hybridfree/eevblog-posts huggingface dataset:
ACECO FC-3002 repair - Page 1
Forum section: electronics / repair

author: pienari
author_rank: Regular Contributor
timestamp: August 06, 2025, 07:57:43 am
content: Hi.I try to repair my old FC-3002 but i havent found good schematics.Symptoms.RF signal meter show full bars all the time.Bad sensitivity under 170MHz and deaf at 400MHz.I think unit have get more then 15dbm rf in so something is blown up.I cant see anything visually broken but i can see first stage is A06G (4pin smd) but i cant find any datasheet.I need to remove it and take some measurements.

author: pienari
author_rank: Regular Contributor
timestamp: August 09, 2025, 06:58:21 am
content: Have anyone found any info ab. A06G .What is that mystery part?

author: Poroit
author_rank: Frequent Contributor
timestamp: August 09, 2025, 07:29:27 am
content: Sorry...nothing showing up in my part of the world.Have you done any comparative tests of of U1 & U2?One of the EEV gurus like "fzabkar" may pick up the post.

author: gamalot
author_rank: Super Contributor
timestamp: August 09, 2025, 01:39:45 pm
content: They look like diodes in SOT143 packages.

author: gamalot
author_rank: Super Contributor
timestamp: August 09, 2025, 01:47:32 pm
content: Avago MSA-0611https://www.mouser.com/ds/2/38/V02-0789EN-211564.pdf

author: pienari
author_rank: Regular Contributor
timestamp: August 09, 2025, 10:02:51 pm
content: That is the one.Thank you.

author: pienari
author_rank: Regular Contributor
timestamp: August 18, 2025, 05:20:26 pm
content: That original part is Obsolete.I think i chould use something else.https://eu.mouser.com/ProductDetail/Analog-Devices-Maxim-Integrated/MAX2611EUS%2bTorhttps://eu.mouser.com/ProductDetail/Mini-Circuits/VAM-6%2b
Acer 5535 (CP2A) AMD Turon X2 Motherboard Failures – any definite answers? - Page 1
Forum section: electronics / repair

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 02, 2019, 08:17:36 pm
content: Hi!There are enormous numbers of these Acer CP2A (AMD Turon X2 CPUs) motherboards on sale, both in complete failed machines, and innumerable eBay listings of the m/b alone, which fail with no display, no proper boot–up and sluggish fan operation.I have one of these machines myself with the same symptoms, and the number of "free" and "paid for" quack "cures" online seems to be as numerous as the sands on the seashore!!They vary from the commercially motivated scam "driver problems" to bios updates, adding piles of coins on the gpu, "professional" bga rework, etc., etc.However the machine I have did actually come on with the normal Acer logo for a few seconds and then the BIOS text, ending with "no operating system found" – (it's a new h.d.d.) – however altho' I measure 5V across the red/black fan leadout wires, there's no signs of any fan rotation!Apart from what seems like an obvious fan failure, are the CPUs/GPUs known to be badly soldered on these series of motherboards, or is everyone barking up the wrong tree because of a voltage regulator or fan supply fault on these m/bs?I might add, altho' I got the "Press F2 To Enter SETUP" whilst the Acer logo was on the screen, netiher Esc, F1, F2 or Del got me access to the BIOS – the keybord apperars to be properly connected to the main board and all the caps lock, num lock, scroll lock etc work during the short period tbe machine runs.I have tried reheating the GPU with my employer's IR machine by the way, and I do have another similarly faulty machine coming in the post, bought very cheap in case I buggered up the first one trying to reflow it!Have any schematics for the Acer CP2A AMD Turon X2 motherboard leaked out? – I don't mind paying a few pounds for a diagram if there's a known regulator fault on these boards!Chris WilliamsPS!Is 5V correct for the CPU/GPU fan supply on these? I'm fairly sure the fan label is marked "12V" on these – is it possible that these boards have all failed or shut off because a higher speed section of the fan supply circuit that provides 12V for high–speed operation dies?
Acer AL1916 monitor PSU repair (DM0565R blown) - Page 1
Forum section: electronics / repair

author: 807
author_rank: Frequent Contributor
timestamp: April 11, 2024, 03:42:21 pm
content: I'm repairing an Acer AL1916 monitor PSU at the moment. The 400v high voltage smoothing capacitor C114 is measuring completely O/C. The case of U101 has blown apart. Fuse F101 has blown. ZD121 reads 6 Ohms in both directions & ZD120 reads 99 Ohms in both directions. While looking at the data sheet of U101 (DM0565R), I noticed that the absolute maximum voltage for Vcc is 20v. However, the zener diode across the Vcc pin to GND is a 1N4748A (22v).Now, whether that zener is used to constantly regulate the voltage, or whether its's used to protect the Vcc voltage from rising too high, I can't understand why 22v was chosen, given that the absolute maximum voltage for that pin is 20v? Wouldn't a 20v or 18v zener have been more appropriate?Until the replacement components arrive, I dont know what voltage the auxiliary transformer winding is supplying to the Vcc pin of the DM0565R.

author: fzabkar
author_rank: Super Contributor
timestamp: April 11, 2024, 11:50:40 pm
content: I would consider replacing C123 as a precautionary measure, even though it is probably fine.As for the choice of Zener voltage, that puzzles me, too.

