hybridfree/eevblog-posts huggingface dataset:
hp 54502a nvram substitute - Page 1
Forum section: electronics / repair

author: nixiefreqq
author_rank: Super Contributor
timestamp: January 17, 2018, 02:40:48 am
content: my old hp1980b is finally dead. all indications are that the final failure was an unobtainable horizontal ceramic hybrid. (ok....the guys in the great white north have one pull, but coded as "untested". it just did not feel worth the risk for a scope that is a high maintenance constant source of irritation........but geeeze I loved it anyway. may it RIP.)its replacement is an hp54502a that on arrival was 100% functional and passed all tests, but the date code on the dallas nvram chip was 1991!the idea of replacing an imbedded lithium battery with another encased battery just seemed wrong. my solution was a separate battery controller, standard sram, and a coin cell.hardest part of the project was removing the the old dallas chip with a manual chinese solder sucker. in the end it surrendered and the board survived intact.the result is ugly, but it works. after replacement and re-cal it appears to be a happy unit.your mileage may vary.
Denon AVR-1912 E2/EA - +8V wrong! - Page 1
Forum section: electronics / repair

author: Studio1@29
author_rank: Contributor
timestamp: January 16, 2018, 04:03:30 pm
content: I have dismantled 5 of the pcb's from the chassis of the AVR:(HDMI_B'D.,)(FRONT_CNT_B'D., )(SIDE_CNT B'D., )(AUDIO_VIDEO UNIT)(REG_CNT, ) in order to check the voltages of the +8v rail on its way from the REG_CNT.To two of the Connector Blocks I have attached two 'Test tails' on certain +8V pins in order that the Voltage may be measured with the AVR powered up.I have attached 'Test Tail 1' to CN101, pin 1, (see page 110 of the Service Manual) andI have attached 'Test Tail 2' to CN14, pin 14 (see page 111 of the Service Manual)The results: Test Tail 1 = +10.78V (it should be +8V)Test Tail 2 = + 4.589V (it should be +8V)The IC801 (see page 114 of the Service Manual) shows pin 30 (of 100) as its *7V power contact.The results at pin 30 of the IC801 read +3.83V. It should be +7V)Can anyone suggest what is wrong here?I am an Octogenarian beginner! (AD 1936) Michael UK

author: mzacharias
author_rank: Frequent Contributor
timestamp: January 16, 2018, 08:33:38 pm
content: IC's like IC801 do go bad fairly frequently. These IC's run fairly warm as I remember, but if it is unusually hot I would say it is defective.A+8 being low (and 7 by the time it reaches IC801) could be a bad IC106, could be loaded down by IC105, could be loaded down by IC801.I think you need to isolate the A+8 from the rest of the circuit and substitute in 8 volts from an external supply. Once you have ruled out the voltageregulator as the problem, one of the other chips is probably bad, and once again I'm looking at IC801.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: January 16, 2018, 09:29:05 pm
content: +1 The Regulators go bad consistently.
Crotech 3031 20Mhz CRT scope circa 1985 no vertical line on square wave  - Page 1
Forum section: electronics / repair

author: alanjosephbrown
author_rank: Newbie
timestamp: January 19, 2018, 01:38:01 pm
content: Hi Folks,Just having a look a second hand scope (Crotech 3031 20MHz single channel) i had bought yesterday. As per manual i set up for self test/cal, which is a 200mV/1KHz square wave. Problem is that on screen only the horizontal line of the waveform is visible. On the cal post i measure only about 100mV using a calibrated bench DMM and a frequency of 946Hz. On checking the manual it stated that the cal post output could be adjusted by trimming, the stated value of the variable resistor was 100 ohm and the measrred resistance (in circuit) was 1.3ohm up to 84.3ohm. At the lowest resistance setting cal output was at 103.51 mV and then 107.79 mV at the top end. And this is as far i have went. I plan to go through all the components and bench test to see if i can find the culprit. Visual inspection of the inside throws up no clues - no signs of overheating.Just so you know what you are dealing with, i am a practising electrician with only experience in heavy industry and this was supposed to be my first foray in the electronic black arts however i need a working scope first!! I picked this up for next to nothing so the temptation is to scrap it but i would like to see it working. It was supplied with a great mint condition manual with all the circuit diagrams and parts but unfortunatley the company has liquidated quite some time ago.What i am hoping is that someone out there has maybe experienced this before and this issue is blatently obvious?Appologies in advance for incorrect terminologies used.Many thanksAlan

author: tautech
author_rank: Super Contributor
timestamp: January 19, 2018, 01:59:26 pm
content: Welcome to the forum.Probe Cal outputs for scopes come in many flavors of voltages but frequency is in older units can be all over the place and some units allow for it to be adjusted as close as possible to 1KHz but it's never precise and best just thought of as a sanity check.Probe Cal voltage is p-p and again not necessarily precise as the fast rising edge and flat peaks are what matters for probe compensation adjustments.The fast rising edge is often not visible but that depends on the phosphor type used in the CRT and it's degree of persistence.Unlike a DSO where the raster is reconstructed from data points, it's normal the CRO vertical edge is hard to see especially at normal viewing intensity (brightness) levels and/or at slow timebase settings.Let a normal scope probe rather than a DMM tell you what's going on here as the circuitry for the Probe Cal is normally supplied from LV and in no way could be anything like 100 V.

