributor
timestamp: January 24, 2018, 09:02:25 am
content: as far as I know, you can get the connector as spare part at the official BMW motorcycle dealer.I think, it was a connector made by AMP which is now TE-Automotive. Some parts I have are marked with AMP.Another possibility is to contact the manufaturer of the wiring harness.http://www.kromberg-schubert.com/Alternatively try to search here:http://www.steckermarkt.de/eshop.php?eslink=1&action=home&shopfilter_category=&s_group_id=%2AGreetingsfossi
Agilent U1733C ESR null is not working/implemented - Page 1
Forum section: electronics / repair

author: Samogon
author_rank: Frequent Contributor
timestamp: January 23, 2018, 09:16:23 pm
content: I noticed that when measuring electrolytic cap inserting it into ports it is quite accurate. But when i use tweezers they have their own series resistance and i cant null it before measuring DUT. So i have to subtract tweezers' resistance from measurement manually. Is it by design? Did i miss something in the user manual?Thank you
Repair Keithley 6517A - Page 1
Forum section: electronics / repair

author: Jxw6637
author_rank: Newbie
timestamp: January 20, 2018, 03:54:46 pm
content: Hello,We need help to give suggestion with a 6517A. It is for GBIP volume resistance Sweep test.Recenty we forget to turn the switch to 230 volts while it is plugged into 230V source. So had the transformer burned with several Sk 1412s, 2N 3904s, and LH1540s, Zeners, and big capacitors. (450V 500uF).After I changed these parts, (ordered new transformer from Keithley) the V souce stays the same as somewhat around 141 V, no matter what voltage you change.The Rv feedback calculated from sweep software seems correct.There is also GBIP Sweep SOFTware PHOTO that I took to help understanding the situations. Please advise me how to do next.THANKS!

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: January 20, 2018, 06:14:48 pm
content: Not sure I can help but are all of the replaced parts from known good suppliers? I believe someone repaired their 6517(A) using parts from eBay that turned out to be bad. I think these were the SK 1412.These meters can be quite dangerous as you have discovered. I am hesitant toI have two in different stages of repair. One had a burnt out transformer and the front panel was arcing on the 60v supply across vias. The 200v supply rectifier bridge was also shorted and overheating. The transformer is very expensive, even by Keithley standards.

author: Jxw6637
author_rank: Newbie
timestamp: January 22, 2018, 02:46:28 pm
content: You are right about the Sk1412s. I googled these parts they seem to be out of production from sanyo for quite sometime. Plus Sanyo semicon has been merged by some other company. Any suggestion on how to get replacable or other equals? Seems all the k1412 from market are pulled parts.Thanks

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: January 23, 2018, 09:40:13 am
content: this one may do the trick: NDFPD1N150C
Where do people get parts for Philips "fluke" devices - Page 1
Forum section: electronics / repair

author: cowasaki
author_rank: Frequent Contributor
timestamp: January 24, 2018, 12:10:10 pm
content: I've bought a couple of DDMs (PM2525) both of which have faults I didn't know about. I'm assuming they have been damaged in transit but thats not going to be easy to prove. Just wondering where people get spares from. Both LCD displays have bleeding crystals and one of the probe sockets is damages/loose.I'm not sure if the LCDs are standard ones as I've not taken them apart yet just in case.

author: Samogon
author_rank: Frequent Contributor
timestamp: January 24, 2018, 09:20:51 pm
content: Scavenging donor units mostly for that old equipment

author: EHT
author_rank: Frequent Contributor
timestamp: January 24, 2018, 09:26:58 pm
content: https://www.qservice.tv/vpasp/shopdisplaycategories.asp?id=81&cat=FLUKE+spares
Gigabyte GTX 1050TI 4GB OC - repair - Page 1
Forum section: electronics / repair

author: IanJ
author_rank: Unknown
timestamp: January 20, 2018, 06:26:34 pm
content: Hi,Repairing a broken graphics card, the previous owner has abused the card and a few resistors/capacitors have been broken off (gawd knows what they were doing!)........just wondered if anyone with a card can tell me the values of the following and if they are actually fitted (some footprints maybe meant to be unpopulated).If can't identify values then at least if the following are populated or not.......or maybe a really good photo of the topside.R77R78R80R81R83R84R85R86R89R90C133R91Here's a pic of an identical card (fans/heatsink etc removed), best I could find on the web but just not clear enough to see:Thanks,Ian.

