hybridfree/eevblog-posts huggingface dataset:
Tig 200p AC/DC welder schematics  - Page 1
Forum section: electronics / repair

author: CHIPHEAD
author_rank: Newbie
timestamp: December 15, 2023, 05:26:37 pm
content: Good dayIs there someone that can help me with schematics for my Chinese Tig 200p ac/dc welder.I have attached photos of my welder.Thanks

author: robby60259
author_rank: Newbie
timestamp: December 16, 2023, 03:27:34 am
content: Hello, What seems to be the problem? I don't have the schematics for the unit, but take the cover off I'm sure many people would like see how its put together.

author: Zenith
author_rank: Frequent Contributor
timestamp: December 16, 2023, 03:50:05 pm
content: I think you'll find it's one of a number of generic Chinese designs for AC/DC TIG welders, and the name Trident doesn't mean that much. There are circuit diagrams for such things on the WWW and apart from Google, tryhttps://valvol.xyz/index.php. It's navigable using a web translator but hard work. I've found welder documentation I've been looking for on that site in the past. You may not find documentation that matches the unit you have exactly.It's been a few years since I've had anything to do with welding machines, but generic Chinese TIG welders were notorious. Great while they last, but very likely to go wrong and when they do, difficult or expensive to fix. I've seen a few tear down videos of them, and no corner was left uncut. There were a few sites selling spare boards.Even with mainstream welder manufacturers, where technical documentation can be found, they strongly encourage board swaps, rather than component level repair.
Tiger Hotpot - Page 1
Forum section: electronics / repair

author: Truk
author_rank: Newbie
timestamp: June 01, 2025, 10:14:55 am
content: I am trying to fix an older Tiger Hotpot 208. I cannot find any data sheets on a Panasonic MIP290 or a SANREX T2DQ6F2. I suspect the MIP290 is a buck converter controller. It is in an 8 pin DIP with one pin missing. The usual data sheet websites only provide a 2009 catalog for the MIP209 which only has the part number in it. The Sanrex is in a TO-220 package. Relays are used to control the heater and the drain motor so I do not think it is a MOSFET.

author: Whales
author_rank: Super Contributor
timestamp: June 01, 2025, 11:03:13 am
content: Looks like the MIP* are a series of switchmode controllers:I was able to find a datasheet for one of its siblings (see attached). Looks like a peak current mode controller for offline (rectified mains) use with an integrated mosfet and current sensing.I suspect (but don't know for certain) that the sibling parts with slightly different numbers have different current limits (ie different voltages going to the negative terminal at the comparator at the top right). This is a very pincount reduced part that does not expose this for the PCB designer to tinker with, so they'd have to supply different chip variants to make everyone happy.Your MIP290 will probably be used to drive a transformer that supplies a small voltage rail (12V? 5V?) for the rest of the ICs in the device to use. If the voltage rails are all fine then this chip isn't your problem.

author: Whales
author_rank: Super Contributor
timestamp: June 01, 2025, 11:10:30 am
content: If your SANREX part is a TO-220 that switches mains AC voltages directly then it's probably a thyristor, TRIAC, SCR or similar.A potentially similar part:https://www.sanrex.com/wp-content/uploads/2015/03/TMG2DQ60C.pdf

author: Whales
author_rank: Super Contributor
timestamp: June 01, 2025, 11:27:40 am
content: I'll add that your hotpot's logic board is likely NOT safely isolated. It might only look like it's running on 5VDC, but that might be 5VDC + 240V. Assume every party of it is live and dangerous until you can prove otherwise. Circuit "ground", heatsinks and metal transistor tabs could all be dangerous.
TiVo Bolt: Adding external storage - Page 1
Forum section: electronics / repair

author: iXod
author_rank: Frequent Contributor
timestamp: June 06, 2021, 06:13:30 pm
content: I have 2 identical TiVo Bolt DVRs, one with lifetime service plan, the other--not so much. Both have identical OS versions, recently downloaded & updated.So I'm cannibalizing one for parts. I'm taking the perfectly good internal 2.5-inch HD (500 GB) from one to use as the external, add-on drive for the other. The internal drive cable (a "Y" cable with SATA and mini HD power connectors) isn't appropriate for the external drive ports (eSATA and USB-A). So I go to Amazon and get this:https://www.amazon.com/gp/product/B01E3G4W5K/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1Perfect, right?So I plug in the drive using the new cable, power up the TiVo, go to the storage menu and see "This device is not supported". Huh.I search a little and find that I "might have to get a specific external HD cable" from TiVo.My question: What the heck could be the difference between this cable and anything TiVo could offer? I've searched endlessly and found no information on the TiVo external (sometimes called "extender") cable.Any ideas?Thanks.

author: dc101
author_rank: Regular Contributor
timestamp: June 07, 2021, 02:34:47 am
content: It's very possible it has nothing to do with the cable, but rather the drive that is connected. My guess would be it's looking for specific hardware id's. A little google search implies that the external storage only works with the official TiVo "DVR Expander", which of course is no longer manufactured.https://tivoidp.tivo.com/tivoCommunitySupport/s/article/My-Book-DVR-Expander-FAQGotta love planned obsolescence. Good luck.If you have access to the firmware, it would be an interesting project to see what exactly TiVo is looking for from an external drive.Edit: Found this forum post that pretty confirms what I was thinking.https://www.bestbuy.com/site/questions/tivo-bolt-ota-1tb-dvr-streaming-player-black/6293218/question/6278885b-7b59-34d2-9ffb-b1ee9e2ca9e3Cheers-Tim
TiVo Roamio Inconsistent Booting - Page 1
Forum section: electronics / repair