author: 807
author_rank: Frequent Contributor
timestamp: April 12, 2024, 11:06:15 am
content: Quote from: fzabkar on April 11, 2024, 11:50:40 pmYep. I'll replace C123 as well as C120 and the optocoupler. Even though they all check out OK, it looks like U101 broke down & put a high DC voltage on the Vfb & Vcc pins.
Acer Aspire 5735Z  laptop power problem - Page 1
Forum section: electronics / repair

author: andypandyplod
author_rank: Contributor
timestamp: May 17, 2021, 05:53:54 pm
content: This computer was working fine until I went to turn it on recently.It works fine on battery,but restarts or turns off when an adaptor in connected.I have tried another adaptor which makes no difference. When looking on the internet this model laptop,and many other Acer,and Toshiba laptops share a common problem. They are fitted with the notorious NEC/TOKIN 0E907 'Proadlizer' value of 900ufd 2.5 volt. This is a different name for a capacitor. It is used on the CPU core voltage circuit. My first thought was to replace this one item with 4- 330ufd 6.3 volt panasonic capacitors( working solution suggested by many repairers). I measured the AC millivolts on a true RMS meter expecting to read a high unstable value.My meter showed about 9 milliohm when the laptop is battery powered .I expected a higher reading when I connected the adaptor,and got the same results. This leads me to think this 'Proadlizer' is fine,and there is a totally different fault somewhere in the power supply circuit on the motherboard. There are no burn marks on the 0E907(see attached photo) Any help would be gratefully received.

author: samnmax
author_rank: Regular Contributor
timestamp: May 18, 2021, 07:16:36 am
content: I second the recommendation to change the NEC/TOKIN, i did it on a friend's Acer Aspire 18" or 21" (it was from the same age as yours). Can't remember exactly the symptoms, but the computer worked fine for years afterwards.There's no need to make a pretty repair, you can bodge some SMD camps like I did (see attachment).

author: andypandyplod
author_rank: Contributor
timestamp: May 18, 2021, 09:45:11 am
content: Thank You,anybody else have any ideas please?
Acer Aspire F5-573G Laptop - diode replacement / schematic - Page 1
Forum section: electronics / repair

author: Factotum
author_rank: Contributor
timestamp: January 02, 2021, 06:52:55 am
content: Hey all.In typical form the wife's laptop was no power up on NYD.Opened it up and tracked it to a dead short near the inlet jack - in this case a diode.I only have partial markings PJ6437 then what looks like "1V". I don't have callipers handy (I'm at home not in the shop for a change). Looks 1806 sized (~4 x ~2 mm).Have been trawling the interwebs endlessly for a schematic / boardview.Can anyone help me with this?Cheers!

author: capt bullshot
author_rank: Super Contributor
timestamp: January 02, 2021, 10:04:58 am
content: Does it work if you just remove the diode?I've seen such a small diode used as reverse polarity / overvoltage "protection" once before, but as it was way too small for this purpose it just turned into a short circuit. Removed it, and job was done.

author: Factotum
author_rank: Contributor
timestamp: January 02, 2021, 11:23:38 am
content: I suspect this is the exact same scenario.I will test...

author: Rasz
author_rank: Super Contributor
timestamp: January 02, 2021, 11:24:36 am
content: diagramhttps://www.badcaps.net/forum/showthread.php?p=926159requires registration (free)

author: wraper
author_rank: Unknown
timestamp: January 02, 2021, 11:38:22 am
content: It's a TVS diode which protects from overvoltage.

author: Factotum
author_rank: Contributor
timestamp: January 02, 2021, 01:48:36 pm
content: Thanks.Done the BadCaps rego and waiting for the approval link so I can have a look at the PDF and work out what value it's supposed to be. Not sure if E5 / F5 boards will be that similar - we'll see...

author: fzabkar
author_rank: Super Contributor
timestamp: January 02, 2021, 07:30:52 pm
content: Here is the PDF (don't you just hate those you-need-to-register-before-you-can-see-the-attachments-uploaded-by-our-members forums?).There is a TVS diode on page 32 at circuit reference PD5. The part number is P4SMAFJ20.P4SMAFJ20, Panjit, unidirectional TVS diode, 20V, 400W, marking IV:http://www.szapl.com/manage/images/201432116858176.pdf

author: Factotum
author_rank: Contributor
timestamp: January 03, 2021, 07:46:00 am
content: Confirming that the laptop boots up OK after removal of the TVS diode.Have noticed the battery is detected but isn't charging. Not sure if this is a dead battery or dead charge circuit yet...
Acer Aspire Switch 10E shorted capacitor - identification help needed - Page 1
Forum section: electronics / repair

author: adriansmith31
author_rank: Contributor
timestamp: March 26, 2022, 05:31:06 pm
content: Hi all,I have an Acer aspire switch 10E tablet / laptop hybrid that has no power. It charges OK but when powered on there is no POST, no video output, nothing on the LCD and the power LED does not turn blue. The CPU gets warm.I found it is not attempting to boot from USB and further inspection revealed that there is a shorted capacitor on one of the voltage rails. The problem is the capacitor is so tiny (perhaps 1mm long by 0.25mm wide) I can hardly see it. In the attached photo I have circled it and pointed an arrow to the offending capacitor. The nearby MOSFET is okay but the capacitor is connected to the SND9039A1 power management and control IC and ground. I'm hoping the chip isn't faulty but I need to change that capacitor.Any idea on it's value and what suitable part would do as a replacement to order? It's so small I can't see any markings and there's no schematic.Any help would be greatly appreciated.

author: bob91343
author_rank: Super Contributor
timestamp: March 26, 2022, 10:40:13 pm
content: I would first remove the part and see if the unit starts working. Then try different values to see if it makes a difference in operation.

author: adriansmith31
author_rank: Contributor
timestamp: March 27, 2022, 09:18:36 am
content: Thanks, will do. I found identical physical size capacitors on an old memory module so Ill try those. Ill update if it works or not as I suspect there may be further things that have failed. It no longer gets hot and it did do when it failed evident by the scorch mark on the underside of the metal heat spreader plate that goes over the motherboard.