author: IanJ
author_rank: Unknown
timestamp: January 21, 2018, 09:53:39 pm
content: UPDATE:Thanks to Dennis over atwww.hardwareasylum.comwho did a review of this card and happened to have a piccy on their website (found via google) I contacted them and they were very kind enough to send me the full res photo from their camera.......perfect!Parts now on order.Ian.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 22, 2018, 04:43:09 pm
content: Quote from: IanJ on January 21, 2018, 09:53:39 pmYou could share it with us ?Someone else might need it.
Who Rebuilds Triplett 630 Type 4 - Page 1
Forum section: electronics / repair

author: lego4040
author_rank: Newbie
timestamp: January 23, 2018, 01:24:56 am
content: I was given an old Triplett 630 type 4 and It needs service. I found two blown resistor but the rest tested ok. Outside it is in great condition and It would be a great addition to my bench along side of my other equipment. I also would need probes since the ones that were with it aren't even correct for it . Anyone have a service place recommendation? I am on the east coast
Prema 6048 zero offset problem - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: January 20, 2018, 04:30:28 pm
content: I've been looking at the zero offset of the different DC ranges on my Prema 6048.0.2V .000001092V 0.000010820V 00.000109200V 000.001082kV 0000.0108Note the pattern here - there appears to be a fixed offset soemwhere in the circuit that is being scaled by the range factor.Yes I know that I can use the zero offset calilbration to change this, but that appears to be causing some odd problems on my meter.Is there anyone out there who's worked on these before that could suggest a probable fault? I'm sort of wondering if this could be U10 (ICL7650) with a bad offset?Dave

author: coromonadalix
author_rank: Super Contributor
timestamp: January 21, 2018, 01:05:10 pm
content: would pulling off the ic's and reseat them in the sockets may help a little, oxydation, residues may add errors ?Edit ; maybe the electrolityc capacitor need to be replaced ??
Fluke 89 iv to be repaired - Page 1
Forum section: electronics / repair

author: Michelep67
author_rank: Newbie
timestamp: January 21, 2018, 12:40:45 pm
content: Goodmorning everyone.I have this Fluke 89 iv that I would like to repair, used incorrectly. The faults, as you can see in the picture, are in some areas. That is: tracks under the broken diode bridge, burnt resistance, another route and not measurable (the Brown one). The tester turns on, but I do not know where to start. I looked for an electrical scheme on the net but I did not find anything. I need help. Thanks Michele

author: alm
author_rank: Super Contributor
timestamp: January 21, 2018, 01:01:15 pm
content: The Fluke 89-IV is (almost?) identical to the Fluke 189, so any service information you find on the latter will be relevant. I remember a few previous topics on this forum. I doubt that you'll find a schematic or component level service information, Fluke stopped doing that sometime before the 89-IV came out.

author: Michelep67
author_rank: Newbie
timestamp: January 21, 2018, 01:11:44 pm
content: Thanks for the information. I read some posts in the forum on the tester I have. Although it is almost the same as the new model 189, where I can find at least an electric scheme, in order to solve something. As an alternative I wondered if there is still a new logic to replace it definitively. Thanks Michele

author: Specmaster
author_rank: Super Contributor
timestamp: January 21, 2018, 01:40:27 pm
content: Quote from: Michelep67 on January 21, 2018, 12:40:45 pmCircuit diagrams/schematics for this meter just don't seem to be available, like so much of the modern stuff, service replacement boards etc seem to be the rule.However, do a search on this forum and you will find that many people have tried to resolve issues with their 89 as well but it looks like most are still apparently trying, try searching for one in the section entitled Test Equipment for a thread under the topic title of "Fluke 89 IV reads AC voltage incorrectly" and there you will find some lovely high res photos of the PCB on both sides that just offer you a glimmer of hope? The link below should take you there but sometimes the links don't seem to work too well.https://www.eevblog.com/forum/testgear/fluke-84-iv-reads-ac-voltage-incorrectly/msg596687/#msg596687