author: alanjosephbrown
author_rank: Newbie
timestamp: January 19, 2018, 03:27:18 pm
content: Hey tautech thanks for the quick response, my bad i meant 100 milli volts, thanks for the info much obliged!!
Flir Tau 2 Infrared Camera Issue - Page 1
Forum section: electronics / repair

author: ixiu
author_rank: Contributor
timestamp: January 15, 2018, 11:42:57 pm
content: I have a Flir core Tau 2 camera that I connect to a laptop via USB. I use the Flir Controller GUI to take snapshots and I encounter the following error when i try to retrieve and view snapshots that i have taken.Additional info:Windows 10 machineSnapshots taken can only be viewed through the GUI, they are not on the SD card (when i look used SD card reader).The software works fine on windows 7.Under properties option on the windows 10 machine you can run the software in Windows 7 compatibility mode but it comes up with the same error.The Flir tau 2 is not compatible with any other FLir software on their website. However there are 3rd party software it is compatible with, but i am yet to find any.Snapshot taken files can only be saved in .jpeg format and that choice is not available until the image is retrieved which is where this error occurs.any help would be helpfulThanks
HP 8647A problem - Page 1
Forum section: electronics / repair

author: tatronic
author_rank: Newbie
timestamp: January 15, 2018, 12:11:58 am
content: Hi,I'm looking for HP 8647A schematic. I have problem with A7 attenuator board. I missing signal on pin 19 (A3J16 ) . This signal is from SIO controller . I'm looking with IC is that.Anybody have ide where to buy good schematic ?Thanks

author: oventech
author_rank: Contributor
timestamp: January 15, 2018, 03:09:51 am
content: Would this help Keysight manuals page for the 9647A.https://www.keysight.com/main/techSupport.jspx?searchT=8647A&id=1000002191:epsg:pro&pid=1000002191:epsg:pro&cc=US&lc=eng

author: tatronic
author_rank: Newbie
timestamp: January 15, 2018, 03:57:35 pm
content: Thanks for link but this is just basic manual and no schematic . I wonder if there is anything like a schematic at all.
Cheap BGA rework in Yurop, anyone? - Page 1
Forum section: electronics / repair

author: User32
author_rank: Contributor
timestamp: January 14, 2018, 03:30:19 pm
content: I have a ThinkPad X31 which could use a GPU and CPU upgrade, but since they're both BGA soldered (like all Xseries ThinkPads) I can't easily swap in a Dothan Pentium M or a Radeon 7500 GPUIs there anyone in NL/EU that can do BGA rework on the cheap? I can get a pre-modded X31 in Germany for 130€ but that's the no other possibility option.

author: Rasz
author_rank: Super Contributor
timestamp: January 14, 2018, 09:05:06 pm
content: Quote from: cleaningOut on January 14, 2018, 03:47:42 pm;-)would you say the same thing to a car enthusiast looking for a shop?Now X31 might not be a 250 GT California Spider (that would be X61/X201), but its up there with Mercedes R107, 1970 Chevelle SS, or Hakosuka.
AB54-S information - Page 1
Forum section: electronics / repair

author: dave.murz.ufl
author_rank: Newbie
timestamp: January 17, 2018, 05:55:07 pm
content: Trying to find information on this Mettler Toledo AB54-S balance. I'm troubleshooting this piece of equipment and I'm having difficulty trying to get more information on this balance. If anyone has any information this balance please help?

author: helius
author_rank: Super Contributor
timestamp: January 17, 2018, 06:34:41 pm
content: The operating instructions are on the manufacturer web site. It's not common for service manuals to be available for precision balances as they were normally intended for factory repairs. But the electronics of a load-cell balance are not that complicated; how far have you got?

author: dave.murz.ufl
author_rank: Newbie
timestamp: January 17, 2018, 08:46:31 pm
content: We were able to get the manuals and the equipment isn't supported by Mettler Toledo anymore. So, we asked for more information and they didn't want to help.The balance will turn whenever it wants to now and the controls work. There is something else that is going on.

author: helius
author_rank: Super Contributor
timestamp: January 17, 2018, 09:18:01 pm
content: I can't understand your problem description. You mean if you press Tare it doesn't stay at zero?

author: dave.murz.ufl
author_rank: Newbie
timestamp: January 18, 2018, 01:50:10 pm
content: When you plug the unit in it doesn't turn on at all and it turns on whenever it wants to. When it does turn on it will show all zero's and will not tare either.
GOULD 4072A - Page 1
Forum section: electronics / repair

author: comet2458
author_rank: Newbie
timestamp: January 11, 2018, 03:19:34 pm
content: Hi to all,i am looking for a service manual for the gould 4072A version2 x ch 200mhz scopethanking all in advancemick

author: bd139
author_rank: Super Contributor
timestamp: January 11, 2018, 05:05:51 pm
content: Someone claims to have scanned it here:https://www.vintage-radio.net/forum/showthread.php?p=559010#post559010If you ask on there, they are terribly helpful with such things.

author: comet2458
author_rank: Newbie
timestamp: January 14, 2018, 12:12:29 pm
content: Hi , thanks for that..BUTthats the manual for the 4072 the 100mhz scope....NOT the 200mhz version
bindingpost  and knobs for HP 339A    distorsion  analyzer - Page 1
Forum section: electronics / repair

author: Stewen
author_rank: Newbie
timestamp: January 16, 2018, 10:01:17 am
content: Hallo ! Wonder if anybody have a binding post for bananaplug and any knob for this instrument ? The leveldoubleknob and the frequency knob , marked 10k 1k 100 and 10 is missing .Regards Stewen ( or does anybody know where to buy these knobs ? )
Acer ES1-571 motherboard charging problem - Page 1
Forum section: electronics / repair