author: Bones558
author_rank: Contributor
timestamp: July 12, 2023, 12:01:32 am
content: I have a TiVo Roamio (TCD848000) that does not always boot (POST) when it is plugged in.It's completely random. Sometimes when I plug it in, it will boot normally. Other times I just hear the fan but no lights (besides the power light) and nothing on the screen.If I unplug and replug the power in and out of it, with a bit of a delay in-between, I can get it to boot at some point.It's fine as long as it keeps power to it.I've tried swapping power supplies with two know-good ones, but that did not help, so problem must be located on the motherboard I'm guessing.Any idea what could be the cause of this based on behavior and general electronics components?Looking for ideas of where to start diagnosis of the motherboard components.I've attached pictures of the motherboard.Thanks!

author: Bones558
author_rank: Contributor
timestamp: July 12, 2023, 12:02:18 am
content: (Closeup photos)

author: m k
author_rank: Super Contributor
timestamp: July 18, 2023, 04:30:26 pm
content: Single 12V power means that there are others later.You can start checking that those other voltages are present.Keep in mind that different position of same lower voltage can be from different source.
TL866 II Plus Self-Check Error - Page 1
Forum section: electronics / repair

author: patolog1964
author_rank: Newbie
timestamp: October 03, 2021, 09:45:19 am
content: I have got a XGEcu Minipro TL866II Plus programmer with the latest software and firmware from XGecu website. It was working perfectly but couple of days ago, I started experiencing problems with the programmer. It showed messages of IC short circuit / over-current messages. When I did self-check from the test menu, I found an Error called "VCC ERROR:. I have attached the screenshot for the same. I need help to fix the issue.Can someone explain me how can i possibly repair this or am i scre*ed?Should i check some pinout traces if its HW problem or is problem with SW?Iˇve tried switching OS to 32 bit,no issue.¨Thanks for any advice,would be grateful for any tips.Iˇve uploaded screenshot of that error down below.

author: drakepirate
author_rank: Newbie
timestamp: March 08, 2023, 05:00:08 am
content: Got similar Error on my TL866II+.Let me know if you solved it Please...Thanks.

author: Yhoni
author_rank: Newbie
timestamp: April 03, 2023, 11:06:43 pm
content: Hello friends, I have the same problem.Anyone could fix it??Could you share it, please?

author: m k
author_rank: Super Contributor
timestamp: April 08, 2023, 02:19:50 pm
content: Go back to earlier firmware and try USB port where it has never been.
TL866 Won't Erase or Program W49F002U - Page 1
Forum section: electronics / repair

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: May 17, 2023, 04:17:00 am
content: I'm trying to flash the BIOS of an old ECS computer because I need XP to work with some old software.The computer booted up with an AMD 1400 just fine.After I swapped the CPU for a 2000, it rebooted again just fine.After accessing the BIOS to set the CPU multiplier clock, I got as far as entering the BIOS screen.It then locked up. Yes the CPU is supported, and rebooting resulted in nothing.Swapping the CPU back, the computer beeps, and results in no video on the monitor.Resetting the BIOS did nothing.Looking at the manual it will default to a PCI video card. Out with the AGP, in with the PCI card.The monitor says wrong resolution for any PCI card I use.Now to the bigger issue. The flash chip is a DIP 32 so direct plugin to the TL866 ver. 6.85.The original file was 2 years older and I wanted to update it.I read and saved the original first of course.I have 2 BIOS ROM files, which I attempted to update and flash it, but the TL866 was having none of it.I checked for a blank IC it said no.No matter what I do the original file is still on the chip.Does anybody have an idea why I can erase the IC but can't program it?I don't see why, it's not OTP.Here's a datasheet.https://datasheetspdf.com/pdf-file/1233812/Winbond/W49F002U/1

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: May 17, 2023, 04:50:51 am
content: It fails in the programming process at address 0x00D336.I can repeatedly erase successfully and an empty check shows it's not empty at address 0x00C080.Here are some photos.
[Solved] TL866II-Plus fails to program flash chip SST39SF020A-70 - Page 1
Forum section: electronics / repair

author: jeraymond
author_rank: Contributor
timestamp: February 23, 2022, 01:24:13 am
content: I'm trying to program an SST39SF020A-70 flash chip with the TL886II-Plus but keep getting a "Programming ...Failed" error at 6.25%. Reading the chip and erasing works OK. I have a few of these chips and tried 3 and all show the same error.I'm attempting to flash the 1.4 firmware for a E3632A onto it (http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent/Agilent_E3632A).I used the programmer a handful time successfully programming AT89S51 chips.I've had no luck with an internet search on finding a fix. Any suggestions?

author: oPossum
author_rank: Super Contributor
timestamp: February 25, 2022, 03:39:07 am
content: A14 may be open circuit or shorted to ground.

author: jeraymond
author_rank: Contributor
timestamp: February 25, 2022, 06:54:25 pm
content: Quote from: oPossum on February 25, 2022, 03:39:07 amThanks for the hint. A14 was shorted to A8 through some dodgy-ness on the PLCC32 to ZIF adapter. I was able to rework it and it fixed the programming problem.What made you suspect A14 was the issue?

