hybridfree/eevblog-posts huggingface dataset:
YOKOGAWA 2558  - Page 1
Forum section: electronics / repair

author: kenramesh
author_rank: Contributor
timestamp: August 17, 2018, 11:47:18 am
content: Hi,need help / suggestionfacing problem with yokogawa 2558 voltage current standarddisplay is not stable , seven segment led's -8 nos. (red ) flash ( 5 of voltage /current setting & 3 of % deviation) when unit is switched-on .Flashing stops when the Range dial is rotated , reading dials rotated which cannot be relied.sometimes the leds are stable but most of the time they go on flashing .Even the OUTPUT ON/OFF switch, SWEEP switch automatically jump back to off position when the leds start flashing.what could be the problem.THANKS in advanceramesh

author: Zucca
author_rank: Unknown
timestamp: August 17, 2018, 01:43:29 pm
content: Open the device, take a DMM and make some measurement.Post some pictures and more informations.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 18, 2018, 01:49:32 am
content: Bad suply lines because of failed capacitors, buldged capacitors, bad contacts, bad solderssure some photos would help, for service manual, i haven't seen any Yokogawa material leaked ?? you can try to ask them
CH1 on GPD-3303S is noisy, can't go down to 0V - Page 1
Forum section: electronics / repair

author: technogeeky
author_rank: Frequent Contributor
timestamp: August 23, 2018, 08:08:15 pm
content: Hello,I recently bought a GPD-3303S power supply. The only known problems were a broken voltage rotary encoder which I've already fixed. It still has the known problem of CH3 overshoot describedherewhich I will fix at the same time as whatever outcome we discover here. The service manual with schematicsis available here.The reason I think there is a problem with the CH1 output are twofold:1. The CH1 output is about 3x more noisy (RMS) then the CH2 output.2. The CH1 output is unable to regulate down to the minimum setting: when 1mV is selected, the output is 20mV (which agrees with the read back).At first I speculated that problem #1 wasn't a problem, maybe it's just coupling of display or digital noise onto the output. But when combined with problem #2 I think it may imply there is a problem.Any ideas on what to check first would be appreciated.Thanks,-tg

author: coromonadalix
author_rank: Super Contributor
timestamp: August 23, 2018, 10:07:52 pm
content: Maybe check the main voltages noise before and after the power mosfets, if its stay the same under no load, checks for bad solders, bad contacts, connectors not fully inserted ??You could compare the two channels analog to digital converters (DAC) inputsFound this :https://www.eevblog.com/forum/testgear/quick-look-gw-instek-gps-3303-power-supply/and a verification adjustment manual :https://www.eevblog.com/forum/testgear/quick-look-gw-instek-gps-3303-power-supply/?action=dlattach;attach=115779

author: Shock
author_rank: Super Contributor
timestamp: August 23, 2018, 10:38:04 pm
content: Have you tried setting higher voltages, what noise do you see there? What happens with a resistive load?

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 23, 2018, 10:56:39 pm
content: Is yours actually this version with the gap or is it the newer one with all jacks equispaced?

author: technogeeky
author_rank: Frequent Contributor
timestamp: August 24, 2018, 01:38:55 am
content: Quote from: Mr. Scram on August 23, 2018, 10:56:39 pmIt's the version with the gap, exactly as pictured.
Will a Samsung QLED TV rated at 60Hz  work on 50Hz? - Page 1
Forum section: electronics / repair

author: rfengg
author_rank: Regular Contributor
timestamp: August 20, 2018, 12:47:00 am
content: All,Got a funny issueto deal with, so out to you guys for your expertise.Got hold of a new Samsung QN65Q9FNAFXXR QLED TV for a good price directly from South Korea where these are made.The label on the back clearly says its rated for 220-240V but 60Hz.I need to take it to a country which uses 220V , however the line frequency there is 50Hz.Was wondering if the 50Hz line voltage will cause any issues?Will there be any flicker on the screen due to the frequency difference?Similar question for a washing machine and a fridge, both are made for 60Hz but voltage wise is fine.......will the motors in these machines run slower if I run it on a 50Hz supply?thanks and BR.

author: james_s
author_rank: Super Contributor
timestamp: August 20, 2018, 12:59:04 am
content: I would be shocked if the TV has any issue at all, almost always the first thing that happens in the power supply is the AC is turned into filtered DC. The only difference between the 50 and 60Hz models is probably the label, assuming the regions in question use the same broadcast format.The second question is definitely a case of "it depends." AC induction motors are frequency dependent and will run slower on 50Hz, which may or may not be a problem depending on what it is. Another issue is that the inductive reactance of the windings will be lower on 50Hz so a motor or transformer designed for 60Hz may saturate and overheat on 50Hz. I don't know if tech has changed but every refrigerator I've seen has an induction motor in the compressor so if it does work on 50Hz the cooling capacity will be reduced because the compressor will be pumping slower.Now a washing machine you might have better luck. In North America they historically have used AC induction motors but in Europe it has been much more common to use DC or universal motors. A lot of modern washers worldwide are now using brushless DC or switched reluctance motors which shouldn't be dependent on line frequency however some machines may have control transformers or small motors driving water pumps that may have issues.
Keithley 2410 strange output behavior on power-up - Page 1
Forum section: electronics / repair

