hybridfree/eevblog-posts huggingface dataset:
Panasonic DMR-BCT820 Blu-Ray - Disc read error - NoREAD - Laser? Service Menu? - Page 1
Forum section: electronics / repair

author: rg58
author_rank: Regular Contributor
timestamp: December 28, 2017, 04:30:58 pm
content: Hi all,Last night this BluRay recorder Panasonic DMR-BCT820 (similar DMR-BCT720/721) stopped playing back BluRay Discs that have been recorded on the same device. The day before it played back the very same disc perfectly - the disc hadn't been taken out and stayed in the drive. Later other BR discs have been tried, including an empty one - all with the same result ('Incompatible Disc'). Overnight I disconnected the recorder from the mains and plugged it back in this morning, but the error still persists. A commercial DVD also failed to play back ('Disc not readable'/'Disc nicht lesbar'). So basically the BluRay drive has DIED last night.How it happend:In the Disc Menu all BlueRay contents showed up, but upon selecting and pressing the OK button on the remote control, the recorder would just switch back to TV (removing the menu/OSD). Accessing the disc menu again, selecting various other recordings on the same disc, the same happend. Then, at some point, it suddenly showed 'Inkompatible Disc' in the menu (since then I was never able to access any disc again). I then changed the disc for another one, and a rhythmic scratching noise was heard from the drive several times. I assume the drive was looking for the TOC and the laser went back and forth.Questions:1) Has anyone experienced this problem before with the Panasonic Bluray DMRs and know how to solve this problem?2) How can we access theService Menuon the Panasonic DMR-BCT820/720/721? Would I be able to run a self-test or test the laser from there?3) Appart from cleaning the laser, what else could I try? Are there any adjustments that could be done? (I'm equipped with scopes etc.)The recorder was purchased in 11/2012, was quite expensive and did an excellent job until now. I am not willing to replace it, nor sending it for expensive repair (>300 EUR?).Thanks a lot!

author: rg58
author_rank: Regular Contributor
timestamp: January 03, 2018, 11:11:55 am
content: I have tried a cleaning DVD with brushes today (HAMA DVD/BluRay Cleaning Set). It was recognized by the drive on the 2nd attempt, a video was playing during the cleaning process.However, the drive still doesn't play back any other DVD or BluRay Disc for some reason ("NoREAD" shows in display & "Incompatible Disc" on screen), tried several different ones. I can only make the Cleaning-DVD play back in about 1 in 3 cases. What's the matter here? Why it doesn't play back any other DVDs and BDs anymore?Btw, I ran the cleaning cycle 5 times now with the same result. The software is 1.25 which is the latest.What else can I try? Is taking it appart my only option now? Does anybody know how to access the service menu?Thanks!
HP/Agilent 34401A calibration error 706 - Page 1
Forum section: electronics / repair

author: leoakirakblo
author_rank: Contributor
timestamp: January 02, 2018, 03:25:24 pm
content: I bough my 34401a used from auction, actually everything working fine.But when i'm trying to calibrate manually, always show the error 706. (Cal value out of range )In setup, CAL MENU> 3:CAL COUNT, the calibration count is 40. This means that i cannot calibrate anymore?Compared with my brand new Siglent SDM3055, the 34401 is +/-50 microvolts of difference.Any thoughts?

author: HighVoltage
author_rank: Super Contributor
timestamp: January 02, 2018, 03:47:12 pm
content: Welcome to the forum.You just have to follow the calibration instructions very carefully.The count has nothing to do with this error, you can do many more claibrations.Which value are you trying to calibrate?What value did you enter in to the DMM?How stable is your source (calibrator)

author: Kleinstein
author_rank: Super Contributor
timestamp: January 02, 2018, 03:53:56 pm
content: Depending on the range, a 50 µV difference to a 5.5 Digit DMM is not that bad. Not sure which of the 2 is off. A useful calibration would need a reference or meter with significant better accuracy. So maybe if you have a HP3458 or Keithley 2002with reasonable fresh cal at hand one could uses these. With a lower grade Sigilent meter, it is well possible the 34401 is still closer to the truth.

author: leoakirakblo
author_rank: Contributor
timestamp: January 02, 2018, 08:05:05 pm
content: Quote from: HighVoltage on January 02, 2018, 03:47:12 pmI did read the manual again and probably i got whats wrong i did. Awhile display shows "full scale" just set the new valuei was trying to insert offset values.I get a Yokogawa 2553 from my workplace but was calibrate on past year summer. (they retire it)I make the procedure only in 1v range, now all ranges match pretty close to my voltage souce.Yeah, probably is better to find some more trustable multimeter reference to do this.

author: HighVoltage
author_rank: Super Contributor
timestamp: January 02, 2018, 09:31:13 pm
content: Quote from: leoakirakblo on January 02, 2018, 08:05:05 pmYes, always set the full value that you want to calibrate and not the offset.Also make sure to do the zero calibration first, with a short block on all 4 input terminals.
Philips default selfcal access code - Page 1
Forum section: electronics / repair

author: veedub565
author_rank: Frequent Contributor
timestamp: December 21, 2017, 10:50:49 am
content: Hi,Does anybody have any idea's about what the default selfcal access code might be for a Philips PM5781 Pulse Generator? I've tried the last 4 digits of the serial, four zero's, and the model number but no good.

