hybridfree/eevblog-posts huggingface dataset:
Hakko 470, 471 de-soldering station repair and schematic - Page 1
Forum section: electronics / repair

author: floobydust
author_rank: Super Contributor
timestamp: September 07, 2017, 06:11:09 pm
content: Need schematic for Hakko 470, 471 vacuum desoldering station.The 474, 475 might be the same PCB.My unit keeps overheating, triac is ok.Update: {see post below}For clarity,The 470, 471 uses AC induction motor and timed vacuum solenoid valve, control PCB B1045.The 470B uses a brushed DC motor and no vacuum solenoid valve, control PCB B2443.

author: macboy
author_rank: Super Contributor
timestamp: September 08, 2017, 01:30:57 pm
content: I've never found one. The best I found was a wiring diagram showing connections between the board and transformer, pump, heater, etc. However, with just one simple single-sided board, reversing the schematic is just a matter of a little time and effort.If you don't have the time to spare, I know of a local dealer that has a couple of 470 base units without guns, and I'm sure he'd be willing to part one out to send you just a PCB, with the remainder going to scrap (the whole thing will eventually go to scrap if it doesn't sell). Since you are also in Canada, shipping the whole unit probably wouldn't break the bank either. PM me if interested and I'd be happy to broker a deal.

author: floobydust
author_rank: Super Contributor
timestamp: September 09, 2017, 02:24:20 am
content: I drew a schematic for the Hakko B1045 temperature controller PCB including the base 470-2.When I connect the heating element, I get full heat, sometimes it backs off but very hot, like thermal runaway.When I connect the 6.6R dummy load I get full heat, can't control it.When I connect a 200R dummy load, the TRIAC seems to stay off. I get nothing but a blip, no heat.The gun has no temperature sensor, instead Hakko seems to be using resistance change in the heating element. I am using a 474 heating element because the 470 is obsolete, but same wattage so should be OK... but might be my problem.Anyone have ideas how to troubleshoot this.macboy, thanks for your note. I will try fix it but that NEC uPC1701 is an oddball IC.

author: floobydust
author_rank: Super Contributor
timestamp: September 16, 2017, 02:41:09 am
content: Update:The station uses the heating element's resistance as a temperature sensor.I'dupgraded to 809 gun (A1313 heater)a long time ago, as the old 802 gun (A1029 heater) are obsolete.Heat gets stuck on when the heater resistance is lower (current higher) than expected. The newer element must have lower resistance. I just did a re-cal and the station behaves better. The controller can probably still go into thermal runaway if I crank up the temperature setpoint. Changing circuit values a bit too much work for now. Added an heater-on LED to keep an eye on it.I did characterize the A1313 heating element. Resistance is 2.85ohms/25C and 8.36ohms 425C; linear slope. Higher tempco than nichrome wire.These are the best desoldering stations I've used, even though old. Pace and Weller just don't work as well.
Soldering Iron Repair\Upgrade - Page 1
Forum section: electronics / repair

author: bustedparts
author_rank: Newbie
timestamp: September 15, 2017, 02:26:23 am
content: Hello fellas. I was soldering away this evening on a project that I am working on . I shut my iron off and I turned it on a few minutes later and It refuses to heat. The Iron is a Yihua 939BD+ and I purchased it about 6 months ago. It has been a pretty decent iron up to this point. But I have no way to gauge it due to this was my first soldering station. Anyway I proceeded to take the wand apart and found a small pcb with 1 what looks to be a cap and 4 wires for the ceramic heater and the mating wires. I took and done a resistance check and the 2 blue wires have about 50 ohms and the red wires have about 80 ohms. I tried to check for some kind of a voltage output and all I got was 5 volts , nothing higher. I am suspecting that the heater is bad. My question has any of you fine gentleman had any experience with this iron. And can I get better parts to replace what has already broke? I have learned my lesson on buying cheap as I am paying the price now. My next question is can I get smc tweezers to work with the base unit I have? Thanks for looking and I hope to hear something soon!

