hybridfree/eevblog-posts huggingface dataset:
Behringer xenyx QX1222 USB microphone not working - Page 1
Forum section: electronics / repair

author: Aheld
author_rank: Regular Contributor
timestamp: February 27, 2024, 06:45:13 pm
content: Hello Forum,I have a Behringer sound mixer QX1222USB for repair, where the USB microphone is not working.The USB connector seems to be very special. It has the normal 4 pins (I think for power supply) and in addition 5pins (I think for sound).I found out which pins are used for sound, but for what are the rest of the pins used for?The sound mixer it self is working fine, but it seems that the mixer is not realizing that the USB adapter is connected and is not switching the path of the microphones.I tried internet search, but neither USB connector pinning is available, nor a schematic for the QX1222USB (the normal QX1222 is easy to find :-) ).Any help is highly appreciated.So long.Aheld
Beko dishwasher water flow meter part identification - Page 1
Forum section: electronics / repair

author: Saco
author_rank: Contributor
timestamp: April 18, 2020, 05:37:26 pm
content: I'm trying to fix my mother's dishwasher and while poking around trying to probe the flow meter I ended up breaking it for good.I'm trying to identify the (seemingly only) part in the flow meter's PCB but just looking online is giving me no good results and comparing with readily available flow meters they seem to be using totally different components.At a first glance it seems to be just a fuse. But that can't be true can it?

author: floobydust
author_rank: Super Contributor
timestamp: April 18, 2020, 06:08:43 pm
content: Not a fuse- that looks like a reed switch. The flow meter impeller must have a magnet and it activates the reed switch every rotation, as it spins.You can find reed switches used in alarm door sensors, or maybe an electronics parts supplier has them.

author: Saco
author_rank: Contributor
timestamp: April 18, 2020, 06:32:21 pm
content: Thank you so much, that seems to be exactly that. I wasn't aware of the existence of reed switches.Now I burned the switch so I can't tell if it's a normally open or normally closed one. Would it be more or less safe to assume it is a normally opened since they seem to be more common?

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 18, 2020, 07:19:07 pm
content: Usually N.O. but not really important as it can stop in either state after spinning depending on the magnet's position.

author: floobydust
author_rank: Super Contributor
timestamp: April 18, 2020, 07:51:19 pm
content: It would say it's N.O. as they are low cost and very common. No need for N.C. here.The only thing to be careful of is orientation, the flat leafs are in the same place i.e. if you put the reed switch in rotated 90 degrees, it might not activate as easily.Bending leads on reed switches always cracks the glass! Buy a bunch. They are very fragile. Or don't bend the leads at all, just a jumper wire.
Belts for a Denon DCD-CX3 CD player - Page 1
Forum section: electronics / repair

author: CHexclaim
author_rank: Regular Contributor
timestamp: January 30, 2020, 12:18:45 am
content: Hello people!I'm looking and cannot find replacement belts for a Denon DCD-CX3 CD player.It is an old unit and it has 3 belts which are quite thick, aprox 2, 3 and 4 mm, and about 5 cm in diameter.Part numbers in the Service Manual are:00D 9KA 2G96 8 BELT FIRST00D 9KA 2G97 1 BELT SECOND00D 9KA 2G97 2 BELT THIRDAny idea where can I search for these, other than the usual?Thank you!!CH!

author: JustMeHere
author_rank: Frequent Contributor
timestamp: January 30, 2020, 01:19:28 am
content: Have you emailed Denon?

author: CHexclaim
author_rank: Regular Contributor
timestamp: January 30, 2020, 01:25:29 am
content: NopeBut it is an old model, about 12 years now. I'll look into that tomorrow. Thanks.

author: andy3055
author_rank: Super Contributor
timestamp: January 30, 2020, 06:40:29 am
content: You could buy a bunch of belts and try whatever that fits:https://www.ebay.com/b/Cassette-Belts/48645/bn_7023229626There are all sorts of belts on eBay and Amazon.

author: CHexclaim
author_rank: Regular Contributor
timestamp: January 30, 2020, 02:17:01 pm
content: Thank you for the relply. I've spent quite a while searching online (ebay, etc.) and considered those, but the ones I've seen are always not more than 2mm in thickness, which don't work..CH!

author: andy3055
author_rank: Super Contributor
timestamp: January 30, 2020, 05:41:15 pm
content: This guy has flat belts:https://www.ebay.com/itm/DVD-Drive-Xbox-360-Repair-Rebuild-Common-Cassette-Rubber-Flat-Belt-Repair-35-pcs/323795307986?hash=item4b63b44dd2:g:5jsAAOSwevtcypaf

author: texaspyro
author_rank: Super Contributor
timestamp: January 31, 2020, 05:30:01 am
content: Check out: Projector Recorder Belt Compaany

author: michalism
author_rank: Regular Contributor
timestamp: January 31, 2020, 01:41:31 pm
content: Hello.I have bought these:https://www.aliexpress.com/item/33009318066.html?spm=a2g0s.9042311.0.0.45e94c4dPHs77whttps://www.aliexpress.com/item/4000103663655.html?spm=a2g0s.9042311.0.0.45e94c4dPHs77whttps://www.aliexpress.com/item/33009318066.html?spm=a2g0s.9042311.0.0.45e94c4dPHs77wCheck the product description for each one of them. It specifies the size of the belts. they are between 2-4mm depending on the length.I hope this helps.

author: CHexclaim
author_rank: Regular Contributor
timestamp: January 31, 2020, 02:05:11 pm
content: Thany for your reply and help. Sorry for the possible confusion in my original description but the belts are square in section, not flat.CH!