author: fzabkar
author_rank: Super Contributor
timestamp: February 25, 2022, 07:44:26 pm
content: 6.25% = 1/16thThat would suggest that the 4th uppermost address bit is stuck at 0.
TL866II-PLUS not enough current causing programming issues - Page 1
Forum section: electronics / repair

author: tonycstech
author_rank: Regular Contributor
timestamp: March 01, 2024, 03:57:26 am
content: Programming graphics cards.Cannot program chip on board.I suspect not enough current.Is that something that can be fixed ?its 50/50. Sometimes i can program but PCB has to be cold, sometimes i cant no matter what until i remove the chip.

author: JimKnopf
author_rank: Frequent Contributor
timestamp: March 05, 2024, 06:46:09 pm
content: You could try an USB-Hub with external Powersupply. But maybe it's time to upgrade to a XGecu T56 or RT809H. Both can be powered with an external PSU. Be aware there are T56 clones in the wild without DC Jack.

author: tonycstech
author_rank: Regular Contributor
timestamp: March 05, 2024, 06:55:55 pm
content: Where can i buy authentic XGecu T56 ?Amazon lists few but their prices differ dramatically.

author: JimKnopf
author_rank: Frequent Contributor
timestamp: March 05, 2024, 07:11:10 pm
content: I bought my one from XGecu official store on Aliexpress. Plain device is around 160 Euro.

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 05, 2024, 07:20:44 pm
content: IIRC they also run an amazon store, all legit sources are listed on their site.
TLA-704  - Page 1
Forum section: electronics / repair

author: gearheadgeek
author_rank: Newbie
timestamp: November 04, 2019, 12:33:11 am
content: hello I have a old tektronix TLA-704 logic analyzer. I dug it out of the closet and went to fire it up and of course the CMOS battery is dead and i fixed that and went into the BIOS to reset everything and went to recognize the hard drive and well its dead (clicking and chirping and all the stuff ) and I know it dead. the question is can I use a Tektronix 039-0048-01 Benchtop Controller to reinstall the OS when I get a new hardware. this time Im going with a IED to 'SD card controller. I found a controller on Ebaythanks in advance
TLA Logic Analyzers - Serial Number Repair - Page 1
Forum section: electronics / repair

author: rfdes
author_rank: Regular Contributor
timestamp: July 06, 2017, 03:39:07 pm
content: My TLA624 analyzer has had a corrupted serial number since I bought it about 5 years ago. The number shows B000000 and am not sure if it left the factory that way or not. One may ask, 'Who cares?'... and I cannot give you a straight answer but in short 'I care'. So, I went off looking for a way to set the serial number to the factory assigned number which is on the back panel label. It turns out that the serial number is NOT in the battery backed NVRAM but embedded in the firmware flash. After some amount of searching and reverse engineering (I have a lot of fun doing this sort of thing), it turns out that the tool Load32.exe (Systems Folder) used to update the analyzer's module firmware has a 'Factory mode' that will allow the serial number to be changed. To force it into the Factory mode requires a password that appears to be module dependent so I patched the tool to bypass the password and now I can modify the serial number for both the TLA700 and TLA600 series analyzers.Of course few people would really care about changing the serial number but I am willing to share the tool if anyone needs/wants to modify their numbers.Anyway, my reason for this post was to offer this tool to whoever would like it.Take care -Jim

author: lukier
author_rank: Unknown
timestamp: July 06, 2017, 03:50:11 pm
content: Quote from: rfdes on July 06, 2017, 03:39:07 pmOver a year ago I've spent some time analyzing Load32.exe, as I have one TLA7AA4 card to repair and I don't remember the password to the factory mode (/F switch) to be module dependent. The password is stored in the encrypted form and the code uses this exact method (and even the key as in the example!) to decrypt the stored constant:http://www.codeproject.com/Articles/2645/Fast-Simple-Secure-Encryption-RoutineMaybe it is different for TLA600 series, I have TLA715 (704 upgraded to 715 to be precise).To be honest there is not much there, just force firmware upgrade and change serial number - didn't help me much. One of my TLA7AA4 cards has corrupted firmware (my fault) and I'll have to copy the Flash from the another, good, card. The problem is that MiniPro doesn't support TSOP56 flashes and I got rid of my 68k BDM tools years ago. I'll have to improvise some programmer out of an MCU, but that will take some time.

author: justin010306
author_rank: Newbie
timestamp: October 29, 2020, 09:34:26 am
content: hi,The serial number of my TLA612 analyzer is damaged. The number shows B000000, can you help me fix it. Thank you

author: rl78family
author_rank: Newbie
timestamp: June 11, 2023, 09:32:51 pm
content: Quote from: rfdes on July 06, 2017, 03:39:07 pmHi, Jim!I have TLA7N3 with wrong serial number. Does your's tool can fix this?
TLA5052B System Disc wanted - Page 1
Forum section: electronics / repair

author: Teichhermelin
author_rank: Regular Contributor
timestamp: October 05, 2021, 03:05:55 pm
content: Does anyone have a source where I can get a system disk? I'm still looking for some drivers!

author: RomDump
author_rank: Regular Contributor
timestamp: October 07, 2021, 12:49:55 pm
content: Quote from: Teichhermelin on October 05, 2021, 03:05:55 pmCan you recheck your model? The Prefix TLA means logic analyzer but the suffix 5052B is an oscilloscope.The recovery CD's for the TLA5000B series are on the xdevs website, (may be floating around on other archive websites).For TDS5000B Oscilloscopes I haven't seen the recovery image online.