author: Michelep67
author_rank: Newbie
timestamp: January 21, 2018, 02:37:20 pm
content: thanks, now I see
Dunkermotoren brushless dc geared motor - Page 1
Forum section: electronics / repair

author: najrao
author_rank: Regular Contributor
timestamp: January 20, 2018, 09:45:37 am
content: I got this beautiful motor for an experiment, from a friend. Not new, perhaps, but in excellent condition apparently.Dunker website gives me a user manual, but not any repair instructions. Connected as specified to a proper dc supply, it does not work.Another, bigger, dc motor of the same construction (BG65X75SI) works exactly as it should.The trouble is: there is no way to take out the built-in pwm drive to see what, and no drawing or detail is forthcoming. You can open enough to see the tailored circuit board inside, but no more.Oh yes, the terminal block is my way of connecting to the plug-in socket on the motor.Grateful for any user experience.

author: anachrocomputer
author_rank: Regular Contributor
timestamp: January 21, 2018, 10:46:20 am
content: Are you sure the wires in those green pluggable terminal blocks are making good contact? Those terminals aren't designed to be used with bare wires like that. If you can, find some ordinary terminal blocks, the type with two rows of screws, and try that.

author: najrao
author_rank: Regular Contributor
timestamp: January 21, 2018, 12:03:26 pm
content: May seem strange to you, but the wire ends are actually soldered to the contact tongues in the terminal block (reassembled after soldering). At the motor end, I have used fitting females crimped and soldered. There can be no question of poor connections. My issue is how to take out the drive circuitry.from within the motor housing. Taking off the end shield, you can just see a circular board with all external connections soldered to pads around the periphery. Impossible to desolder from in situ. I was hoping someone has found a way.Thank you, though.
Farnell Power Supply D30 2 - Page 1
Forum section: electronics / repair

author: Edgard
author_rank: Newbie
timestamp: January 20, 2018, 06:24:58 pm
content: Hello,I obtained an old powersupply Farnell D30 2 in non working condition.I would like to make an attempt to repair it but i have no manual or even a repair manual.Is there anyone who can help me with at least a schematic.thanks for any reply.greetings from a hobbyist from Belgium.Edgard

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 21, 2018, 05:06:59 am
content: You should post a picture. Many units are distributed on different names.

author: anachrocomputer
author_rank: Regular Contributor
timestamp: January 21, 2018, 10:42:49 am
content: I have one of these power supplies, and I have written up a blog post about fixing it:http://anachrocomputer.blogspot.co.uk/2013/04/fixing-big-farnell-psu.htmlCould you post a description of the fault(s), with photos? I can probably help you with diagnosis, even if we don't find a schematic. Those old Farnell PSUs are very reliable, and very fixable if they do fail.I don't know of any other names that Farnell used. But very similar supplies were made in later years by Thurlby-Thandar.

author: bd139
author_rank: Super Contributor
timestamp: January 21, 2018, 11:28:47 am
content: Farnell supplies usually die because the engineers didn’t bother to put protection diodes across the pass transistor or output. So if you connect something which can source voltage like a battery or large cap then shut the power supply off at the primary side it’ll blow up. Stupid stupid design.Always check the pass transistor and driver transistor first. Probably ok apart from them. Then stick a big ass 1n5401 across the unregulated to regulated connections on the pass transistors and across the outputs.
CSA8000 won't pass splash screen - Page 1
Forum section: electronics / repair

author: ezalys
author_rank: Frequent Contributor
timestamp: January 20, 2018, 09:18:33 pm
content: Hey everyone!Our lab has a CSA8000 oscilloscope that boots up just fine but won't pass the splash screen. Has anyone else experienced a similar problem? Have you found a solution?

