hybridfree/eevblog-posts huggingface dataset:
RS232 cable, it’s always complicated. - Page 1
Forum section: electronics / repair

author: GGMM
author_rank: Frequent Contributor
timestamp: March 19, 2023, 08:14:51 pm
content: Hello,Now my Oscilloscope Yokogawa is working, i tried to connect its RS232 DB 9 pins on my PC to work with with some softwareI had a cable on A...x that I liked because it ended with a male RS232 plug and had, it seems to me, a female-female adapter.https://www.aliexpress.com/item/32708918256.html?spm=a2g0o.productlist.main.1.15bf62caD2RVTY&algo_pvid=98371c0b-379d-41d0-978d-53bc381df108&algo_exp_id=98371c0b-379d-41d0-978d-53bc381df108-0&pdp_ext_f=%7B%22sku_id%22%3A%2263745466606%22%7D&pdp_npi=3%40dis%21EUR%213.37%213.37%21%21%21%21%21%40212272e216792563159755975d071b%2163745466606%21sea%21FR%213599008081&curPageLogUid=4PTAxk0ranMEI thought, well, I’ll be able to connect either directly to a female DB9, or a male DB9 with the adapter.But it doesn’t seem to work....The adapter seems to be wire. ie 1 to 1, 2 to 2, etc.So I wondered if this can work knowing that at least 2 and 3 should be crossed?According to this sitehttps://radio.pagesperso-orange.fr/RS232.htmThe female adapter should be at the best connected like:5-54- 6.13-32-31.6-48-77-89 NCOtherwise it is recognized on the CH340 USB port on windows. But NO connexionYour ideascdt

author: Swake
author_rank: Frequent Contributor
timestamp: March 19, 2023, 09:49:18 pm
content: Yep, you wrote it:Tx to RxRx to TxIf both sides are DB9 the 2 goes to 3 and 3 goes to 2. It is actually simpleIf you don't want to splice up your new cable you might want to acquire a "null-modem" adapter or cable.Have a look at this:https://en.wikipedia.org/wiki/Null_modem

author: rhb
author_rank: Super Contributor
timestamp: March 19, 2023, 11:41:39 pm
content: Back when I was in grad school 35 years ago and needed to connect a lot of stuff via RS-232, I made a cable which has 2 red-green leds and a double pole double throw switch to reverse the connection. It just requires flipping the switch until both leds are green and xon/xoff works. I used it as test cable and once I determined what type I needed I made one up. It's just 2, 3 & 7, so not much soldering. I kept a toolkit with a small vise, iron, etc. It's a huge boon when you don't have a manual. I used DB-25s and have a full complement of adapters.

author: GGMM
author_rank: Frequent Contributor
timestamp: March 20, 2023, 07:49:30 am
content: Hi,USB/RS232 cable reminderI was wondering if the chip in the cable is a "smart" fact and capable of automatically detecting the direction of connections.the female adapter is a straight fact.You put the cable directly without adapter (you have a USB / RS232 male DB9), you add the adapter (simple straight F/Female 9 pin connector) you have a cable with a USB / RS232 female DB9.The circuit then manages the direction of the wires. (?)I think it’s possible.I’ll dig into that.

author: GGMM
author_rank: Frequent Contributor
timestamp: March 20, 2023, 10:53:56 am
content: hi,it's good with an old adaptator.Subject to be close
RTB2002 Repair/Diagnose - Page 1
Forum section: electronics / repair

author: CrazyTiger
author_rank: Regular Contributor
timestamp: April 26, 2020, 01:44:26 am
content: Hi,I got this RTB2002 70MHz version from a local university, apparently, it was found faulty. My initial response in the back of my mind was "jackpot, I am getting something free possibly with a busted fronted from misuse, simple repair".What I got was totally a different case. First, check I found the unit was looking new, no scratches boots normally. However, the trace is full of noise on both channels.Here is a snapshot with the unit measuring 10MHz output from its own aux output.On very rare occasions, the unit works ok for a few seconds, clean signal, no noise.What I have eliminated so far:0. Self-Alignment passed with no error, though the noise is still there.1. Frontend input section, they look and measure identical on both channels, the input impedance is measuring 1MOhm and the multimeter function measures spot on.2. Trigger section looks good and the counter is measuring spot on, so I believe that is also ok.3. Due to the nature of the failure being intermittent, I suspected maybe the 10 bit ADC chip is not soldered properly, so the entire board went into a reflow oven as well.4. I have checked all the local dc-dc converters, they measuring correctly, I am yet to check the noise on the local supply though. need an isolated scope for that.5. LMK04816 was found to be running hotter than all the chips, replaced that. This chip is providing the necessary clock out to both the ADC Chip and ACQ FPGA I believe, The chip is still running hot after replacement, will have to look deeper into the section.So far, I have made zero progressNext up, what I will be looking into:1. The section of the board from the differential output to the ADC chip.2. Measure ripple/noise of the local supplies, there are tonnes of these.Any other Idea on what else I can look into?More pictures coming

author: goaty
author_rank: Regular Contributor
timestamp: April 26, 2020, 06:07:56 am
content: Maby ram issue or fpga.Also if test pass, maby displaying only related ( copied ram content from acq to display processor)Need schematic 😁
Rtm2024 Display  - Page 1
Forum section: electronics / repair

author: Xyphro
author_rank: Regular Contributor
timestamp: November 16, 2021, 04:39:45 pm
content: Hi!I am going to get a rtm2024 with broken display. While waiting for it I'd already like to order a replacement display.Does anybody know which display I need to look for or have inside photos of RTM2000 series scope to identify some details?Best regards,Kai

author: Xyphro
author_rank: Regular Contributor
timestamp: November 23, 2021, 04:41:58 pm
content: In case anybody else comes accross the same question - see attachment.
RTO1000 mainboard & Fronted board interface and programming - Page 1
Forum section: electronics / repair

author: myhobo
author_rank: Regular Contributor
timestamp: February 14, 2020, 04:09:55 pm
content: This is the RTO1024 oscilloscope main board and signal acquisition board. At present, the program on the main board is broken. I don't know if it can be programmed through JTAG.