author: slafkoo
author_rank: Newbie
timestamp: January 11, 2018, 02:41:40 pm
content: Greetings all!Since this is my first post, little introduction from my side, I'm Tom from Croatia, SysAdmin, late 20es, been around electronics whole life, but recently started to go deeply into it. I have basic electronic knowledge and soldering skills, like repairing bad contacts, make simple circuit and that stuff. been long time lurker on this forum, now i decided to reg and make my first post since for the problem i have, can't find any solution on interwebs.So the problem is laptop motherboard for Acer ES1-571 with i3cpu. I have old Acer ES1-512 with pentium N-crap cpu which is collecting dust and since mobo from ES1-571 fits into 512 i decied to buy it. I got it very cheap from ebay, it was listed on defect so i knew i was getting into. Seller specified that motherboard turns on but there is no video on external display. So, when i received it, swamped the mobos in laptop, did hard reset and there was video on display. yay! Booted into Windows, everything works.But, then i noticed that battery is not charging. It says the battery status (%) but there is a error messages "Plugged in, not charging". Unplugging the power cable from laptop, laptop instantly shuts down and trying to power it on without cable pluged in, doesnt work.What i tried:Battery reset procedure - 0 successTried different battery with higher V - 0 successTried different DC jack - 0 successTried different power adapter - 0 successChecked the fuses (F5201, F5202, F5401) on mobo with multi meter - signal passing trough, so they are OKContacts on battery connector (BTY1) looks fine.Don't know what else to try, so if someone could suggest something or guide me to fixing this, i would be very grateful.Below are attached pictured of mobo, top and botom sideThanks in advance!Ignore termal paste

author: Rasz
author_rank: Super Contributor
timestamp: January 12, 2018, 09:06:40 am
content: no idea if diagram is available for this crap, but its pretty much always a ~copy and paste from similar designs, like this :http://www.rom.by/files/1670_petra_uma_mb-aspire_v5-531_v5-571-11324.pdfyou can almost use that one 1:1 if you subtract 400 from part numberson the diagram charge controller PU4003, on your board its PU4403 etcfirst check PU4402, PR4417, PR4404 etc
SMD 3 terminal filter capacitor help - Page 1
Forum section: electronics / repair

author: ScottM
author_rank: Newbie
timestamp: January 10, 2018, 05:09:16 pm
content: I am doing a repair to an I/O board in an ECU from a Volvo excavator and need some guidance on replacing /selecting a destroyed 3 terminal pass thru filter capacitor. I'll admit I'm pushing my abilities but have little choice as replacement boards are not available and I can't justify $2000 for a used unit that might work.So here is what I know. The ECU is an old Contronic E system and the I/O board burned a 3 terminal cap on a circuit that is the 0V point for 5 different sensors. The first component is an 1806 size 3 termianl capacitor. It was literally burned off the board. This is a 6 layer board. I do not believe the damage went below the 2 layer. I am finishing repairs and replacing the missing pad but need help selecting a replacement capacitor.What I know is that of the 5 sensors that use this path 2 provide a variable resistance, 2 provide a variable voltage and 1 is a 4-20ma circuit. I believe the damage occurred when the oil pressure sensor which is powered with 24V was disconnected and a connection was made from unfused 24V to this 0v path. I think. I have bench tested all the sensors and am replacing the 4-20ma one as it is not consistent.There was another capacitor right next to this that provides an 8.5v source for the 4-20ma sensor that I will also replace. out of the circuit it measures 22Kpf. The closest I can find in that package is 33Kpf rated 300ma at 100V. Is this OK and would it seem appropriate for both replacements? Other ideas?Any thoughts are helpful. Thanks.

author: floobydust
author_rank: Super Contributor
timestamp: January 11, 2018, 09:16:55 pm
content: These are for EMI filtering, and try act as a fuse if a ground fault occurs...Usually 1800pF-4700pF at 100-250V, not too large capacitance for fast/high impedance signals like an O2 sensor.Look atMurata NFMfeedthrough capacitors, EMI filter, andTDKYFF series.The SMT package size is large, which will narrow down your options.
How do you make a decision is the uC bad or not? - Page 1
Forum section: electronics / repair

author: Chriss
author_rank: Frequent Contributor
timestamp: January 11, 2018, 02:56:59 pm
content: Hi!I'm interested on the variate of making the conclusion does a uC is bad or not.So, lets say we have a circuit with an LCD driver and a uC.The uC can be whatever uC (I dont ask for a specific one).The board is bad.You want to repair it.Everything looks fine bit the lcd still not working.So, a doubt is on a defective uC.How to agree with it?I do these tests:1. by using the datasheet of the uC check for power on voltages2. checking for a shortening on the Vcc and Vss line3. check for overheating4. if I have some known output signals I will check with scope thatIs there any more test's what we could do to be more sure about a bad or not bad uC?What is your method?Thanks.

author: Kjelt
author_rank: Super Contributor
timestamp: January 11, 2018, 03:09:59 pm
content: Check the reset pin condition (check correct level but also the raise/fall time during power up which is sometimes a major culprit).Check the oscillator(s) inputs.Check any outputs (see if the thing has a heartbeat eg if it does something at all).Sometimes it is just a broken GPIO pin those are the hardest to check find if it is not your own program running.