author: richnormand
author_rank: Unknown
timestamp: January 31, 2020, 10:20:44 pm
content: Glad you found some generic replacements. If that does not workout leave a saved search with your exact model on ebay to your email.Sometimes you get lucky, last year I got exact replacement belts for my 35+ year old Sony CDP-55 (If I remember the model correctly) for I guy that was retiring and selling off his inventory.It was new-old-stock in the original Sony sealed envelope for about $25 including shipping.
Bench PSU not much current limit adj range after pots replaced - Page 1
Forum section: electronics / repair

author: Circlotron
author_rank: Super Contributor
timestamp: October 01, 2024, 12:20:03 am
content: I've got one of these cheapo noisy bench power supplies that I use for rough-enough-is-good-enough purposes. A while back the voltage setting was becoming unstable, jumping up and down several volts. I read somewhere that they have dodgy pots. As luck would have it, I had a big bag full of exactly suitable 10K pots that work threw out, so I replaced all four and things were back to normal, or so I thought. I was so pleased with myself... Some time later I found that the adjustment range on the current limit setting is not what it should be. Should go from zero to 5 amps, but it only goes from about 4 to 5 amps.Now I'm *fairly* sure all four original pots were 10K but maybe they weren't. Does anyone have one of these that they could have a look? Or maybe a schematic. Haven't found a schematic on the interwebz. Seems like the same case is used with any number of different internals.

author: FIXITNOW2003
author_rank: Regular Contributor
timestamp: October 01, 2024, 06:23:27 am
content: only circuit i can find on this not all 10K!

author: Circlotron
author_rank: Super Contributor
timestamp: October 01, 2024, 07:50:20 am
content: In the meantime I found the info that put me onto the bad pots, but it seems I didn't look too carefully. The fine adjustment pots are both meant to be 1K. It's weird that the volts setting works okay with one wrong pot but not the current setting.

author: Circlotron
author_rank: Super Contributor
timestamp: October 01, 2024, 10:50:08 am
content: Quote from: Circlotron on October 01, 2024, 07:50:20 amJust now I set the coarse voltage pot to 20.0V and with the fine pot I could wind it up to 22.9V Could someone try that with their same PSU and see what the figure is?

author: Circlotron
author_rank: Super Contributor
timestamp: October 01, 2024, 10:55:03 am
content: Quote from: FIXITNOW2003 on October 01, 2024, 06:23:27 amThat one is a bit different to mine.https://www.eevblog.com/forum/testgear/mch-k305d-cheap-switching-lab-power-supply/

author: J-R
author_rank: Super Contributor
timestamp: October 02, 2024, 05:43:46 am
content: Quote from: Circlotron on October 01, 2024, 10:50:08 amI get 22.7V, I think you got it.

author: Circlotron
author_rank: Super Contributor
timestamp: October 02, 2024, 10:14:30 am
content: I got a pair of 1K pots today. I'll put them in the fine adj positions and see how it goes.

author: Circlotron
author_rank: Super Contributor
timestamp: October 02, 2024, 10:28:26 am
content: Okay, so I pulled it apart and I think I've found the problem...

author: J-R
author_rank: Super Contributor
timestamp: October 02, 2024, 10:58:27 pm
content: Quote from: Circlotron on October 02, 2024, 10:28:26 amOops, lol
Bench supply shuts off randomly - Page 1
Forum section: electronics / repair

author: Circlotron
author_rank: Super Contributor
timestamp: May 20, 2022, 04:38:18 am
content: Got a 15 volt 40 amp SMPS bench supply that has recently started shutting off for no apparent reason. Turn it on and leave it running with no load and anything between 5 minutes and 2 hours it just goes off. Display goes out too. Like it was unplugged from the wall. Turn the AC mans off and wait for a short time and turn it back on and away it goes until next time it decides it's had enough. If you turn it off then back on too soon it doesn't restart so it sounds like it might be *wrongly* tripping some kind of overtemp or overload shutdown.is anyone familiar with these PSUs? Likely they are packaged and sold under various names worldwide. Anybody got a schematic? I'm quite okay with working on SMPSs.

author: fqahmad66
author_rank: Regular Contributor
timestamp: May 20, 2022, 04:51:54 am
content: First thing will check if anything smells burning. then feel if something is getting hot and lastly tighten all the heatsink mounted parts screws. If that does not point to something then look for a schematic.

author: timenutgoblin
author_rank: Regular Contributor
timestamp: May 20, 2022, 05:01:37 am
content: There's an EEVBlog video on YouTube of this PSU.https://youtu.be/bX8IIjf15qYCheck the description of the video.

author: eurgenca
author_rank: Regular Contributor
timestamp: May 20, 2022, 05:17:17 am
content: Yeah and you have schematic under files.https://eevblog.com/files/SPS9400_ServiceManual.pdf

author: Circlotron
author_rank: Super Contributor
timestamp: May 25, 2022, 12:40:01 pm
content: Looks like I might have it sussed.On the underside of the board there was a small amount of corrosion between the adjacent drain and feedback pins of the TOP222 switcher IC. Plenty of peak volts on the drain so it wouldn't take much to conduct over to the feedback pin and shut it down. Been running for 2-1/2 hours now. When it was first handed to me it would only run five minutes my my bench. Let's see if it's still running when morning comes. 10:40pm here now.
Benchtesting a power supply - Page 1
Forum section: electronics / repair

author: Memphis007
author_rank: Newbie
timestamp: December 08, 2020, 10:52:36 pm
content: Hi everyone !I'm trying to ensure that a power supply is delivering proper voltages and would like to know if I could do it the way I thought, schematics for it below :I have an auto-transformer that I can adjust to the required 9.7V for the logic input power, i don't mind display input for now. On the schematics I find weird the joined 3j3-4 and 3j3-3 pins, why those pins are tied together ? Should I connect those as indicated ? Should I add an isolation transformer before/after the auto-transformer ?Thanks for your answers.