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: January 12, 2018, 03:20:37 pm
content: after having repaired my KEI 2410,i've found one "final" glitch, that i would like to fix, but don't exactly know where to start. also, i'm not sure as to whether there's still some component fault hiding there, or whether this actually is a design flaw of the instrument.hence,it would be great if someone could perform a similar test on his/her machine and tell me how it behavesthis is how you can reproduce the (at least in my eyes) faulty behavior:1) switch off the 24102) connect a nixie tube (any segment you want) to the output of the 2410.3) turn down light in lab4) switch on the 2410 (just switch on power switch, no need to switch the output on), and watch a short blink of the nixie as soon as the 2410 has finished initialization.so, there is a spike of more than 150V present at the output, although the output is OFFi verified that with scope and 100:1 probe, the spike goes up to 500V(!) volts. i checked the HV disconnector (COTO) relay, and that's ok. further investigation showed that, during init phase, the voltage directly at the HV output stage creeps up to -1kV (some milliseconds), and then snaps sharply back down to zero volts (microseconds). it seems that the sharp voltage transition is capacitively coupled through the HV-disconnector relay to the output terminals.yes, i know that the manual tells you to disconnect everything from the output before you switch the instrument on. but that doesn't cut it for an instrument that costs 7 grandsany ideas what to check?

author: jzj1988
author_rank: Newbie
timestamp: August 17, 2018, 07:41:32 am
content: hi,i want to fix my 2410,and do u have any circuit diagram for reference？hope U will reply me as soon as possible ,thanks !

author: coromonadalix
author_rank: Super Contributor
timestamp: August 17, 2018, 10:38:35 am
content: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwiHoeqm8vPcAhWm6YMKHVUtCjoQFjAAegQIABAC&url=http%3A%2F%2Fdownload.tek.com%2Fmanual%2F2410_902_01B.pdf&usg=AOvVaw200rnNb16Dcv6xqaOKPGuBNo schematics in it .... searched a lot on google
Fluke 8800a - Ohm PCB fault? - Page 1
Forum section: electronics / repair

author: SimoS
author_rank: Newbie
timestamp: August 16, 2018, 09:49:49 pm
content: Hello everybody. My first time in this forum, I appreciate the level of discussion and the competence of many people.I recently started to work around tube amplifier and set-up a small laboratory, really as a beginner.I found a Fluke 8800a in a local website of old stuff and bought it for few euros.It worked good for AC/DC measurments, but not for Ohms.I open it, cleaned, substituted batteries on the Ohm PCB (2xAA - the previous ones had a leakage so it was a dirty job).All the ohm measures are now greater than real. In example a 1.2MOhn resistor is 6MOhm if measured with 20MOhm scale, or 1.6MOhm if measured with the 2000kOhm scale. During time (hours) the measures on the display decrease gradually.I tested all the power levels indicated in the manual on the main board and they are correct.I tested the Ohm PCB with 1Ohm resistor, and the voltage drop 1mV as indicated in the manual.I check the power supply by the batteries all around the Ohm PCB and it's a nice 3.2Vdc.Any suggestion? Iknow it's an old device, but quite accurate on the VAC/VDC part and an opportunity for me to learn something new.Thanks in advance for your help.

author: lowimpedance
author_rank: Super Contributor
timestamp: August 16, 2018, 11:23:28 pm
content: Make sure you have 'really ' cleaned the ohms assembly and carefully the main PCB where the ohms assembly plugs in, as any residue from the leaking batteries could easily upset the very high impedance's in these areas, (who ever thought batteries in a bench meter was a good idea should be) . Also as well as a good cleaning check for any corrosion damage to tracks and bad solder joints, does gentle flexing of the PCB change the reading in any way.Incidentally the 8810a model revised the ohms to a proper isolated supply to eliminate the dumb battery idea. But it was an optional extra as was the other plug is cards (AC, and I/O) so the basic meter was only DC volts until you coughed up more cash. So be careful if you find an 8810 for a good price that you check what options if any have been installed.
Tektronix TDS520A A11 processor board Capacitors - Page 1
Forum section: electronics / repair

author: videoradar
author_rank: Newbie
timestamp: August 14, 2018, 08:42:57 am
content: Hi All,I just obtained a Tek TDS520A.The A11 processor board is missing all the electrolytic caps and I can not find the values anywhere.Most of them are fed from the same rail but there are a few that are not.Any help would be much appreciated.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 15, 2018, 12:36:13 am
content: Seen on another forum :Tek used five type of voltage +5 -5 +15 -15 and 24vTried in vain to find the schematics ... maybe finding some pictures around the web would help a little ?Any tek 520 fanboys here ?

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 15, 2018, 09:37:44 am
content: Hi!Download the free TDS520B Component Level Package from k04BB or the w140 Tek Wiki – I believe there are design differences between the TDS520A & TDS520B but it should give you a guide – there are schematics & parts lists in it, failing that I THINK you can get a "CLIP" (Component Level Information Package) from Artek Manuals for the 520/520A versions!Chris Williams

author: andy2000
author_rank: Frequent Contributor
timestamp: August 15, 2018, 02:28:26 pm
content: Schematics for the TDS544A are available here. The processor board should be close enough to help.http://hakanh.com/dl/kits.htm

author: videoradar
author_rank: Newbie
timestamp: August 15, 2018, 04:17:10 pm
content: Thanks guys.The TDS544A schematics are very similar. I shall order the caps and fit them then power up and pray.Peter.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 15, 2018, 08:35:47 pm
content: bookmarked this one thks
Obtaining Resistor Values from Printed Hybrid Modules? - Page 1
Forum section: electronics / repair