author: Zigortxu
author_rank: Contributor
timestamp: October 07, 2021, 05:35:44 pm
content: Hello,I just upload to xdevs the Recovery disks, tekscope and software options disk for TDS5000B. Perhaps is not available for a few days until they review it.I hope it helps someone.Zigor

author: Teichhermelin
author_rank: Regular Contributor
timestamp: October 08, 2021, 03:41:15 pm
content: I made a mistake ... it's a TLA5204B...Will stop by there sometime..thank you all!
Tektronix TLA5203 Dead HDD, need Windows HDD image - Page 1
Forum section: electronics / repair

author: LogicAnalyzerHelp
author_rank: Newbie
timestamp: February 04, 2020, 07:12:48 pm
content: I have a TLA5203 that I cannot find the Windows HDD image backup CD; would anyone possibly have/know where to find a copy of that CD? I have tried contacting Tektronix with no luck. The TLA5202 install CD is unfortunately not the same one as the TLA5203 as there's different motherboards in each device and will not work in the 03 variant.Thanks!

author: RomDump
author_rank: Regular Contributor
timestamp: February 05, 2020, 01:45:35 pm
content: A Tektronix Windows image CD will be faster to restore the O/S but it will be harder to obtain. You probably going to have to manually install Windows 2000/Windows XP O/S and then manually install the TLA drivers from the Tektronix Website.

author: LogicAnalyzerHelp
author_rank: Newbie
timestamp: February 05, 2020, 07:56:43 pm
content: I didn't realize that I could do that. I will go about doing that then, thought it had some special registry edits that were unavailable from the drivers. Thank you very much!
TLA700 series logic analyzer - power supply question - Page 1
Forum section: electronics / repair

author: rfdes
author_rank: Regular Contributor
timestamp: April 03, 2024, 08:50:27 pm
content: Does anyone have knowledge whether these series of power supplies used the horrid 'RIFA' caps that plague many instruments of this vintage? If so, I'll tear mine open and replace them.ThanksJim
TMK C-15 Condenser Checker Schematic ? - Page 1
Forum section: electronics / repair

author: RichardM
author_rank: Frequent Contributor
timestamp: December 23, 2021, 03:35:56 am
content: Hi AllI have one of these capacitor/condenser checkershttps://www.radiomuseum.org/r/tmk_condenser_checker_ilc_15.html#which is similar to the Heathkit C-3 but also different (2 transformers to start with). Google does not return a great deal of information so I thought I would see if anyone on the forum is familiar with these and if a schematic exists. Mine does not work and had a couple of suspicious loose wires dangling about.CheersRichard
TM0141ADCW LCD Problem - Page 1
Forum section: electronics / repair

author: xoom
author_rank: Regular Contributor
timestamp: July 17, 2023, 06:00:08 pm
content: Hi Everyone,Got one control panel to check where LCD is not working right.When give power to it LCD like glitches and shows all columns and rows. But when fully initializes it just shows few columns.Thought maybe its zebra strip or flex ribbon problem (it have both ribbon for columns and zebra for rows) Cleaned zebra strip but no difference.When turning knob on board can see LCD changes. Checked Data lines and other control lines with scope and looks like good signals.Here are photos when turning knob:Here are board photo:Can SRAM (LY62256SL-70LL) be the problem?Any suggestions appreciated.Thank you.
To all the MacBook BGA reball doctors on this forum... Expert question - Page 1
Forum section: electronics / repair

author: JM1010
author_rank: Contributor
timestamp: January 01, 2022, 02:53:45 am
content: My Macbook 1707 PMIC got hot. Removed the chip and the fifth pad from the bottom left (PP5V_S4) was burned. After carefully scraping the pad to expose some copper it shows a 0.3 ohm short. I know this is a complex issue but what is the best way to deal with this? Where is the trace to this pad is also not clear. Is it fair to assume we need to scrape away the ground plane around this pad? If so, which layer is ground: is it top or second layer?. If it's not the best way to deal with this, what do you recommend ?Thanks for your guidance.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 09, 2022, 12:44:46 pm
content: at least an equipment i.e. reflow oven is required for safe soldering

author: m98
author_rank: Frequent Contributor
timestamp: January 09, 2022, 01:37:47 pm
content: Unlikely the short is directly at the pad. If it's not caused by your desoldering, it's more likely to be a cracked capacitor, blown MOSFET, or something like that. But in any case, give that board a very good clean and carefully look for any displaced components in the solder area, on the front and back.

author: wraper
author_rank: Unknown
timestamp: January 09, 2022, 01:43:42 pm
content: It looks like you scraped into the ground layer underneath to which the pad was not connected as the (now burned) trace going to it resided on the top layer. If it's the case, then you need to insulate the layer underneath by UV solder mask and run a wire on top of it.Quote from: abdulbadii on January 09, 2022, 12:44:46 pmReflow ovens are not used for repairs.

author: JM1010
author_rank: Contributor
timestamp: January 10, 2022, 12:10:11 am
content: Thanks for the advice guys! Will try to pinpoint other sources of short on this rail but worse case will have to do as suggested Wrapper ie sever trace - put solder mask and hope for the best:)

author: wraper
author_rank: Unknown
timestamp: January 10, 2022, 09:24:58 am
content: Quote from: JM1010 on January 10, 2022, 12:10:11 amI said it's most likely not even the rail you look for but unrelated GND plane underneath it. A large number of the periphery pads are connected by the traces and not plugged vias. There is a crater on the PCB where it seems that trace was running before.
To definitely differentiate black zeners diode - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 23, 2023, 02:37:50 am
content: How do we differentiate black zeners like below with that of a diode ?