author: veedub565
author_rank: Frequent Contributor
timestamp: January 02, 2018, 07:30:00 am
content: Just in case this helps somebody else, I've figured it out now. On my unit at least, it's the model name backwards. So for PM5781 the access code is 1875
Hiss on left channel of Sony HCD-H1600 - Page 1
Forum section: electronics / repair

author: Bert98
author_rank: Newbie
timestamp: December 31, 2017, 09:21:24 pm
content: Hello everyone.I got an used Sony Mini HiFi component HCD-H1600. It has some issues, the most important one is that you can hear a hiss on the left channel, that's audible both wearing headphones, or though the speakers.You can hear this hiss, even when the volume is at its lowest settings.I've download the service manualfrom here.I'm not sure what to check, because I'm not an expert on electronics, or in these type of equipment. Maybe someone here can point me on what to check. I think the problem might be on IC205 (I hope not).The device has some other issues. I don't think they are related, but I'll list them just in case:- Bars Graphic EQ are not properly responding to sound. Some time they get frozen.- CD player tray does not go out.Anyway, I don't think they are related to the hiss problem, but just in cause. The hiss is not really that bad when you there's some sound playing, but I'd like to try and remove it anyway.Have a great 2018!
power unit repair  TEKTRONIX  TDS 460A - Page 1
Forum section: electronics / repair

author: lihach
author_rank: Contributor
timestamp: December 28, 2017, 08:20:27 am
content: During operation, there was a short circuit in the power board (119-3939-01)At the same time, some of the elements burned, which I had already made. Help determine the value of the burned resistor P-25. Maybe someone will take a photo of the site. The gratitude is grateful.

author: shakalnokturn
author_rank: Super Contributor
timestamp: December 28, 2017, 11:23:16 am
content: I followed your topic on the Tek group too. I do not have the same model PSU, but a lot of Power Systems Inc. PSUs are very similar.Any way you could take clearer photos, including copper side?I think your R25 is linked on one side to the large ceramic resistor (0.22ohm?) and switching transistor emitter, other side to optocoupler and green module pin8. Can you confirm?Check large ceramic resistor between primary ground and switching transistor emitter is not open, if it did open check for burn marks near pin8 on green module.

author: lihach
author_rank: Contributor
timestamp: December 28, 2017, 01:55:01 pm
content: I think the green module is working. After the resistor 25 burns, the oscilloscope is fully operational before being turned off by the button. Burned R-25 and controlled zener VR-3Need photo R-25

author: lihach
author_rank: Contributor
timestamp: December 29, 2017, 09:05:13 am
content: I CAN DRAW THE DIAGRAM OF THIS SITE BUT IT SHE WILL NOT SAVE ME IN THIS CASE.THIS IS THE RESISTANCE NOT IN THE CHAINS THAT YOU DESCRIBED

author: Armadillo
author_rank: Super Contributor
timestamp: December 29, 2017, 09:47:20 am
content: https://www.eevblog.com/forum/repair/help-needed-to-identify-component-in-tds460-power-supply/msg1386184/#msg1386184You can request from him since he had his opened up as well.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: December 29, 2017, 01:18:19 pm
content: Yes,I answered on my post. Its a 1.33k resistor.

author: lihach
author_rank: Contributor
timestamp: December 29, 2017, 01:26:27 pm
content: Thank you very much. I no longer hoped that somewhere I can find such information. Because this requires disassembling the device. I am ready to answer all your questions. Why did you come to repair your power supply unit?

author: andy2000
author_rank: Frequent Contributor
timestamp: December 31, 2017, 04:53:23 pm
content: I recently repaired a TDS460, and the power supply was full of leaking caps. Many of them weren't obvious, but there was electrolyte underneath them. It may be related to your failure.

author: lihach
author_rank: Contributor
timestamp: January 01, 2018, 08:36:08 pm
content: I myself am to blame. Conducted measurements without galvanic isolation
R&S SM300 Low Output - Page 1
Forum section: electronics / repair

author: K1JOS
author_rank: Regular Contributor
timestamp: December 31, 2017, 03:07:38 am
content: Just got a SM300 and find the output is down about 50-55 dBm across the range of frequencies. The service manual is about useless as it says to change module.I see R&S in USA has a flat fee policy - I'm sure that will be expensive.... does anyone know of a reputable and reasonable R&S repair center in USA?Jerry NY2KW
requesting OCZ Vertex 3 SSD unbricking assistance - Page 1
Forum section: electronics / repair

author: TyroneSlothrop
author_rank: Newbie
timestamp: December 30, 2017, 10:24:58 pm
content: I have a OCZ Vertex 3 120GB SSD which is not recognized by the BIOS. When powered on, a red and green inside the drive are both visibly lit. The red LED indicates a fault with the controller.I would like to recover data off this drive. First, is there any way to unbrick this? Opening up the drive, I notice two I/O interfaces. The first appears to be a bi-directional serial interface. The second is a JTAG port.The controller is a Sandforce SF-2281. OCZ recommended upgrading the firmware on drive. Given that the SATA interface is bricked, does anyone know how to upgrade the firmware through either of the other two interfaces on the board.This was a very interesting thread here but it seems to apply only to the Vertex 2:https://www.eevblog.com/forum/repair/ocz-vertex-2-ssd-firmware/25/
Symmetricom X72 Serial Port Fried - Page 1
Forum section: electronics / repair