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 15, 2018, 12:21:29 pm
content: Hi!Just a quickie one!Can anyone point me in the direction of techniques that will help me measure the printed resistor values on ceramic hybrid modules?I come across great numbers of these in the Industrial Electronics Repair I'm employed in – I know chaps on here & elsewhere have reverse–engineered some of these to rebuild them in more conventional form!Chris Williams

author: CJay
author_rank: Super Contributor
timestamp: August 15, 2018, 12:38:48 pm
content: Quote from: Chris56000 on August 15, 2018, 12:21:29 pmI've reversed a few, I've only ever used a multimeter, it's handy if you have a hybrid you can remove all the other parts from of course.They're not always (rarely?) standard values so don't panic if you see 'odd' values but you of course need to take into consideration the surrounding components, the resistors are often laser trimmed on test as well (you can see the laser marks which is rather cool)

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 15, 2018, 12:48:00 pm
content: As a matter of fact, one of the big pros with hybrid circuits is the resistance-value trimming capabilities. So you will find all sorts of nonstandard values.

author: CJay
author_rank: Super Contributor
timestamp: August 15, 2018, 01:20:03 pm
content: Quote from: schmitt trigger on August 15, 2018, 12:48:00 pmIt is indeed, I've seen plenty with trimmed or really 'odd' values however on a good number of the ones I've reversed the designers had just transcribed a design with standard values so they were all close enough to off the shelf parts to make it trivial to replicate
Gould datasys 7200 problem - Page 1
Forum section: electronics / repair

author: satanistik
author_rank: Contributor
timestamp: August 15, 2018, 06:39:59 am
content: HiI have damaged gould 7200 scope - Its start and hold on Truetrace screen, I replaced leaked battery and repair damaged trace on PCB. Holding keys plot and hold all not work because system not scan keyboard. When I measure adres bus with scope probe, I accidentally connect A16 and A17 and program start. This combination work to force start. In first time scope make auto calibration, next start normal. RTC and settings memory work properly. All channels work, DSP and trutrace function work, printer work, all keys ok. Not work storing function - in any option ( RAM disk, Floppy or HDD) i have "no disk in drive" message. If I try format FDD or HDD some internal error are displayed.When system stop on start logo - all adres and data bus are stop - no any activity, /Hold cpu signal are HIGH. Short circuit start method probably skip some program area.When I can found EPROM dumps?This scope can start without added HDD controller?I thing its a problem with driving F82C721 because this hip control floppy and parallel printer port, floppy not work and If I changeplot device to parallel and pres "plot" key - the screen freeze and all activity on data/addres bus stop. On Enable pin of F82C721 I can see any pulse during startup or print operation. If I change Print to serial or GPIB, system still work and I see single pulse onGPIB enable controller.
DENON DSB-100 envaya mini Bluetooth speaker not working? - Page 1
Forum section: electronics / repair

author: obd.tech
author_rank: Regular Contributor
timestamp: August 14, 2018, 11:26:51 pm
content: Hi Guys,i have a DENON DSB-100 envaya mini Bluetooth speaker not working.This seems to suffer from a pretty common failure and short life span, when i did a google search, lots of unhappy owners which is a shame, as this speaker is supposed to be rather 'Stunning Sounding!'i managed to take it apart, hoping to find a failed li-on 18650, but it had 3.54v. Looks like it has a protection pcb on the battery.I charged the battery up directly with my hobby b6 charger, still dead, no response or even battery status led.Anyone had a play with one of these, that could give me any advice (Preferably not 'Chuck it')i'm very limited in electronics knowledge, but have a few toolsand 10x microscope (nothing i could see visibly damaged)Would like to fix this great looking little speakerBit of an ask!!?Thanks in advance for any help
Titanium MD-1600L AA / AAA battery charger rapair - Page 1
Forum section: electronics / repair

author: zerohimself
author_rank: Contributor
timestamp: August 12, 2018, 01:03:59 am
content: hey guys, i have a project that i think i can tackle, but need a little help. I am trying to self teach myself all of this, i have all the right tools, but i'm lacking some knowledge here.I have this Titanium MD-1600L AA / AAA 16 bay battery charger. From day one, one of the bays always says charging, and doesn't work. I suspect it's something with the current dectection circuit ( and probably something common to all four slots... like a ground maybe), but I don't know enough to identify it. I can start comparing to the other similar circuit, but I was really hoping someone could steer me in the right direction and help me learn something in the process.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 13, 2018, 09:34:03 pm
content: your best chance would be to find specs on the ic's in it, i don't see their markings ...
Mastech HY10010E... has anyone got the schematic ? - Page 1
Forum section: electronics / repair

author: coromonadalix
author_rank: Super Contributor
timestamp: August 13, 2018, 09:04:01 pm
content: Asked it at Mastech, they did not wanted to give me a copyjust received as an response : its an different technology you wont need it??Intermittent problems, maybe an cold joint somewhere, just want a schematic before playing in it.
Substitute relays mechanic to solid state relays - Page 1
Forum section: electronics / repair

author: Jasonbit
author_rank: Regular Contributor
timestamp: July 26, 2018, 05:36:28 pm
content: Hello folks,I have one this guys (https://snag.gy/Zr85Dn.jpg). This relays are used to serve interface between microcontroller and schematic power (110V). This means which are used on rather higher frequency during work. It is frequently this relays burn/broke your command contacts. I am thinking substitute this little guys to relays solid state. I think that best solutions because I will eliminate the spark (when command contacts connect) and I will have a component which will be work very better on higher frequency. What do you think about this?I have another question. Exist any model the solid state relays which I can use on this bases (https://snag.gy/zXFVKl.jpg)?Note:I haven't search yet on producer (which I will also need discovery which are) if this relay bases will give to the solid state relays. Since the bases are of the Finder I think it is better first place to search, what do you think/suggest?Thanks