author: nostril
author_rank: Newbie
timestamp: January 23, 2023, 03:41:08 am
content: There are a number of options, including:1) checking the part number written on the component2) checking its position in the context of the rest of the circuit3) measure the component's zener/avalanche voltage4) ask the person who designed the circuitHope that helps

author: Gyro
author_rank: Super Contributor
timestamp: January 23, 2023, 10:33:45 am
content: Quote from: abdulbadii on January 23, 2023, 02:37:50 amI wish you would stop it with the lazy one line cryptic questions.

author: jonpaul
author_rank: Super Contributor
timestamp: January 23, 2023, 11:00:23 am
content: curve tracerlab power supply andVOMj

author: Audiorepair
author_rank: Frequent Contributor
timestamp: January 23, 2023, 11:06:47 am
content: Put your meter in diode mode. Zeners nearly always measure in the 700mV range, standard diodes in the 500mV / 600mV range.Other diodes like Shottky types can measure way lower.You can do this with the diodes in circuit.Try it, you will usually easily spot the zeners.

author: Simon
author_rank: Unknown
timestamp: January 23, 2023, 02:54:48 pm
content: some context to your question would help
To  pull out, remove a solderless bent pin-ends IC - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: July 02, 2021, 11:54:13 pm
content: How do we pull out or remove a solderless bent pin-ends IC from PCB ?tried using a small long nose plier to straighten and accomplish all with no avail, seems that the pinching part still not suitable and small enough

author: bdunham7
author_rank: Super Contributor
timestamp: July 03, 2021, 12:19:46 am
content: An assortment of dental picks.https://www.ebay.com/itm/312530359484You have to carefully get under each pin and lift it.How and why are they not soldered?

author: abdulbadii
author_rank: Frequent Contributor
timestamp: July 03, 2021, 12:24:30 am
content: The IC was desoldered and cleaned up from every sticking solder

author: bdunham7
author_rank: Super Contributor
timestamp: July 03, 2021, 12:34:11 am
content: I use narrow snouts on my desoldering gun and I can usually get around the pins and straighten them as I desolder--it's hard to get all the solder out with the pins still bent. Once they are fairly straight, you can put a PDIP puller on the iC , heat the leads with a hot air nozzle and wiggle the IC out.https://gokimco.com/collections/hakko/products/hakko-n61-13-high-power-desoldering-nozzleNot an easy job, even with the right equipment.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 03, 2021, 05:18:11 am
content: Agree with the previous description. If you don't need to reuse the IC, just cut the pins off and remove them individually. One risk in pulling is that you may pull the through-hole plating out and attached track with the pin. Then you have a more difficult repair job.I also find that blowing rather than sucking solder is more effective, but it is also more messy. Nevertheless, it doesn't take much cold solder to keep the IC stuck. That's where hot air is a lifesaver.

author: coppercone2
author_rank: Super Contributor
timestamp: July 03, 2021, 05:39:08 am
content: just don't cut the pins too short, when you cut them make sure you cut them really close to the top of the IC with a thin cutter otherwise you will have a little turd playing peekaboo with you and refuses to pop out until you end up lifting the trace fucking with it

author: Ian.M
author_rank: Super Contributor
timestamp: July 03, 2021, 07:37:37 am
content: Lift the bent over pin ends with a scalpel or xacto knife with a slightly blunted blade, while heating the pin/pad with the iron. Try to spring the pin away from the sides of the holes as you do so, holding it away with the blade as the pad cools. Straighten the bent pin ends with miniature flat nose smooth jaw pliers. You are now no worse off than if the IC had been inserted without bent pins. Where you go from here depends on how tight the holes are on the pins, if the pin shoulders are bonded to the top side pads by residual solder, and whether or not you need the IC intact.
To solder and desolder a very small things - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: September 11, 2021, 05:16:31 pm
content: Would you share your golden tricks to be able masterly solder and desolder a very small pins (holes) tightly laid in a narrow PCB ?

author: David Hess
author_rank: Super Contributor
timestamp: September 11, 2021, 10:14:33 pm
content: My first trick is lots of Kester 1544 or equivalent rosin flux brushed on.

author: DaJMasta
author_rank: Super Contributor
timestamp: September 13, 2021, 12:08:49 am
content: You're probably going to have to be more specific for particular applications, but some options to look into:Hot air gun with a narrow nozzleTweezers with a bendInspection optics (magnifier, microscope, etc)Good gel flux (at least for me)Fine solderKapton tape to protect adjacent partsHolder for the PCBSometimes even a preheater can help you get in and apply less heat from the topside to narrow spaces.
Toaster oven LEDs - Page 1
Forum section: electronics / repair

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 08, 2020, 12:48:16 am
content: The blue backlight on my Breville's display has died, making the display quite difficult to read.Before I take this thing apart, are there special appliance LEDs that are for high temperature? Operating temperature doesn't seem to be a factor when searching suppliers.

author: Haenk
author_rank: Super Contributor
timestamp: June 08, 2020, 07:05:38 am
content: The display and electronics is separated (and insulated) from the heated part, so most likely the cheapest part will be fine. (Heat would certainly kill the LCD way faster than anything else...).
Toby guitar amplifiers - Page 1
Forum section: electronics / repair

author: Swagonmaster
author_rank: Newbie
timestamp: August 25, 2023, 02:43:56 pm
content: Back in the 1960's there were some guitar amplifiers made in Texas (Toby Speakers are an offshoot of that company) and information about the repair of them is really hard to find. If there are any of the (likely) older folks that have any information or suggestions I would appreciate hearing it. Yes, we've tried contacting Toby Speakers but to the best of their knowledge none of the info about the amps was kept after the original owner died and the amp production ended. After 50-60 years and previous attempts at repairs board level diagnosis is tough. BTW, these are solid state amps not tube type.