author: The Soulman
author_rank: Super Contributor
timestamp: December 08, 2020, 11:31:39 pm
content: Quote from: Memphis007 on December 08, 2020, 10:52:36 pmI'll answer backwards:Should I add an isolation transformer before/after the auto-transformer ?YES!On the schematics I find weird the joined 3j3-4 and 3j3-3 pins, why those pins are tied together ?The original transformer has two 9,7V secondary windings in series with the center tap connection connected to ground.For testing you'd need to replicate that, or simply use the original transformer?

author: The Soulman
author_rank: Super Contributor
timestamp: December 08, 2020, 11:41:37 pm
content: From what type of device is this? a (french?) vcr or something?

author: Memphis007
author_rank: Newbie
timestamp: December 09, 2020, 08:44:24 am
content: Ok, seems much clearer now, I should have looked closer at the transformer schematics... it makes perfect sense.It's from a Williams pinball machine. That's why I wanted to avoid removing the original transformer from the cabinet.
Benq E2420HD backlight issue, black after few seconds - Page 1
Forum section: electronics / repair

author: RichardM
author_rank: Frequent Contributor
timestamp: August 02, 2022, 12:06:55 pm
content: Hi allLooking for some help. My Benq E2420hd monitor has developed a problem. Shortly after turn on the screen goes black but the green power led stays on. I have been reading many posts over the last few days but I am none the wiser what may be wrong specifically or what to test. I don't believe it's the backlight tubes themselves as if you turn the monitor on and off again once the PC has booted I can see the windows login screen for a second. Unfortunately I cannot find a service manual for this model.The voltages look OK, 5v, 3.3v, 24v inverter voltage etc but again I don't have a service manual. I have attached a couple of photos of the power supply board. Diode and transistor checks seem fine in circuit. All electrolytic caps were removed and test OK. Looking for some ideas on what to look for or test.Richard

author: abdulbadii
author_rank: Frequent Contributor
timestamp: August 02, 2022, 04:48:43 pm
content: Faulty inverter causes the back light not functioning fullyCheck high V capacitor on the power supply inc. ESRFind the fault in the inverter circuit board very nice if got its schematic upload directly here
Berkeley Nucleonics 7010 Digital Delay Generator, Repair - Page 1
Forum section: electronics / repair

author: tridac
author_rank: Regular Contributor
timestamp: January 08, 2023, 07:40:07 pm
content: Hi,I'm looking for a manual, or even just a schematic to repair this item. Dating to around 1975, single board with mainly 74S series ttl. All the division ratios seem to work solid output on the gate output, a bit jittery on the initial output socket, but nothing on the delayed output. It uses a dual channel MMH0026 in a heatsink for the two main outputs. Power rails look good, some psu caps replaced, but has been in store for a decade or more and old ttl does tend to degrade with age. BNC won't help, saying their archive was lost and in any case, don't supply to individuals, even though I've worked feelance, own company, for decades. Nothing fancy, more or less all ttl on a single board, so a schemaitic would be enough to fix it, though it does include a good ovenised 10MHz clock. Anyone have any ideas ?...Regards & Thanks,Chris

author: LaserSteve
author_rank: Super Contributor
timestamp: January 09, 2023, 01:49:15 am
content: . Drop me a Pmwith your email.Steve
Berkeley Nucleonics Fast Pulse Generator - Page 1
Forum section: electronics / repair

author: Omicron
author_rank: Regular Contributor
timestamp: September 25, 2021, 07:43:24 am
content: I'm trying to repair a Berkeley Nucleonics 201E fast pulse plugin for their 6040 pulse generator (https://www.berkeleynucleonics.com/model-6040). The issue is that the output is low in amplitude and it's not possible to set the low and high levels of the pulse anymore.There are two DACs in this device. One sets the source voltage of the output GaAsFET and thus determines the low level of the output pulse. The other sets the drain voltage and so determines the high level. The circuit between the DACs and the transistor seems quite involved though having a bunch of OPAMPS and power transistors in some sort of control loop. I'm still trying to figure it out.Nobody happens to have the schematic for this plugin? I've asked them but they say they can't provide it anymore due to company policy.
Bertan Spellman 225-10R HV power supply + EPROM DUMP - Page 1
Forum section: electronics / repair

author: doktor pyta
author_rank: Frequent Contributor
timestamp: October 02, 2021, 08:19:41 pm
content: Just some photos and eprom dump for recently repaired Bertan / Spellman225-10R HV power supply.The failure fortunately was not in the potted HV part.It was broken voltage selector switch.Kerry Wong did very good job documenting this device (20kV version):http://www.kerrywong.com/2016/11/20/bertanspellman-225-20r-hv-power-supply-teardown/EPROM:http://rfscientific.eu/memory-dump-directory
Best flux for component removal - Page 1
Forum section: electronics / repair

author: furnacemike
author_rank: Newbie
timestamp: June 16, 2022, 01:12:41 am
content: Anyone have any suggestions for the best kind of flux to use for hard to remove components on PCBs? I've heard Chipquik but there are so many different kinds and flavors...Edit. Sorry, I should update: I am looking for the best all purpose flux, for both lead and lead free applications.Thanks,Mike

author: Mario87
author_rank: Frequent Contributor
timestamp: June 16, 2022, 07:04:17 am
content: I use ChipQuik SMD4300TF10, works well and the datasheet specifies it is good for leaded & lead free applications.http://www.chipquik.com/datasheets/SMD4300TF10.pdf

author: Chalcogenide
author_rank: Regular Contributor
timestamp: June 16, 2022, 07:34:46 am
content: +1 for the SMD4300TF10. It works great and lasts a good long time when reworking.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: June 17, 2022, 02:07:40 pm
content: that'd be cheap plain rosin

author: rob77
author_rank: Super Contributor
timestamp: June 17, 2022, 02:40:50 pm
content: rosin based fluxes are good for almost anythinge.g. RMA-223 (even the chinese ones works well for me).
Best forum for 1959 Grundig cabinet radio repair - Page 1
Forum section: electronics / repair