author: myhobo
author_rank: Regular Contributor
timestamp: February 14, 2020, 04:11:47 pm
content: the fronted board
RTV162 versus ASI388 - Page 1
Forum section: electronics / repair

author: dnessett
author_rank: Regular Contributor
timestamp: January 24, 2020, 11:43:10 pm
content: I searched the forum for information on both these adhesives and got no hits. Does anyone know the pros/cons of using either of these to attach new electronic components on old circuit boards? In particular I want to replace electrolytic capacitors on an old HP device (HP11729C). The original capacitors have 3 leads, one of which was to control mechanical movement. The new capacitors only have two leads (like normal capacitors) so, I thought I would put a ring of sealant around the base of the capacitor and attach them to the existing PC board.My understanding is I should use an electronics grade adhesive. Both RTV162 and ASI388 are advertised as such, but RTV162 costs ~$28 (US), while ASI 388 costs ~$8 (US). Obviously, if ASI388 has no disadvantages, I would use it. But, the cost difference may arise because ASI388 is inferior. Anyone have experience with it?
RTX 3060 12GB OCR ScreenArtefacts - Page 1
Forum section: electronics / repair

author: XxMandragoraxX
author_rank: Contributor
timestamp: January 30, 2025, 08:41:31 am
content: Hello, I have a problem with my GPU and when I moved house, I packed up the computer and when I went to turn it on I found artifacts on my screen.I assumed it was the GPU so I tried changing it for another one and indeed that is the fault.The question is if you know what this failure could be due to, I understand that it was due to a hit during transport or something like that, but I would like to rescue this graph if possible since it works very well for the use I give it.It is an RTX 3060 12GB OCR. Do you have any idea where the error could be?

author: squadchannel
author_rank: Frequent Contributor
timestamp: January 30, 2025, 09:15:58 am
content: It is definitely a BGA's solder ball crack. It is probably repairable by reflowing, but it would require extensive equipment to be done.

author: XxMandragoraxX
author_rank: Contributor
timestamp: January 30, 2025, 11:41:34 am
content: I thought it was the memoir, could it be made with a heat gun?

author: Haenk
author_rank: Super Contributor
timestamp: January 30, 2025, 02:46:38 pm
content: It might be the GPU chip, or one or more memory chips, due to the severance I'd guess it's the GPU itself. Likely the PC got bumped, the heatsink bumped the chip.Only a pro could fix that (desolder, reball, solder); heatgunning or oven might fix it for a very short time, but I doubt it.The 3060 is likely cheaper to buy new (used) than the labour cost to fix it.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: January 30, 2025, 02:53:57 pm
content: your error is the same as this

author: parawizard
author_rank: Regular Contributor
timestamp: January 31, 2025, 03:52:59 am
content: Not easy rework work to do. You can use MATS utility to try and figure what memory bank is bad. You have to then know the memory bank layout of the board. You will have to try replacing those chips. If not those you would need to rework the GPU itself. Check out Northwest repair on YouTube. I'm not sure what he charges.

author: XxMandragoraxX
author_rank: Contributor
timestamp: January 31, 2025, 07:22:11 am
content: very useful, thanks for sharing this video. Let's see if I can repair it. I will update the repair in the forum to see if I am successful!!
Ruark Vita Audio R1 Mk4 processor repair and remote control IR codes - Page 1
Forum section: electronics / repair

author: rh100605
author_rank: Regular Contributor
timestamp: July 30, 2025, 04:49:34 pm
content: This post describes how I replaced the Arm M0+ processor in a Ruark Audio R1 Mk4 DAB/FM and Bluetooth radio.As an aside it includes the Infrared remote control Hex codesA 3.3 volt regulator failed applying 5 volts to the Infineon S6E1C1 Arm M0+ processor that manages the radio.The processor flash contains the boot loader code so when I replaced the processor it did not self configure to read the external flash memory.I considered writing a short boot loader and loading it via the SWD port but the boot loader also manages USB updating of the external flash memory.The code is specific to Ruark not as in radios with a DAB module such a the FS series from Frontier Silicon, generic to a processor such as the Chorus3I chickened out and copied the boot loader from another R1 Mk4 radio using a Jlink EDU SWD probe and the Segger program Ozone.Then I flashed it to the new processor using the Segger Flash Lite program . This proved to be a low cost very fast solution.Attached is the bootloader code and the Ruark R1mk4 flash binary ( RED dot).I found debugging the radio faster if I used a remote control so I discovered the NEC1 protocol codes which are listed below.The device code always starts with 0x00E7For example Power is 0x00E701 which, in decimal, would be the code used in the free application RMIR to program a Contour One for all URC1210remote as a Ruark R1 MK4 remote.Power 01+ 00= 09==> 15<== 0A>ll 0C also selectMenu 0DSource 16PR1 0EPR2 14PR3 06PR4 08
Bose AWRCC5 CD problems, failure to start up and DAB module firmware update CD - Page 1
Forum section: electronics / repair