author: Jwalling
author_rank: Unknown
timestamp: January 20, 2018, 09:40:24 pm
content: Quote from: ezalys on January 20, 2018, 09:18:33 pmProbably a dead battery on the PPC board. This should help:https://www.eevblog.com/forum/testgear/tek-csa7404-repair-project/
SH-E 878 DIY clock 7 segment display issue - Page 1
Forum section: electronics / repair

author: d3javu
author_rank: Regular Contributor
timestamp: October 27, 2016, 04:19:51 pm
content: Hi Folks,I recently bought this cheap DIY kit, able to power up and appears to be working but having a weird issue where the number increase is not in correct order. I have checked the circuit and couldn't find any issue. Haven't check the MCU signal though. I took a short clip (please excuse the out of focus), please advise where it could have probably gone wrong. Thank you!

author: tooki
author_rank: Super Contributor
timestamp: June 09, 2017, 12:48:07 pm
content: Out of curiosity, did you ever figure out the problem? (I have the same kit, but mine works fine.)

author: d3javu
author_rank: Regular Contributor
timestamp: January 24, 2018, 06:46:54 am
content: Never thought time flies so fast. Been busy past year so had no time to work on the board. I will try play around with it to see if any outcomes. Thinking of getting another board too.
PM 2527 - Problem - Page 1
Forum section: electronics / repair

author: uVolt
author_rank: Newbie
timestamp: January 20, 2018, 09:21:03 am
content: Need some help with the service manual and with suggestion with what to look at first. The multimeter powers up the display is ok but it can not measure anything.

author: FransW
author_rank: Frequent Contributor
timestamp: January 20, 2018, 10:43:01 am
content: Service Manual:doc.xdevs.com/doc/PHILIPS/PHILIPS%20PM%202525%20Service.pdfRegards, Frans

author: FransW
author_rank: Frequent Contributor
timestamp: January 20, 2018, 10:48:32 am
content: Sorry, 2525 vs 2527:freeservicemanuals.info/en/servicemanuals/viewmanual/Philips/PM2527/

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: January 20, 2018, 11:49:20 am
content: Does the display show a fixed reading or is it "measuring" (ie, the value is chaging) but without any correspondence to the input?If the former, I would check if the trigger circuit is working correctly. If that is rueled out, perhaps inject a signal internally past the analog front end, at the input of the ADC (and do the reverse too, measure what signal is there when you apply an input). That way you can rule out any of the analog frontend parts.The fact that the display is working seems to indicate the main MCU is fine. If the problem isn't in the analog frontend, check if the optocouplers that connect the ADC to the MCU are doing ok. This was where one of my units had a problem (with optocouplers, in my case it wasn't an opto related to the ADC but to the front-end switching).If it is the front-end, check those optocouplers and check what relays should be switching for different ranges. The service manual covers this in some detail and should be clear in combination with the schematic that is also available in the service manual.
Questions about micro switches  such as the SZM-V16-FC-62 - Page 1
Forum section: electronics / repair

author: kaptain_zero
author_rank: Regular Contributor
timestamp: January 19, 2018, 06:05:15 am
content: Our 5 year old over the range microwave oven/ventilation fan is acting up. I have traced it back to the micro switches in the door latches.There are three switches, one is normally open, one is normally closed and the third switches between 2 of the 3 contacts with the third being common.A quick check at the usual appliance parts store shows that one switch is $4 but the other two are around $40 each! Needless to say, I'm looking for options as those prices are a bit rich. I am having some difficulty finding the exact switches and I have come across some that are marked FA-xx and FD-xx and I was wondering just what that indicates? All three switches are held in place on plastic prongs and a couple of springy plastic hooks, so the through holes and the activation button orientation is important.The current switches are marked:SZM-V16-FC-61SZM-V16-FC-62SZM-V16-FC-63RegardsChristian

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 19, 2018, 12:08:29 pm
content: To me all the switches appear the same in your microwave a standard micro-switch.I do not understand why some of them are supposed to cost 40 dollars..If you can easily remove or picture them in the appliance do so we can then have a look and identity them correctly.Cheers.