author: JohnPi
author_rank: Regular Contributor
timestamp: December 29, 2017, 11:32:05 pm
content: I accidentally touched the Tx and/or Rx pins of my X72 to the +23 V supply I was using -- the Tx output is stuck at +23 V now. The rest of the oscillator works (and I can use the EFC to adjust the frequency), but now my project to use a Teensy to control the system is on hold.Does anyone have pics of the PCB inside ? Are those components likely repairable ? It's likely some TTL-type of buffer, but I haven't opened the case yet.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 30, 2017, 04:46:43 am
content: http://www.rdrelectronics.com/skip/nov/X72.pdfhttp://www1.symmetricom.com/media/files/support/productmanual/man-x72.pdfmay help a little if you dont have them alreadyhttp://webmaail.ko4bb.com/getsimple/index.php?id=manuals&dir=06_Misc_Test_Equipment/Symmetricomsome pictures ...Normally you should have some buffers / transceiver chip(s) try to find their number once the case is opened ... no service manual found while ggolgling ...
Commodore 64 power supply repair. - Page 1
Forum section: electronics / repair

author: Bashstreet
author_rank: Frequent Contributor
timestamp: December 29, 2017, 12:31:08 pm
content: Hi all.I been working on making a replacement power supply for my loved C-64All is fine and dandy but i have bit of hiccup with the 9 volt AC that it requires.I bought a 9 volt transformer but as it is unregulated even under load with the commodore it gives some 11.5 volts.. Quite a bit from where i ideally want to be...Chematichttp://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c64/250469-rev.A-left.gifhttp://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c64/250469-rev.A-right.gifBy looking the schematic i do not see anything too sensitive on the 9 volt lines.... but have a look.I would ideally want to regulate the 9 volt line to... well 9 volt but it needs to stay AC as the 60hz is used internally in some timing functions.How one regulates AC without effecting it's frequency ?Cheers.

author: anachrocomputer
author_rank: Regular Contributor
timestamp: December 29, 2017, 02:14:21 pm
content: The original C64 PSU may well have been a simple 50/60Hz transformer in a box. See if you can find the original schematic.Now, a typical mains transformer is rated at full load, and has a regulation of typically 20%. That means that a nominal 9V AC transformer is designed to produce 9V when fully loaded at its rated current. If it's unloaded, the voltage will be higher. The 20% load regulation spec means that there will be approximately 20% variation in voltage between off-load and full load.Remember that there's also some allowable variation of the input voltage (mains voltage) and if the input is a bit high or low, the output will be too.

author: stj
author_rank: Super Contributor
timestamp: December 29, 2017, 06:16:18 pm
content: the original was a transformer with several windings, combined with a 7805 on a useless heatsink.useless because they potted it!!

author: Rasz
author_rank: Super Contributor
timestamp: December 29, 2017, 07:18:19 pm
content: first half is about c64 supplies:

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 30, 2017, 01:03:54 am
content: The 9VAC is rectified internally to feed some linear regulators. They are already running quite hot. I made my 64 power supplies with the 9VAC transformer from the 2-pin VIC-20 power supply.However, if you have a broken C64 power supply, there's your 9VAC transformer. Simply remove the bad 5V and splice in a good regulated 5V 2A wall wart into the power connector.That's what I do now.

author: stj
author_rank: Super Contributor
timestamp: December 30, 2017, 02:28:08 am
content: i fixed one once by mounting a heatsink on top with a 78s05 and wiring it to the exposed pcb pads inside after cutting the old pins.i wouldnt do that now though - the caps are too old to leave in place.
could someone have .hex for Rigol flash?  - Page 1
Forum section: electronics / repair

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 31, 2017, 02:32:13 am
content: could someone have .hex for Rigol flash?

author: tooki
author_rank: Super Contributor
timestamp: December 31, 2017, 03:23:38 am
content: Don’t be lazy. You realize Rigol makes dozens of products?

author: Monkeh
author_rank: Super Contributor
timestamp: December 31, 2017, 04:00:25 am
content: Quote from: tooki on December 31, 2017, 03:23:38 amHe's not being lazy, he's spent the last five months asking random people for a raw firmware image!
Anyone know what this switch is called? - Page 1
Forum section: electronics / repair

author: kevjet62
author_rank: Newbie
timestamp: December 29, 2017, 11:44:00 am
content: Found on a fujifilm camera. I'm hoping that a new switch will help me fix this

author: Chriss
author_rank: Frequent Contributor
timestamp: December 29, 2017, 11:47:34 am
content: That's are micro switches.Try to search for micro switch for your camera.I would send the picture to some fuji repair center and ask them for info.I do that often for other stuff and they are in most of case help me.Sent from my GT-I8260 using Tapatalk

author: kevjet62
author_rank: Newbie
timestamp: December 29, 2017, 11:54:00 am
content: okay thanks chris!

author: chris_leyson
author_rank: Super Contributor
timestamp: December 29, 2017, 12:46:30 pm
content: Panasonic ESE23Fxxx series looks like a good candidatehttps://industrial.panasonic.com/cdbs/www-data/pdf/ATB0000/ATB0000C16.pdf

author: anachrocomputer
author_rank: Regular Contributor
timestamp: December 29, 2017, 02:17:41 pm
content: The photo shows three switches on a PCB. Which switch are you trying to fix?The top one in the photo looks like a tact-switch, but given that it's from a camera, it may well be a dual-action type (press gently to focus, press a bit harder to expose).The switches in the PDF referred to above look about right for the lower two switches in the photo.
Good Will GW Instek GDM-8045G multimeter - Page 1
Forum section: electronics / repair

author: anderoo
author_rank: Contributor
timestamp: December 25, 2017, 07:52:31 am
content: Hi guys. I'm looking for a user/service manual for the Good Will / GW Instek GDM-8045G multimeter (pic below is not mine but same appearance).I picked up one in a job lot that looks in good shape but I'd like to go through the cal procedure before trusting it.I've checked the usual online manual repositories and also the GW website to no avail.I did find the user/service manual for the very similar looking GDM-8145 (that manual is attached below) but I 'd like to get the correct manual for the older GDM-8045G because I suspect that there has been a board revision.I'm hoping that someone has the PDF on their hard drive and can post it here for me.Thank you.