author: mnt22
author_rank: Contributor
timestamp: August 13, 2018, 10:47:08 am
content: HiFirst you need to consider the load current than the rest is easy SCR- and TRIAC-Based SSRs will doAnd for the "base" a1 and a2 is the control signalAre connected to the DC input of the SSR and remaining two wires connected to T1 and T2 of the SSR, this article will helphttps://www.allaboutcircuits.com/technical-articles/basics-of-ssr-solid-state-relay-the-switching-device/
Another Tek 7603 - Page 1
Forum section: electronics / repair

author: Zenwizard
author_rank: Regular Contributor
timestamp: August 16, 2018, 02:22:07 am
content: Working on repairing and calibrating a bench scope for the lab and went with a 7603 for the large screen. I am having some trouble with the 130 Volt rail. All the other power supply rails are in spec but this one is running at 145Vdc. the weird thing is there is 4Vp-p ripple on the rail. I have checked the parts in the 130V section and found a blown out zener it should have been 43 V it was not going in to reverse till 57V also found some resisters that were off in value. I got them replaced. I am starting to suspect C806 which is the bulk filter cap for the 80V feed part of the 130V rail. Or is there any where else I should be looking?

author: capt bullshot
author_rank: Super Contributor
timestamp: August 16, 2018, 05:23:58 am
content: I'd suppose to check the transistors Q852 and Q850 and the few resistors and diodes around them. The circuit looks quite simple, Q852 does the regulation part by comparing the voltage from the R855/R856 divider to the +50V (as reference). Q850 is the pass element. Since the output voltage is too high, I'd suspect one of the transistors gone short C-E, the divider resistors drifted, R853 failed open. The 43V zener is used for startup / protection, not conducting in normal regulation, so it may have failed as a secondary failure.The 4Vpp ripple would be the result of Q850 fully turned on or shorted. In case C806 was failed (dried out, lost capacity), the ripple would be way much higher.
2 burned resistors on FG-2002C Goldstar function generator  - Page 1
Forum section: electronics / repair

author: stevengendron
author_rank: Contributor
timestamp: August 12, 2018, 01:53:14 pm
content: Hi! I have a Goldstar FG-2002C function generator and 2 resistors (R84 and R85) burned.I looked everywhere online and I can't find the diagrams. Is there anyone how has acces to these kind of documents that could tell me what these resistors values are please ?Or if anyone has the same generator and has time to look inside to help me it would be really appreciated.Thank you

author: stevengendron
author_rank: Contributor
timestamp: August 12, 2018, 02:10:36 pm
content: By the way, the body color is green but it is identified has R on the PCB. Is that really a resistor or is it a choke ?

author: Andy Watson
author_rank: Super Contributor
timestamp: August 12, 2018, 02:36:37 pm
content: Where does the upper end go to?A square inch of PCB is not much to go on, but, it looks like the resistors are in parallel and possibly connect to what looks like the output of an amplifier - so does the other end of the pair go to the output BNC ? If it does I would say there is a good chance that they are 100each - giving you a 50output impedance. And they've probably been damaged by power being shoved back-up the output!Another photo with a slightly larger view of the PCB, same ligthing, may be useful. Also a photo of the same area on the reverse side of the PCB.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: August 12, 2018, 03:49:55 pm
content: Quote from: Andy Watson on August 12, 2018, 02:36:37 pmThis would be my guess as well. These resistors probably provide the 50 ohm output impedance, and it seems to be quite common for these output resistors to burn in function generators. I'd replace them with larger power-handling units and also elevate them a little bit above the PCB.

author: stevengendron
author_rank: Contributor
timestamp: August 12, 2018, 04:21:20 pm
content: Thanks. You where right. It did not go directly to the output (it passed trought switches first) but by following the traces on the pcb, I found that it was inderectly connected to it.I installed 2 x 100 ohms resistors and it worked.thank you

author: coromonadalix
author_rank: Super Contributor
timestamp: August 12, 2018, 05:42:19 pm
content: You have an hand made schematic for an FG-8002 :https://www.eserviceinfo.com/downloadsm/63443/Goldstar_FG-8002.htmlHe wrote : there maybe errors
Apple Lisa Keyboard assistance  - Page 1
Forum section: electronics / repair

author: georgeretro
author_rank: Newbie
timestamp: August 12, 2018, 08:24:50 am
content: Hi all,I ask for your assistance in relation to the caps lock mechanism on the Apple Lisa Keyboard. It contains a tiny gold pin and a compression spring. (I have a photo of mechanismhttps://postimg.cc/image/lwpyl31uj/)Would anyone know the size of this spring? In particular the 'out diameter', so I can find an appropriate size.Thank you all in advance,
ITT Shadow NE18T70 - Page 1
Forum section: electronics / repair

author: kelchm
author_rank: Regular Contributor
timestamp: February 08, 2018, 03:15:43 pm
content: Does anyone know if there is a 'modern' equivalent of the ITT Shadow NE18T70 part? This seems to be a common power switch in HP and other test gear from ~20-30 years ago.So far I've only managed to find very overpriced ($30 each) ones that ship from China or crusty looking NOS that looks like they sat on a shelf in 95% humidity for three decades.