author: EbarlaS
author_rank: Newbie
timestamp: March 29, 2022, 12:42:02 pm
content: I am curious how did you identify the problem. Since u dont have any schematics, even any other component shorted, it can cause, that capasitor shorted too. I have a shorted capacitor problem like 20 of them at SiO which i couldnt figure out which power and where power coming causing them shorted. So i suggest you to be sure before you remove the capacitor. I guess it will work fine without that capasitor if it is the real one which is causing trouble.. good luck...

author: adriansmith31
author_rank: Contributor
timestamp: May 07, 2023, 07:16:25 pm
content: This is an old topic but I thought I'd share what the problem was. Unfortunately it was more than just the capacitor; the power management IC which controls charging and regulation of various supply rails was found to have a tiny hole in it. The chip itself was shorted and this was found on the underside of the board a small distance away from where the magic smoke had stained the heatsink.I decided it wasn't worth the effort to source and replace it so I scrapped the tablet.
Acer ER320HQ backlight issues - Page 1
Forum section: electronics / repair

author: CaptainBucko
author_rank: Regular Contributor
timestamp: December 19, 2024, 12:01:14 am
content: I have two Acer ER320HQ monitors. Both have dark background (I presume backlight issues) in on the left and right hand sides of the screen. Otherwise image is clear. Can these be repaired? The monitor is supplied externally with 19v DC and I have confirmed that supply is good and stable. Any further thoughts?

author: MathWizard
author_rank: Super Contributor
timestamp: December 19, 2024, 12:40:48 am
content: If it was me, I would at least map out the basic's of the PSU section inside the screen, and make sure enough power is getting to the LED's. It looks like some are working. Most of the voltages are probably ok, but it could be that running all the lights, some PSU section has a problem and can't keep up.If you track back from the LED's to some voltage rail, and then some regulator/controller IC, you might find it's datasheet and see if it's putting out the right voltage.Of the 2-3 monitors I've worked on that had a 24V external power brick, they still had a few step down converters and regulators inside for the various chips, and in those monitors, some PSU section for cold cathode Florescent lamps.I have a broken TV, that displays nothing, but the PSU section seemed good, So I guess it's the LED's gone bad, but IDK what replacements to get, or if it's worth it. I bet I'd get it full of dust, taking apart the actual panel. And then those things are tricky to take apart and reassemble.

author: tom66
author_rank: Super Contributor
timestamp: December 19, 2024, 10:57:41 am
content: This will be failed LEDs in the backlight unit. Quite common unfortunately.It can be repaired, but you need to be able to source the backlight strips. Often you can find these on eBay for scrapped monitors if you type the model number of the LCD panel in. Note that the LCD panel model is not the same as the model of the monitor itself, you need to disassemble the monitor to find the panel label.In most cases, replacing the backlight LEDs requires disassembly of the LCD panel module itself, which for a 32" screen is best done on a large workbench with enough room to fold the panel over carefully onto some padding material. Be careful to avoid getting dust into the backlight unit, as you'll see that when it is on. Be extremely careful not to damage the LCD flexes as if you do, the panel will have dead columns/lines/etc.
ACER Extensa 5630 laptop CMOS battery replacement within 5 minutes  - Page 1
Forum section: electronics / repair

author: micha1102b
author_rank: Contributor
timestamp: September 24, 2019, 07:55:13 am
content: Hi,if you need to replace the flat CMOS battery in your ACER Extensa 6530 laptop but are horrified by only thinking of the task of stripping the machine down to the bare motherboard just to reach the dead cell (as intended by the manufacturer),here is a 5-minute-solution without any disassembling (actually not even a screwdriver needed) I explain in my short YT video:https://youtu.be/LgbV4nwZYYoI tested it on an Extensa 5630 only, but according to the service guide from ACER it should work on the Travelmate 5730 series too.Best regardsMicha
ASUS GL553V Repair - Page 1
Forum section: electronics / repair

author: negativ3
author_rank: Regular Contributor
timestamp: October 08, 2019, 01:37:16 am
content: Hi EEV'ers,I am kind of stumbling about trying to fault find an Asus laptop that won't start. It doesn't even show a battery charging led when the charger is plugged in, which it should. For me, a circuit diagram would be of great assistance as reverse engineering takes me a lot of time.I have a feeling that a bypass cap has gone bad, but so many caps are reading short that I don't just want to randomly start de-soldering them with my fingers crossed.See attached pictures of what I've probed and observed so far, any assistance you can offer to guide me on things to check would be appreciated.

author: Rasz
author_rank: Super Contributor
timestamp: October 09, 2019, 01:03:23 pm
content: Quote from: negativ3 on October 08, 2019, 01:37:16 amfrom my experience blown mosfets are more likely, unless you can see actual mechanical/water damage on the capsremoving mosfets is 30 seconds with hot air, just pul them all off and recheck

author: PKTKS
author_rank: Super Contributor
timestamp: October 09, 2019, 01:09:09 pm
content: MLCCs are also very common pigs... they crack adhoc.Alternative method is try using your bench supply to avoidtriggering the OCP and a thermal camera to spot the bastard...Neither one of these two tools are cheap nor expensive.But for this new age of microscopic tiny little things... required helpPaul

author: negativ3
author_rank: Regular Contributor
timestamp: October 09, 2019, 03:34:44 pm
content: Quote from: Rasz on October 09, 2019, 01:03:23 pmOk, removed and tested the three mosfets pictured as follows:DVM on diode check-ve to source+ve to Drainreading approx 0.4V-ve still on source+ve to gate+ve moved over to Drainreading 0.000V-ve still on source+ve still on draintouched gate-source with a fingerreading back to 0.4VDoes this look normal? seems like they are switching ok.A short is still present across a ton of MLCC and electrolytic caps.