author: Chriss
author_rank: Frequent Contributor
timestamp: January 11, 2018, 03:17:47 pm
content: Thank's for the replay.I will put together a list so we have here a list how to test a uC the best way.Maybe a hierarchy of the test's would be also nice.My best regards.
Datron/Wavetek 4600 Transconductance Amp - Page 1
Forum section: electronics / repair

author: gab_au
author_rank: Contributor
timestamp: January 11, 2018, 08:29:35 am
content: Hi all,I recently bought a faulty Wavetek/Datron 4600 Transconductance amp and having repaired it, I now have a question or two as I've not had one previously. I've got the service manual but would like the operation manual - should I turn on the drive voltage before turning on the output or vice versa or does it not matter?2nd question - it appears this thing dissipates 150W in standby, am I reading that section on autobias correctly? If that is right, would anyone know what the typical operating temp of the heatsink should be? This ones runs too hot to touch, is that "normal".ThanksGreg
Tektronix Oscilloscope 2225a - Page 1
Forum section: electronics / repair

author: ramptonp
author_rank: Newbie
timestamp: January 11, 2018, 12:08:00 pm
content: I have a Old Analogue 2225 Tektronix Oscilloscope. When I switched it on yesterday after a few months of inactivity, the screen didn't light up and after 5 seconds or so I heard a pop and a burning smell from the rear. I had a look inside and found that a capacitor on the main power supply board had blown up (see attached photo). This capacitor is labelled on the circuit board as C903. I have found a service manual with circuit diagrams and this capacitor is placed between neutral and earth, it says 0.0022 next to it. There is an identical capacitor between the live and earth too (C904) but this one appears to be ok.After contacting Tektronix directly they do not have parts for these anymore so I am trying to find an alternative.If any one can help it would be much appreciated.

author: tggzzz
author_rank: Super Contributor
timestamp: January 11, 2018, 04:18:54 pm
content: It is one of the infamous Rifa smoke generators.Have a look on this forum for Tek 2445/2465, and apply the techniques shown inhttp://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf

author: bd139
author_rank: Super Contributor
timestamp: January 11, 2018, 04:59:21 pm
content: Indeed. Congratulations on your first and probably not last RIFA explosion. Those RIFA X2's just love to explode. I've had at least 5 go off on me at some point or another. My Tek 2225 will no doubt explode soon as well. It has eaten about £20 of electrolytic caps already.Remove all of them. Replace them with roughly the same value X2 / Y2 class capacitors. Cheap Chinese ones will do the job. You can get them here individually for a reasonable price in the UK:https://www.bitsbox.co.uk/index.php?main_page=index&cPath=65_81Note: X2 capacitors go across the mains. Y2 capacitors go from the mains to earth. I think there's a combination of them in there. Make sure you use the correct ones for the job.comedy timing of one exploding here:

author: ramptonp
author_rank: Newbie
timestamp: January 11, 2018, 08:21:23 pm
content: Ok thanks for that I will take a look.
Fluke 8800A - Page 1
Forum section: electronics / repair

author: Seabird
author_rank: Newbie
timestamp: January 09, 2018, 09:47:36 pm
content: Hello forum members:I am looking for a replacement power on/off switch lever (the green one!) to replace the broken one on my meter. If anyone has any suggestions as to where I can get one (tried Fluke - meter too old) it would be most appreciated.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 10, 2018, 12:40:47 am
content: maybe buying an defective unit would help you ?? there a 40$ to 100$ models on Ebay

author: Seabird
author_rank: Newbie
timestamp: January 10, 2018, 04:09:47 pm
content: Thank you coromonadalix for your reply. eBay will probably be my next step but I thought I would first see if any blog members had one that maybe looking for a new home!
Gould 1425 - Page 1
Forum section: electronics / repair

author: DeanKindleysides
author_rank: Contributor
timestamp: January 03, 2018, 06:37:09 am
content: Looking for manual/service/circuit diagram for Gould 1425Can anybody helpSent from my iPhone using Tapatalk

author: DeanKindleysides
author_rank: Contributor
timestamp: January 10, 2018, 04:01:39 pm
content: Still no luck with manualSent from my iPhone using Tapatalk
[SOLVED] YEC 6038A0003301 CCFL inverter help pls - Page 1
Forum section: electronics / repair

author: Chriss
author_rank: Frequent Contributor
timestamp: January 14, 2018, 10:47:58 am
content: Hi!I have this type of inverter YEC 6038A0003301 for CCFL lamp from a bad laptop.Does somebody know what is the voltage on the VDDP pin 16 of the MSC1691 ic?Actually, I figured out the power connector pinouts for GND, VCC and PWR_on pins but I don'thave a clue what is the PWR_on and VCC voltage for this inverter.I don't have the laptop so I cant check by measurement...Here is a link about the IC but I'm not sure about the description because I translated it from CN to EN...http://m.dzsc.com/data/html/2011-10-14/98866.htmlHere is the pinout and this is working well:If somebody need...Thank you very much.My best regards.
Plasma - Page 1
Forum section: electronics / repair

author: Vestigius
author_rank: Newbie
timestamp: January 08, 2018, 10:28:22 pm
content: Olá tenho uma fonte de um plasma LG que estouraram uns poucos componentes e a placa é um pouco cara ,preciso do esquema é uma eay60713301 ps-7471-1a-lf alguém pode me ajudar?

author: EEVblog
author_rank: Unknown
timestamp: January 09, 2018, 01:38:49 am
content: REMINDER:This is an English only forum.

author: Muttley Snickers
author_rank: Unknown
timestamp: January 09, 2018, 01:47:04 am
content: Quote from: Vestigius on January 08, 2018, 10:28:22 pm"Hello I have a source of a LG plasma that burst a few components and the board is a little expensive, I need the schematic is a eay60713301 ps-7471-1a-lf can anyone help me?"Just so people don't have to search, Google translate indicates the request is something like the paragraph above.