author: kelchm
author_rank: Regular Contributor
timestamp: February 09, 2018, 04:52:25 pm
content: Just to follow up on this it looks like the C&K NE182UEE6AMP is a good match and is readily avilable from both Digi-Key and Mouser.I'll confirm once I receive the switch and verify the metal bracket from the old switch is able to be swaped over.

author: MouradR
author_rank: Newbie
timestamp: August 11, 2018, 03:02:58 am
content: Hi Kelchm,I have the same issue that I am looking for this main switch. If you received the C&K version could you please confirm that it is a perfect match and the metal bracket can be swapped over?https://au.mouser.com/ProductDetail/CK/NE182UEE6AMP?qs=u2NJ%252b70r0gq%2F3TOHxPM8mA%3D%3DCheers,MR

author: coromonadalix
author_rank: Super Contributor
timestamp: August 11, 2018, 09:55:11 am
content: i think its a good substitue minus the metal screws holder, you can remove it by slowly unbending the 4 small pins, and slide it away from the switch
HP 3312A serial prefix 2501A schematics? - Page 1
Forum section: electronics / repair

author: precaud
author_rank: Frequent Contributor
timestamp: August 10, 2018, 07:27:20 pm
content: I have a 3312A with serial prefix 2501A that I'd like to get working again. It has an issue in the tuning amp. The manual shows component locations for prefixes 1432A, no update pages. The A2 board and the tuning circuit in this thing has many differences. Does anyone have schematics/layout for the later units? The board part number is 03312-66502 Rev. E.

author: precaud
author_rank: Frequent Contributor
timestamp: August 10, 2018, 10:07:59 pm
content: Never mind, I figgered it out.
PME271m Film Capacitor for Sewing Machine Foot Pedal - Page 1
Forum section: electronics / repair

author: dav0j
author_rank: Newbie
timestamp: August 10, 2018, 07:53:26 am
content: Hi guys,Trying to repair a foot pedal for a 40 year Janome Sewing machine.The capacitor has blown and leaking gunk which I think is some fire suppression liquid and can’t seem to find any replacements locally.It’s a PME271m. Anyone familiar with these? Looks ancient as

author: dav0j
author_rank: Newbie
timestamp: August 10, 2018, 07:57:57 am
content: Pic belowhttps://m.imgur.com/a/b1TCref

author: Gyro
author_rank: Super Contributor
timestamp: August 10, 2018, 08:05:35 am
content: Ah, the infamous Rifa Metalized Paper capacitor!Yes, they're known to fail in old age due to moisture ingress and cracking of the epoxy - Do a forum search for 'Rifa'.Replace it with an equivalent rating Polypropylene Film one - use an Class-X rated one for across the mains use.EDIT: If it's connected mains to ground, then it needs to be Class-Y.

author: dav0j
author_rank: Newbie
timestamp: August 10, 2018, 09:27:40 am
content: Thanks Gyro!

author: Gyro
author_rank: Super Contributor
timestamp: August 10, 2018, 09:47:48 am
content: You're welcome.I forgot to say, welcome to the forum.
tektronics 2225 series vertical adjustment pot - Page 1
Forum section: electronics / repair

author: v0ltair3
author_rank: Contributor
timestamp: August 08, 2018, 12:55:19 pm
content: Hi everyone,I've recently purchased an old tek 2225 that has the vertical positioning pots quite damaged and is challenging to adjust.According to the service manual, the pots (R123) are 470 ohms but I have no ideia were to find them... the most similar was on ebay someone selling the entire front board of a equivalent model where I could eventually salvage those, but I am not 100 sure about the state and 25$ for a pot is a tough...here the pot design from the ebay bid:Any ideia where I can find those ?? or this is really something I can't find on the regular market ?Thank you so much in advance,V0lt

author: bd139
author_rank: Super Contributor
timestamp: August 08, 2018, 01:35:00 pm
content: Not sure if you can still get them but they were made by Mullard / Philips under the CRC12 type. See datasheet here:http://server-die.alc.upv.es/electroweb/datasheet/resist/crc12.pdfNot sure who sold them or if they continued to sell them after Philips sold off their subsidiaries who made these.I had a 2225 and this worried me somewhat I have to admit.

author: Old Printer
author_rank: Frequent Contributor
timestamp: August 10, 2018, 01:11:23 am
content: I bought one of these and the horizontal pot was going bad. Had no luck with an individual pot but picked up a complete front board in perfect shape from Q Service. I was about $45 shipped to US. Not at all hard to install.
Metex 9802A Frequency Adjustment Potentiometer - Page 1
Forum section: electronics / repair

author: Azimath
author_rank: Newbie
timestamp: August 15, 2018, 08:17:00 pm
content: Hello,I have a Metex MXG 9802A function generator and found that the frequency adjustment was not working at all. Upon disassembly I found that the frequency adjustment potentiometer has a bit of plastic connecting the shaft to the wiper which had come apart. My problem is that the potentiometer shaft is something I've never seen where the center shaft acts as a fine adjustment through some sort of ball bearing arrangement either as a planetary gear or to set the right amount of friction between shafts. The potentiometer is otherwise an ordinary looking 50kOhm one. The shaft was attached to the plastic by putting it through a hole then punching the end of the shaft so I cant install it onto a new potentiometer.Is it possible and or worth it to get an exact or close replacement? I wasn't able to find one on Google since I dont know exactly what this is called. Should I just install another 50k pot? (I can live without the adjustment but would prefer to repair it with the right part if it isnt unreasonable to do so)Thank you,-Azimath
SMD fuse marking? - Page 1
Forum section: electronics / repair

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 08, 2018, 09:36:03 am
content: I have an SMD fuse that I cannot identify. It is approx 10mm long and carries the sole marking 'AUR'.It is probably around 10A 250V and I will replace with a wire-ended glass fuse for fault finding purposes, but would like to know of its other characteristics for future reference.Has anyone info on this as I can find nothing. It lived on a 2011 USA-manufactured PCB.Regards, BT

author: cowasaki
author_rank: Frequent Contributor
timestamp: August 08, 2018, 10:39:45 am
content: Could the rating be on the underside?