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 13, 2020, 01:55:12 am
content: I've got the chassis out of the cabinet now and everywhere I look at this thing there's new stuff to me. A solid-state full bridge rectifier module, strange 7 v light bulbs, a temperature cutout?, strange connectors, etcI can't even be sure what kind of fuse I should buy...What vintage radio repair forum would be the best for this vintage of commercial Grundig stuff?

author: vk6zgo
author_rank: Super Contributor
timestamp: November 13, 2020, 03:24:04 am
content: This would probably be worth looking athttps://www.vintage-radio.net/forum/As it's a UK forum, they are mostly Brits, so are "as mad as cut snakes", but in a nice way.Seriously, they are a nice, helpful, lot, & much more likely to know about the Grundig than random Aussies & Canucks, etc, would!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 13, 2020, 04:22:24 am
content: Thanks, I'll look into it.

author: andy3055
author_rank: Super Contributor
timestamp: November 13, 2020, 04:30:50 am
content: Is there a model number? See one below.http://www.mbzponton.org/n2awa/grundig2066px.html
Best laid plans; Pot upgrade KL283 fail - Page 1
Forum section: electronics / repair

author: jeffjmr
author_rank: Regular Contributor
timestamp: February 08, 2022, 03:50:43 am
content: Pleased with the overall performance and stability of the inexpensive KL283 DC load but the pots are WAY too coarse. The fine pot acts more like the coarse and for lower voltage or current settings I find the coarse pot virtually unusable.No problem, I naively figured. Replace them with some good multi-turn ones.Ack! The fine tune one has six terminals! I couldn’t find even a single turn to match let alone a bulkier 3 or 5 turn example.It appears only two of the terminals are used and they both appear to connect in parallel with the coarse pot. So then it occurred to me maybe I could just replace the coarse pot with a nice multi-turn and make the fine one superfluous but the PCB mounts up tight to the front panel with the body of the pots flush so any pot thicker than the original just isn’t going to work. In the attached pic the fine pot is the lower six terminal one, the coarse three terminal above. The other channel is identical and is equally difficult to make anything but coarse adjustmentsIf anyone has an idea how to improve this situation, please share.Thanks,Jeff
Best Replacement for MOSFET(Fuji 2SK3548-01SC)? - Page 1
Forum section: electronics / repair

author: Trurl
author_rank: Regular Contributor
timestamp: January 03, 2020, 03:21:16 am
content: My failed Dell monitor(2407WFPb) psuhttps://www.scribd.com/doc/207782153/Dell-2407-WFP-Power-Supply-Rev-A11-Schematic-Diagramhas a TO-3P MOSFET(Fuji 2SK3548-01SC)https://www.datasheetq.com/datasheet-download/139786/1/Fuji/2SK3548which needs an alternative replacement.My initial choice:ONSemi(Fairchild)FQA11N90_F109https://www.onsemi.com/pub/Collateral/FQA11N90_F109-D.PDFhas 11A Drain Current(1A higher than the 10A of the Fuji), but I noticed that theRds(On) is quite lower and Qg is quite higheras well.So now I'mconsidering a 9A Drain Current version with Rds(On) and Qg much closer to the original.ONSemi(Fairchild)FQA9N90C_F109https://www.onsemi.com/pub/Collateral/FQA9N90C_F109-D.PDFI'm thinkin' that the 9A Drain Current spec is conservative as there are references to 11A in the Turn On Times and Gate Charges Test Conditions.I think the 9A version would be an overall closer match to the original part than the 11A version. Which do you think would be the safer/better choice?Thanks…
Best way to repair damaged sensor wires on lab equipment - Page 1
Forum section: electronics / repair

author: Ghost25
author_rank: Newbie
timestamp: August 24, 2024, 03:57:31 pm
content: I have a piece of lab equipment I am trying to repair, it's an Applied Biosystems Veriti 96 Thermocycler. The problem is that it gives error codes "Error Number: 0x8013 Data: 0x00,0x00,0x00,0x00" which are related to the lid and refuses to run. I found some good info here:https://www.labwrench.com/thread/135279/veriti-96?page=2Apparently others have reported that this issue happens because the wires are bent at the lid hinge every time the lid is opened or closed and this causes the wires to become damaged and lead to an open circuit. Apparently the green wire is ground, the blue and black are to a thermal overload device, and the purple and white are across the temperature sensor. A user reported that the resistance across the blue and black should be 7ohms and across white and purple should be 10Kohms at 25C. I measured the resistance across the wires by removing the clip and that seems about right.I think I saw the resistance across the blue and black go to overload when I closed the lid which makes me think the issue is there, but it's hard to say for sure since it could be that I momentarily moved the probe off the lead as I closed the lid.I was able to get the machine to run by removing the lid housing and the shrink wrap around the wires and moving them so they are not bending in the same spot as always. So I'm fairly confident it's an issue with the wires leading to the lid.I'm thinking the best option is to splice some new wire in the middle region, I think it's the blue or black but again not sure. I'm also worried about using the wrong wire and messing up the resistance, also these are near a heating element that is 105C. This is what I could read on the wires:Green: 24 AWG 1180 AWM StyleBlue: RBR-S CSA AWM A/BBlack: 300V 200CPurple: basically unreadableWhite: Style  24 AWG TFE 200C 300VI think it may be this wire:https://www.iewc.com/product/000000000032044488But where can I get a reasonable amount of this, and are they all the same? This one seems close:https://www.mcmaster.com/products/high-temperature-wire/high-temperature-thin-insulation-wire/american-wire-gauge-awg~24/length~10-ft/I was thinking I would just buy a soldering iron (maybe a Pinecel V2?) and splice in new wire, but maybe there's a better way to troubleshoot or repair?Photos of the wires:https://imgur.com/a/XOw1kbS