author: negativ3
author_rank: Regular Contributor
timestamp: October 09, 2019, 03:38:10 pm
content: Quote from: PKTKS on October 09, 2019, 01:09:09 pmDo I set the PSU to the required voltage, turn down the current, then connect?Seems logical but should I expect the voltage to be limited below a "certain" current?Asking before hooking it all up...

author: PKTKS
author_rank: Super Contributor
timestamp: October 09, 2019, 04:27:20 pm
content: That depends. Kinda use a common sense here.Your goal is to spot a dead short culprit.Some folks already have skills to do so even with alcoholBut a thermal camera is far more easy, you do see the spot.You should guess or start by the utmost front end feedingenough ("enough" is relative) current to have a hot spot(considering how "hot" should hot to be visible.)Figures like 2 or 3 Amps (using CC adjust) are enoughsome hard chips require 4A or 5A (voltage will float of coursestart low... up to desired)The image of the hot spot will give you at least a region to startSome folks even "isolate" parts of the front end to apply morebrute force to to a really hot spot.. mileage varyPaul
acer Iconia One 10 B3-A30 tablet - Page 1
Forum section: electronics / repair

author: vinceroger
author_rank: Regular Contributor
timestamp: November 07, 2020, 08:01:42 pm
content: Hi guys im repairing a tablet which has a faulty charge port but i have found a diode shorted on the positive line near too the usb port possible tvs diode? all i can read on the old diode is H7 it also has a dot above the H and 7 can any of you help with identification the diode location is inline with the number 5 and the screw hole.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 08, 2020, 01:41:12 pm
content: 11v Zener?http://www.marsport.org.uk/smd/mainframe.htmIs it a SOD523 package as in the Codebook?https://media.rs-online.com/t_line/L6261885-01.gif

author: vinceroger
author_rank: Regular Contributor
timestamp: November 08, 2020, 07:43:27 pm
content: Hi in good light tomorrow i will try and take a good picture and measure the part ive also asked this same question on badcaps.net we thought it maybe a tvs diode because one of the pads where the part is removed from is short too ground the other pad goes to the usb charge port

author: vinceroger
author_rank: Regular Contributor
timestamp: November 09, 2020, 11:11:45 am
content: Quote from: Audiorepair on November 08, 2020, 01:41:12 pmHi just measured the part it is 0.6 by 0.8 so yes maybe a sod523 now all we need too do is find out if its a zener or a tvs diode its on the 5volt plus line so guess the parts for over voltage/surge protection? one pad one pad goes to the + usb pin one pad reads ground.

author: vinceroger
author_rank: Regular Contributor
timestamp: November 09, 2020, 03:30:32 pm
content: Hi guys well i fitted the replacement charge port (i left the bad diode out) the tablet powers on and charges/works fine so im giving it back too my friend as is, but i will advise them i have left the protection diode out as i cant source one (this repair is a free one anyway.)
Acer Monitor 1716F Power Supply - Page 1
Forum section: electronics / repair

author: paul_g_787
author_rank: Frequent Contributor
timestamp: January 04, 2021, 05:50:32 pm
content: Hi.Thought I would share this one as I have never seen anything like this before. My office monitor would not switch on the other morning so though I would have a quick look.Never seen an IC exploded like this before.Oh dear.I have found replacement ICs on eBay. They are an Alpha and Omega AOP605. The exploded one had a direct short on pin 3 and 4!!Anyway I have ordered replacements for the bulging capacitors. They are Suscon brand??? I am replacing all of them just to be safe.Can anyone find the schematic for this board??I cannot find the datasheet for my revision monitor 1716FsI cannot see any other faults or find any other shorts. Any advise on what else to check?

author: paul_g_787
author_rank: Frequent Contributor
timestamp: January 04, 2021, 05:55:09 pm
content: A couple shots here of the power supply

author: kripton2035
author_rank: Super Contributor
timestamp: January 04, 2021, 05:59:44 pm
content: i would change the blown circuitand the two bulky caps you can see on the pictureand test the esr of the other chemical caps.

author: fzabkar
author_rank: Super Contributor
timestamp: January 04, 2021, 07:28:09 pm
content: Are any of these models similar to yours?https://elektrotanya.com/showresult?what=acer+AL1716&kategoria=All&kat2=AllBTW, I would be very suspicious of MOSFETs source through eBay.

author: SpecialK
author_rank: Regular Contributor
timestamp: January 04, 2021, 09:02:48 pm
content: Quote from: fzabkar on January 04, 2021, 07:28:09 pmI'm not sure where you could find an AOP605 other than eBay. I haven't had luck obtaining A&O from Digikey or Mouser.

author: kripton2035
author_rank: Super Contributor
timestamp: January 05, 2021, 07:06:46 am
content: yep there are not a lot of sellers out there for this devicehttps://octopart.com/search?q=aop605&currency=USD&specs=1

author: SpecialK
author_rank: Regular Contributor
timestamp: January 05, 2021, 02:58:05 pm
content: Quote from: kripton2035 on January 05, 2021, 07:06:46 amThat link says 2 results. The first says min $100 order, the other to ask for a quote. Probably need to order a spool of 2500.

author: paul_g_787
author_rank: Frequent Contributor
timestamp: January 06, 2021, 09:41:00 pm
content: Quote from: fzabkar on January 04, 2021, 07:28:09 pmNo it appears they used several different power supplies. I have already looked at those and they don't match unfortunately. Mine is the 'F' model - AL1716F
Acer Nitro KG271 won't turn on - Page 1
Forum section: electronics / repair

author: VanioBoy
author_rank: Newbie
timestamp: September 04, 2025, 01:03:18 pm
content: I have been struggling for a week and I can't find the problem. The monitor, although it was working, suddenly turned off and will not turn on again. The power and standby indicator next to the power button is also not lit (does not respond in any way). I measured the output voltages on the power board and described them in the picture. When I press the power button, the output voltages from the picture do not change.Board model:715G5665-P01-003-003MCould the problem be in the main board?What else would you advise me to check?