author: Simon
author_rank: Unknown
timestamp: January 09, 2018, 07:02:56 am
content: Thank you Muttley, hopefully the OP learns english fast
Remote Controller For LED String Light Dimmer  - Page 1
Forum section: electronics / repair

author: Lee Newsum
author_rank: Newbie
timestamp: January 09, 2018, 12:07:08 am
content: I have one of these system in one of my rooms (not installed by me) so i have bin best part of a year and replaced if in the middle of the year and looks like the new one as gone bad too.this looks like the one have.eBay auction: #https://www.ebay.co.uk/itm/RF-RGB-Wireless-28-Key-Remote-Controller-For-LED-String-Light-Dimmer-12-24V-WB/263387145351?epid=2143122925&hash=item3d5318e487:g:KP8AAOSwcj1aMigjso what can I get to replace it that would last?thanks for your help.
Crimp box format socket to fit 0.05" (1.27mm) square PCB pin - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: January 08, 2018, 02:34:28 am
content: I initially thought this would a a simple item to find, but it seems it's a bit harder than that.The chopper PCB in the HP 3420 has two 0.05" square PCB pins to which I need to connect two wires - so easy?No - I've so far been unable to locate a free crimp socket to fit a 1/20" square pin.Any suggestions most welcomeThanksDave

author: pamphonica
author_rank: Regular Contributor
timestamp: January 08, 2018, 10:54:05 am
content: This series is 0.045" square and might provide a basis for experiment.http://www.molex.com/molex/products/datasheet.jsp?part=active/0009503021_CRIMP_HOUSINGS.xml#partdetailJeremy
Active Clamp Forward Converter - Page 1
Forum section: electronics / repair

author: Mattheprofessional
author_rank: Contributor
timestamp: December 20, 2017, 01:07:18 pm
content: Any one here who knows about Active Clamp Forward type converterSent from my Redmi 4A using Tapatalk

author: Mattheprofessional
author_rank: Contributor
timestamp: January 08, 2018, 09:12:36 am
content: Quote from: Mattheprofessional on December 20, 2017, 01:07:18 pmNobody??Sent from my Redmi 4A using Tapatalk
Blew up my Ming He D3806, what is the value of R8 - Page 1
Forum section: electronics / repair

author: kvd
author_rank: Contributor
timestamp: December 27, 2017, 09:04:27 pm
content: I blew up my Ming He D3806 buck/boost converterand now R8 needs to be replaced. However I cannot read its value anymore. Can anyone check it for me?Thanks

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 28, 2017, 04:46:07 pm
content: take a photo of circuit

author: Inverted18650
author_rank: Frequent Contributor
timestamp: January 07, 2018, 06:58:19 pm
content: Here ya go mate.

author: GreyWoolfe
author_rank: Unknown
timestamp: January 07, 2018, 07:26:28 pm
content: If you are talking about the resistor that says 102, that is a 1K\$\Omega\$ resistor

author: Inverted18650
author_rank: Frequent Contributor
timestamp: January 07, 2018, 08:35:35 pm
content: Obviously. I listed the pic for the OP instead of simply typing “it’s a 1K.”

author: GreyWoolfe
author_rank: Unknown
timestamp: January 08, 2018, 12:47:52 am
content: Quote from: Inverted18650 on January 07, 2018, 08:35:35 pmOOPS, that was a brain cramp, IASSUMEDthe OP posted the pic, should have read the poster name.. It's a good thing that I have the emoji. If I truly banged my head on a wall as often as I use it, I would have dane bramage. I will go hide under my workbench now.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: January 08, 2018, 01:01:17 am
content: No worries at all Woolfe, and thank you for all the contributions here. Your assistance is always appreciated and it’s clear your level of knowledge is light years ahead of mine. I was just hoping you didn’t think I was an idiot.
Another mystery IC - Page 1
Forum section: electronics / repair

author: jkf1000
author_rank: Regular Contributor
timestamp: January 05, 2018, 01:36:49 pm
content: I am repairing a Motorola handheld radio and as part of the fault finding I found a shorted IC but after an hour of googling I have found no further information about its function. There is a company in Ireland (Donberg Electronics) that has 2 in stock but even they have no further details or a datasheet for it. I would like to know what it is before going ahead with an order. Any help in identification would be greatly appreciated. Karl

author: CJay
author_rank: Super Contributor
timestamp: January 05, 2018, 04:07:36 pm
content: Which Motorola handheld?

author: jkf1000
author_rank: Regular Contributor
timestamp: January 05, 2018, 05:33:31 pm
content: Its a XTN446 PMR radio

author: coromonadalix
author_rank: Super Contributor
timestamp: January 05, 2018, 08:12:44 pm
content: found this : T30C30 RF IC PA Driver & LNA TEMICa few sell this ic in the web, ebay has one selling thislots of fake service manual links ...

author: jkf1000
author_rank: Regular Contributor
timestamp: January 06, 2018, 10:52:13 am
content: Looks like you have had better luck with google than me. I did find the one on Ebay which may be worth a look. Donbergs are cheaper per unit but there is a minimum order value. Thanks for the replies. Karl.