author: rh100605
author_rank: Regular Contributor
timestamp: July 30, 2025, 04:21:49 pm
content: The Bose AWRCC5 and AWRCC6 are AM FM radios with a good sound and use a well made CD player that rarely fails but the aluminum electrolytics do.The DAB module ( 2 models one with mains switch and one without) uses the external BoseLink connection and needs a firmware update to be loaded to the AWRCC5/6 to operate.DAB+ is not available. Both firmware CD images are attached below. Using a binary editor it is hard to tell the difference!Make a CD with the firmware update as the only file and then load the CD into the AWRCC5/6 without the DAB module attached. Wait until CD ejects under software control. Attach DAB module, then push AM/FM on the remote until you see Boselink illuminates on the display.The AWRCC5/6 circuit boards use a lot of Aluminum surface mount electrolytics with values between 10 mfd and 220 mfd many of which are inside screening cans or next to power integrated circuits such a voltage regulators, Processor or CD motor driver that use the PCB as a heat sink.Thus many of these capacitors have short life and go high AC impedance or fail entirely.AWRCC5/6 symptoms include waiting for ever to initialize, CD reading unreliable, CD ejection and loading unreliable.I have found that the smaller value electrolytics such as 1 mfd and 0.47 mfd on the larger main board, do not fail. Despite pureists insisting that all capacitors should be replaced.I photographed the board so I knew all the values and polarity positions. See photo attachedReplacing the capacitors on the smaller CD pcb normally suffices. I grip them with wire cutters and twist them back and forth until the wires to the solder tabs fail. Then using flux and solder wick remove the two solder tabs left on the board.I purchased replacements from Digikey and chose Nichicon 105 degC 5000 hour capacitors . Sometimes I had to use the next physical size up which just fit or even the next voltage rating up.This is expensive but should last a long time.Another failure mode is that when testing the radio, with the top removed, it is very easy to move the CD such that the earthed metalwork touches the heat sink tab of two power transistors ( Fairchild pnp KSA473YTSTUA and npn KSC1173YSTUA pair ) , This results in both transistors failing and no power.
rubber (EPDM) printer sync roller - Page 1
Forum section: electronics / repair

author: zilp
author_rank: Frequent Contributor
timestamp: August 24, 2023, 06:48:21 am
content: I have a laser printer that shifts the image vertically on the page, and I strongly suspect the lack of grip of the sync rollers is responsible.Unfortunately, I can't find a matching replacement part, so ... and suggestions how to either DIY this, or have it custom-made at a reasonable price?It's a bunch of small rubber rollers on a (driven) steel axle, diameter ~ 14 mm, according to the service manual they are made of EPDM, though I guess other materials should work as well.As this is the sync roller, the diameter is very critical to get the right feed speed, so just adding a layer of something grippy unfortunately doesn't work.

author: ch_scr
author_rank: Frequent Contributor
timestamp: August 24, 2023, 02:24:10 pm
content: There are special cleaner products to make the roller in printers grippy again, e.g. "Electrolube RRR250 Rubber Roller Restorer".Would give one of these a try. An actual printer technician might know which one works particulary well (or not), let's hope one chips in.

author: BradC
author_rank: Super Contributor
timestamp: August 24, 2023, 03:37:29 pm
content: Quote from: ch_scr on August 24, 2023, 02:24:10 pmI have a can of that. Has worked wonders on an old A0 DesignJet 750 which is still running.

author: zilp
author_rank: Frequent Contributor
timestamp: August 26, 2023, 10:29:39 am
content: Quote from: BradC on August 24, 2023, 03:37:29 pmAny clue what those rollers are made of?Also, the datasheet that I found for that stuff suggests that it's purely a cleaner!? Like, is this really just paper dust stuck to the rollers rather than a change in the rollers' material?!I guess I am a bit skeptical that these magic tinctures that don't even specify which materials they are supposed to be used on do actually do anything, or if they do do something, that they don't just damage the material even further ... it just smells so snake-oily ...

author: SeanB
author_rank: Super Contributor
timestamp: August 26, 2023, 03:13:58 pm
content: Most of them are a blend of MEK and alcohol, often ethanol. MEK is easy to obtain, and cleans the synthetic neoprene and natural rubber well, though it also does dissolve a lot of plastics. You just as a first attempt can use a cotton bud damped down with methanol or isopropyl alcohol, and rub the rubber surface vigorously, and see if that helps. You will see a black layer on the cotton, but that is normal. Leave to dry before you attempt to put paper through again.

author: zilp
author_rank: Frequent Contributor
timestamp: August 27, 2023, 08:24:05 am
content: Quote from: SeanB on August 26, 2023, 03:13:58 pmThe MSDS for that electrolube stuff lists unspecified alkanes and "3-BUTOXYPROPAN-2-OL", so no ketones, and no ethanol/isopropanol/methanol either.Now, what I could find suggests that EPDM is pretty resistant to (m)ethanol, IPA, and MEK, so I guess it wouldn't hurt to wipe it down with some IPA ... but then, I'd think that paper dust also isn't particularly soluble in IPA, so I'd be surprised if it had any effect!?
Rubber Belt For Printer - Page 1
Forum section: electronics / repair

author: 2X
author_rank: Frequent Contributor
timestamp: June 29, 2024, 07:03:27 pm
content: Hello,I have the below rubber belt from an old printer. Do you know where can I find a belt like this or what characteristis I have to find the same... like the diameter, number of seretions?