author: VanioBoy
author_rank: Newbie
timestamp: September 05, 2025, 08:33:29 am
content: I spent a few more hours testing capacitors and resistors. I found that a resistor with the number R914 should be 0.24 ohms, and when I measured it with a multimeter it was 0.7 ohms. Is this normal?

author: coromonadalix
author_rank: Super Contributor
timestamp: September 05, 2025, 11:29:28 am
content: parts nearby could affect the read value(s)on the secondary you have 2x black rectangles fuses have you checked themyou also have one on the primary side

author: VanioBoy
author_rank: Newbie
timestamp: September 05, 2025, 12:52:22 pm
content: I removed the resistor R914 and measured it with a multimeter, but it still shows 0.6-0.7 ohms.I checked all the fuses, they are good.But I wonder if there should be some voltage on the on/off terminal?

author: nfb
author_rank: Contributor
timestamp: September 05, 2025, 09:08:49 pm
content: According to your notes the +5V voltage supplying the main board is present so the power supply probably works. I would check the main board.

author: VanioBoy
author_rank: Newbie
timestamp: September 09, 2025, 10:22:55 am
content: This is the main board.Model: 715G8705-M0B-000-005KI have marked the elements where there is no voltage.

author: VanioBoy
author_rank: Newbie
timestamp: September 09, 2025, 01:17:39 pm
content: I read that if I apply 3V to the on/off pin, the backlight should work. I tried this, but it doesn't work. When the 220V is off and I plug in the cable between the power board and the main board, the backlight blinks for a split second.In this position, I read 17V at the backlight pin.Does this mean that the power board is damaged?

author: VanioBoy
author_rank: Newbie
timestamp: September 10, 2025, 11:43:02 am
content: Quote from: VanioBoy on September 09, 2025, 01:17:39 pmWhen I connect all the cables and apply 3V to the on/off switch, the backlight turns on. Nothing else happens.
Acer P1200 Projector - identifying component & value - Page 1
Forum section: electronics / repair

author: DerekHawker
author_rank: Newbie
timestamp: June 21, 2024, 11:19:20 am
content: Hello, I wonder if anyone can help? I have one of these I'm trying to repair.https://www.projectorcentral.com/Acer-P1200.htmAcer P1200 ProjectorIt sat in a drawer for years, worked for a couple of hours a few weeks ago, and then the following time it was switched on, fizzed, smelt of burning and tripped the fusebox. By coincident, on the same day I borrowed an old tape player from a friend and he mentioned that certain components can dry out if not used regularly.On opening the projector I can certainly see at least three components that have visibly blown. Two I can identify easily enough by the coloured bands but the green ceramic disc capacitor (?) has lost the section where the identifying marks/numbers would be. Might anyone be able to help determine what I need to buy as a replacement? Please see photo 7. Many thanks in advance for any advice!

author: fzabkar
author_rank: Super Contributor
timestamp: June 21, 2024, 03:46:03 pm
content: It's an NTC thermistor. These are used for inrush current limiting. They do not normally fail in isolation. I expect that one or more of the semis will be shorted, usually the chopper transistor.

author: wraper
author_rank: Unknown
timestamp: June 21, 2024, 03:57:06 pm
content: To correctly identify NTC, you should provide it's marking on the other side and its diameter. EDIT as I see there is nothing on other side, you need to find a missing piece of its green coating with marking. As of 0.16 Ohm resistor, it's a 99% sign of shorted MOSFET, and another resistor bedside it is probably dead too.

author: dark_hawk
author_rank: Regular Contributor
timestamp: June 21, 2024, 06:28:24 pm
content: Had a projector board like that for repair a while back.Like fzabkar said, the problem won't be the NTC, something else blew.In my case it was a small SMD diode in the PFC circuit which blew the mosfet, the NTC and the fuse.

author: DerekHawker
author_rank: Newbie
timestamp: June 21, 2024, 09:21:56 pm
content: Thanks so much for your responses. I'll do some research tomorrow based on your suggestions, though I think this may be beyond my abilities/comprehension.
ACER Predator Helios 300 10750h rtx2060 not charging battery after short circut - Page 1
Forum section: electronics / repair

author: BMW528i
author_rank: Contributor
timestamp: October 17, 2023, 09:34:55 am
content: Hello i bought a non working helios and quickly found it had very minor liquid damange. A capacitor was shorted out as marked in the photo and i removed it, fixed the short. Now the laptop turns on works okay other that the fact the battery remains at the same voltage all the time and never charges. any input would be much apreciated, i'm new to board repairs thanks!