author: anderoo
author_rank: Contributor
timestamp: December 28, 2017, 12:23:23 pm
content: Since the user/service manual is elusive I thought it might help someone in the future if I posted any info that I have been able to find on this meter.I found some pics on a Chinese language website of the internals and discovered that the multimeter chip set consists of the Siliconix LD120 and LD121A 4-1/2 digit A/D converter set.In addition, the true RMS measurement capability is implemented with an Analog Devices AD536A True RMS-to-DC converter IC.For ease of reference I've attached data for the AD536A and for the LD120/LD121A chip set, which I found in the 1985 Siliconix data book.

author: anderoo
author_rank: Contributor
timestamp: December 28, 2017, 12:32:57 pm
content: Here is a link to that Chinese website which contains a repair blog for a trio of Good Will GW Instek GDM-8045G bench multimeters.http://www.5bcl.com/Article/Print.asp?ArticleID=3297In case that website goes down I've copied the board photos and partial schematics from that website to this post.The main board is designated GDM-503C, and the display board is designated GDM-270D.

author: anderoo
author_rank: Contributor
timestamp: December 28, 2017, 12:34:57 pm
content: A couple more photos of the main board are attached.

author: anderoo
author_rank: Contributor
timestamp: December 28, 2017, 12:37:58 pm
content: Oh yes, I'm still looking for a proper user/service manual with the calibration procedure.It should be easy to calibrate this meter - there's only 14 trimpots on the main board !!!

author: coromonadalix
author_rank: Super Contributor
timestamp: December 28, 2017, 10:58:06 pm
content: to be on the safe side, i would measure ohms between the 3 pins of each trimpot and keep a note just in case ... sometimes you can sort in wich circuit they are used ... 1 trim dor each range loll 14 trimpots is a lot but not uncommon, on some eevblog threads there was an meter with literally tons of them ...
Looking for EG&G 5208 service manual - Page 1
Forum section: electronics / repair

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: December 28, 2017, 03:01:15 pm
content: HiI'm searching for the EG&G 5207 / EG&G 5208 Lock-in Analyzer service manual.EG&G 5205 / EG&G 5206 might help as well since the models seem to be simillar.So far I was "only" able to dig up the operating and programing manual as well as some bearly readable schematics.They are available online but I put them together here in case somebody else is looking for them:https://www.dropbox.com/sh/werqbcnf27fh2dh/AAA7ZW23XLb81NtVUOrdQ7V7a?dl=0Thank you so much and regardsAndreas
Cannot identify a part. Please help! - Page 1
Forum section: electronics / repair

author: tudorv
author_rank: Newbie
timestamp: December 24, 2017, 07:40:33 pm
content: Hello,i have to change a part on an intercom pcb but i cannot correctly identify the part just after the indicative, maybe any of you can drop a hint.here are some pictureshttps://ibb.co/bDvremhttps://ibb.co/mgpv5Rhttps://ibb.co/ecHts6https://ibb.co/exQDs6https://ibb.co/cypHKmhttps://ibb.co/ceOoQRhttps://ibb.co/cSDBemhttps://ibb.co/hGZHKmThank you!

author: ataradov
author_rank: Super Contributor
timestamp: December 24, 2017, 08:00:04 pm
content: They look like 330K trim pots. The adjustment slot is covered with wax to fix the setting, and possibly prevent water ingress. Try to dig though the circle and see if you can find the adjustment slot.They also appear to be covered with conformal coating with the rest of the board.And if they are adjustable, you will need to know the adjustment as well.But the placement is strange for trim pots, so I may be wrong here.

author: DC1MC
author_rank: Super Contributor
timestamp: December 24, 2017, 08:11:47 pm
content: Feriite beads (filter coils)https://www.avnet.com/shop/us/p/brc2016t330k-3074457345625656089

author: ataradov
author_rank: Super Contributor
timestamp: December 24, 2017, 08:12:44 pm
content: Quote from: DC1MC on December 24, 2017, 08:11:47 pmYes, this makes more sense given the placement.

author: tudorv
author_rank: Newbie
timestamp: December 25, 2017, 10:30:02 am
content: Yes, this must beBut can you tell what value is this one?https://ibb.co/exQDs6I desolder the other one which is working and measuring it it shows 3.2ohmsThank you

author: tudorv
author_rank: Newbie
timestamp: December 25, 2017, 10:51:44 am
content: could be this one?https://ro.mouser.com/ProductDetail/Taiyo-Yuden/BRC2016T101K/?qs=sGAEpiMZZMsg%252by3WlYCkU5iuzh4MJmq0iCImZVKIwr8%3D

author: DC1MC
author_rank: Super Contributor
timestamp: December 25, 2017, 11:18:02 am
content: I would be very amazed if it will make a difference; so I would say, go for it, it will be anyways way better than 330K trim potNinja edit: Go get yourself one of these cheap LCR meters if you're overly concerned about the exact value, but to me it looks that both mine and yours will work perfectly.