author: bustedparts
author_rank: Newbie
timestamp: September 15, 2017, 07:52:50 pm
content: I replaced the heater with a stock replacement and that ended up fixing the no heating issue. And I done some research and I found this heater and it looks just like the one I replaced.http://www.tequipment.net/Hakko/A1560/Soldering-Accessories/?v=7561. It says it is a 65 watt heater. My iron says it is a 70 watt . So I am going to give this heater a try , and I am going to order a few replacement tips for a hakko as I heard they fit tighter .
Agilent E3610A front cover replacement - Page 1
Forum section: electronics / repair

author: MichR
author_rank: Contributor
timestamp: September 14, 2017, 07:10:01 am
content: HelloSo as title says I am looking for a front cover replacement. The label does not adhere well to the panel and part of the display filter has become discoloured. Anyway, the power supply is performing well and I am really pleased with it.What do you suggest to do? Personally, I would replace the entire front cover, but it's just impossible to find it as a spare part. Do you have a source for that? Is someone here going to sell me one?Please let me know, I really want to restore the power supply's original look.Thank you
Dead Acorn A3010 - Page 1
Forum section: electronics / repair

author: angust_uk
author_rank: Regular Contributor
timestamp: September 11, 2017, 11:51:34 am
content: Hi allI dusted off my old A3010 recently for a bit of nostalgia, and found that it now refuses to boot. No floppy initialisation (or floppy LED flashes), speaker sound or video output. I changed the battery a while ago (thankfully there wasn't too much corrosion on the PCB), and have checked all the oscillators I can find as well as for stable power rails. All fine, but still no joy at all. Not sure what to try next - is there any way to check to see if the CPU is running? (it gets warm to the touch, so it's doing something at least!).The usual reset procedures (e.g. holding delete whilst booting) don't do anything as far as I can tell.Any input gratefully received (this was my first 'proper' computer and there are a lot of my old BASIC programs I'd love to have a look at again!)Angus

author: bd139
author_rank: Super Contributor
timestamp: September 11, 2017, 01:02:32 pm
content: Try reseating the OS ROMs. They get a bit funky with age.As for seeing if it's running or not, you would need a logic probe or scope and poke around the address bus on the ARM CPU.

author: stj
author_rank: Super Contributor
timestamp: September 11, 2017, 03:57:53 pm
content: it probably uses a small electrolytic to generate the reset pulse when the power is connected.

author: philpem
author_rank: Frequent Contributor
timestamp: September 13, 2017, 12:15:22 pm
content: Did you wash the board around the battery with white vinegar or similar (and a second wash with distilled water) to neutralise the battery electrolyte?If not, a bit of the electrolyte might have leaked into the tracking...The machine blinks out an error code on the floppy LED if it fails POST. What's the error code? (if I remember rightly, it's 32 bits blinked in groups of four bits, long is a '1' and short is a '0', with a long gap at the end before it repeats)EDIT - oops just noticed you're not getting the blinks. Check the power rails (they're clearly marked in the power supply area). Probably a dud or weak voltage regulator or a fried capacitor. I seem to recall these machines (unlike the A3000) run a linear power supply which is built onto the motherboard.
SILICON BRIDGE RECTIFIER DIODE - Page 1
Forum section: electronics / repair

author: ksb
author_rank: Contributor
timestamp: September 15, 2017, 09:48:34 am
content: Friends, i need a help! I am searching for B40/35-10 rectifier replacement part. this part already obsolete.

author: bjcuizon
author_rank: Frequent Contributor
timestamp: September 15, 2017, 09:56:07 am
content: After a quick google search I found this link. Check it out:http://www.weisd.com/test/GenericParts_WEISD_view.php?editid1=B40/35-10..and apparently the nte5322 is an equivalent

author: tautech
author_rank: Super Contributor
timestamp: September 15, 2017, 10:05:29 am
content: Looks very much to me like a generic 400V 35A bridge, you can find them most anywhere.https://www.jaycar.co.nz/400v-35a-bridge-rectifier/p/ZR1324
repairing 50 watt inverter - Page 1
Forum section: electronics / repair

author: aviyan
author_rank: Newbie
timestamp: September 06, 2017, 12:10:20 pm
content: My 50 watt inverter was damaged due to the mistake that I haveput the opposite terminals of the battery to inverter. I think its MOSFET has been blown up. Please help me out how figure out the exact MOSFET out of the circuit board.