author: kaptain_zero
author_rank: Regular Contributor
timestamp: January 19, 2018, 10:49:27 pm
content: Quote from: Bashstreet onTodayat 01:08:29 AM

author: drussell
author_rank: Super Contributor
timestamp: January 20, 2018, 03:14:23 am
content: Just buy one or two of the $4 SPDT ones for spares.You can use that type in place of the SPST one, just leave the extra NC contact disconnected.The SPDT will also work as a replacement in the case of an NC version, if you ever need one, just leave the NO contact disconnected instead...

author: kaptain_zero
author_rank: Regular Contributor
timestamp: January 20, 2018, 05:01:06 am
content: DOH! Why didn't I think of that?!?!?!Yes, it would be dead easy, there's plenty of room for the wires and I could always slip some heat shrink over the one spade that shouldn't be used.....Some days I over think things......<groan>Thanks a bunch!RegardsChristian
New contact burnishing tools found - Page 1
Forum section: electronics / repair

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: January 19, 2018, 03:51:45 pm
content: I just discovered tweezer-style contact burnishers, which might come handy for cleaning/restoring severely corroded or degraded contacts. They seem to be suitable for application on pin contacts in single and multipole connectors. As stated by the mfg., they are intended for flat contacts, but I think that use on round pins would be possible with a bit of dexterity.In EU sold under the label of 'KS-Tools', Article # KS TOOLS 118.0030For example here:https://www.ebay.de/itm/KS-TOOLS-Kontaktreiniger-Pinzetten-Satz-3-tlg-fur-Steckergehause-118-0030/311484763186?epid=1361494474&hash=item4885f04c32:g:Rl8AAOSwLzdWRgjp

author: floobydust
author_rank: Super Contributor
timestamp: January 19, 2018, 09:51:40 pm
content: This looks a bit heavy duty, for very large contactors and relays.I use a piece of paper. Most small switch and relay contacts are merely plated.

author: cvanc
author_rank: Frequent Contributor
timestamp: January 19, 2018, 10:19:52 pm
content: Quote from: floobydust on January 19, 2018, 09:51:40 pmI have a 'real' burnishing tool (uhhh... somewhere... LOL) but have also done the piece of paper trick with excellent results. Dipping it in some isopropyl is helpful. Fairly stiff non-glossy paper, like a strip cut from a business card, works very well. The paper can turn completely black so it's clearly getting a lot of gunk off.

author: Electro Detective
author_rank: Super Contributor
timestamp: January 19, 2018, 11:06:33 pm
content: They look handy for some workbut way too big for meWhen the specialty tools fail or don't quite 'get in there' I always end up resorting to scissored fine sandpaper customizations, tweezers, tape, rough porous paper/cardboard, contact fluidhope, impatience and foul languageto get stubborn switches, sockets and blackened contacts working again
Example of Really bad repair on HP214B pulse generator I just got from Ebay - Page 1
Forum section: electronics / repair

author: Insatman
author_rank: Frequent Contributor
timestamp: January 19, 2018, 08:30:14 am
content: Hello, I just thought I'd share how badly some people will "repair" equipment on Ebay. I bought this unit and before shipping the vendor contacted me. zHe said during his pre-shipment test the unit had a "busted capacitor" and that he would repair it before shipping. About two weeks later I receive the unit and it works with some minor issues. It smelled like magic smoke however even before turning it on. The rear AC input jack has lots of carbon and upon closer inspection was severely damaged and had been repaired with hot glue! Photos attached. During my replacement of the AC input connector I also noticed that they spliced wire using masking tape as insulation. Unbelievable. At least the replacement capacitor they used was decent quality and the correct value and rating. See photos

author: Insatman
author_rank: Frequent Contributor
timestamp: January 19, 2018, 08:58:29 am
content: Closeup of AC entry module...they must have tried powering it with alligator chips or something similar to make this happen.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 19, 2018, 12:00:47 pm
content: Unbelievable.... How much do a standard plug cost.. Ether the repairer was desperate to get it work fast or had absolutely no fundsI cannot imagine person with such equipment not having few of those plugs around at least in salvage i do not know.. maybe case of desperation