author: tudorv
author_rank: Newbie
timestamp: December 26, 2017, 08:55:50 pm
content: yes, i will order one of them and i will seethank you!
Tektronix 2440 parts (knob, pwr switch cover) and advice needed - Page 1
Forum section: electronics / repair

author: bklein
author_rank: Contributor
timestamp: December 30, 2017, 04:59:00 am
content: I bought a 2440 off Craigslist for $50 on a whim and got it home and saw the white phosphor cloud in center screen when I turned it on. Took the case off to get ready to repair it and turned it on and the cloud changed to the display screen text and a trace eventually appeared. Now, several months later, I tried it again and got the cloud but it heated up and got the screen text and then finally the trace image appeared and everything works.1. Is this a sign of bad caps? I can pull and test them all if so.2. I read that there is a memory chip inside that has built in battery backup that will eventually die. Worth keeping this around if this is going to die eventually?3. My scope has a missing Intensity knob (knob support base underneath is good), the power switch's clear cover has broken off. I guess I can make something like it and glue it in but wondering if someone has a spare. My scope is also missing the control panel cover (cap). Interested in buying if really cheap. I normally use a digital scope but may like to use this one for XY modulation visuals etc.Barry

author: EHT
author_rank: Frequent Contributor
timestamp: December 30, 2017, 10:31:31 pm
content: Regarding the old Tek parts there is a small online shop - QService, who stocks a lot of bits and bobs for Tek, HP etc. I used it recently and got stock in very good condition.
Function generator Toellner TOE7720 - Error 5 - Page 1
Forum section: electronics / repair

author: Swake
author_rank: Frequent Contributor
timestamp: December 25, 2017, 01:49:49 pm
content: Hello,Got a programmable function generator from Toellner model TOE 7720.On power up it shows Err. 5 on the display.Pressing the 'CLEAR' button eliminates the message from the display and the generator starts working. The error might be related to some form of internal memory as there are buttons for 'STORE' and 'RECALL' but I don't know what it does precisely and cannot find out how and if it works.If anyone got an idea what that error 5 might be or has a manual or schematic I would appreciate the help. Thanks in advance!
Transformer Question - Page 1
Forum section: electronics / repair

author: law_freak
author_rank: Contributor
timestamp: December 24, 2017, 08:29:58 pm
content: I'm working on a radio from a 1956 Oldsmobile. This question relates to the power supply.Why are the primary and secondary of the power transformer not isolated? Why is 12VDC applied to both the center tap of primary and the center tap of the secondary?I understand how a vibrator power supply works, but would have figured that only the primary winding would have 12VDC applied to its center tap.Schematic attached. The unlabeled line from the connector is 12VDC from the battery.Radio model #983334 by Delco

author: IanB
author_rank: Super Contributor
timestamp: December 24, 2017, 08:42:42 pm
content: Both sides of the transformer share a common ground reference. It is common in motor vehicle applications to reference everything to the vehicle chassis, which is presumably what is happening here.Note that it is not possible to apply 12 V DC to a single terminal like the center tap of a transformer. All voltages are potential differences, and therefore to assign a potential difference of 12 V DC you must specify the two points in the circuit between which this potential difference exists.

author: chris_leyson
author_rank: Super Contributor
timestamp: December 24, 2017, 08:45:42 pm
content: QuoteYou could just as well have grounded the secondary center tap but my guess would be that it might have something to do with common mode noise on the +12V.

author: floobydust
author_rank: Super Contributor
timestamp: December 24, 2017, 08:46:54 pm
content: It's to get an extra 12V on the secondary side. The 280V is referenced to +12V so a bit less output voltage (268V) needed from the vibrator/transformer.
Samsung LCD TV: Replace image board or use LVDS driver? - Page 1
Forum section: electronics / repair

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 25, 2017, 12:36:28 am
content: Hi all, my samsung LN55C630's main board failed. I tried flooding the underside of the chips with flux and reflowing them until they were nice and bouncy when you poke them, but I'm afraid I killed the board. Oh well.I can't find any replacement boards of the same model , but I can find some for different TV sizes, which may just have a different firmware or less features.Anyway, I'm using this TV as a big monitor to watch movies on from my PC. The input lag is dreadful, so if possible, I was thinking of putting the board out of a monitor into this TV, perhaps even a 144hz monitor (This TV's panel can run at a native 120hz)But the cheapest 1080p 144hz monitor I can find is 150$, which isn't dreadful, but the connector seems slightly differernt for the LCD. The monitor (I took one off my desk to look inside of) has a cable with like a moulded array of pins and wires, and the TV uses a flat flex cable. The pin pitch and number looks the same, however.The monitor's cable is far too thick to fit into the TV LCD's connector though, so this isn't an easy solution.Does anyone know of a high refresh rate LVDS driver that would interface with this LCD panel? Here's a spec page for it:http://www.panelook.com/T546HW01%20V1_AUO_55_LCM_overview_1356.htmlAs long as I can get the LCD to display an image, I should be able to hack the power supply to drive the backlight.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: December 25, 2017, 12:51:07 am
content: Update: Just looked closer at the TV's panel, and its cable has connections on the other side of the flat flex as well, which look to be impedance matched, so they aren't just grounding.The monitor did not have these.I guess scrap that idea, unless someone else has some input
Lecroy WaveRunner showing signals from nowhere ??????? - Page 1
Forum section: electronics / repair

author: darkstar49
author_rank: Frequent Contributor
timestamp: December 23, 2017, 08:53:58 pm
content: check the pic... channels 1-3 show signals from the void !!!!!!I recall having seen similar things in another thread, but can't get to it... if someone has a pointer... I'd be glad !!