author: X
author_rank: Regular Contributor
timestamp: September 06, 2017, 12:21:06 pm
content: If you're lucky, it's just the fuse that's gone. Many of these inverters have a rectifier diode connected after the fuse in parallel with the input supply (reverse biased, of course) and when connected in the wrong polarity, the diode shunts the current and hopefully blows up the fuse. Worse case, the diode fails short-circuit.

author: ATFForklifts
author_rank: Newbie
timestamp: September 12, 2017, 08:11:10 am
content: Hope this article would help you to get rid out of this issue -http://www.powerelectronictips.com/how-and-when-mosfets-blow-up/

author: Armadillo
author_rank: Super Contributor
timestamp: September 12, 2017, 09:40:03 am
content: Can you send some close up photos of the board, top and bottom and mosfet so that members can help you identify parts.Remember to discharge capacitor.
Fixing GPU - Page 1
Forum section: electronics / repair

author: FurnaceRocker
author_rank: Newbie
timestamp: September 07, 2017, 02:12:18 am
content: Hey I'm in the market for a new gpu, and was noticing quite a few gpus on ebay for parts/not working. Wanted to ask, has anyone had much experience fixing graphics cards (NOT just cooking it in the oven)? I'm comfortable fixing electronics, I've been doing it as a hobby for a few years now, but I'm no where near an expert, so if that's the needed skill level I'm out.Thought I'd throw it out there and see if anyone had any experience, thanks!

author: Rasz
author_rank: Super Contributor
timestamp: September 08, 2017, 09:44:10 pm
content: without expensive rework station you are limited to power problems, blown fuses, blown power sectionor being super lucky (one logic gate)

author: DaJMasta
author_rank: Super Contributor
timestamp: September 08, 2017, 09:51:53 pm
content: That's basically it, without good tools and technique, large BGA rework is finicky at best. There's also basically no schematics available and you're always working on multilayer boards.So if you're interested and the card is real cheap, it's probably still interesting to attempt... but I doubt there's a good niche repair market to try to make a buck or get a bunch of cheap graphics upgrades.If you end up doing it, it may be a decent idea to use a secondary computer for testing - in the event you short a power trace from the motherboard and release a bit of smoke.

author: wraper
author_rank: Unknown
timestamp: September 08, 2017, 11:12:31 pm
content: Unless you buy it for nearly free, like 10% of the working GPU price, it's not worth it. Especially if you don't have specialized equipment and experience.
Farnell EC30/2 - what X/Y rated capacitor from negative to earth? - Page 1
Forum section: electronics / repair

author: bd139
author_rank: Super Contributor
timestamp: September 08, 2017, 11:57:58 am
content: I've got a Farnell EC30/2 bench supply here. It has a lurking cracked and knackered RIFA X class smoke bomb capacitor in it across the negative and ground terminals. This is GOING as I distrust the infernal things after a few small fires.This is a floating supply with no isolation or floating voltage limits specified.Now AFAIK this should be a Y rated capacitor in 2017. Am I ok stuffing a Y1 across it instead?

author: macboy
author_rank: Super Contributor
timestamp: September 08, 2017, 12:47:17 pm
content: In general, class X are for line to neutral applications, and class Y are for line or neutral to ground applications. So yes, if anything it should be class Y, and since Y1 is "better" than Y2, you should be OK.

author: bd139
author_rank: Super Contributor
timestamp: September 08, 2017, 01:02:51 pm
content: Perfect - thanks for feedback
Active speaker SMPS problem - Page 1
Forum section: electronics / repair

author: Rutherberg
author_rank: Regular Contributor
timestamp: September 07, 2017, 01:06:10 pm
content: Hello,Again, I have a hard time to diagnose an SMPS in an active speaker.It is a Behringer Eurolive B912 NEO, schematic is attached.It came with a power problem, last time it was used, it was powered by a diesel generator, so AC source wasn't very stable.Last time powered on (with proper power source), I heard a loud explosion inside, D7 and D9 are exploded and jumper J1 blowed.Bridge D63 is not shorted, T1 and T5 neither.Could you help me find the problem ? What could be potential problems ?Thanks in advance !