author: m k
author_rank: Super Contributor
timestamp: August 30, 2024, 05:17:55 am
content: Laser printers have a heater, junkyards should have some.Heater element wires can be thicker, if memory serves they are not very bendy.
BF451 replacement - Page 1
Forum section: electronics / repair

author: Wawavoun
author_rank: Regular Contributor
timestamp: May 09, 2022, 11:53:49 am
content: Hello thereAny idea for an easy to find replacement for BF451 transistor ?Case TO92PNPIc 25 mAVCE - VBE 40 VHfe 30-90F 350 MHzThanks.Philippe

author: strawberry
author_rank: Super Contributor
timestamp: May 09, 2022, 12:37:13 pm
content: ft 320MHz Vce 45V BC557Bhttps://www.digikey.com/en/products/detail/onsemi/BC557BTF/975577

author: Wawavoun
author_rank: Regular Contributor
timestamp: May 09, 2022, 12:58:26 pm
content: Thank you !I even think I have that in the workshop...

author: Jacon
author_rank: Regular Contributor
timestamp: May 09, 2022, 03:40:04 pm
content: It depends - BF451 was a HF transistor - it has Ccb = 0.32pF typ.BC5XY are universal transistors, with Ccb almost 20x larger !!!So - what is the use case for it?

author: Wawavoun
author_rank: Regular Contributor
timestamp: May 09, 2022, 04:42:39 pm
content: It is for mixing sync pulses and video signal.BF451 for sync pulses and 2N2219 for video signal.

author: mariush
author_rank: Super Contributor
timestamp: May 09, 2022, 05:00:11 pm
content: If the voltages are under 30v , NTE2401 maybe ?https://www.digikey.com/en/products/detail/nte-electronics-inc/NTE2401/11652069Not to-92, but soldering 3 copper leads to the terminals would not be hard.

author: strawberry
author_rank: Super Contributor
timestamp: May 10, 2022, 06:06:15 am
content: used in many TV sets KSA1015 Cob 2pFhttps://eu.mouser.com/ProductDetail/onsemi-Fairchild/KSA1015YTA?qs=ljbEvF4DwOP4wK7PS53%252BtA%3D%3D
B&G Zeus Boat Plotter with broken NMEA2000/CAN Bus / Burned Resistor Value? - Page 1
Forum section: electronics / repair

author: maxmatteo
author_rank: Contributor
timestamp: November 21, 2024, 10:36:26 am
content: Hey there,i have a b&g zeus 2 board here which works fine, except a complety non functional CAN-BUS/NMEA2000 System.Bus Diagnose Shows BUS-OFF and 255 TX Errors.I checked the CAN Transceiver (ON Semi AMIS 30660) and Isolator IC (ISO7221), all look fine but i do not have the proper Supply Voltages.12V Comes in via a small 3 pin Transistor(?) and then through a standard 7805 regulator.i see 7805 IN 2.7V and OUT 1.2V. so i assume we have some power issue here.Close to the 7805 i see a burned Resistor, but cant identify any possible value. 4009? Would be way to much i guess.Resistor currently measures 15kOhms.Thanks for any educated guessMax

author: Jon_S
author_rank: Contributor
timestamp: November 21, 2024, 02:34:25 pm
content: Quote from: maxmatteo on November 21, 2024, 10:36:26 amI would suspect it is a SOT23 diode from the pinout, and the fact that pin 2 doesn't look to be connected to anything.Quote from: maxmatteo on November 21, 2024, 10:36:26 am4.99 Ohms is a standard value and would be marked '4R99'. I can't make out the second character enough to be sure it is an 'R', but that seems plausible.

author: maxmatteo
author_rank: Contributor
timestamp: November 21, 2024, 04:11:12 pm
content: thanks for the help.diode confirmed! just saw a voltage drop on one pair of pins!regarding the resistor:so its either 4,99 (4R99) Ohms or 49,9 (49R9) OhmsI tried with 50 Ohms and got proper 12V and 5V after the 7805.anything against using 50 ohms? i guess its just for current limiting?

author: Jon_S
author_rank: Contributor
timestamp: November 21, 2024, 05:28:48 pm
content: I think what you have labelled as a diode (by the regulator) is actually a Unidirectional TVS. A small-ish series resistance before a TVS is really common for simple surge protection. The resistor just limits the peak current into the TVS, as you are trying to protect your own electronics not clamp the whole vehicle. Also, when when a surge exceeds the TVS power limit they tend to fail short and the resistor pops before the traces do...which is nice!So, if you don't have an excessive voltage drop over your resistor then everything should be good.

author: andyalford
author_rank: Newbie
timestamp: September 28, 2025, 07:47:17 am
content: I have a Zeus3 9 and a Zeus3 12 with similar problems.Did you manage to fix your display? I hope so.If so,- any tips for what to look for?- how did you manage to dry it before resealing the unit?

author: maxmatteo
author_rank: Contributor
timestamp: September 28, 2025, 08:51:37 am
content: yeah replacing the resistor was the only fix needed. can bus worked perfectly after that.optical inspection and testing for shorts might give a hint. then check voltages or signal integrity of data lines
BGA-9 component identification - Page 1
Forum section: electronics / repair

author: zzattack
author_rank: Regular Contributor
timestamp: January 05, 2022, 04:36:57 pm
content: I'm trying to figure out what component we have here.SMT top marking reads "+ALJ 117". It's a BGA9 package. If the + indeed denotes (I'm not sure) the corner for pin A1, then pins A1/B1 are tied together, A2/B2 are, and A3/B3 are. There's a 1uH inductor between A2/A3 and B2/B3.On this board C1 and C3 appear to be no connects, and I have not been able to determine where C2 goes yet. Quite possibly a power plane.Voltage readings are taken on a seemingly working device, but this IC gets very hot (>90°C) very quickly (<5s). I'm worried about powering it on.The usual SMD top marking databases do not have a corresponding entry for this BGA9. Anyone wanna hazard a guess?