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: June 29, 2024, 07:29:52 pm
content: Contact PRB, Projector Recorder Belt Company with all the infomation you did not include they might have one for a ?Jeff

author: Gyro
author_rank: Super Contributor
timestamp: June 29, 2024, 07:41:05 pm
content: Looking at listings on ebay for timing belts (machine not car, look in the Business, office and industrial section), the quoted dimensions are tooth pitch, eg, 2mm, diameter / number of teeth (both are usually stated) and width.P.S. They're also known as synchronous belts.

author: 2X
author_rank: Frequent Contributor
timestamp: June 29, 2024, 08:27:10 pm
content: Quote from: Gyro on June 29, 2024, 07:41:05 pmAlso I found the below:https://in.rsdelivers.com/browse/mechanical-fluid-power-tools/mechanical-power-transmission/belts-pulleys/timing-beltshttps://www.google.com/search?q=timing%20belts%20for%20printer&udm=2&tbs=rimg:CTdIbu0pjozyYSPlDMFM5M52sgIAwAIA2AIA4AIA&hl=el&sa=X&ved=0CCYQuIIBahcKEwjQtOrg0YGHAxUAAAAAHQAAAAAQWw&biw=1920&bih=911&dpr=1Many thanks for your help.
Rubidium Standard repair - Page 1
Forum section: electronics / repair

author: veedub565
author_rank: Frequent Contributor
timestamp: August 26, 2021, 06:48:26 am
content: Hi just looking for some pointers on fixing up a rubidium standard.Quartzlock A10-LPRO. the VCO does not lock, I can see the voltage ramping up and down (on the VCO monitor pin), checking with a frequency counter shows the frequency ramps up and down through 10MHz. So this appears to be functioning normally.The module gets hot, too hot to hold my hand on it, so it looks like the heaters are working.Lamp monitor voltage is 5.07v and this is where I suspect the problem lies. From what I've read healthy lamp voltage is 6-9v.The BIT lamp does not illuminate, so I assume the rubidium is not locking and that iswhy the VCO won't lock either. I did look at this in the dark with the cover off, and I couldn't see any sort of glow from the unit.
Runaway Thermals on an Amplifier - Page 1
Forum section: electronics / repair

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: September 19, 2019, 04:47:34 am
content: Hi all,I've got an issue on this subwoofer/amplifier combo I just recapped. It was causing a noticeable hum at idle, so I replaced all the previous no-name caps with Nichicon Gold Audio Eletrolitics. It was running just fine when I was testing. Now, the two tansistors are running at extreme temperatures on idle. I've troubleshooting and double-checking my cap placements, no luck. I do find this circuit rather odd though because on my -60v and +60v rail they test open circuit, I can test for resistance and it shows they are connected somewhere, however, I attribute this to my meter possibly testing with a high frequency and misinterpreting the isolation transformer. When testing with my LCR meter (DER EE) at 100hz, however, the resistance is in the 100s of megohms. I'm sort of stumped beyond this, because after decapping the main capacitors to see if that was the issue and recapping them after testing, it was not heating up and only drawing 200mA. But, after switching it on and off again, it was back up to drawing .5A.Could this possibly be the transistors gone bad? The thermal camera shows nothing else is really heating up that would tell me there's a fault elsewhere causing this.The trannys are Toshiba 2SA1943 and 2SC5200, with the 1943 appearing to be the hottest.

author: bob91343
author_rank: Super Contributor
timestamp: September 19, 2019, 05:25:34 am
content: Your message is so confusing that I can't figure out what you are doing. Read it again and try rewriting it so as to make sense to someone who knows nothing about your setup.

author: oPossum
author_rank: Super Contributor
timestamp: September 19, 2019, 05:42:33 am
content: The bias may have drifted too high. Measure the voltage between the bases of the output transistors and the driver transistors. And also across the two large emitter resistors.

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: September 19, 2019, 05:44:29 am
content: Hey Bob,Thanks for the reply. Sorry its late here, would explain why it might not make sense. Anyways, to reiterate on the issue, basically, the transistors pictured are being short-circuited (I think) and causing them to reach extreme temperatures. I have done some troubleshooting and nothing seems amiss from my knowledge. This board is the power amplification part of the active subwoofer, meaning it's built into its enclosure. At idle its drawing significant current, as well as heating the heat sink up to sizzling temps.But I think I just found the problem, I used thermal grease for thermal conductivity to the heatsink rather than mica or thermal pads. This was a first to me, but I now know tranies can short out when on the same metal backplate. So far this issue has not occurred when switching to thermal pads.
Runt Pulse on data line - Page 1
Forum section: electronics / repair

author: don.r
author_rank: Frequent Contributor
timestamp: February 08, 2024, 05:24:29 pm
content: I am getting a runt pulse on a data line. Chips involved are 6803MPU, 6521 PIA and 1024x4 static CMOS ram (6514). Aside from swapping to known good devices, how do I narrow it down?EDIT it isn't the RAM because it occurs on all data lines (RAM only occupies first 4).

author: srb1954
author_rank: Super Contributor
timestamp: February 08, 2024, 07:48:39 pm
content: Quote from: don.r on February 08, 2024, 05:24:29 pmPresumably you have an EPROM as well since the 6803 doesn't have internal program memory.Check the outputs of your address decoder to see which device is activated and whether it is a read or a write cycle. This should help determine which device is driving the bus and whether it is a bus contention between the processor and another device during a write cycle or just a weak drive from one of the bus devices during a read cycle.Not all runt pulses on a data bus indicate a real problem; it might just be that nothing is driving the data bus at the time and the lines drift to some intermediate voltage. Put some pull-up resistors, say 10k, on the data bus to see if the runt pulse still appears, indicating that something is still driving the bus.