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: September 07, 2017, 05:11:57 pm
content: D7 and D9 are overvoltage protection for the reservoir capacitors. They most likely failed due to excessive input voltage. Though, they could also have failed due to an incorrect mains voltage selection, or perhaps due to very asymmetric loading of the rectifier such that one cap has more than 200v across it, the other a lot less.J1 would only be connected if on a 120v supply. It causes the rectifier to act as a voltage doubler instead of as a bridge.Basically, when faced with this kind of repair you need an isolating transformer (and I mean isolating,notcenter tap earth as are used on building sites) and a variac or dim bulb tester. If you have nothing else to hand the dim bulb tester is easy to make up.Main point to note is that you cannot do 'scope checks on this kind of equipment without an isolating transformer.

author: b_force
author_rank: Super Contributor
timestamp: September 07, 2017, 09:21:31 pm
content: Quote from: IanMacdonald on September 07, 2017, 05:11:57 pmI don't see why?Yes, it's a bridged amp, but simply build with two mono amps with an inverted signal.So there is nothing floating or something.OR do you mean to gradually higher the input voltage to see what's wrong?(like using a variac or variable transformer).In that case, yes that's the way to go.Generators are a pain for amplifiers.I can show one from my work were a part of the PCB is just totally gone (as in REALLY gone)Pretty classic design btw, with the IRS20955.Only a bit weird with a TDA7293 (pissing away energy)
Does anyone recognize this 11 pin relay socket? - Page 1
Forum section: electronics / repair

author: Anton4
author_rank: Newbie
timestamp: August 31, 2017, 07:10:31 pm
content: The broken relay was a TEC relay 1226 24VDC

author: cvanc
author_rank: Frequent Contributor
timestamp: August 31, 2017, 08:47:43 pm
content: I was going to say it's like the old Potter & Brumfield KHP series, but it's not quite the same - your seems to be 3PDT and the KHPs are 4PDT. Good luck with your search...

author: kasone
author_rank: Contributor
timestamp: September 01, 2017, 11:22:22 am
content: Possibly this:https://www.digikey.com/product-detail/en/te-connectivity-potter-brumfield-relays/PT78603/PB1536-ND/2397751

author: Anton4
author_rank: Newbie
timestamp: September 06, 2017, 07:27:16 am
content: Attaching a picture of the relay that broke down (TEC 1226 735100), didn’t finds any similar so I started looking for the socket to find a relay that fits.Is an unusual relay socket due to the coil connectors are not in line with the pins for the contact, the coil connectors is closer to the edge.To temporarily get around the problem, cables are soldered from the old socket to a new relay.
SMPS FAILED, feedback wanted. - Page 1
Forum section: electronics / repair

author: The_Todd
author_rank: Regular Contributor
timestamp: September 07, 2017, 01:29:21 am
content: Hello guys,Just after a bit of wisdom about this power supply.So its completly dead with blown fuse. Now if you look at the tracks near (i think) the secondary winding for the IC power supply, the has been a serious short curcuit. Now im getting pretty good at fixing these but this puzzles me a little. What would cause this? Perhaps a short in a voltage divider or diode.Its a HMI power supply used for industrial use, so thesegenerally arent a dodgy design. Also im not too fussed about fixing it, this is just spare parts that I work on to learn.Cheers,

author: The_Todd
author_rank: Regular Contributor
timestamp: September 07, 2017, 01:32:36 am
content: here are some pics, also should note this is after some very light ultrasonic cleaning.

author: Armadillo
author_rank: Super Contributor
timestamp: September 07, 2017, 02:22:37 am
content: my 2 cents;I would consider this as catastrophic failures, sudden and at large current meaning a dead shorts so severe that the protection networks didn't have the time to capture it.Mosfet or the Output schottky diodes short circuit or the pmic chip itself, In this case, the review sign indicates high percentage that the schottky diodes dead shorted.Just my opinion.