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 09, 2018, 04:58:21 am
content: I was hoping no-one brought up this question. At least it gives me the chance to use a red-face emoticon!Not having a Thermotweeze iron, I used two irons to unsolder the fuse and it lifted off nicely, however my inward pressure caused the tips to 'cross' and it disappeared- it didn't jump far, and my workbench is fairly tidy but I cannot find it. I will have another look, but there was no print on either side. In the second unit that I am repairing the fuse body had vapourised or shattered leaving just the end caps on the pads.BT

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 09, 2018, 08:04:03 am
content: I located the fuse- it has no other markings that 'AUR'.I note that some manufacturers use a single capital letter to ID SMD fuses, but cannot find this particular one.The two units will live with wire-ended 10A fuses for the time being !Thanks, BT

author: Nusa
author_rank: Super Contributor
timestamp: August 09, 2018, 09:24:37 am
content: Now that you've found it, is it blown? If not, you may be able to determine its value.
Help to identify this chip for Wacom Cintiq 13HD Touch Display - Page 1
Forum section: electronics / repair

author: reddemonic
author_rank: Newbie
timestamp: August 11, 2018, 02:53:14 pm
content: Hello everyoneI have a Wacom Cintiq 13HD Touch Display needed a repair. the device can power up, but the display gets a static effect and "no input signal" message. when I open up I found this chip is burnt. could be a MOSFET or Reset chip or voltage regulator that requires for the HDMI signal to work.I then went on eBay to buy a working display so I can see the Markings on that chip.when I search "C163H" on google, nothing comes up.the large chip below is a 24C02WP EEPROM SOT8 chip.can anyone help me out?Thanks!
Ghosts in the ... eh ... Samsung - Page 1
Forum section: electronics / repair

author: RobK_NL
author_rank: Frequent Contributor
timestamp: August 08, 2018, 04:24:23 pm
content: I have a Samsung UE32D5000 television that suffers from ghosting; with each large change of the image, the previous image remains faintly visible for a very noticeable amount of time.As it seems to worsen with higher temperatures, I am tempted to think this might be related to dying electrolytics. Before opening the thing up, though, I'd be happy to get any informed advice on this.Thanks.

author: stj
author_rank: Super Contributor
timestamp: August 08, 2018, 05:21:26 pm
content: i have seen that effect once, i think it was on the lcd panel pcb.probably loss of panel bias voltage, but i just swapped out the whole panel rather than messing with it.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: August 08, 2018, 05:52:41 pm
content: Eh, "the whole panel"?Do you mean the actual LCD panel or the driver board? Any pointers as to where to get such for less than what a new TV would cost?

author: stj
author_rank: Super Contributor
timestamp: August 08, 2018, 06:26:56 pm
content: i mean the actual panel, i suspect the fault is on the small pcb on the rear that interfaces the flat connector to the actual glass.

author: wraper
author_rank: Unknown
timestamp: August 08, 2018, 06:42:13 pm
content: Best case faulty T-CON board which should be exchangeable (check voltages, especially Vcom) or LCD panel itself.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: August 08, 2018, 06:51:14 pm
content: Great, thanks!

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 08, 2018, 06:56:25 pm
content: I second T-CON, fixed a TV that remembered the channel logo's long after you switched channels.
HP e3610a Capacitor replacement identification- rubbery - Page 1
Forum section: electronics / repair

author: Gtx21
author_rank: Contributor
timestamp: August 09, 2018, 07:59:34 pm
content: I'm looking to identify capacitor C8/C14 from an HP e3610a power supply.The service manual lists it as part 0160-7449, "CAP .33UF 50V 10% PE"The cap is labeled "334K" , and has an odd translucent rubbery coating that I'm not familiar with.The texture of the cap has me confused suggesting to me that it's a type I don't know about that perhaps isn't used any longer? Given that it's going into a lab power supply, I'd rather not replace it with a cap that is missing a key performance perameter.Here is a pic: C8 and C14 are the same cap.https://goo.gl/images/26s9aU

author: TimFox
author_rank: Super Contributor
timestamp: August 09, 2018, 09:17:26 pm
content: I assume that "PE" in the bill-of-materials means "polyester", the generic term for "Mylar", film capacitor.

author: cvanc
author_rank: Frequent Contributor
timestamp: August 09, 2018, 10:24:20 pm
content: Agreed; looks like a common Polyester / Mylar film cap. Should be very easy to source, but they aren't known for failing often, FWIW... are you sure yours are bad?