author: don.r
author_rank: Frequent Contributor
timestamp: February 08, 2024, 08:31:50 pm
content: Yes, there is an EEPROM but it checks out fine. Everything operates as normal save for one of the outputs of the PIA. I may be chasing a ghost with the runt pulse and might have to do some part-swapping. First, I will break out the MDO and check the lines and see what is happening during the runt. It is a highly repeatable event so whatever is causing it is not intermittent.
Russian Cap ID - Page 1
Forum section: electronics / repair

author: Audiorepair
author_rank: Frequent Contributor
timestamp: March 16, 2023, 09:57:34 am
content: Hi,can someone confirm the specs on this cap?My photo translator comes up meaningless.Cheers.

author: RoGeorge
author_rank: Super Contributor
timestamp: March 16, 2023, 10:00:32 am
content: 2000uF/20V

author: SeanB
author_rank: Super Contributor
timestamp: March 16, 2023, 10:11:19 am
content: Made Oct 1961, so very likely now really due for replacement, even if it still actually has roughly the right capacitance, the case is very likely close to corroding through.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 16, 2023, 10:15:38 am
content: The quality of the russian parts varies a lot. Some are junk from the start and some are totally overkill (more like military grade parts) in even more normal circuits.So there is a chance the old capacitor could still outlast a new replacement.

author: wraper
author_rank: Unknown
timestamp: March 16, 2023, 10:20:07 am
content: Do not suggest just changing it. It's not a usual electrolytic cap but quite a special one. It's a glass sealed cap, so it should not lose any electrolyte over time and will probably outlast modern replacement.http://www.155la3.ru/egc.htm

author: Audiorepair
author_rank: Frequent Contributor
timestamp: March 16, 2023, 11:08:00 am
content: There are 3 of them, one is shorted.One reads just over 2000uF, the other 1850uF or so, so I'm leaving those two alone for now.This is a valve microphone power supply.

author: yfayula
author_rank: Newbie
timestamp: March 16, 2023, 09:24:05 pm
content: 2000 microFarad 20Volts
RV Surge protection and AC line analyser  - Page 1
Forum section: electronics / repair

author: Carl E
author_rank: Regular Contributor
timestamp: September 17, 2024, 01:49:34 am
content: I am attempting to repair a surge guard AC line analyzer that was hit with a spike ( I think). Ive replaced all 6 MOVs but cannot get the LED which indicates the protector is working to turn on. There are other LEDs that indicate miss wired or open ground or neutral which work fine. The only difference between between the working LEDs and the non working, is the working LEDs are connected across LI and Neutral and the surge LED is connected from L1 to GND. All LEDs are in series with a 1N4007 and a 220K resistor. The surge LED was destroyed by the surge, Im using a generic LED instead. I tried to change the 220K resistor for the surge LED to 100K and that lights up the LED, but now the circuit trips the GFI when plugged in.Any thoughts ??

author: Kim Christensen
author_rank: Super Contributor
timestamp: September 17, 2024, 04:11:55 am
content: Quote from: Carl E on September 17, 2024, 01:49:34 amWell, you doubled the current between L1 and protective ground. 220K vs 100k @ 120V = 0.54mA vs 1.2mA. I guess it's possible that there was already some leakage and now the extra 0.66mA sets it off.Or possibly, it was a 10K resistor and not a 100K like you thought? (Bad eyes, bad lighting, brain fart)

author: Carl E
author_rank: Regular Contributor
timestamp: September 17, 2024, 12:18:25 pm
content: Thank you for your response.Ive double checked the value as yes, getting old can make colors blurry, measured with a DVM it is 220K. RED, RED, YELLOW, changed to a new resistor, BROWN, BLACK, YELLOW. The LED barely lights, could it be I need a special high output LED if one exists? It also does not trip the GFI so it is possible that I didnt read the resistor correctly. Brain Fart.'Bad eyes, Old age. YUK.

author: Kim Christensen
author_rank: Super Contributor
timestamp: September 17, 2024, 03:30:37 pm
content: If you've pulled a LED from your junk box that's pre-1990 vintage, then yes, just put a new modern LED in there with a 220K. It'll be plenty bright.

author: Carl E
author_rank: Regular Contributor
timestamp: September 18, 2024, 02:04:52 am
content: Thank you
RVS216A Ross video service manual or schematic sought - Page 1
Forum section: electronics / repair

author: minsik
author_rank: Contributor
timestamp: December 19, 2023, 11:58:36 pm
content: Hi looking for a possible service manual for a Ross Video video switcher RVS216A an 16 input analog mixer with effects, fading, wipe etc.Ross Video support forum have helped by providing a package ZIP of related info but no actual cct into. the operation manual does have very basic block diagram stuff.Looking to work on a unit thats quite old and now has a temperature fault when hot and doing a fade it blacked out and needed a reset and a couple of other temperature related faults.Yes i have bought the old freezer spray and have a hot air source (favorite hair dryer) so equipped as well as can be I suppose.Seems I have gone as far as the source and they cant help more than they have done so. This is just a long shot try!I believe was also available in RVS210A 10 input maximum version so that would also be great if I can get the actual schematics.thanks for considering.Minsik.

author: minsik
author_rank: Contributor
timestamp: January 21, 2024, 03:40:17 am
content: thanks top all who read. I now have full original technical manual so all is well.Keeper og the acce4ssories and cables had it with the original user and install manuals in a plastic tub.Can now proceed to repair.MInsik
RX 480 fan/led pcb diagnostics - seeking help - Page 1
Forum section: electronics / repair

author: Cheap Charlie
author_rank: Newbie
timestamp: November 08, 2021, 02:06:00 am
content: I’ve got 2 AMD RX 480 GPUs, recently the fans and logo led stoped functioning one one of the cards.I’ve disassembled both cards and interchanged components to narrow down the source of the issue (fan/led PCB).I’ve pulled out the multimeter probing component. I’ve found some anomalies comparing readings from the known good PCB, I am however at a loss to determine exactly which component is causing the fault.Anomalies:1) resistance between input negative and FAN 2 negative, bad board 0.5, good 29.7.The same readings are achieved at Q1/2/3 across both boards.The traces for the above appear to run back to R7/8/9 respectively.Any advice on where to from here would be appreciated.Note, the PCB at the top of screen (missing coating adjacent fan1 pins) is the faulty PCB.