author: donlisms
author_rank: Frequent Contributor
timestamp: August 25, 2023, 04:28:54 pm
content: Mm. If it's important enough, reverse engineer a schematic. Most guitar-oriented devices are not excessively complex. It will be tedious and time consuming. When you're done, you'll know the thing by heart!
Toellner TOE 7404 function generator. - Page 1
Forum section: electronics / repair

author: ktulu
author_rank: Regular Contributor
timestamp: December 07, 2018, 08:50:31 am
content: Hello.I have a TOE 7404 function generator for which I'm unable to find schematics or service manual. (or calibration guide maybe)The only thing available is a few page long basic user guide...I would be really thankful if somebody could share at least some schematics.Thank you.

author: Chris56000
author_rank: Frequent Contributor
timestamp: December 07, 2018, 03:53:40 pm
content: Hi!I've got something but it's barely readable and will need redrawing before I can post it I'm afraid!What fault symptom do you have?The last one of those generators went for over £150 which was too much for me to buy, regrettably!Please bear with me and I'll try and get them redrawn & posted!Chris Williams

author: ktulu
author_rank: Regular Contributor
timestamp: December 07, 2018, 05:38:44 pm
content: Thanks, I will wait.

author: ktulu
author_rank: Regular Contributor
timestamp: December 08, 2018, 09:27:03 am
content: I managed to find schematics for the older version that has no frequency counter, thanks to a couple of nice fellas from a german forum. The entire board is redesigned, (sadly) they went from through hole to smd.Also there are many component changes after a quick look.At least I have some starting point. (I want to perform some alignments)

author: paulbt
author_rank: Regular Contributor
timestamp: June 01, 2020, 10:53:13 am
content: Hello!@ktulu could you please share your findings? I mean the schematics for toe7402...

author: ktulu
author_rank: Regular Contributor
timestamp: June 06, 2020, 07:01:49 pm
content: I've downloaded from here:http://ftb.ko4bb.com/getsimple/index.php?id=download&file=06_Misc_Test_Equipment/Toellner_TOE_7402_7404_7702_7_LF_signal_generator_operating_and_Service_Manual.pdf
toellner toe 7723 function generator repair (Potential EPROM Data Loss) - Page 1
Forum section: electronics / repair

author: lorenzo01
author_rank: Newbie
timestamp: January 31, 2024, 02:39:35 pm
content: Good morning everyone, about 6 months ago, I acquired a Toellner TOE 7723 function generator in mint conditions that a few days ago stopped working :-(To be more specific, it would power on, display a number on the screen, and some LEDs would light up, but the keypad was no longer responsive.After an extensive troubleshooting, I have come to the conclusion that there is absolutely nothing wrong at the hardware level (I even went as far as testing each chip individually by removing them from the board).The only issue that comes to mind is that the EPROM memories may have lost some data over the years (presumably, the generator dates back to 1986).So, I am asking anyone who has access to the firmware for this device to make it availableThe image show the two EPROMs containing the firmware
Tom Tom One GPS Rollover – which type of GPS chip is affected? - Page 1
Forum section: electronics / repair

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 10, 2019, 09:29:56 pm
content: Hi!I'm trying to get an old Tom Tom One to work following the gps wnro problem and despite using the 9.541 software, the unit will not display time or lock!Can anyone advise me:–Which particular GPS Receiver chip is affected;Is it possible to exchange this? i believe Tom Tom Ones used several types of these devices on their boards, which type of chip do I need and can anyone post clear pictures of non–updatable chips that don't work, and updatable ones that do please?I don't mind buying another TomTom One m/b if any Member can confirm which type is OK!Chris Williams

author: pelule
author_rank: Frequent Contributor
timestamp: May 11, 2019, 04:35:46 pm
content: I got informed by Tom Tom on their web site for an required update/fix/pelule

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 11, 2019, 06:47:04 pm
content: Hi!I've already installed the 9.541 Navcore that is supposed to correct the issue, along with the glgps.dat in the."bin" folder of the TomTom that's supposed to correct the issue but it's making no difference – the TomTom's time is till jumping back to "0:00" after finding two satellites, and it's taking over 15 minutes to get a lockChris Williams

author: LateLesley
author_rank: Frequent Contributor
timestamp: May 11, 2019, 08:37:22 pm
content: I believe this is more a firmware issue, rather than a chip hardware one. If you have copied the files, I read you may need to reset the device though the pinhole it the bottom 3 times. It may need to hard reset to accept the new files. Also someone else mentioned about an ASR folder causing problems (freezing). So maybe check if you had copied that, and if you had, retry without it.https://www.gpspower.net/tomtom-navcore/353135-new-application-navcore-software-v9-541-released-many-nav2-devices-2.html
Tom Tom Via (Modern "My Drive Connect" Type!)–NO connection to My Drive or PC? - Page 1
Forum section: electronics / repair