author: The_Todd
author_rank: Regular Contributor
timestamp: September 07, 2017, 02:40:23 am
content: hey, looks like you may be right, reading the schotty diodes (2 3-pin types in parallel) I get very weird reading in biased and reverse biased testing. so if these are shorted, shouldn't it burn out the terminals on the secondary side? how does it effect the secondary winding on the primary side?also lucky i don't want to fix this, they actually pop-riveted the schottys onto the heat sink :Scheers.

author: CJay
author_rank: Super Contributor
timestamp: September 07, 2017, 06:34:37 am
content: i'll have a go at repairing all sorts of things because it gives me a kick to fix things other people have rejected as too hard or scrap but I'd not bother with that one, too damaged, too cheap and not interesting enough to be fun.Riveted on devices aren't an issue, they're more common than you might think and in some high price items too, pop riveters are cheap and it's trivial to drill rivets out.

author: Armadillo
author_rank: Super Contributor
timestamp: September 07, 2017, 07:06:25 am
content: Quote from: The_Todd on September 07, 2017, 02:40:23 amCatastrophic failure meaning it will take many things with it, likely the fuse, mosfet will be destroyed with it on the primary side. The secondary winding may just survive but not sure. You can ring test it if you are curious enough. I don't think its cost effective to repair this one. Concentrate on your hung chang more worth the time, simple horizontal amplifier to CRT coil.

author: The_Todd
author_rank: Regular Contributor
timestamp: September 07, 2017, 09:19:54 am
content: Haha yeah, the scope looks like my next big project lol
Replace unshileded cable with shielded cable, is it a good idea? - Page 1
Forum section: electronics / repair

author: OmegaHyperion
author_rank: Contributor
timestamp: September 05, 2017, 09:23:37 pm
content: Well, the title basically asks the question,What im up to this time, is repairing a piece of equipment, where i need to create a custom cable of sorts. Basically i need to put 2 75 ohm 2.8mm OD 2KV (at least) rated coax cables, together with 4 normal conductors into a single cable.The coax isn't the problem, as i already know what will work. The question is, i would like to replace the 4 conductor ribbon cable that got destroyed, with 2 separate cables. The most convenient one for bundling the cable, is a 2.8mm OD shielded 110ohm cable.The 4 conductors are for the fallowing:+-15V power for an opamp.Opamp Offset control cables (going to a pot that is more convenient to access, then where the amp is)The question is, will the heightened capacitance of the shielded cable pose a problem with the amp offset correction, and if not, should i ground the shields, or leave them floating? (the connector happens to have a ground connector).If this poses a problem, ill go for unshielded cables.

author: Armadillo
author_rank: Super Contributor
timestamp: September 05, 2017, 09:38:01 pm
content: I think the shielding forms a capacitance and helps reduces RF and background noises since the application is merely DC power supply.But for practical purpose, this benefit can be simply replaced by a ceramic capacitor so in reality is a expensive way to run the cable like so.Furthermore the braids could come in contact with the core cable creating a short circuit.I would just follow the original for flex and aesthetic even though it will work with slight benefit.

author: OmegaHyperion
author_rank: Contributor
timestamp: September 05, 2017, 10:14:48 pm
content: I should probably also clarify what cable i am looking at using, its this:http://www.produktinfo.conrad.com/datenblaetter/475000-499999/486595-da-01-ml-VERDRAHTUNGSLTG__V_ST_D_Y_2X0_4_1__de_en.pdf

author: Armadillo
author_rank: Super Contributor
timestamp: September 05, 2017, 10:19:10 pm
content: Be sure that the core size  is thick enough for the power supply current and the voltage drop is the same or better than the original.Edit: 0.4mm2 Forget it! Just Drop the idea.