author: AmnevaR
author_rank: Contributor
timestamp: November 08, 2021, 08:42:49 pm
content: First rule of troubleshooting... Thou shalt check voltages

author: Cheap Charlie
author_rank: Newbie
timestamp: November 09, 2021, 11:50:01 pm
content: Thank you.Where would you recommend I capture voltages at?I’ve replaced a few failed caps and fuses on motherboards over the years, but this one has me a little stumped with the variation in resistance.

author: AmnevaR
author_rank: Contributor
timestamp: November 10, 2021, 09:29:05 pm
content: As I understand the power to this board comes from the pin header on the right (second photo)?I would measured what voltages comes to this pin header and then disconnected the board from graphics card and hook up a power supply to the pin header (with the same voltage and limited current if possible or just use jumper cables to the graphics card at your own risk).And then I would measured what is the voltage in various points on the PCB. I see some voltage regulator 78... something and some 8 pin chip. Look up the datasheet for those parts and check what pins are connected to power, measure them.Or maybe the problem lies somewhere else ... scratched track... cracked resistor?This bloody black solder mask doesn't help either...
RX 480 MOSFET (MDU1511) weird short? - Page 1
Forum section: electronics / repair

author: MPereira
author_rank: Newbie
timestamp: May 01, 2019, 04:48:43 pm
content: Hey guys!I've recently bought a dead RX480. It doesn't have the 12v on the motherboard side shorted, and neither on the PSU side, the fusistors seem to be ok as well. The thing is that all the mosfets on the card are shorted on the Drain and the Source. (All the Gate's seem to be fine) The mosfets are MDU1511 and MDU1514, is this supposed to be normal? The drain shorted to the negative on the card?? There are a lot of smd capacitors that are shorted on the card aswell. I've tried to input 3v on the 12v line of the pci (I know it is an awfull lot) and I couldn't find anything warming up.There is a small burnt area on the graphic card. (Attached pic) And a couple capacitores out of place close to the pci (I suppose these are not the problem, because the graphics card should at least boot on the 8x pci slot).What do you guys think? is the short on the drain supposed to happen? What should I test next? If I have a short should it be present on the input pins?Thanks in advance

author: PKTKS
author_rank: Super Contributor
timestamp: May 01, 2019, 06:00:42 pm
content: Hard to say on loose terms.But VRMs depend exclusively on the supervisor chipsets usedAnd... in all cases (integrated or serial coupled doublers/drivers) theHIGH SIDE and LOW SIDE MOSFETS can not be "shorted"if so they are dead.CAPS can not be shorted as well as if so they will dead short the MOSFETS.But ... along the road .. a damaged GPU will dead short the whole chainRemember ..we are dealing with pure beasts which power up a 100W to 200W/300KHzto 500KHz at least device. Driving low as 1V we have peaks of 100A or in excess of 200A.That will be loosely split in phases ...Enough to fire in flames and build holes.and the only safe way to tell for sure is removing and testing .. evenafter that removing and testing the supervisors - e.g. you remove the chipto test if the shorts are still there, even the PCB layer may be damagedand/or being repaired and faulty againbe safePaul
[SOLVED] RX-V483 - HDMI Output - Weird Image - Page 1
Forum section: electronics / repair

author: Versace_69
author_rank: Newbie
timestamp: September 10, 2022, 03:23:05 am
content: Hello all,Hope everyone is doing good.I am creating this post today because I have a trouble from nowhere with my receiver...My HDMI output is outputing a weird image :I have a PC (HDMI in 1, 4k, 60 fps) + PS4 (HDMI in 2, 1080p) plug in my receiver, then HDMI output to the TV on ARC.I have tried to plug directly my computer to the TV, everything is good.I have tried to switch HDMI cables, same trouble.I have tried to output my PC, through the receiver, to the TV, same trouble.I have tried to output my PS4, through the receiver, to the TV, same trouble.The "normal" ouput is repeated 4 times on top of screen with waves, as you can see above.The rest of the screen is weird...I suspect a faulty component but I don't know a lot about electronics.I have opened the receiver, but I didn't see nothing strange on boards:I have a multimeter, so I can't check some component continuity or resistivity...I have also contacted Yamaha, I'am waiting for an answer from them, but my receiver is old so I don't sure is still under warrantyEverything was working good last time I used it.No over temperature in the room, have an Air Conditionner.Help is welcome.Receiver is a RX-V483.My TV is a Sony XR65X90J.Thank you.BR,Versace_69.

author: phoenixdigital
author_rank: Contributor
timestamp: September 10, 2022, 09:23:14 am
content: Just as a test try dropping the FPS on the PC if you can to see if it's related to high bandwidth.If there is also a setting on the amp for FPS drop that too.