author: fzabkar
author_rank: Super Contributor
timestamp: January 05, 2022, 08:11:03 pm
content: I'm guessing that the manufacturer is Maxim:http://www.smdmark.com/en-US/search/code?id=%2BaIt looks like a boost converter. Are you sure that your 3.8V and 0V annotations aren't reversed?The "L" in "ALJ" doesn't look like an L to me. Are you sure about this?"117" looks like a YWW (Year / Week) date code.Edit: Does the circuit take the voltage from a 4V lithium battery and boost it to drive a string of LEDs?

author: zzattack
author_rank: Regular Contributor
timestamp: January 05, 2022, 10:48:26 pm
content: I expected the + in +ALJ to denote the pin 1, but you're saying it's part of the marking? In that case indeed it is likely a Maxim ic. I found another picture of the board where the same ic is marked +ALJ125 so the date code assumption makes sense.There is indeed an OLED screen and 3.7 Lipo. What is your guess?Might be a MAX8969 in WLP9 package.

author: fzabkar
author_rank: Super Contributor
timestamp: January 05, 2022, 11:43:25 pm
content: Is the year of manufacture 2021?If so, then I would search Maxim's web site for suitable candidates. You may need to use the Wayback Machine for earlier years (web.archive.org).I think this is the sort of chip you should be looking for:https://www.analog.com/media/en/technical-documentation/data-sheets/3459fc.pdf

author: zzattack
author_rank: Regular Contributor
timestamp: January 06, 2022, 12:11:37 am
content: Given the pads layout, recommended sizes for the inductor and decoupling capacitors I'm fairly confident it's indeed the MAX8969.A working spare will reveal what output voltage was used, but I'm willing to hazard a guess it's the 5.0V version.

author: fzabkar
author_rank: Super Contributor
timestamp: January 06, 2022, 12:26:51 am
content: https://datasheets.maximintegrated.com/en/ds/MAX8969.pdfThat chip's maximum output is only 6V, yet you are measuring 30V at that point. :-?Edit: This web site agrees with your choice:https://www.firstxw.com/view/235586.htmlSo does this one:https://gbatemp.net/threads/switch-no-backlight-and-cracked-chip.592312/I found one site selling an MAX8969EWL50+ with a marking code of +AJZ. That's the 5.0V version.
BGA resoldering - adapters maybe  - Page 1
Forum section: electronics / repair

author: sicco
author_rank: Regular Contributor
timestamp: May 09, 2022, 10:47:28 am
content: I have two TDS3000 scopes where the PowerPC CPU is a 352 pins NXP860 CPU was faulty (or I thought it was...) and it was hot-air soldered from the main board. Since then I obtained a few new chips, nicely balled, and I tried to solder those back on. First with a 'manual' Aoyue 968, and later also with an IR6500 rework station. Even got myself an Alibaba re-balling kit. But long story short, none of my attempts were 100% successful. There were always a few pins that were not soldered properly. Or shorts. By now the mainboards have lost some solder pads and tracks. So soldering it back on (without patch wires...) will never succeed anymore.Now my question: would it not be feasible to get some multi-multi-layer flex PCB with tinned through hole vias for each BGA pin that I can then hand-solder pin by pin, first the BGA chip to the flex PCB, and then the flex PCB to the main board.Or maybe something with 4 quadrants, and connectors so that I can click-in 4 times for north, east, south west 4x? Only the outer square 4 pin rows have real signals, the inside box is just GND and +3V3 pads. With type type of SMD click on connectors used nowadays in smartphones etc, it should be possible to do 4 pin positions every ball pitch distance?Anyone offering such 'repair kits'?What would they be called if they do exist? I mean what search term would I type in to find them?

author: tooki
author_rank: Super Contributor
timestamp: May 09, 2022, 04:56:10 pm
content: I’m sure it could be made, I just wouldn’t expect it to work very well. The added parasitics (capacitance and inductance) and trace lengths added could wreak havoc on high-speed signals like memory buses.

author: chihaxinh
author_rank: Regular Contributor
timestamp: July 11, 2022, 10:03:35 am
content: You need provide pcb condition picture , see to what pad missing , if pad missing in pcb mainboard, you can remake pad . Hard to rework because CPU and mainboard have large GND zone in center.Hope you can repair mainboard.Nam.
BGA REWORK - Page 1
Forum section: electronics / repair

author: Softboxdz
author_rank: Contributor
timestamp: September 25, 2021, 12:57:00 am
content: Hello guys, I’m new in here I want to ask some questions about Bga rework of consoles specials.1 : I have WDS 620 semi automatic 5300w what do you think about it? And did I can reball ps3 and Xbox with it?2 : how do I made my profiles for each mother board? I’m not asking about temperature I want a base to build a profile .3 : what kind of flux and solder balls are best for console?Finally if you are an Bga experts you can give me some advice cuz I’m newbie in Bga world

author: Softboxdz
author_rank: Contributor
timestamp: September 26, 2021, 01:10:43 am
content: no one response

author: Softboxdz
author_rank: Contributor
timestamp: September 29, 2021, 12:15:59 am
content: Still no one reply

author: daisizhou
author_rank: Super Contributor
timestamp: September 29, 2021, 01:48:40 am
content: See if your BGA is a machine with optical alignment function?This kind of machine is too expensive for novices, and the optical alignment function is generally not used.The key is your understanding of the environmental temperature control and machine performance, as well as the curve setting.For example, different chips, PCB thickness, manufacturing process curves are different, and the seasons, summer and winter are also different. It takes a long time to test to fully understand your machine.The picture below is my machine

author: KevinA
author_rank: Regular Contributor
timestamp: September 29, 2021, 07:09:53 pm
content: Search the web.Pace have a good video showing how it is done with just basic rework equipment.