author: OmegaHyperion
author_rank: Contributor
timestamp: September 05, 2017, 10:25:52 pm
content: Good call, i had asumed the ribbon cable was a typical one, with 0.25mm^2 conductors, turns out its a 0.785 mm^2 conductor. Should have checked instead of assume i know.
Fluke 1520 repair help - Page 1
Forum section: electronics / repair

author: Rzadrejko
author_rank: Newbie
timestamp: August 15, 2017, 12:55:10 am
content: Please help ! Fluke 1520 blown up parts.See the picture attached. I need the 3 digit letter/number code on the sot-23 device and the resistor value.Thanks in advance.

author: jheatac
author_rank: Regular Contributor
timestamp: August 15, 2017, 01:27:54 am
content: Is that an insulation tester?Sent from my SM-G920V using Tapatalk

author: jheatac
author_rank: Regular Contributor
timestamp: August 15, 2017, 11:33:15 am
content: Sorry, I thought I had one I could take apart and tell you the values but mine is a 1587Sent from my SM-G920V using Tapatalk

author: Falkra
author_rank: Regular Contributor
timestamp: August 23, 2017, 01:04:07 pm
content: Hi, if you are still interested (too late ?) I can post pictures of mine.

author: Rzadrejko
author_rank: Newbie
timestamp: September 05, 2017, 09:10:25 pm
content: Thanks a picture would be great.Rich
Fixing damaged PCB of ERSA MULTI-TC soldering iron - Page 1
Forum section: electronics / repair

author: K
author_rank: Contributor
timestamp: September 05, 2017, 11:30:06 am
content: So I got myself a non-working ERSA MULTI-TC soldering iron, as a freebie along some purchase, and a couple of nice tips for it.As I had used this type of iron before and quite liked it, at first I thought just to buy the replacement controller PCB and simply replace it - the board was listed as available on ersa-shop.com. But, alas, it turned out that it is not intended for purchase, and I was informed that the iron should be sent to ERSA for repairs. This is still an option, but at first I wanted to understand how feasible is it to repair it myself.As far as I can tell the previous owner decided to change the power cord and in the process somehow damaged the controller PCB - the temperature control pot is squashed into pancake and also probably did other damage trying to fix it afterwards. The remains of the poor pot and knobs were just stuck into the handle. The PCB did not smell funny, so for now I assume the magic some is still in.The PCB itself was somewhat covered in flux, all I did was gently wash it with some acetone before taking the pictures.I have sourced what looks like a compatible pot (PIHER, 6mm, 5k), however upon inspecting the PCB discovered that it looks somewhat bad:- one broken trace and a maybe be a missing SMD component on one side (Picture "ERSA MULTI-TC Top"),- a broken trace without clear indication from where to where it was going on the other side (Picture "ERSA MULTI-TC Bottom").As far as I can tell there are no pictures or schematic of this PCB anywhere on the internet, so I need some help:- Is there anyone with ERSA MULTI-TC, willing to open it up and check for the traces and that SMD component and its value?- And maybe poke multimeter around the legs of pot, to see which ones are tied together?- Any other suggestions on how to repair it? Or should I just send it to ERSA and be done with it?Thanks!
HP 3562A - Power Supply replacement cap - Page 1
Forum section: electronics / repair

author: innkeeper
author_rank: Unknown
timestamp: September 04, 2017, 04:28:13 pm
content: I had my HP 3562A suddenly die. i traced it down to a bad tantalum cap in the "power down" section of the PS circuit. (schematic below)So here is my question. Is there any harm in putting in a 2.2uf aluminum electrolytic in there either temporarily or permanently.from what i can tell its a simple RC timer circuit for power sequencing on the startup - it ultimately controls the start of the PWM.At the moment, all i have on hand is 2.2uf aluminum electrolytics.i can order the part but that will take a few days plus its a holiday.Id love to get this up and running now, but, I don't want to cause any unforeseen issues in my rush to get this up.second question is, ... the cap went resistive (56kohms) Could i be missing something that could have caused this that i need to be checking or am i just looking at simply a bad cap on an old piece of gear and i shouldn't worry about it.I usually wouldn't be so worried / questioning myself about a simple fix but I don't wanna screw this upits not a piece of gear i can afford to replace.