author: Versace_69
author_rank: Newbie
timestamp: September 10, 2022, 06:47:52 pm
content: Hello,Thanks for input, I have found the trouble maker was my power bar... Everything was plug on the same (Subwoofer, Receiver, TV, PS4).When I remove everything on plug directly on the wall plug, and on another wall plug with extension cord, no more trouble...
Rx-v675 ACPWR_DET Low - Page 1
Forum section: electronics / repair

author: mjk52
author_rank: Newbie
timestamp: December 30, 2024, 12:45:15 am
content: Hi,I've been puzzling with this receiver for a while now. Is there a specific IC I should be looking at that generates this acpwr_det voltage?My receiver is showing this voltage as 3.0V instead of 3.3V.After searching here I saw that the 3.3M is not generated from the OP(3) board. Is it the same for ACPWR_DET?Receiver works perfectly fine when I am able to switch it on, but cuts off after a bit of running. I sometimes get a PS3 fault, but not all the time.Thanks in advance.Edit.The voltage readings on the onboard sensors all show within range, the PS1 is not constant, it reads from 114-118PS2 is constant at 120PS3 is constant at 154However on the protect faults. PS3 has an entry showing 95. So it would have been low.After going into no protect to check the voltages and faults, the receiver switches on perfectly fine and runs perfectly fine for a while, then switches off with usually the PS3 fault. I haven't seen anything physically wrong with any of the caps, and have even replaced the usual yamaha caps just in case.The 3.3M voltage is perfect all the time. It's just the acpwr_det that is low.

author: mjk52
author_rank: Newbie
timestamp: January 03, 2025, 08:14:29 am
content: Hi, I've checked ic84, 85 both those regulators are working fine. Outputs are normal, 3.3V.IC83 main processor, pin12 is showing 2.99/3v same as all the other obviously marked acpwr_det points.There's nothing in the schematic that I can see that shows what is generating that acpwr_det voltage. If anybody else has an idea please let me know.The other thing that is now not working is the standby LED. I see no voltage going to it, so I'm not sure if that is also part of yamahas protection.

author: m k
author_rank: Super Contributor
timestamp: January 13, 2025, 10:17:02 am
content: 3.3M is a power source for standby LED and it's generated by IC85.So if IC85 is fine somewhere must be a contact problem.
Ryobi 40V Battery Repair - Page 1
Forum section: electronics / repair

author: AMDFX8150
author_rank: Newbie
timestamp: September 13, 2023, 07:36:30 pm
content: Not sure where to begin with this as I have already figured out what is bricking these batteries, but not as much as to unbrick them. TTI has changed the game on the 40V batteries as you can no longer open them and jump the two pins GND and RST after you have performed your repairs. The new generation of batteries deems themselves permanently faulted by using a host control (NXP-LPC824J) to keep triggering the device_XREADY bit on the actual BMS (Texas Instruments-BQ76930). This scenario is what people are encountering when they "go to use it for the first time this spring and, come to find out my battery is wasted". Once the battery triggers PF state the system will slowly drain the pack over a pair of 750 Ohm resistors until all cells reach zero. The problem at hand is that TTI had enabled CRP on the 824J disabling SWD connectivity. I was able to get into an 824J on a 6AH that failed and pulled pack to 0v, but only after erasing it. This is what tells me CRP is enabled, I have quite a few "failed" packs at my disposal being a 6, 7.5 and a 12 AH. I have been able to preserve the cells by desoldering the 750 Ohm resistors, the 12 is strange in the way it failed as it has not enabled the resistors to pull it down to 0v. I hate when manufacturers pull this kind of thing because these batteries are not even 2 years old and have a lot of life left and just end up in landfills. If anyone has ever gotten them to work again after entering failure state, or knows how to get around CRP please jump on the train and get the word out, this is a huge fist to the face for those who like to fix over replacing.

author: Swake
author_rank: Frequent Contributor
timestamp: September 16, 2023, 12:05:10 pm
content: For Makita batteries there are new PCB's available from the usual Chinese sources. Maybe you can find something similar for the Ryobi batteries.
Ryobi 4v cordless drill not charging ! - Page 1
Forum section: electronics / repair

author: spike47
author_rank: Contributor
timestamp: August 01, 2024, 08:27:18 pm
content: HiSorry not been into electronics for quite awhile so a bit slow !.Have a Ryobi 4v cordless drill, problem not charging, voltage at input 6.2v!, what do I have to check in between ?.have done a schematic, but not sure, if it is the correct way !.cheersSpike

author: spike47
author_rank: Contributor
timestamp: August 01, 2024, 08:39:47 pm
content: Did a test from neg lead onto board and first pin on D1 and getting 6.7v then tested the other side of D1 , no voltage !,

author: IanB
author_rank: Super Contributor
timestamp: August 01, 2024, 08:58:57 pm
content: I'm confused. What is the question? I see pictures where you have taken something to bits. What have you taken to bits?To my knowledge, there have been two generations of Ryobi 4 V tools. The first generation had batteries that use an external charger. The second generation has batteries that charge from a USB port.I do not know of a tool with a built in battery, and I do not know of a tool that has built in charging of a battery.Please give some information to go on. What is the tool model number? What is not charging? Is it the charger, the battery, or...?What is the thing you have disassembled, and what are you looking for?What is the 6.7 V you are describing?If you calm down, take a deep breath, and give careful and logical information, there may be a possibility to help you.

author: eleguy
author_rank: Regular Contributor
timestamp: August 02, 2024, 07:49:05 am
content: Maybe bit rusty "Red cylinder" (=battery) has just seen better days?