author: rx8pilot
author_rank: Super Contributor
timestamp: December 23, 2017, 08:55:25 pm
content: Memory.

author: darkstar49
author_rank: Frequent Contributor
timestamp: December 23, 2017, 08:57:14 pm
content: You must be kidding !!Memory issues leading to a square wave, a ramp and a sine waveI'm not that sceptical by nature, but no... can't eat that one !! ;-

author: darkstar49
author_rank: Frequent Contributor
timestamp: December 23, 2017, 09:06:46 pm
content: finally found it... doesn't smell too good.... (looks like this simulation mode is entered when the PCI interface card can't talk to or gets unexpected results from the acquisition board...https://www.eevblog.com/forum/testgear/i-have-a-strange-issue-of-lecroy-sda-6020-could-you-please-help-thanks!/25/

author: darkstar49
author_rank: Frequent Contributor
timestamp: December 23, 2017, 09:28:02 pm
content: would be highly interested in get some info on how to disable simulation mode in the service menucan't find the check boxes mentioned in the other thread...?

author: rx8pilot
author_rank: Super Contributor
timestamp: December 23, 2017, 10:09:17 pm
content: I meant to make that more complete, but was distracted.I wanted to say it is just saved waveforms in memory - not a fault with memory itself.Short and misplld from my mobile......

author: darkstar49
author_rank: Frequent Contributor
timestamp: December 23, 2017, 10:57:56 pm
content: As in the other thread... there’s an issue with the acq board...
Sony 14" PVM-14M4U Trinitron  - Page 1
Forum section: electronics / repair

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 19, 2017, 03:17:31 am
content: I'm contemplating buying this monitorhttps://www.ebay.ca/itm/Sony-14-PVM-14M4U-Trinitron-HR-Video-Monitor-with-SDI-input-output/122859722024?hash=item1c9b029528:g:t-UAAOSwBjdaIdCTfor my retro-computing nerdery. No real reason except it looks cool.But this one is "as is", and I guess it is full of ASICs. Does anyone know if what's shown here is a known fault (unrepairable Sony IC failure, let's say), or might be an easy fix?It can't even display its own OSD, so the problem's closer to the tube than the inputs.

author: drussell
author_rank: Super Contributor
timestamp: December 19, 2017, 05:03:48 am
content: Who knows... With no attempt to show a signal from an external input you can't tell if it works basically fine bit the on screen generator stuff is wonky (could just be noisy power, bad caps, etc.) or something farther down the chain is really messed up.Looks like it is probably fixable, though.... Mostly seems to work.... though I have no experience with this model, so who knows!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 23, 2017, 07:08:20 pm
content: Bleargh. I won the auction for 1$, I paid immediately the global shipping charges, then the seller sent me a mail asking for more money for the shipping, then he cancelled the sale.I thought the global shipping program made things easier to ship for sellers? I guess he felt burned that I won for 1$...What does he think "professional" monitors for an extinct standard are worth?
HP6623A Power Supply Agilent Keysight 662x Series - Page 1
Forum section: electronics / repair

author: View[+]Finder
author_rank: Unknown
timestamp: December 19, 2017, 04:19:16 am
content: No 'soft front panel'; no "BenchVue" even for $399 . . .So I wrote my own--video to follow

author: View[+]Finder
author_rank: Unknown
timestamp: December 20, 2017, 02:07:59 am
content: Here's the link to the HP6623A front panel video on YouTube:https://youtu.be/kE1Yrx2FBJkComments would be helpful . . .

author: SMB784
author_rank: Frequent Contributor
timestamp: December 21, 2017, 04:11:25 pm
content: I love this, and I would love to implement it with my open 6623a. My questios are twofold: how have you connected the software to the 6623a (with direct GPIB or GPIB to USB dongle)? Secondly, would you be willing to provide your code and any relevant documentation?

author: View[+]Finder
author_rank: Unknown
timestamp: December 23, 2017, 01:38:47 am
content: Quote from: SMB784 on December 21, 2017, 04:11:25 pmYes to your first question, the soft panel is connected to GPIB thru the Agilent 82375B USB interface. The software runs on a Win7 PC under Python 2.7.14 (must be installed) and it uses TKinter (part of Python) for the GUI and PyVISA for the GPIB interface. The VISA I use is from Keysight, not NI.As to your second question: maybe.As you know, a 6623A is equal to an hour in the gym just to get it situated, so the idea of a soft panel came about from its location on a lower shelf rather than up high so I could see the screen. After spending a full day searching for a ready-made solution and freaking out over Keysight's charging $300 for BenchVue and that the 662x series is not supported. I decided to write my own front end. Yes, LabView allows panels to be built, BTDT, and I no longer use it.Once I got into the coding process it occurred to me that there might be other older instruments that could be managed in a similar way. As it happens, I support a private charity that is involved in helping kids learn electronics and there might be a donation-opportunity if this panel idea is popular. In other words, not commercial for profit but maybe an eBay 'for charity' site.So, at the present time there is no documentation at all--other than the internet for the Python etc. and you would need to have installed all the supporting software mentioned above. I intend to convert the code to an executable, but when??The source code is still 'alpha' and contains some propietary stuff. The options at present are 1) Wait fo a 'beta-version' executable (a few weeks?); or 2) Participate in my project with the idea of supporting a worthy cause.Thanks for asking and enjoy the yearend festivities,Cheers,Donal