author: MadTux
author_rank: Frequent Contributor
timestamp: January 19, 2018, 10:20:15 pm
content: That's the usual Schaffner-Paffner behavior.Schaffner used some shitty (I guess paper/oil dielectric) capacitors that draw moisture from air which degrades the dielectric. If equipment isn't in use for longer times, they blow up soon after the instrument is plugged onto power again. I wouldn't be mad at the seller, they fixed it as fast as possible and send you a working instrument. Be happy it didn't blow up in your lab, the magic stench is horrific!
Repair of M-Audio Studiophile AV 40 Speakers - Page 1
Forum section: electronics / repair

author: Dzambaz
author_rank: Newbie
timestamp: January 20, 2018, 02:56:04 pm
content: Hi,I would like to share my experience with the repair of the M-Audio Studiophile AV 40 speakers power supply section. The failed component and the chain of events that led to this outcome were rather unusual and I believe that the video that I made covering the repair would be interesting to all involved in failure diagnostics and repairs in electronics.Your questions or comments related to the repair are welcome.Thanks,Goran
behringer od300 effects pedal - Page 1
Forum section: electronics / repair

author: andybarrett1
author_rank: Regular Contributor
timestamp: January 18, 2018, 04:15:39 pm
content: HiThank you for reading... Can any body help me with the schematic or help ID this Chip (IC1)I want it to be a op-amp but really not sureBRAndy

author: Andy Watson
author_rank: Super Contributor
timestamp: January 18, 2018, 04:37:35 pm
content: Most likely a quad op-amp - would need to see more of the surrounding circuit to be sure:http://www.st.com/resource/en/datasheet/tl064.pdf

author: floobydust
author_rank: Super Contributor
timestamp: January 18, 2018, 09:08:14 pm
content: It is aTL064Cmade by ST, quad op-amp.Behringer stuff is pretty cheap inside, the electrolytic capacitors are very low quality and cause problems. First thing I check.

author: andybarrett1
author_rank: Regular Contributor
timestamp: January 19, 2018, 08:15:30 am
content: Hi AllTL064CI can see it now...... Thank you for replies.BRAndy

author: kalel
author_rank: Frequent Contributor
timestamp: January 19, 2018, 09:29:45 am
content: Quote from: floobydust on January 18, 2018, 09:08:14 pmSorry for off topic but just curious, which brand (preferably not overpriced) would you recommend for guitar effects, that is known for decent quality components?

author: andybarrett1
author_rank: Regular Contributor
timestamp: January 19, 2018, 10:03:57 am
content: HiFrom a repair point of view all the pedals I have seen are a much of a muchness .... Hand wired EFX and Amps are an exception !BRAndy
What blows out in a C band LNB? - Page 1
Forum section: electronics / repair

author: xibalban
author_rank: Regular Contributor
timestamp: January 15, 2018, 01:37:02 pm
content: So,There was a stupid incident of injection of 440 V AC onto our mains (which normally is 220 V only). The high voltage jumped through the gaps on the common room switch (16 A SPST switch), and managed to damage my TV, and set-top-box connected to the common mains 3 pin socket.The TV was saved, as the HRC fuse blew and I replaced it. The STB burned with a bang and I replaced its circuit board. But, the damage was more. The surge went up through the Coaxial Cable and damaged my 4x1 DiSEqC Switch (no visible burns though) and ran up till all my 4 C Band LNBs connected to the DiSEqC switch and jacked them too. None of the LNBs work, and when I pried one of them open, there is no visible damage (like burns, etc.) The circuit board, is extracted and photographed as attached:I could identify the IC as LM339 and the Transistor (BTW, that's where the coaxial cable seems to be connected) reads vaguely 883.My question is, can the circuit be repaired? Which component usually blows up if there's a power surge through the coaxial cable?