author: m k
author_rank: Super Contributor
timestamp: October 23, 2023, 08:40:13 am
content: Have you tried putting something back there?
Acer projector P5530 Model D1P1704 - Page 1
Forum section: electronics / repair

author: miette_Kruemelchen
author_rank: Contributor
timestamp: April 22, 2024, 07:09:15 pm
content: Hello members of the EEVblog Electronics Community Forums,I'm in need of a service manual for an Acer projector. Specifically, it's the Acer projector P5530 Model D1P1704. I urgently require the service manual or at least a helpful tip for further troubleshooting.Issue: The device powers on, but the projector lamp does not light up. After a while, the LED indicator on the lamp display starts blinking.Previous actions taken: The lamp has already been replaced, but with no success. The two fans inside the device are running properly. The issue may lie within the power board. The N-channel MOSFETs on it have been tested and are in good condition. Unfortunately, everything is already assembled, so I'm unable to conduct further tests at the moment. Therefore, a service manual would be extremely helpful. Alternatively, can anyone provide a tip on how to check the power board without the mainboard?Who could assist me with this? Thank you in advance!Best regards,Sven

author: MathWizard
author_rank: Super Contributor
timestamp: April 23, 2024, 07:18:18 am
content: Here's some LED codes from a manual. If this thing is pretty new, you probably won't find a schematic. IDK what voltages the 240W bulb uses, but there's probably not very many voltage rails to check, if it's already running.From the pic's I'd guess there's a boost stage like to 340V maybe, and then another stage or 2 for driving the lamp.And the little transformer on the far left might be for 5V standby, or 5/12V for all the circuits outside the PSU. If I had this to work on, I'd make my own schematic in LTSpice, but yeah it takes time.I'd look up all those chips on the PSU, see if they have Vcc, and if any of them have an ENABLE pin, or a power-good pin. Pretty much all those controller chips will be checking for under-voltage/over-voltge, over-current, and might be shutting down.There could be some power problem on the other boards, you can check for shorts on some other boards. And there could be a logic signal coming back to the PSU saying to not drive the light.If I knew the low voltage rails to the rest of the machine, I'd even try powering that from some modem or cablebox PSU, or benchPSU if you have one, just to measure the current draw.https://global-download.acer.com/GDFiles/Document/User%20Manual/User%20Manual_Acer_1.0_A_A.pdf?acerid=636595271962374228

author: miette_Kruemelchen
author_rank: Contributor
timestamp: April 24, 2024, 07:00:25 am
content: Hello MathWizard,I want to express my sincere gratitude for your prompt and helpful response to my post. It means a great deal to me that you took the time to assist me further.I will definitely take your advice to heart and endeavor to create a circuit diagram using KiCad to identify potential sources of error.Once again, thank you very much for the valuable insights you proposed in your forum post. I truly appreciate your assistance!Best regards,Sven
Acer tablet battery - Page 1
Forum section: electronics / repair

author: orbanp
author_rank: Regular Contributor
timestamp: October 14, 2020, 12:17:28 pm
content: Hello Everyone,I have an Acer Iconia One 7 tablet that just stopped turning on, it was just dead.It is working now, but not sure why, and have a number of questions.The tablet was barely used and fairly new, it was never on the net.The battery was not discharged, previously I used it a couple of months before.Not loosing much, I took the tablet apart and suspecting the battery I checked it.There are three connections to the main-board, "+", "-", and a line marked "T".There was no voltage at the connector, but the battery terminals showed 2.7V.There is some electronics directly on the battery cell, it looks like a boost-buck? controller, two tiny ICs a couple of R-C components, and component that looked like a coil.Just curious what is that circuit on such batteries?Plugging in the USB charger did do nothing.The battery is a single cell Li-Po battery, 3.7V, 2.8Ah.I charged the battery directly a bit, with a VC-CC PS, babysitting it all the time, bringing it up to about 3.6V.Still the tablet was dead, no voltage at the connector terminals.Plugging the main board directly to a PS of 4V (leaving the "T" terminal out), the boot-screen flashed up for a moment.Increasing the voltage a bit the boot-screen flashed a bit longer.Then I reassembled the battery and the tablet miraculously booted up as if nothing happened.There is 3.6V at the connector terminals when the tablet is running.Just curious, what happened, a software glitch? Never tried to press the "Reset" button.Any insight into the above?Thanks, Peter

author: m k
author_rank: Super Contributor
timestamp: October 14, 2020, 02:12:00 pm
content: Most likely "T" is for temperature.Li-Po should have a protection circuitry.My guess is that the Li-Po protector had a hickup.Maybe it doesn't come back.

author: retiredcaps
author_rank: Super Contributor
timestamp: October 14, 2020, 06:19:18 pm
content: Did you leave the tablet off via power off or was it in sleep/standby mode?If sleep/standby, you can download battery apps that show you what installed apps might be draining the battery while it's in sleep mode. Or your tablet isn't going into deep sleep mode for some reason.

author: orbanp
author_rank: Regular Contributor
timestamp: October 15, 2020, 12:00:45 pm
content: Thanks for the replies!The tablet was powered down, was not in the sleep mode.The circuit on the battery had one "power device" on it, one of the ICs the pins on one side were all tied to a PCB layer. Probably some FET device.Could not identify the circuit, the IC markings were too short and too cryptic.I could not find circuit diagram or service manual for this tablet, I did find a service manual for another Acer tablet, it only had a block diagram and instructions for diagnostics software to identify problems.The block diagram only showed a battery, and a battery management IC next to the main processor, but no detailed info on the battery.Thanks, Peter
action camera where to get a new battery - Page 1
Forum section: electronics / repair

author: nvidia
author_rank: Regular Contributor
timestamp: July 26, 2023, 01:35:23 am
content: https://youtu.be/9rq3D2PR4QIi have been given the same one as in this video without a battery would anybody know what one it takes? and where to buy one

author: thm_w
author_rank: Super Contributor
timestamp: July 26, 2023, 11:16:50 pm
content: Take it out and measure it. My guess is its a copy of the gopro hero 5/6/7/8 battery which you can find everywhere.If its not, its likely not worth finding a replacement battery.

author: wasedadoc
author_rank: Super Contributor
timestamp: July 27, 2023, 07:31:17 am
content: Quote from: thm_w on July 26, 2023, 11:16:50 pmYou missed the OP's "without a battery" bit".