author: jkf1000
author_rank: Regular Contributor
timestamp: January 07, 2018, 09:07:26 pm
content: I have bitten the bullet and ordered a couple from Little Diode on Ebay after they accepted a best offer price, still no luck with a data sheet but you can't win them all. Karl
Service Manual or schematics for GE VS Series On-line UPS - Page 1
Forum section: electronics / repair

author: bolovan
author_rank: Contributor
timestamp: January 11, 2018, 07:25:45 am
content: Hello all,I need a repair manual or schematics for GE VS Series UPS (1000VA).I can't find anywhere.If help:There are two boards: controller board (IM0128A5)...and power board (inverter, power line etc) with series: GROUP 1017691Thanks for help...and sorry for my bad english
Req: Keysight N9310A service manual - Page 1
Forum section: electronics / repair

author: bernroth
author_rank: Regular Contributor
timestamp: January 06, 2018, 08:21:40 pm
content: Hello folks!Happy new year to all!I'm seeking for the service manual from the Agilent/Keysight N9310A signal generator.I have found some references in google but nowhere to actually download it.Any help very appreciated.Best regards,Bernhard

author: Samogon
author_rank: Frequent Contributor
timestamp: January 06, 2018, 08:47:33 pm
content: Afraid it doesn’t exist for public access.

author: bernroth
author_rank: Regular Contributor
timestamp: January 06, 2018, 09:09:22 pm
content: Well, yes, that was somehow expectedAny official way to obtain it or to get the block diagrams?
DSE/Xytronic T2000 Soldering station - Page 1
Forum section: electronics / repair

author: hector.pascal
author_rank: Contributor
timestamp: March 15, 2015, 02:07:51 pm
content: My T2000 may have lost temperature control and be overheating the element. Has anyone got a schematic, or can confirm how the control loop works? Also does the Xytronic element have a thermocouple, or PTC resistance for temperature measurement?Thanks,David

author: hector.pascal
author_rank: Contributor
timestamp: March 16, 2015, 02:39:18 am
content: Thanks Wilfred.My impression from other posters, on other forums, is that since DSE started concentrating on "shifting boxes", rather than being "techie", they are much less friendly to requests of this sort. They just want you to buy new gadgets. But it's worth a try!David

author: hector.pascal
author_rank: Contributor
timestamp: March 24, 2015, 12:06:19 am
content: Well, as Wilfred suggested, I sent a nice message to DSE Spare Parts on 16th March asking for help.To date they have not even acknowledged my email.David

author: hector.pascal
author_rank: Contributor
timestamp: March 24, 2015, 11:33:51 pm
content: Well Wilfred, my pessimism was misplaced. I re-sent the same email, but to "Technical Support", and this time it fell through all the right holes!I got back a Schematic, Manual, Component List and pcb layout. Elements and barrels are still available, but tip stocks are running out, and will not be replenished.All in all EXCELLENT service for a product that's been in production for about 20 years!WELL DONE DSE!David

author: KG7AMV
author_rank: Frequent Contributor
timestamp: April 25, 2015, 05:08:59 am
content: Up load the info so others can easily find it with out having to contact them.

author: hector.pascal
author_rank: Contributor
timestamp: May 10, 2015, 01:19:49 am
content: I am a little concerned with the copyright issue here, as DSE and Xytronic are both still existing and operating companies. But if people PM me, I am happy to send them the details.DavidVK6JT

author: Mikki-T
author_rank: Newbie
timestamp: January 07, 2018, 09:06:31 am
content: HiI just found your post as I'. after the schematics abd part lists for the DSE T2200 soldering station. Would you be able to email me a copy, please?I'd really appreciate it as my trusty iron has just diedCheers, Mike
Help sourcing encoder - Page 1
Forum section: electronics / repair

author: jheatac
author_rank: Regular Contributor
timestamp: January 05, 2018, 09:17:34 pm
content: Hello,I have a volume encoder that I cannot seem to find. It is in a Monster branded MP3 player, however I only have the board, not the whole unit, so I don't know the model.The only marking is on the back. I will take a picture in the next post.Vertical, PCB Mounted with panel nut (not used in this application), Mechanical, 20 PPR, w/ momentary push button. knurled shaft - I believe would be 6mm, 25mm long (this seems uncommon)3 terminals are 2.5mm apart2 terminals are 5mm apart2 mounting holes in PCB look to be 11mm centers or 11.75mm outside to outsideterminal rows are 14.8mm apart (2 on one side, 3 on other)11.7mm wide x 13.8 long x 7.2mm tall not counting panel mount or shaft.My measurements may be just a little off because I don't have a set of metric calipers. I'm converting thousanths to mm with a calculator.Thank you for your help

author: jheatac
author_rank: Regular Contributor
timestamp: January 05, 2018, 09:21:17 pm
content: Here are picturesSent from my SM-G920V using Tapatalk

author: saike
author_rank: Regular Contributor
timestamp: January 05, 2018, 10:26:18 pm
content: Did you remove it with a hammer or an axe?The link is to a gray encoder but it looks as though it may be from the same family?http://uk.farnell.com/bi-technologies-tt-electronics/en11-hsm1aq20/incremental-encoder-100rpm-5vdc/dp/2787193

author: jheatac
author_rank: Regular Contributor
timestamp: January 05, 2018, 11:12:20 pm
content: Quote from: saike on January 05, 2018, 10:26:18 pmIThe knob broke off which is why it is being replaced.The desoldering iron wouldn't free the pins. I cut the 5 connectors and wiggled the mounting tabs out, then I heated and pulled the pins individually.I then took it apart to count the number of tabs on the wheel.Thanks for the reply.I have found several bases that would fit up, but the shaft isn't long enough. I will check it out. Thanks!

author: saike
author_rank: Regular Contributor
timestamp: January 06, 2018, 12:23:51 pm
content: My quip about the hammer was a very poor attempt at humour, which now I look at it again seems like an aspersion on your component removal skills which it definitely wasn't.I just thought about it a bit and surely a 2 bit gray encoder must have the same output as an incremental encoder?So maybe the device in the link is the same one as the original.