author: View[+]Finder
author_rank: Unknown
timestamp: December 23, 2017, 02:06:56 am
content: https://www.amazon.com/gp/product/B009OXZ0OU/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1For a quiet replacement fan for an older PSU HP6623, 6624, . . .
Metcal mx-500 soldering station heatsup when turned off!? - Page 1
Forum section: electronics / repair

author: Amitoha23
author_rank: Newbie
timestamp: December 26, 2017, 03:05:55 am
content: Hello.My name is Amit and need your help in understanding what is wrong with my mx500 stations.They seem to heatup (the stations not the tips) even when the switch is turned off.so hot that the thermostat disconnecting the solder.I have replaced Q1 Q2 as i thought. One of them is faulty . In the first 12 hours it was ok but then it started heating up again.It seems that current is being consumed when its in off state as i can hear the transformer working. And of course the teansformer heats up but also the fets.Thank you for your help

author: Bratster
author_rank: Frequent Contributor
timestamp: December 26, 2017, 05:04:13 am
content: The power switch on the mx500 is on the secondary side of the Transformer. So even while it is off you will still hear the Transformer hum.However everything else should be off and it should only get a tiny bit warm.Sounds like you have some fairly serious issues with that if even with the switch off it is staying on in some fashion.Are either of the lights on when you turn the switch off?Sent from my Nexus 6 using Tapatalk

author: Assafl
author_rank: Frequent Contributor
timestamp: December 26, 2017, 07:22:16 am
content: Well, the 7818 that powers the circuitry gets disconnected when the power switch is off. The power regulator LM2576HVT does get power (but should be powered down by Q12. Also I don't think the oscillator gets power (it gets the 18V regulated down to 7V or so by a 6.8v Zener) so in theory a scope should show no activity on the FETs.I assume you have the attached schematics (but if not.
how to flash rigol via jtag? - Page 1
Forum section: electronics / repair

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 21, 2017, 11:27:54 pm
content: how to flash rigol via jtag? help

author: denimdragon
author_rank: Regular Contributor
timestamp: December 22, 2017, 12:05:34 am
content: Did you figure it out?

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 22, 2017, 11:53:07 pm
content: thanks for reply!not yet its impossible in real life, theoretically seems the only one way to restore1) find same oscill2) make 2 damps of memory3) ds1302ca does not have flash sockets you need to assembly it manually3) flash your brickrigol support don't want to support their old models
Philips PM 6674 Universal Frequency Counter - Page 1
Forum section: electronics / repair

author: Todd_H
author_rank: Newbie
timestamp: December 22, 2017, 10:35:09 pm
content: I recently acquired a Philips PM 6674 frequency counter and the unit was working fine and suddenly quit working. The display digits don't light when turned on. Checked fuse and some voltage test points and all seem fine. I'm not sure but while connected to "Internal Out" BNC the coax might have shorted to ground but I'm not sure. Shortly after that the instrument went blank.I have the service manual but have to come to a halt and probably could use some help with this troubleshooting. Anybody have any experience repairing these or willing to repair? Any help appreciated.Todd
Beckman RMS3030 zebra strips - Page 1
Forum section: electronics / repair

author: stillcurious
author_rank: Newbie
timestamp: December 16, 2017, 04:25:44 pm
content: Help! I am new to this blog. I have a Beckman RMS3030 mm that is in need of main processor zebra strips (elastomeric connectors). I don't know if I lost them recently or years ago. As I am unfamiliar with these devices I am hoping someone who visits this blog can help me find new or used replacements. I have attached a jpg from mrmodemhead's website that shows the zebra strips for the main processor board in addition to the processor board mount in which the strips are inserted.Any advice is appreciated.

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 21, 2017, 11:23:23 pm
content: https://www.alibaba.com/product-detail/silicone-rubber-zebra-article-zebra-connector_328303805.html

author: stillcurious
author_rank: Newbie
timestamp: December 22, 2017, 09:09:01 pm
content: thanks but suggestion not cost effective. ordered some used segments from ebay seller in Poland that will require modification of both the mount and the elastomeric segment. the cost of the segments is less than ten dollars. the segments should arrive some time in January. thanks for looking.Stillcurious
Anybody have a Keysight Parts account - Page 1
Forum section: electronics / repair

author: marshallh
author_rank: Unknown
timestamp: December 13, 2017, 06:00:19 pm
content: I have a huge favor to ask - I'm trying to get a new power supply for my DSOX3014A but am blocked by red tape.Keysight have rejected my estore applications most recently because my shipto/billto are a residential and not commercial address. But, I am a consultant with a home office.If you'd be willing to order this part 0950-5277 and shoot it my way I will compensate you for your time and the cost. Location is midwest USALink:https://www.keysight.com/my/faces/partDetail.jspx?partNumber=0950-5277

author: marshallh
author_rank: Unknown
timestamp: December 22, 2017, 06:21:02 am
content: Got it sorted. Talked with Keysight some more, ordered and today I popped the replacement in my DSOX and it works great.The old supply is going to a member here who can maybe find why it failed. (This PSU in general seems to have at least 4 other failures on this forum alone)

author: ivaylo
author_rank: Frequent Contributor
timestamp: December 22, 2017, 07:15:08 am
content: Yeah, they have shipped to my home address and I don't remember doing anything exceptional to convince them. Must've been 7-8 years ago though. Glad it got sorted out...
MSA 4000 thermal camera, lines/noise on image. - Page 1
Forum section: electronics / repair

author: Bratster
author_rank: Frequent Contributor
timestamp: December 22, 2017, 05:54:42 am
content: Hello thermal camera experts, I have an MSA 4000 thermal camera that I just got off eBay for a decent price. Upon power up it has what it looks like patterns of lines and noise on the display. It does however work and show an image that looks great aside from the noise.I checked the video out and it shows the same as the built-in LCD display.Any ideas on what I should be looking at?Thank you!Sent from my Nexus 6 using Tapatalk
rigol firmware brick how to restore? - Page 1
Forum section: electronics / repair