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 08, 2019, 08:55:20 pm
content: Hi!This question is about one of the new type Tom Tom Vias with "My Drive" type operation and NO access to the file system!Can anyone suggest a reason why one of these will NOT connect to the "My Drive" app, a PC or an Android 'fone?Before anyone says "there's a software update for these!!!", this device is of the type that CANNOT be connected to a PC to view the file–system – only their stupid "MyDrive" application can connect to this newer type of device, and the "My Drive" refuses to recognise the device!Am I looking at an internal hardware fault? I was given this TomTom from a friendly colleague who couldn't get it to work on three of his PCs and devices either!Chris Williams

author: fzabkar
author_rank: Super Contributor
timestamp: August 11, 2019, 10:15:40 pm
content: Quotehttp://download.tomtom.com/open/manuals/VIA_52_62/refman/TomTom-VIA-EU-RG-en-gb.pdfhttp://download.tomtom.com/open/manuals/via/refman/TomTom-Via-en-GB.pdf
Tomahawk 375 Plasma Cutter Failure Analysis - Page 1
Forum section: electronics / repair

author: seancsnm
author_rank: Regular Contributor
timestamp: September 09, 2024, 01:18:16 am
content: My Lincoln Tomahawk 375 plasma cutter recently failed and I'm trying to troubleshoot to see exactly what happened. It had maybe 20 hours on it when it failed. Details surrounding the failure are in the images, but to sum it all up, it looks like a thermistor dropped to a low resistance and failed. I only have a very surface level understanding of how these plasma cutters work - Lincoln or some other source can explain better than I can. But what puzzles me is why a thermistor (presumably NTC) was placed between the ground and pilot arc signals. What purpose does it serve? I can only guess that it provides a failsafe current path for the pilot arc when the air gap between the torch and workpiece is too large. But even that doesn't make a lot of sense. Why not just put an air gap on the PCB in that case? And why a thermistor instead of a standard resistor?So my question is, why a NTC between those two signals, and does anyone have any clue what would make suitable replacement specs? Oh, and what could have caused the failure in the first place? I am new to using plasma cutters and acknowledge that I abused the machine a little with what I did to the air nozzle, but the failure occurred a good bit after I replaced the nozzle with a new one.
Too much heat from Marantz PM4200/N2B - Page 1
Forum section: electronics / repair

author: etet
author_rank: Newbie
timestamp: September 01, 2019, 05:52:02 pm
content: Hi,I have this amplifier for repair.I found scheme for Marantz PM4200/N1B fromhere:https://www.manualslib.com/download/1388318/Marantz-Pm4200.htmlHeat comes from C4467.As i notice it has higher base voltage.I move back and back and notice that problem startfrom first transistor after IC AN7062N - A1268.On second chanel base ot A1268 has 1.7V, but on chanelthat produce a lot of heat A1268 has 2-2.1V on his base.Where to continue to check for fault?Regards

author: Chris56000
author_rank: Frequent Contributor
timestamp: September 22, 2019, 08:20:42 pm
content: Hi!I suspect you didn't get a reply because you didn't quote the circuit component reference nos., and nobody could work out where exactly you were referring to - never mind tho', I can!This circuit is a direct coupled high-voltage complementary-symmetry class AB output stage with a high-voltage dual power op-amp IC31 (AN7062) providing the main amplifying stage!http://pdf.datasheetcatalog.com/datasheet/panasonic/AN7062N.pdfFirst of all, make sure the emitter protection resistors R359/R361 aren't damaged or high value, replace these if they are, check the bias resistor R353 (330R 1W), then I'd consider replacement of IC31 itself - it isn't horrendously expensive:-https://www.ebay.co.uk/itm/1PCS-Power-Amplifier-IC-PANASONIC-DIP-18-AN7062/401500437221?hash=item5d7b4a7ae5:g:fbwAAOSwDmBY5xSeIf replacing IC31 doesn't help, you'll have to go through the transistors Q349/Q351/Q353/Q355/Q357 to see if you've got a leaky or defective one!Don't forget to reset the quiescent current ("Idling Current") using VR31 as given on page 4 of the Service Manual after repairs are complete!Chris Williams

author: shakalnokturn
author_rank: Super Contributor
timestamp: September 23, 2019, 08:52:49 pm
content: Though I can't be bothered to go and look for the schematic right now and can't be sure what's used in this model also beware of thermal compensation or bias voltage "double/triple" diodes and the quescient current trimpot itself, they are often causes of the current going too high.Chris forgot to mention, if you haven't already done, check the solders there should be dozens that need reflowing if this amp hasn't been butchered before....
Toolkit M7 chager display - Page 1
Forum section: electronics / repair

author: Tangent_Tracker
author_rank: Regular Contributor
timestamp: January 27, 2023, 02:18:30 pm
content: Hey folks, so the display on my toolkit M7 cracked. It's about 1.8" wide and has 10 connectors on the ribbon cable. Toolkit are ignoring my ticket for a replacement so screw them!Is it likely I could get a similar display to work? Suspect it is TFT give the crack and visible liquid, just not sure what the pin config is but surely can't be custom? Connector goes straight to a micro so must be some standard interface such as SPI or i2C I'd think...I should try probing the outputs but not got the room on bench atm...Pics below...https://photos.app.goo.gl/3opZ5tRrQfgd73aA8https://photos.app.goo.gl/9xjDwvbqGwh45CfB6
Topward 6303A repair - Page 1
Forum section: electronics / repair