author: Gtx21
author_rank: Contributor
timestamp: August 09, 2018, 10:39:10 pm
content: I've never seen a Mylar Cap with a rubber coating. Is that just an old method of manufacturing?As for the replacement. It's physically damaged. Someone tried to replace a transistor and must have bent it back and forth a few times so it snapped at the base. Or they just cut it for some foolish reason.If I'm extra good, I could probably solder the stub on there or make a new lead, but I don't like cludgy repairs in my power supplies. :/

author: coromonadalix
author_rank: Super Contributor
timestamp: August 09, 2018, 11:45:13 pm
content: they are Polypropylene Film Capacitors or mylar, or polyester film capacitor, they where more stable over chemical capacitors.search google : " polypropylene capacitor " and check in the images section, you'll have an good idea of how they lookNowadays they dont look as you picture, but you may be able to find some very good substitutes, dont do any cludgy repairs has you say, its not worth it.

author: orin
author_rank: Frequent Contributor
timestamp: August 10, 2018, 01:02:08 am
content: Yes, some kind of film cap. E3620A manual has it as "0160-7449 6 CAP-FXD .33UF +-10% 50V POLYP-MET" which I'd read as metalized polypropylene.
Replacement LCD for a FLIR Ex? - Page 1
Forum section: electronics / repair

author: onesixright
author_rank: Frequent Contributor
timestamp: November 12, 2017, 02:04:44 pm
content: Anybody a idea where to buy a LCD for a FLIR eX series?Thanks.

author: Fraser
author_rank: Super Contributor
timestamp: November 13, 2017, 09:48:01 pm
content: The E4 teardown thread details the LCD part number and the OEM is detailed.Sadly no source has been found for these outside of FLIR.https://www.eevblog.com/forum/thermal-imaging/flir-e4-wifi-resolution-and-menu-hack-thread/msg1211887/#msg1211887Fraser

author: cvanc
author_rank: Frequent Contributor
timestamp: November 14, 2017, 02:40:32 am
content: Does FLIR sell service parts to end users?

author: onesixright
author_rank: Frequent Contributor
timestamp: November 14, 2017, 07:21:13 am
content: Quote from: Fraser on November 13, 2017, 09:48:01 pmThanks Fraser! I googled it, nothing shows upI will contact FLIR.

author: walyynow
author_rank: Newbie
timestamp: August 02, 2018, 01:36:57 am
content: Hi,Have you purchased this display? from flira or from anywhere?I have same problem but with e40. ( I know there are two diffrent LCDs)Reragds

author: onesixright
author_rank: Frequent Contributor
timestamp: August 08, 2018, 12:05:39 pm
content: Quote from: walyynow on August 02, 2018, 01:36:57 amHi,Sorry for the late reply. No I did not. I had the opportunity to buy a E4 with broken screen, and that didn't happen after all.I think I did call the distributer, but I can't find anything anymore
Fluke 75 repair help required please - Page 1
Forum section: electronics / repair

author: Bazzamer
author_rank: Newbie
timestamp: August 07, 2018, 08:44:44 am
content: Hi All, Could someone please help or advise. I have a fluke 75, display was all over the place so cleaned display contacts, cleaned out rotary switch, display still all over the place but all digits there. Checked R1 and was open, so replaced, now when you turn on every segment comes on display, no bleep between ranges, and is the same on every range as rotary switch has no affect on display.Any help would be appreciated as i used it when i was at work, i just dont want to throw it, by the way R1 ruseable 1k resistor i got from a well known company, you have to buy 5 but under a tenner.Many ThanksBazzamerPS. Battery used for testing, it should do a self test but does not seem to do that, no bleep nothing same on every range.Thanks for the help.

author: mzacharias
author_rank: Frequent Contributor
timestamp: August 07, 2018, 04:06:36 pm
content: Maybe post a picture showing the problem?
Searching for service manual: Oltronix C15-2D - Page 1
Forum section: electronics / repair

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: August 07, 2018, 03:46:36 pm
content: Dear friends,today I got hold of another 1970s Oltronix LabPac power supply. This time it is the C15-2D model. Sadly I could not find a schematic or service manual. Already wrote emails to some service manual sellers, but if you happen to have a copy in your personal archives I would be more than happy to buy you a beer in exchange for a copy.Thank you and kind regards,Frederik
Russian Oscilloscope Manuals? - Page 1
Forum section: electronics / repair

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 01, 2018, 05:20:50 pm
content: Hi!Does anyone know if there's any known repository of complete Russian Test Equipment & similar manuals (not just the schematics)?It would be nice to have reference to the original documents so setting-up and calibration information can be deduced fro the docs - whilst I'm NOT an expert Cyrillic reader - I do have quite a good 'phone translator so I can use my knowledge and experience to write up new English Documentation as a research project!Chris Williams

author: ivaylo
author_rank: Frequent Contributor
timestamp: August 02, 2018, 07:34:50 am
content: Install a Cyrillic keyboard for your device (I recommend a phonetic one so your Latin keyboard is perfectly usable) and google is pretty good at finding stuff on the Russian sites.