author: Softboxdz
author_rank: Contributor
timestamp: October 10, 2021, 02:05:10 am
content: You have basically the same machine except for alignment system … how do you make a profile example on ps3 Rsx .?

author: daisizhou
author_rank: Super Contributor
timestamp: October 10, 2021, 05:58:01 am
content: If you are familiar with your own machine, you do not need to apply a centering system。The core of the whole BGA is temperature control.If you don’t know how to control, you can shoot a PS3 video to me, I will teach you how to adjust.Or tell me "whatsapp"
BGA Stencil Manufacturer - Page 1
Forum section: electronics / repair

author: PeterG
author_rank: Frequent Contributor
timestamp: May 15, 2024, 08:46:34 am
content: Hi all,i have been searching for a reball stencil for an Intel N100 CPU. It is a BGA1264 layout.There does not appear to be anyone offering this off the shelf so i need to have one made. Does anyone know of a service that does this?TIA

author: rkabz
author_rank: Contributor
timestamp: May 27, 2024, 12:47:06 pm
content: If you could create a PCB with the footprint on it then you could get a stencil made by JLCPCB, maybe from a Gerber file?

author: PeterG
author_rank: Frequent Contributor
timestamp: May 30, 2024, 11:14:44 pm
content: Thanks for the idea, i had not thought of taking this path. At least i can make it compatible with my jig.
Biamp amp-a460 Pascal T-PSU repair - Page 1
Forum section: electronics / repair

author: Halide
author_rank: Contributor
timestamp: February 13, 2023, 10:25:28 am
content: Hello all,I have biamp amp-a460. Unfortunately the PSU is probably damage - I can't measure any voltage.The fuse in power supply is fine but the small power converter do not generate 3V3. I try to push 3V3 from other supply but it do not change nothing.Maybe someone repair that type of amp and have some schematics, power supply connector pin out description or something like that?Best regards,Bartosz
Bidirectional positive-logic to negative-logic converter? - Page 1
Forum section: electronics / repair

author: jayeye
author_rank: Contributor
timestamp: June 05, 2019, 05:43:37 pm
content: I am trying to interface TTL circuitry to an old piece of equipment (a Texas Instruments PC-100C printer cradle). That one has two supply rails, at (approximately) -10V and -15V; logic 0 is, of course, 0V, logic 1 is -10V on some and -15V on some others. If these were unidirectional lines, I could do the trick with just some variant of max232, but they are not, they are bidirectional. If they had only one supply, I could invert the TTL logic, make a level converter to, say, 10V, then connect the TTL Vcc to the old equipment's Vss and power the TTL circuit from a battery. Digging around, I found a patent to convert TTL to ECL levels, but (a) that appears too complicated (ECL working in the active region of transistors and all that), and (b) not sure it will actually work for bidirectional signals.Help?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 05, 2019, 09:07:45 pm
content: What kind of bidirectional signals? Is there a direction flag (typical of controlled buses) or is it open-collector or what?How much current do the signals provide? Are we talking old fashioned PMOS (few mA)?Do you have access to Vss?Tim

author: jayeye
author_rank: Contributor
timestamp: June 05, 2019, 10:53:41 pm
content: Yes, I have access to Vss. The schematics call the -10 and -15 (or thereabouts, I don't have them right in front of me) Vgg and Vdd. The two-phase clock is one of them, the rest of the signals are the other. Not sure if they are open-collector (well, open-drain, while the circuitry is almost certainly cmos, it needed to be compatible with the very old SR-52 calculator which was PMOS, hence the weird voltages). There is no explicit direction indicator signal, but I'm sure I can reconstruct one by counting clock cycles from another signal (that's how the equipment does it).
BIRD directional power sensors 4021/4022 - Page 1
Forum section: electronics / repair

author: jfphp
author_rank: Regular Contributor
timestamp: November 06, 2020, 10:55:28 am
content: Hello,Did anybody try to repair a model 4200 RF directional thruline power sensor from Bird ? The main board is fully closed with a black glue (tear ?). Is it just a box or, like a scope HV multiplier, does the black glue catch all the components ?My 4022 has a funny malfunction : OK till 399 Mhz and from 400 Mhz (cal point) to 1 Ghz overload in FWD and full range on reflected. I guess it is a rom cal failure but how can I have a physical access to it (electronic access is possible with a 4029 calibrator but unobtainable...). Thank you.

author: TheSteve
author_rank: Unknown
timestamp: November 06, 2020, 08:47:26 pm
content: I've repaired one but it was a simple power supply failure.I also spent some time logging the com between the power sensor and the main unit as I thought it might be nice to make a custom unit that replaces the main unit but never got around to it.
Bitmain APW3 power supply - Page 1
Forum section: electronics / repair

author: profdc9
author_rank: Frequent Contributor
timestamp: June 11, 2020, 01:21:41 am
content: This Bitmain APW3 power supply AFAIK is still functional, I just want to know what's in it. It produces 100-140 A at 12 VDC from 100 to 240 VAC. It is a switching power supply and I want to figure out if it can operate from high voltage DC (380 V), whereas normally it uses 200-240 VAC, without the magic smoke or flames.I attached a photo of it. It was very dirty. My understanding of modern power supplies is that there is typically some kind of a rectifier, then some power factor correcting boost converter, then a transformer stage. I am trying to identify those parts here. Unfortunately, the board is so heavily gooped up with silicone that removing the silicone might damage some of the parts. There is a big heatsink which I suspect may have the recitifer and boost converter switch on it. The step down stage I think uses an isolated transformer driven by a half-bridge. I think the big inductor is for the boost converter.Could someone else who has more experience with this maybe see if they have any more clue what is in here before I possibly damage it by scraping away the silicone?Thank you,Dan