author: SeanB
author_rank: Super Contributor
timestamp: September 04, 2017, 06:22:38 pm
content: If it is a 105C electrolytic put it in, provided it is a 35V or higher part. modern electrolytics are quite good if a decent brand, and will work there well enough.

author: innkeeper
author_rank: Unknown
timestamp: September 04, 2017, 11:36:31 pm
content: Thanks, i needed that little reassurance i was not missing something.So, i threw in a 50v 2.2uf 105C electrolytic in it to get it running. although it is not a good quality one, It will due till i get the replacement.if it will fit, i'll try and put in a higher voltage tantalum in there like a 35v vishay tantalum as a replacement just for peace of mind.reading the spec sheet the temperature spec goes up with derated voltage.should be good for another 28 years... could that be right - i guess it could - date codes i am reading are 5 week 89 and 14th week 89 and it looks like its never been opened.... pretty amazing!freaking power supply design is impressive. my first time working on one of these, but holy crap, its engineered like it as going to space and designed to actually be worked on. i am highly impressed.
Hardcard 20 Plus + bios dump - Page 1
Forum section: electronics / repair

author: poot36
author_rank: Frequent Contributor
timestamp: September 03, 2017, 04:40:12 am
content: Here are the two bios eprom files from a Hardcard 20 Plus+. Version F35 NEC D27128C socket U114 and Version B33 NEC D2764C socket U113. The file is a rar extension that I have changed to zip to upload here. You may have to change it back to make it work. These are raw binary dumps from the eprom chips.

author: poot36
author_rank: Frequent Contributor
timestamp: September 04, 2017, 06:54:05 pm
content: Note if you downloaded the old version of the dump before today it has extra padding at the start and end of the file. I have corrected that today. Please delete the old version and use the updated version. I have edited the original post with the correct version.
Tektronix 2335 oscilloscope No Power - Page 1
Forum section: electronics / repair

author: radioman56
author_rank: Newbie
timestamp: July 27, 2017, 08:04:51 pm
content: Hello Guys I Have a Question on my Tektronix 2335 oscilloscope That has No power.I've never repaid one of these but price was cheep on ebaya few days ago found a owners/Repair manual but not quite understanding it.has any one repaired these to bring it back to lifeMuch Thanks from Bill

author: alm
author_rank: Super Contributor
timestamp: July 27, 2017, 08:27:17 pm
content: Plug in the power cord? Check the fuse? There is no way to tell with the extremely limited information that you provide.This document may provide some guidance:http://sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf

author: ivi_yak
author_rank: Regular Contributor
timestamp: July 28, 2017, 12:52:47 am
content: send me pcb photo

author: tguillaume
author_rank: Newbie
timestamp: September 04, 2017, 03:42:56 am
content: Hi I repaired a 2236 a while back. It is similar. The PSU is a switching power supply so very dangerous, high voltage all over so be very careful! First of all download the service manual and follow step by step. There is also a tek scope repair guide which is great help. On the PCB there are a few jumper wires very useful to isolate the power supply from the rest of the circuit. Get a variac to be able to progressively ramp up the power. Without that you will end up blowing up components by the dozens. A 75w lights bulb in series with the main power line can help if you don't have a variac. Good luck!Sent from my SM-G950F using Tapatalk

author: tggzzz
author_rank: Super Contributor
timestamp: September 04, 2017, 09:22:58 am
content: Quote from: tguillaume on September 04, 2017, 03:42:56 amCaution with using a variac with an SMPS. Join TekScopes and readhttps://groups.yahoo.com/neo/groups/TekScopes/conversations/topics/139963especially message 6to understand why that can damage the scopeCaution with using a light bulb with an SMPS.https://youtu.be/9jd9idAlXDY

author: bd139
author_rank: Super Contributor
timestamp: September 04, 2017, 09:31:32 am
content: This. Really annoys me that debug approach.For those who can't be arsed to read that:1. Watts in is relatively constant in and out of the SMPS. However as P=IV, lower voltage = more input current = more stress and more violent explosions.2. Lamp is a non linear V-I device. This turns it in an oscillator as the source impedance changes as it warms up.Use this rather stupid old tech with linear supplies only and even then I question the value other than for dropout tests and then only the variac. A lamp test is stupid when you can pretty much test all the likely problems away independently with a DMM BEFORE you have to even apply power.