author: thm_w
author_rank: Super Contributor
timestamp: July 27, 2023, 09:14:42 pm
content: Quote from: wasedadoc on July 27, 2023, 07:31:17 amMeasure the empty cavity of the case.
AD Safety Capacitor replacement in vacuum  - Page 1
Forum section: electronics / repair

author: Sebzy
author_rank: Contributor
timestamp: September 23, 2020, 03:08:11 pm
content: Out trying to find a replacement capacitor for my vacuum here but there's something strange so I thought to ask.The marking on the box type safety capacitor showsAD 0.22uF K X2WEX GPF 40/085/21/C25oV~ 275V~EN60384-14I can see on the bottom of the potted package a 1M 5% resistor. Do all X2 safety capacitors have an integrated resistor?Safe to replace with an off the shelf .22uF X2?Thanks

author: Gyro
author_rank: Super Contributor
timestamp: September 23, 2020, 03:23:44 pm
content: Damn, I though from the title that this was going to be some sort of exciting exercise!No, X capacitors don't automatically include discharge resistors. The need depends where the capacitor is wired in the circuit - if it is wired directly across the motor (after the mains switch) then it can be a standard X2. If it is before the switch and directly across the mains plug then, yes it does. The aim here is not to give the user a shock across the pins of the plug.If necessary, you can just wire a 1M resistor across the capacitor pins. Just check that the element limiting voltage is high enough in the datasheet.

author: Sebzy
author_rank: Contributor
timestamp: September 23, 2020, 03:30:56 pm
content: Ah yes nothing excitingWas wired across the mains. Thanks

author: Cerebus
author_rank: Super Contributor
timestamp: September 23, 2020, 09:03:09 pm
content: Quote from: Gyro on September 23, 2020, 03:23:44 pmI too am deeply disappointed.As compensation perhaps the O.P. can replace the capacitor while tightrope walking, vacuum cleaner in one hand, soldering iron in the other, a RIFA X2 capacitor clamped between their teeth.
Adafruit Grand Central M4 Repair - Page 1
Forum section: electronics / repair

author: sausage
author_rank: Regular Contributor
timestamp: December 01, 2021, 09:32:26 pm
content: Wanted to share about my latest repair. This was an Adafruit Grand Central M4 pcb that turned out to have a badly placed MOSFET by the pick and place machine.https://blog.waynejohnson.net/doku.php/repairing_adafruit_grand_central
Adapting an ZD-985 Desoldering Gun for the Hakko FX-888D? - Page 1
Forum section: electronics / repair

author: Paul3854
author_rank: Newbie
timestamp: January 11, 2024, 12:33:27 pm
content: I wonder if it is possible to adapt the 88-552A Desoldering Gun used for the ZD-985 Desoldering Station.I understand the ZD-985 is a clone of the Hakko 817 and 407 which use thermistors.Reading this forum post about the ZD-985https://www.eevblog.com/forum/reviews/zd-985-desoldering-station-cross-compatibility/Someone linked a Greek forum of a DIY desoldering station using the 88-552A gun which they noted down 1.5 to 35 ohms across the thermistor pinshttp://www.hlektronika.gr/forum/showthread.php?t=70303Someone also on Autodesk Instructables attempted to adapt an 88-552A gun with Xtronic 9020 but ran into issues that the Xtronic 9020 uses an iron with a thermocouple, which led to the large resistance difference between the iron the the desoldering gunhttps://www.instructables.com/Soldering-to-Desoldering-Station-Hack/Since the ZD-985 is just a clone of the Hakko 472 and 817 gun, I found this forum post discussing the resistance of the thermistor "54 ohms at 23C"https://www.eevblog.com/forum/repair/hakko-472-desoldering-pump-adding-a-aoyue-b1002a-desoldering-gun/For the Hakko FX-888D, I found this eevblog forum where someone shared that the manual claims "between 43 and 58 Ohms"https://www.eevblog.com/forum/projects/what-is-the-resistance-of-the-hakko-fx-888d-thermistorheater-at-higher-temps/However also in the discussion, is stated that the sensor is just the same as the Hakko 936, with the link to this lovely post with a table, and based on the trend should be around 50 ohms for 23Chttps://www.eevblog.com/forum/reviews/genuine-vs-fake-hakko-936-ceramic-heater-a1321/25/Now for the elephant in the room, the voltage and power disparity.The 88-522A desoldering gun is 24VAC 80W, however, the Hakko FX-888D for some odd reason is a distinctive 26VAC 65W.I understand with the higher voltage, since the heater element is just like a resistor would draw more current, but should not overheat as it is limited to 65W?I have found researching desoldering stations that use 27VAC like the ML-859, but cannot find just the gun tool for sale. The Yihua 948 seems to be also 27VAC, however, uses a thermocouple, based on an Amazon review I read of a buyer using it to adapt to an AOYUE station. Hakko has desoldering stations rated for 29V however the gun itself is over $300 and would assume uses a thermocouple as well as Hakko stopped using thermistors in their desoldering guns.Obviously, with a 12-24V mini vacuum pump that claims -80kpa which is around 600 mm HG, the same as the other ZD desoldering station, the ZD-915.While the Hakko FR-301 desoldering gun is heavily recommended, I am not too fond of the pump within the gun, and all Hakko desoldering stations are extremely expensive. I have tried the ZD-915, but it really sucked (not literally).
ADC hybrid for 3456A (U500) I want to try to blow 98k19 resistor inside - Page 1
Forum section: electronics / repair