author: jheatac
author_rank: Regular Contributor
timestamp: January 06, 2018, 03:10:17 pm
content: Quote from: saike on January 06, 2018, 12:23:51 pmI took no offense. Your assessment based on the pictures were pretty well spot on!I am very much a newbie at electronics. It looks to me that a mechanical encoder has the pulses split evenly at 50% of the cycle. A gray encoder looks like the cycles are slightly offset. Is that the difference?

author: saike
author_rank: Regular Contributor
timestamp: January 06, 2018, 07:33:52 pm
content: QuoteIt looks like that to me from looking at the data sheet. It should still work ok whatever the original item is.
Need Recommendation for Repair Shop for R&S Signal Generator? - Page 1
Forum section: electronics / repair

author: K1JOS
author_rank: Regular Contributor
timestamp: December 31, 2017, 11:49:12 pm
content: Can anyone recommend a good (and reasonable) repair shop in the USA for a 3 GHz signal generator (R&S)? The problem is either in the final power amplifier or attenuation blockHappy New YearJerry

author: DaJMasta
author_rank: Super Contributor
timestamp: January 01, 2018, 07:58:05 am
content: An SMIQ generator? If you're feeling plucky and want to get your hands dirty, the full schematics are available and there's at least a couple threads on here working on the final output board - it is certainly possible to fix on your own. There are also attenuators available on ebay and the like, since a decent number of them are floating around.

author: Aleksandar
author_rank: Contributor
timestamp: January 04, 2018, 01:48:10 pm
content: Hi,If you buy a service manual, be careful!!!There are two versions of the output stage.My SMIQ03B (0.3MHz-3.300MHz) has three transistors in the output stage and it's an older model. The newer model has two transistors.Of course, the difference is not just that.The older model has a designation of the scheme 1084.9800.01 SANew, all digits are the same, but only suffix S.I'm throwaway money and hoping to have the correct schemes.And what I bought is barely (scarce) visible! Almost unusable!So I recommend that you look for a sample of a single sheet in PDF, before payment!That's my experienceGood luck!Aleksandar

author: DC1MC
author_rank: Super Contributor
timestamp: January 05, 2018, 09:14:57 am
content: Quote from: VancleVector on January 05, 2018, 09:06:27 amThis sound like a thermal issue, maybe some solder joint cracked and when the board is hot, the contact is gone.Or (this is much worse), a power supply it's out of spec and it heats the whole board and after a while the CPU stops working or crashes, if possible check the power supplies first.
Replacement enclosure for a Quark PMM - Page 1
Forum section: electronics / repair

author: NottheDan
author_rank: Frequent Contributor
timestamp: January 06, 2018, 12:00:31 pm
content: I recently got a Quark 330A PMM (with a Lead-Acid battery in the back) that unfortunately came with the outer casing smashed to bits. Does anybody know where one can get a replacement case? Or do I need to junk another old instrument for its housing? Seems like quite a few British manufacturers used this style during the 70s/80s.
OWON ODP3031 DC Power Supply Output Voltage Display Problem - Page 1
Forum section: electronics / repair

author: ramin110
author_rank: Contributor
timestamp: December 08, 2017, 07:00:28 am
content: Hi everyone.First of all sorry for my English.I did some experiences with my digital power supply to step up voltage from 30 voltage to higher voltage and after doing some examples I figure out output voltage display on power supply LCD is not showing correctly and always shows around 2.475 voltages on it.This problem occurred when I use a capacitor and a coil directly connected to power supply output and bouncing wires causes back EMF field and produce very high voltage back to my power supply output but in the output of power supply a very big diode connected to prevent back emf (I thing!).Here is a list of power supply behaviors:1.The output voltage and current limiting working fine.2.The output sensing wires working fine.On the main board one IC called ( MPC3901A) (Low Cost Power Monitor Reference) doing ADC jobs and when I put a resistor on the ref pins the LCD display changes it's measurement. Also 4 (SGM 8272) High Voltage Rail-to-Rail Output Operational Amplifiers ICs.I took a picture and attached it here so you can understand better than my poor English.I will appreciate any help from you guys to help me fixing my power supply.There is a topic about this power supply with some taken photos.https://www.eevblog.com/forum/testgear/odp3032-experience/Best regardsRamin

author: ramin110
author_rank: Contributor
timestamp: December 08, 2017, 10:19:55 am
content: updates:d32e is a DAC8532 (Dual Channel, Low Power, 16-Bit, Serial Input DIGITAL-TO-ANALOG CONVERTER).when I change the voltage, pin 4 ( Vout b) voltage is changing respect to voltage coming from front panel mcu but pin 3 (Vout b) is always same and when I set the voltage output to 2.504 as same as LCD output voltage display both pin 3 and pin 4 voltage is same.

author: ramin110
author_rank: Contributor
timestamp: January 05, 2018, 06:26:34 am
content: The problem is fixed now.After Changing the MCP3901A IC the LCD Display Works fine. The owon company was king enough to send me a free MCP3901A IC to replace it.Thanks
Opto-Coupler?? brand - Page 1
Forum section: electronics / repair

author: Holgerduke
author_rank: Newbie
timestamp: January 04, 2018, 02:17:47 pm
content: Hello, there is someone who knows what brand this Optocoupler is, is in need of a replacement??

author: madires
author_rank: Super Contributor
timestamp: January 04, 2018, 02:46:48 pm
content: Do you got a schematic for the device?