author: mrpelikan
author_rank: Newbie
timestamp: March 09, 2024, 10:17:54 pm
content: About time I contributed something back to this forum.Last week I was given a Topward 6303A (has moving-coil meters for output current & voltage) in non-working condition. The slave channel only worked in parallel mode. In series or individual mode the slave had no output.The circuitry for mode switching is complicated but for good reason - when going from one mode to another a break-before-make is necessary to avoid a momentary short-circuit on the three relays immediately behind front panel. These relays switch the power supply outputs to independent, series or parallel. Fortunately its less likely there's a problem in this section as removing these boards from behind the front panel is a real mission.A previous contributor kindly posted a pdf of the 6303D and its mostly relevant for the 6303A. The 6303A doesn't have the 7805-regulated supplies at top of the master & slave drawings (are probably for the LED displays) and those areas are unpopulated on the 6303A boards. Also control of the transformer secondary relays L1, L2, L6, L7 is different on my unit.The screen printing on all boards had different component numbering to the 6303D. Also the white screen printing on yellowish laminate can be difficult to read if lighting isn't just right...For anyone experiencing the same fault, on the slave board check Q23 and Q24. Q23 is in the voltage control circuit, Q24 in the current limiting circuit.Q23 (NPN, type 2SC1815 in my unit) collector-emitter was around 3kohmQ24 (PNP, 2SA1015) collector-emitter was less than 0.5 ohmUnfortunately these devices seem to be less available now, especially in single-digit quantities. Also the pinout of both has base (left) and collector (centre) transposed compared with many potential equivalents. I ended up using BC547 & BC557 respectively from my junk box and carefully "crossed their legs" on base & collector. On power up the unit behaved as it should and was satisfying to know that a supply in otherwise good condition has been kept out of landfill.Hope this helps someone somewhere.
Topward 7020 problem, Help! - Page 1
Forum section: electronics / repair

author: GoldenGun
author_rank: Newbie
timestamp: July 21, 2020, 06:11:57 pm
content: So i recently bought a topward 7020 off of ebay for £50, when it arrived I turned it on and tested the cal point and the proper square wave appeared tho it was a bit dim on max intensity but a problem i noticed was that the waveform for ch1 only was jumping up and down the screen for no reason and moving the position knobs wouldn't stop it but this only happened to ch1 so I opened it to check for dust and grime even if the seller said it was dry stored for years I found some rust on the transformer and on a few screws but besides that everything looked good, no blown capacitors nothing so I took the board with the potentiometer on it off to clean it(I thought it was the potentiometer) so i used contact cleaner on it and put it back in then i closed the thing up and surprise now the waveform on ch1 and 2 didn't appear at all i touched the probe to the cal point, my finger, messed around with the coupling and the other stuff on the front but no waveform would appear not even moving the knobs on the front would change anything besides the left right position, so i opened it up again to make sure i put everything back together properly and nothing seems wrong so I looked it up and found a person with a 2021 had a similar problem but going through the thread didn't show me anything that could help i checked the transformer voltages and it was all good, so I made this thread to ask for help.

author: tunk
author_rank: Super Contributor
timestamp: July 21, 2020, 06:53:44 pm
content: Maybe bad solder joints disturbed when you took it apart?

author: GoldenGun
author_rank: Newbie
timestamp: July 21, 2020, 08:20:17 pm
content: I wouldn't think it was solder joints since i couldn't get the board out fully all I could get out was mini board on which the potentiometer was mounted on and i made sure the solder joints and cable worked by continuity checking them.

author: GoldenGun
author_rank: Newbie
timestamp: July 22, 2020, 09:40:00 am
content: Update I managed to get a trace on the screen and now it displays the square wave but i still have the problem that the trace on both channels isn't stable it jumps around and sometimes doesn't want to display while doing so, any ideas?
Toroidal inductor rewinding. ATX PSU - Page 1
Forum section: electronics / repair

author: oliver602
author_rank: Regular Contributor
timestamp: July 30, 2020, 11:22:59 am
content: I have an old Rasurbo ATX PSU that failed.I would like to try and rewind an inductor that got too hot. It is right next output wires, it has been removed in the photo.Is this an inductor, transformer, choke, something else? Why is it so close to the output?Could someone point me to the entrance of this rabbit hole?

author: wraper
author_rank: Unknown
timestamp: July 30, 2020, 11:30:22 am
content: If it was overheated, icon powder core IME very likely lost it's parameters as well. Rewinding will not make it a good inductor.

author: wraper
author_rank: Unknown
timestamp: July 30, 2020, 11:42:29 am
content: It's a group stabilization inductor. It helps several output voltages to follow each other, as there is no separate stabilization for each power rail.

author: oliver602
author_rank: Regular Contributor
timestamp: July 30, 2020, 03:36:55 pm
content: Can the iron powder core be replaced with one of the same size or are there other parameters that need to be matched?

author: wraper
author_rank: Unknown
timestamp: July 30, 2020, 04:04:51 pm
content: You can only guess what the original specs were is you have no good core to measure. You could try making a test winding, measure inductance and calculate permeability to see if it makes sense for a good iron powder core. Core coating color indicates material type/permeability. Though there is no common standard AFAIK. But you could try to match it with color scheme here:

author: oliver602
author_rank: Regular Contributor
timestamp: July 31, 2020, 06:36:54 pm
content: The coating on this core is a dirty cracked brown so I'm not sure what to do here. Perhaps it was black. I'm not good at math. Outer diameter is 20.5mm, inner diameter is 12.25mm, width is 6.8mm.It has three winding. I counted a turn when the wire passed through the centre of the core.9 turns of 1.25mm diameter wire.21 turns of 1.25mm diameter wire and22 turns of 0.65mm diameter wire.

author: oliver602
author_rank: Regular Contributor
timestamp: August 01, 2020, 12:35:39 pm
content: How critical is the core size and permeability? Would it say be safer to go for a higher permeability core?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 02, 2020, 03:44:47 am
content: It was most likely #26. #52 would also do.Tim

author: oliver602
author_rank: Regular Contributor
timestamp: August 07, 2020, 11:38:56 am
content: I rewound the inductor on a yellow/white core and the power supply is working again. I tested it with a 1.6A load on 12V and all the voltages look OK. But the inductor gets very hot after a few minutes.