author: beowulfenator
author_rank: Contributor
timestamp: August 06, 2018, 09:10:43 pm
content: I've taken the liberty to preselect some soviet manufacturers:https://www.rlocman.ru/op/search.html?rz=020402&fr%5B%5D=%C0%EA%F2%E0%EA%EE%EC&fr%5B%5D=%C1%E5%EB%E2%E0%F0&fr%5B%5D=%C2%C7%D0%C8%CF&fr%5B%5D=%C7%C8%CF-%DD%F2%E0%EB%EE%ED&fr%5B%5D=%C8%E7%EC%E5%F0%E8%F2%E5%EB%FC+%28%C0%E1%EE%E2%FF%ED%29&fr%5B%5D=%C8%CA%CE+%C7%C8%CF&fr%5B%5D=%CA%E0%EB%E8%E1%F0&fr%5B%5D=%CA%EE%ED%F2%F3%F0&fr%5B%5D=%CB%CE%D0%D2%C0&fr%5B%5D=%CC%C7%C8%C0&fr%5B%5D=%CC%CD%C8%CF%C8&fr%5B%5D=%CC%CF%C7&fr%5B%5D=%CC%DD%D2%C7&fr%5B%5D=%CF%F0%EE%F4%E8%E3%F0%F3%EF%EF&fr%5B%5D=%CF%F0%EE%F4%EA%E8%EF&fr%5B%5D=%D0%EE%F1%E0&fr%5B%5D=%DD%EB%E5%EA%F2%F0%EE%E0%EF%EF%E0%F0%E0%F2&fr%5B%5D=&pr1=&pr2=&q=&sr=d&or=&vi=Another site with a few soviet models:http://www.astena.ru/teh_15.htmlI speak Russian natively, so if you have any questions, feel free to ask.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: August 07, 2018, 06:01:54 am
content: The most full collection of user manuals and schematic diagrams:https://jais.ru/support/principialnye-shemy-priborov-tehnicheskie-opisaniya-rukovodstva/

author: iMo
author_rank: Super Contributor
timestamp: August 07, 2018, 08:08:26 am
content: Do somebody know by chance an expert with hands-on repair experience with C1-99 o'scopes?
Tektronix TAS 485 - bad menu button, flex PCB (solved) - Page 1
Forum section: electronics / repair

author: beowulfenator
author_rank: Contributor
timestamp: July 12, 2018, 08:23:54 am
content: Hi!I just got a used Tektronix unit and it turns out one of the menu buttons is not working. Apparently the traces on the flex PCB have been rubbed off!Is there a good way to repair this flex PCB?Thanks!

author: wraper
author_rank: Unknown
timestamp: July 12, 2018, 08:40:42 am
content: Try to replace destroyed carbon traces with conductive glue.

author: philpem
author_rank: Frequent Contributor
timestamp: July 12, 2018, 12:15:43 pm
content: Mask with Kapton tape to form the track pattern, then paint over with silver paint (the stuff used for repairing flex-PCBs and TV remotes).When it's dry, remove the tape, apply fresh tape for the pattern on the other side and repeat the painting.Keep the layer thin so it doesn't impede the button, but not so thin that there's almost nothing there. A glue spreader used as a squeegee might help (with that technique, the kapton tape will set the layer thickness).

author: beowulfenator
author_rank: Contributor
timestamp: July 12, 2018, 05:45:58 pm
content: Any recommendations to the specific brand of silver paint/glue?

author: beowulfenator
author_rank: Contributor
timestamp: August 06, 2018, 08:55:47 pm
content: I've successfully repaired it using some conductive lacquer:http://termopasty.pl/en/products/graphite-varnish-en/Surprisingly, the resistance of this lacquer is actually quite high - on the order of kiloohms in traces several centimiters long. But then it is comparable to the resistance of existing traces on the PCB.Adhesive tape as a template worked reasonably well. The first time I applied this lacquer the layer was too thin apparently, but then i added more on top of what I had and it all worked fine. I wasn't able to reproduce the thin traces (two interlocked "fingers" coming from each side), so i just laid two thick tracks next to one another.Thank you all for advice!
GFG-8215A Function Generator... No Waveform!!  - Page 1
Forum section: electronics / repair

author: stevengendron
author_rank: Contributor
timestamp: August 05, 2018, 09:34:45 pm
content: Hi !I just bought a function generator. When I turn it on, I can see a dc signal comming up on my scope. If I adjust the amplitude, the DC signal also gets amplified. However, I can't see any waveform.An interesting fact : When I turn off the unit, I can see the waveform that should have been generated for a fraction of second until the power is completely off.Before I continue to investigate for several hours, is there anyone who could have encountered the same problem before or could have an idea of what is the problem ?Thank you for your tips

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 06, 2018, 07:18:33 pm
content: Hi!This kind of fault nearly always indicates a missing power–supply voltage, which may NOT be simply missing from the psu circuits, there may be damaged or open–circuit pcb tracks, burnt–out supply feed resistors, particularly if surface–mount, or even defective op–amps with an output stuck near a supply rail!Good Will circuit–diagrams are not easy to come by, but open up your gen and write down the type number of all the main devices used in the unit, then look up their datasheets online – the datasheet will indicate where (and what in the case of multi–supply devices like op–amps or Analogue–Digital converters) the power supplies are for each device are.In a F.G., there's usually +5 for digital control and display functions, and ±12 or ±15V for analogue processing and waveform output.Have a look round inside and let us know what you find!Chris Williams

author: stevengendron
author_rank: Contributor
timestamp: August 06, 2018, 07:22:15 pm
content: Thank you ! I'm having my final exams this week so I will take a look next week. I will keep you updated

author: stevengendron
author_rank: Contributor
timestamp: August 08, 2018, 03:02:38 pm
content: I finally had some time to take a look at it.After playing with the knobs, I realized that when the Duty knob was on the adjustable position, the waveforms appeared.So I opened the generator to take a look at the contacts of the knob switch on normal position.When i opened it, by looking at the pcb, I could tell that somebody already resoldered the switch before.I looked at the traces on the pcb and the switch was supposed to make a contact with 2 resistors.One of the contacts had no continuity when I tested it with my multimeter.I figured out that the trace on the pcb had probably melted.So I soldered a wire between the switch and the resistor.I works fine now.