author: capt bullshot
author_rank: Super Contributor
timestamp: January 04, 2018, 02:54:12 pm
content: Looks like an ancient IL-1http://www.farnell.com/datasheets/716806.pdf

author: Holgerduke
author_rank: Newbie
timestamp: January 04, 2018, 02:54:43 pm
content: schematic for the device

author: madires
author_rank: Super Contributor
timestamp: January 04, 2018, 03:30:44 pm
content: If you don't get an IL1 you could try a 4N25.
Motorola RF power transistors type TPS - Page 1
Forum section: electronics / repair

author: Aleksandar
author_rank: Contributor
timestamp: January 04, 2018, 12:24:35 pm
content: Hi to all,Does anyone know where I could find information about RF transistors of the series,TPS1001, 1002, 1008, and 1032?Thanks in advanceAleksandar
How to fix Tek P5200 offset voltage problem - Page 1
Forum section: electronics / repair

author: thlee
author_rank: Contributor
timestamp: December 23, 2017, 03:36:38 pm
content: I used my Tek P5200 high voltage differential probe to test SMPS. I had found big offset voltage -9mV at 1/50 mode. If I changed to 1/500 mode, the offset voltage was less than -1mV. I tried to adjust R26 to minimize the offset voltage. Unfortunately, I couldn't adjust to 0 mV at 1/50 mode. The adjustment range of offset voltage was from -2mV to -15mV. When I had adjusted the offset voltage to -2mV at 1/50 mode, I measured offset voltage +6mV at 1/500 mode. Anybody have the calibration procedures of Tek P5200 HV probe? Or how to minimize offset voltage of both modes?

author: tautech
author_rank: Super Contributor
timestamp: December 23, 2017, 07:11:54 pm
content: For the 5200A there's Combined User/Service manual on Teks website.Part Number: 077053602.~3.5 MBYou'll need to register to download it.

author: thlee
author_rank: Contributor
timestamp: December 24, 2017, 02:36:26 am
content: Thanks for your reply. I have download P5200A (Part Number: 077053602) manual from Tek website. The both HV probe designs are totally different. The labels and locations of the pots cannot match the P5200 so I cannot use for my calibration.

author: mk_
author_rank: Regular Contributor
timestamp: December 24, 2017, 12:44:16 pm
content: See attachments, not exactly the same probe but maybe a little help...Michael

author: tautech
author_rank: Super Contributor
timestamp: December 24, 2017, 07:00:14 pm
content: Quote from: thlee on December 24, 2017, 02:36:26 amSend Tek Support an email asking for the Service manual for P5200.They might want the SN# to confirm you have one so send that too.

author: tautech
author_rank: Super Contributor
timestamp: December 24, 2017, 07:58:15 pm
content: This is typical of all manuals I can find for P5200.While it's called a service manual there's bugger all in it for adjustments.https://www.tek.com/manual/p5200

author: thlee
author_rank: Contributor
timestamp: January 04, 2018, 05:05:50 am
content: Thank you all for giving invaluable information and advice to me. I have drawn the schematic diagram and uploaded it to anybody for their maintenance. In the first time, I made a mistake to have adjusted the R26 until I saw the reference schematic diagram from Michael. The function of R26 is set with the maximum output voltage Vo from the video Op Amp. Comparing with the P5200 and P5205 schematic diagrams, we found the pot for offset adjustment in the P5205 probe. I think the Tek. engineers also know the same problem. After that product, all high voltage probes are added the offset pot to their products.
help me figure out the secondary turn winding for transformer here is the rating - Page 1
Forum section: electronics / repair

author: leopaulevans
author_rank: Newbie
timestamp: January 10, 2018, 03:10:44 pm
content: i have the fuse was blown bcuz mistakenly connect to a 220v current replace it rewire it but the out voltage was 5volts less ,attach are photos with the ratings

author: ArthurDent
author_rank: Super Contributor
timestamp: January 11, 2018, 02:25:07 pm
content: If you connected a device with a 120VAC transformer to 220VAC the output voltage on the secondary windings of the transformer would be doubled and there probably would be power supply components damaged by the higher voltage surge before the fuse blew. The momentary high voltage would probably not be enough to cause arcing and shorts between turns in the primary winding of the transformer. I would suspect a problem with the transformer last but to check it I would disconnect all the secondary windings, power the transformer from the correct voltage, and measure the A.C. secondary voltages to see if they agree with those listed on the rating label.I suspect you’d find the transformer was still o.k.. If both secondary voltages read low then there would be shorted turns on the primary and besides the lower voltages on the secondary windings, the transformer will overheat and be worthless. I think that unwinding the transformer like you’ve started to do will cause more problems and you’re likely to cause problems on what could be a good transformer. I’d be looking at what the secondary windings were connected to for damaged components.
POWER SUPPLY OF F&D SUBSPEAKER A53OU - Page 1
Forum section: electronics / repair

author: navales314
author_rank: Newbie
timestamp: January 02, 2018, 03:09:47 pm
content: my power supply didn't work it is two weeks ago i found it cracked ic CR18818 but i can't found any store have a similar pinout of this ic CR18818 ?Sent from my SM-J105B using Tapatalk

author: Yansi
author_rank: Super Contributor
timestamp: January 02, 2018, 03:25:46 pm
content: https://es.aliexpress.com/item/10PCS-CR18818-DIP/32757442178.html

author: navales314
author_rank: Newbie
timestamp: January 02, 2018, 11:59:09 pm
content: Quote from: Yansi on January 02, 2018, 03:25:46 pmI try but the result is no product!You have a any idea to share it even a similar of this product or f know about pinout cr18818 you can draw it up thank you!Sent from my SM-J105B using Tapatalk

author: lihach
author_rank: Contributor
timestamp: January 03, 2018, 07:33:55 pm
content: http://joerix.com/electronic/2013/12/95256.html#.Wk0v7dJl8y4