author: TheMG
author_rank: Frequent Contributor
timestamp: June 11, 2020, 01:52:00 am
content: Yes that definitely has a PFC pre-regulator (boost) converter, and that is what the big inductor is for. You're not going to find any relatively modern power supply of that power level without PFC, certainly not with only a 10A IEC socket!Impossible to say how the PFC pre-regulator driver IC will behave subjected to a DC input as opposed to the normal rectified AC sine it receives, but since 380VDC would be very close to the regulation voltage of the PFC stage, it won't be doing much anyways.I can obviously make no guarantees but chances are pretty good that it will just work. Attempt at your own risk.

author: profdc9
author_rank: Frequent Contributor
timestamp: June 11, 2020, 03:06:12 am
content: Thanks! Well I may give it a try, but keep a fire extinguisher and some kind of kill switch/circuit breaker handy.
B&K 1470: Sourcing Scale Illumination Bulb(s) - Page 1
Forum section: electronics / repair

author: Luthier Vandros
author_rank: Newbie
timestamp: June 21, 2024, 01:24:51 am
content: Hello!Long time lurker, first time poster. I'm searching for a source for the bulbs used in the B&K 1470's scale illumination circuit, part no: 400-026-9-001. Can anyone point me in the right direction? My boolean skills haven't aged well.TIA!

author: BILLPOD
author_rank: Frequent Contributor
timestamp: June 22, 2024, 06:14:53 pm
content: Good Morning Luthier, here's a complete one on E-Bay, for parts:https://www.ebay.com/itm/176072965382
BK 1550 power supply - Page 1
Forum section: electronics / repair

author: Graybear
author_rank: Newbie
timestamp: February 14, 2020, 06:55:40 pm
content: Hi looking for a circuit diagram for a BK 1550 power supply.Cd4013be ic keeps failing after a short time.Have also noticed current limit function not working.Ouput voltage is fine.Have found page 1 of schematics but missing page 2 may help.
BK 1743 power supply coarse V pot - Page 1
Forum section: electronics / repair

author: ledtester
author_rank: Super Contributor
timestamp: June 28, 2019, 07:06:03 pm
content: Hi all,I picked up a BK 1743 power supply for $5. It's missing the coarse voltage control pot (VR1).Does anyone have a schematic or an idea of what it should be? All of the other front pots are B25K, so I guess it stands to reason that it should also be that value

author: coromonadalix
author_rank: Super Contributor
timestamp: June 29, 2019, 02:47:36 pm
content: I would try it with the same value B25k ...... do a listing of the ic's in it, try to find the main regulator ic if there is, it maybe build around op amps tooAn user manual, no schematicshttps://cdn.testequity.com/documents/pdf/bk/1743B_manual.pdf

author: ledtester
author_rank: Super Contributor
timestamp: July 02, 2019, 08:23:49 pm
content: While I wait for a B25K pot I hooked up a 15K resistor and a 10K pot. Was able to adjust the output voltage from 0 to about 12.7V so I think 25K R is the right value.The only ICs on the board are a CA324E and a CA723CE - so basically an LM324 op-amp and the classic 723 voltage regulator.

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: May 09, 2020, 01:26:33 am
content: Just to confirm, it is 25k pot. I’ve just opened mine up.

author: mawyatt
author_rank: Super Contributor
timestamp: May 09, 2020, 01:17:06 pm
content: Quote from: Ordinaryman1971 on May 09, 2020, 01:26:33 amIf the pot is used as a proper pot (3 effective wire) rather than a variable resistor (2 effective wire) a simple solution to get you back up and running until the proper 25K pot arrives is get whatever pot you have on-hand that is higher in resistance (say 50K or 100K) and place a parallel fixed resistor (50K or 33K) so paralleled result is 25K. This usually works well when used as a voltage divider (proper pot use), but also when the pot is used as a variable resistor (the knob position relative to output is non-linear tho).Best,Mike
BK 2120B 20MHz Oscilloscope help - Page 1
Forum section: electronics / repair

author: Dennis T
author_rank: Newbie
timestamp: January 13, 2022, 06:25:48 am
content: Hello,I had a friend just give me this scope that appeared to be in working order except for one obvious problem. When you adjust the horizontal sweep to a solid trace it isn’t even across the screen. It has a slight angle down from left to right.I have looked for a service manual but have not located one so far. So if anyone has any information on how to correct this issue please let me know.ThanksDennis

author: ledtester
author_rank: Super Contributor
timestamp: January 13, 2022, 06:57:06 am
content: Try the "trace rotation" adjustment.

author: Dennis T
author_rank: Newbie
timestamp: January 13, 2022, 07:24:44 am
content: You can tell I’m new when it comes to a scope. Just adjusted it and now it’s perfect.Thanks for the help.

author: andy3055
author_rank: Super Contributor
timestamp: January 13, 2022, 07:36:27 am
content: Their manuals are here:https://www.bkprecision.com/support/downloads/manuals/en.htmlSee attached.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: January 14, 2022, 03:25:27 pm
content: Now that you have a working scope, please get some probes that match the input impedance.That is, if you do not have them.Use 10X probes almost all the time to prevent accidental scope damage and get better traces.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: January 16, 2022, 03:22:59 am
content: The 2120B appears to be a 30MHz scope.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: January 16, 2022, 09:05:26 pm
content: I have used these things. They are nice for audio and for "High Freq". 30 MHZ is plenty to start with and the scopes preform quite well at audio freq.They are really pretty good scopes for someone to start with, especially at the this price.