author: coromonadalix
author_rank: Super Contributor
timestamp: August 02, 2024, 12:21:45 pm
content: the battery develop a memory effect, and wont charge, time to change ithappened a lot in other similar tool
S.O.S HELP REQUESTED  SONY FH 909R - Page 1
Forum section: electronics / repair

author: reachdeb
author_rank: Newbie
timestamp: September 15, 2023, 07:48:12 pm
content: Hi there all, first of all sincere greetings to you all from Singapore.I am seeking your kind attention, facilitation and guidance.I have a sony FH 909 R system. The system is working fine. But the spectrum analyser display visual, is working somewhat awakward. My knowledge of electronics is limited so my apologies for my apparent ignorance.Here I am. I opened the spectrum analyser display part.I realised there is a green color film that is pasted on the spectrum display part. The film I guess due to age has completely degenerated, thus effecting the spectrum analyser display visual.Can any one please guide me as what is the purpose of the green color film?I tried to use the a normal green color PVC sheet/ green color cellophane sheet. but it did not work.So there I am with great hope to get this issue resolved. Thus highly appreciate your valued guidance & input.Warm regards Deb

author: Swake
author_rank: Frequent Contributor
timestamp: September 16, 2023, 09:01:35 am
content: If it is a LCD then it is polarized film.

author: reachdeb
author_rank: Newbie
timestamp: September 25, 2023, 12:52:34 pm
content: Many thanks. Yes replacing the polarised film the problem stood resolved.

author: Swake
author_rank: Frequent Contributor
timestamp: September 25, 2023, 01:01:32 pm
content: Thanks for the update.
S3V00 DIODE?? LAMBDA JWS75-12iA Switching Power Supply - Page 1
Forum section: electronics / repair

author: daveyk
author_rank: Frequent Contributor
timestamp: September 18, 2020, 06:25:12 pm
content: Okay, I realize the power supply probably isn't worth fixing, but I like to try things because of the challenge.In the primary of the first switching transformer there is a 82uf 470V 105c cap that is basically open. The consequence being the a larger axial thru-hole diode that appears to feed voltage to the transformer is shorted.The only nomenclature on the diode is "S3V00". Maybe that is a TVS3V00? Either way, my googling skills are not good enough to find any data on the diode.Does anyone here know what that diode is? Guessing, I would say maybe 3 watts.My googling skills are not good enough to locate a schematic for the power supply either.I think, for expediency, I will replace the power supply, but I would still love to fix it.Dave
SA Advantest R3132 not working - Page 1
Forum section: electronics / repair

author: fant
author_rank: Contributor
timestamp: January 02, 2022, 09:40:47 am
content: Good morning and good new year.Received a broken spectrum analyzer Advantest R3132 not working.The problems are:1) On boot it shows an error on , but this is easy, as described on other messages;2) No sensitivity on input, as for picture, also there is no peak on 0 Hz frequency, IF bandwidth is working as video bandwidth, frequency setup is working, but no signal on the screen.If I try to calibrate the unit ( SHIFT+7 ) appears the error on the picture "error on calibration"Anybody knows what to do with problem n° 2 and also if anybody has the SERVICE manual (I need the schematic diagrams).I have the user manual, but no schematic on itThank you in advance
Sabaj D5 DAC/AMP Repair - Help me Find this IC! - Page 1
Forum section: electronics / repair

author: FennekoFox
author_rank: Newbie
timestamp: January 17, 2024, 08:36:09 pm
content: Hey everyone, I am currently troubleshooting my Sabaj D5 DAC and Amp that I have been using at work for the last 5 or so years. One day I go to the lab with the audio working when I leave and when I get back to my desk nothing.D5 outside of extruded caseBackground: The unit powers up the display and control functions work and the pre amps output audio but the headphone outs don't function. After some basic troubleshooting steps I find that the 9V power rail that feeds some small IC's at the end of the signal path has no voltage. Between those IC's and the 9V rail is a diode I get 1K resistance to ground on the regulator side and a short to ground on the IC side indicating at least one of the IC's have failed. Below you can see that only these three IC's are connected to that power rail and at least one of them is bad.9V rail (x-ray)Headphone Connections (x-ray)Now to my problem I cant seem to source this part... I am assuming that this IC is a pair of SPST analog switches but I cant find the part number referenced anywhere. The IC's are marked 48088/1851U and its a rectangular QFN style package with dimensions of 2.75mm x 1.9mm. I have determined most of the pad functions below and was hoping that someone may be able to help me source this part or at least get me some more info on it. I believe the package is called a 16-UFQFN but I mostly work with bare die so I am not too familiar with QFN package variations.Worse case I will just de-solder all three IC's and then just bridge the signals to the XLR port as I don't really use the 6.35 jack anyway but I would like to avoid a janky solution is possible.IC to be replacedIC to be Replaced (x-ray)

author: coromonadalix
author_rank: Super Contributor
timestamp: January 18, 2024, 03:04:58 am
content: it as ESS ES9038Pro DAC as the audio DAC processor, and its output are differentialnow theses ic must be differential amplifiers ... since we see balanced pcb tracesmm ok it seem OPA1612 would be the small soic8 ic's ?? but the amplifiers

author: fzabkar
author_rank: Super Contributor
timestamp: January 18, 2024, 03:45:20 am
content: https://web.archive.org/web/20210515024128/https://www.esstech.com/wp-content/uploads/2021/03/ES9038PRO-Datasheet-v3.7.pdfSGM4808B, SGMicro, Wide Power Supply Range Audio Click-Pop Noise Eliminator, 2.7V - 12V, 1 ohm, TQFN-2.6×1.8-16L:https://www.sg-micro.com/uploads/soft/20220614/1655179841.pdf

author: FennekoFox
author_rank: Newbie
timestamp: January 18, 2024, 04:44:06 pm
content: Quote from: fzabkar on January 18, 2024, 03:45:20 amThis is exactly the part thanks for your help on this. How did you end up finding it, I am always looking to improve my methods.

author: fzabkar
author_rank: Super Contributor
timestamp: January 18, 2024, 05:32:00 pm
content: https://ipv4.google.com/search?q=filetype%3Adoc+OR+filetype%3Apdf+%22absolute+maximum%22+4808BI use "absolute maximum" to filter out spammy web sites.