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 15, 2017, 10:41:22 pm
content: rigol firmware brick how to restore?

author: Armadillo
author_rank: Super Contributor
timestamp: December 16, 2017, 03:59:35 am
content: Ranging from the worse forms of guides/documentation to the poorest of support and so I heard, I actually begin to suspect Rigol is more like marketing house than any true instrument developer / manufacturer. And for that reason, I am not going to buy any Rigol, no matter how cheaply they will have on offer.The firmware is just like the secret keys and if there are no leaks, no schematics, I am afraid no one here is able to crack it.I understand your distress. I am sorry, I am not able to help.You should write to the Manager or CEO of Rigol. But I doubt, like a marketing house or profit entity, they would bothers to help, otherwise they would.Good Luck.Edit: I contacted Rigol China, and they are great people there and they quickly provided the solution to the problem of the DG1022.

author: martinator
author_rank: Contributor
timestamp: December 17, 2017, 06:48:02 pm
content: Is this any help?https://www.eevblog.com/forum/blog/the-dark-side-of-the-rigol-hack-bricked-scope-how-to-fix-it/

author: wictor
author_rank: Regular Contributor
timestamp: December 18, 2017, 05:41:31 am
content: Quote from: ivi_yak on December 15, 2017, 10:41:22 pmHi, could you tell the device type and model number.

author: Armadillo
author_rank: Super Contributor
timestamp: December 18, 2017, 06:26:29 am
content: Quote from: ivi_yak on December 15, 2017, 10:07:42 pmDS1302

author: Armadillo
author_rank: Super Contributor
timestamp: December 18, 2017, 06:29:21 am
content: Quote from: NiaDebesis on December 11, 2017, 09:46:28 pmDG1022

author: NiaDebesis
author_rank: Frequent Contributor
timestamp: December 18, 2017, 08:07:22 am
content: Quote from: Armadillo on December 18, 2017, 06:29:21 amI have called(italian support) and emailed (us support) Rigol 6 days ago, but nothingInviato dal mio SM-G920F utilizzando Tapatalk

author: Armadillo
author_rank: Super Contributor
timestamp: December 19, 2017, 05:00:28 am
content: Quote from: NiaDebesis on December 18, 2017, 08:07:22 amRigol china provided the solution inhttps://www.eevblog.com/forum/repair/rigol-1022u-doesen't-boot-up/msg1378626/#msg1378626

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 21, 2017, 11:36:06 pm
content: hi, thanks for your reply!How to contact with amazing people of china support?
TEKTRONIX 2465 with DMM Test 76 Fail 01 - Page 1
Forum section: electronics / repair

author: Lenny
author_rank: Contributor
timestamp: December 16, 2017, 04:31:23 pm
content: Hello,I have a problem with my Tek Scope. It shows Test 76 Fail 01. The maual says Malfunction of DMM, or if this is the only failure V/F input Multiplexer U5020 input pin 2.I recapped the PSU and the DMM. I already changed U5020, but the fault is still there.I can ignore the fault and use the DMM with no problems.Does anyone have any Idea what to to?Lenny

author: Testtech
author_rank: Regular Contributor
timestamp: December 21, 2017, 07:11:35 pm
content: I would recal the DMM and see if that fixes it.
Micronta 22-167 help? - Page 1
Forum section: electronics / repair

author: subdude17349
author_rank: Newbie
timestamp: December 19, 2017, 06:38:24 pm
content: Folks, I posted on an old thread in test equipment, but maybe I'll have better luck here in repair. I have an old Micronta 22-167 that has burned out a resistor. I'm hoping someone may have one of these meters laying around and would be willing to look and see what value R21 is.Thanks!Jim

author: drussell
author_rank: Super Contributor
timestamp: December 20, 2017, 07:29:18 am
content: According to the parts list, it is a4.99, 0.5%, 1 watt, wirewound:Quote

author: mzacharias
author_rank: Frequent Contributor
timestamp: December 20, 2017, 12:14:10 pm
content: If the "4.99 ohms" value is correct, you can parallel two 10 ohm resistors. Analog meters of this type simply aren't that critical. I don't know the history of this meter but since it obviously has been abused by burning out a current shunt, I wouldn't rule out other problems as well.

author: subdude17349
author_rank: Newbie
timestamp: December 20, 2017, 01:06:07 pm
content: Great info, thanks very much!I'm not ruling out other problems, but R21 was obviously smoked. And I can tell you with certainty that it hasn't been abused, I bought it new in 93 or so. Most of it's life has been spent verifying dc voltage or continuity. And BTW, it's not analog.I have other meters, but just wanted to see if I could resurrect this one.Again, thanks!Jim

author: mzacharias
author_rank: Frequent Contributor
timestamp: December 20, 2017, 09:55:46 pm
content: Quote from: subdude17349 on December 20, 2017, 01:06:07 pmWell, at some time or another, it was touched to a voltage source while in mA mode, or the resistor wouldn't have burned. The good news is, it's not some eBay deal with an unknown history and possible multiple problems. Outlook is hopeful.