author: velik_kazakov
author_rank: Regular Contributor
timestamp: September 29, 2020, 10:17:30 am
content: Hi guys,I continue to work on one of my HP 3456A. It have a problem with one of the resistors inside U500 (98k19 from the ADC part of the chip). It is more 102K and I want to ask - can I try to blow resistor inside the chip. I have good foil resistor 98k2 and if I blow inside resistor I can to solder externel one. All other resistors inside the chip are good.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 29, 2020, 10:35:35 am
content: Never heard of this one, you know if you try to blow it you can make more damadge ?? be prepared to find this part ...The problem is with the resistance value, no low voltages will be able to burn it, unless you are able to grind the part casing and try to cut a trace in it ??I dont know this u500 ic, can you try to adjust it with an resitor in parallel, if you are able to measure it it should be doable with a low tempco precision value

author: Kleinstein
author_rank: Super Contributor
timestamp: September 29, 2020, 10:42:45 am
content: Blowing a 100 K resistor is difficult and it may do more damage than good. One may be able to increase it's resistance by hard to be sure it would be reliably in the GOhms range. The residue would be still in parallel to where it should be.As far as I see U500, the 98.19 K resistor is at pin 15, toward the 12 V reference. So one could just interrupt the link outside of the chip, e.g. bend away pin 15 or cut a trace on the board. That would be much easier and lower risk than blowing the actual resistor.

author: velik_kazakov
author_rank: Regular Contributor
timestamp: September 29, 2020, 11:44:03 am
content: yes, but it have a connection inside from pin 15 to pin 16 via 100k. First I think to disconcet pin 15 and to add 2 externel resistors from 12v to pin 16 and pin 9 , but internal will stay conected ~ 200k betwin pin 9 and pin 16. Thats is the reason I ask can I blow internal one. will try with external parrale ~ 6Mohm to solder in parallel to 98.19, but can't find good resistor with this nominal.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 29, 2020, 12:24:50 pm
content: With another 100 K connected to pin 15, it would be nearly impossible to electrically burn the 98.2 K and keep the 100 K intact. So some 6 M in parallel is probably the only option. With the extra resistor much larger than the 102 K inside it does not have to be as stable - the TC and drift may be up to 60 times higher. So no need for 1 ppm/K performance, but 50 ppm/K would be good enough to still be at the 1ppm/K level for the combined resistance. Because of the odd value I would expect some 2 - 4 resistors in series.

author: velik_kazakov
author_rank: Regular Contributor
timestamp: September 29, 2020, 12:32:09 pm
content: Thanks!Now it work this way with external resistor, but it need to be very strange nominal. Will kepp this way and to solder some series resistor to adjust the exact value.
Add 1E1 1E5 Option for 83712A signal generator and update to 83712B - Page 1
Forum section: electronics / repair

author: wldshy
author_rank: Contributor
timestamp: August 26, 2025, 06:14:14 pm
content: @_wldshy_OCXO Connector1. +15V OVEN+2. -15V OVEN-3. +2.5V OVEN MON4. NC5. GND6. +12V（Controlled by Program）
Odd tarnish or lacquer on rectifier diodes - Page 1
Forum section: electronics / repair

author: klausman
author_rank: Regular Contributor
timestamp: February 21, 2025, 10:15:33 am
content: I am still working on the Sony TA-FB930R and I spotted something in the power supply. The bridge rectifier diodes (30DF2-FC) hav some odd flaking lacquer or tarnish on their legs:In contrast to those photos, to the naked eye it looks more like a coating that went missing.The question I have: should I try and remove all of it? leave it be? Add clear coat? At the moment they are working fine, but I don't want to revise the rest of the amp and leave a timebomb sitting.

author: bigendian
author_rank: Regular Contributor
timestamp: February 21, 2025, 10:25:56 am
content: Live it as is, is some oxidation but the diode should work anyway properly. In case, re-do fresh solderings below.

author: Gyro
author_rank: Super Contributor
timestamp: February 21, 2025, 07:13:33 pm
content: Quite a lot of axial lead rectifier diodes have Silver plated leads. It's black silver tarnish, which shouldn't extend under the solder (Silver wets very well).
Addendum to my initial post on tv transformer - Page 1
Forum section: electronics / repair

author: ewcc
author_rank: Contributor
timestamp: December 07, 2020, 08:00:03 am
content: Hi,I would like to thank MarkF for outlining the possible points of failure on this JVC tv power board. I had spent about six months waiting for different parts and attempting to fix this JVC tv power board.After so long, I *FINALLY* fixed the TV. (My very first TV fix!! whoot!)The issues were along the lines of what MarkF wrote.1) A ceramic capacitor was blown (this was the first thing I replaced)2) The Bridge Rectifier was dead. (2nd thing I had to replace)3) I had also replaced a mosfet of some sort. (That probably wasn't the problem)After all three were replaced, I tested the voltages on the dc standby output. Still got zero.After doing some testing, I came to this green bulgy component. After searching hard, I foundit was a LittleFuse fuse CD102 (or was it a 120?) Now my understanding of fuses then wasthat if I tested continuity, it would beep. If it didn't beep, it was busted. However, whenI tested this 'fuse', it wasn't continuous.. but it had resistance. Looking up the datasheetfor this particular part, it was supposed to be about 1k ohm (memory is now hazy... forsome reasons the word 'nf' popped into my mind... capacitance?? ) but when I took it outof the board, it was tested for around 2M. Clearly something was amiss.I ordered it online and when it came in, I replaced it. And was completely floored whenthe DC standby 5v was there!After popping it back into the TV, the TV worked!Of course... after fixing the TV... all the analogue channels that mattered no longer worked as they (the government) had switched off the analogue reception for local TV broadcasters. So I still had to shell out for a Digital TV box. I had hoped to figure out how to take this non-digital TV and make it digital. But.. that was *WAY* too over my head. So I relented and bought the tv box. ;/Thanks for all the help!Ed