author: rg58
author_rank: Regular Contributor
timestamp: January 15, 2018, 05:30:09 pm
content: LNCs are very sensitive devices as they use special low noise GaAs-FET or HEMT transistors on their inputs for the weak satellite signal, followed by a broadband MMIC amplifier to drive the signal down the cable. Changing those ones is very difficult, hard to get and expensive. The rest might be possible to replace, but I believe it is not worth a repair. Sorry to say, but you might have to get a new one.

author: xibalban
author_rank: Regular Contributor
timestamp: January 23, 2018, 11:25:44 am
content: Quote from: rg58 on January 15, 2018, 05:30:09 pmThanks for the response. I called up the LBN manufacturer and enquired if they sell PCB only as I had the metal casing already. They said, NO. I have no choice other than buying a new LNB.
help to identify smd sot23-6 - Page 1
Forum section: electronics / repair

author: harrimansat
author_rank: Regular Contributor
timestamp: January 17, 2018, 09:30:25 pm
content: Anyone can help me to identify this IC?Is a stepdown regulator, 12v to ?Thanks!

author: Wimberleytech
author_rank: Super Contributor
timestamp: January 17, 2018, 10:51:01 pm
content: Looks like a buck converter. Power it up and measure it!
Bose SoundDock Series 2 - Page 1
Forum section: electronics / repair

author: Specmaster
author_rank: Super Contributor
timestamp: January 20, 2018, 12:04:50 am
content: I'm attempting a repair on Bose SoundDock and the indication is that the DSP is the culprit and as it is the dominant PCB, everything passes through it which includes the diagnostic routines.I believe the cause of the problem to be the cap shown in the accompanying photo on which I can get no reading whatsoever but I can on the others, there 8 in total and strangely enough it also the only one on the board that does not show its full rating, or am I missing something here?I cannot find a service manual anywhere for this at all, seems that they might be like Apple in that dept.Any help you could offer is appreciated, thanks
Samsung PN58C550 Not Turning on - Page 1
Forum section: electronics / repair

author: Fisher77
author_rank: Regular Contributor
timestamp: January 14, 2018, 11:46:14 pm
content: Took a chance and bought this one for 20 bucks. TV would not turn on when I got it. I found the QP802 MOSFET blown and both the F801S, and the F802s blown. The FET is a 20N60C3 I replaced it and both fuses, turned on the TV, ran for about 5 minutes, and it blew the FET and fuses again. I have checked the components around the FET. All seem to be ok. I then checked the ICX801 which is a 3BR1065JF and the components around it. No pins are shorted on it. Found no problems with any of the components around it. One problem I do have is the capacitor CX898 flew the coop. Never fails when I mess with these small SMD's.I was hoping someone might be able to tell me what cap might should be there, and get some help diagnosing the problem with this power supply.Any help is greatly appreciated.Pictures:THe top and bottom view of the whole board are from ShopJimmy. I could not get good clear pictures with my camera.The last picture shows the missing cap location in a red box.https://ibb.co/iXHSXRhttps://ibb.co/kTyjCRhttps://ibb.co/i03Cz6https://ibb.co/hdekK6https://ibb.co/mVKwRmhttps://ibb.co/d7cEe6Datasheets below are PDF File Downloads3BR1065JF Datasheet:https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiV5K25y9jYAhXhRN8KHb0fDJoQFggrMAA&url=https%3A%2F%2Fwww.infineon.com%2Fdgdl%2FInfineon-ICE3BR1065JF-DS-v02_01-en.pdf%3FfileId%3Ddb3a30431ce5fb52011cf41346a204ef&usg=AOvVaw27s5R1GH6ar_ONdFMUxwZ020N60C3 Datasheet:https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjxvpSMzdjYAhWLx4MKHal_BQEQFggoMAA&url=https%3A%2F%2Fwww.infineon.com%2Fdgdl%2FInfineon-SPP_I_A20N60C3-DS-v03_01-en.pdf%3FfileId%3Ddb3a304318f3fe290119090054e32a20&usg=AOvVaw3DmR6X4IjXVbSJBkMJIrVh

author: Fisher77
author_rank: Regular Contributor
timestamp: January 17, 2018, 08:36:16 pm
content: Bump