author: oldway
author_rank: Super Contributor
timestamp: September 04, 2017, 01:07:03 pm
content: It is a 2335, not a 2235......2335 has only linear power supplies....
Philips pm 3055 front panel button stuck. - Page 1
Forum section: electronics / repair

author: DoorVb
author_rank: Newbie
timestamp: September 02, 2017, 03:41:01 pm
content: Recently I picked up a Philips pm 3055 for free, it was working but the volts per devision on channel A couldn't go lower then 0.1. I figured that wouln'd be a giant problem as I can use channel B.Channel B was working fine until a button got stuck (The one in the red circle is broken and the one in the blue circle appears to be working but I can't say for sure). Now the oscilloscope is stuck beacuse of this one button.Any help would be appreciated.

author: Shock
author_rank: Super Contributor
timestamp: September 04, 2017, 02:35:57 am
content: Service manual is herehttp://www.qsl.net/vk5bar/AHARS-Resources/Philips%20PM3055/PM3055%20Service%20Manual.pdfHere is a similar logic problem. Once you fix the button you can do comparisons between channel A and B but you can only go so far without needing another oscilloscope to aid in troubleshooting.https://www.eevblog.com/forum/testgear/pm3055-phillips-scope-1x10x-problem-on-channel-a/In the service manual chapter 10-3 covers the front panel controls. That pcb is static sensitive, also the shafts of the pots are plastic and fragile as well, I can see you already have a broken one.If it's a stuck button you can try cleaning it on the pcb with iso alcohol, remove it and perform micro surgery (if you can get it open) or rob one from elsewhere e.g. Channel A. It's also possible to retrofit similar buttons but pretty pointless unless you are attempting to repair channel A.Either way unless it comes unstuck you will need to dismantle the oscilloscope.

author: george.b
author_rank: Frequent Contributor
timestamp: September 04, 2017, 03:41:06 am
content: Removing the front panel isn't difficult. If memory serves me right, it is held in place by two screws on the back of the panel, on the inside. They should be accessible by just removing the top cover.
R&S CMU200 front module upgrade (FMR5 to FMR6). Possible? - Page 1
Forum section: electronics / repair

author: Velund
author_rank: Regular Contributor
timestamp: September 01, 2017, 01:43:32 pm
content: Hello!I have older CMU200 unit with FMR5 (AMD-based) processor board, very "tired" LCD backlight and keyboard, and a number of other blemishes. PS/2 keyboard port on the back of instrument. Got offer for a complete front with FMR6 (Celeron) from unit being parted, that also have PS/2 on the back.Is it possible to simply swap front modules (FMR5 to FMR6) and have a working unit? Is serial number of unit stored somewhere on motherboard or CPU board have the serial "on the board"?

author: Bicurico
author_rank: Super Contributor
timestamp: September 01, 2017, 04:48:56 pm
content: Hi,I am by no means the best person to reply, but I think you can actually swap the module - it is just a PC, by all means.Even if it is not compatible, it would probably be worth it for the LCD alone... Depending of the price.Regards,Vitor

author: eb4eqa
author_rank: Regular Contributor
timestamp: September 03, 2017, 09:06:10 pm
content: Hi,It will work. I have interchanged them and found no issues.If your main issue is the backlight, you may very well find another aged one in the replacement front panel. What I recommend is to upgrade the backlight to LED. Amazing improvement:http://www.rbarrios.com/projects/LCD2LED/Regards,Roberto

author: Velund
author_rank: Regular Contributor
timestamp: September 03, 2017, 09:31:25 pm
content: Quote from: eb4eqa on September 03, 2017, 09:06:10 pmReplaced it yesterday, with moving old HDD from FMR5 to FMR6. No problems observed. Backlight is way brighter that I had on FMR5 (almost unusable with a daylighjt during sunny day).Another problem was keyboard - after a week without use, keys (especially the row under the display), stoped to work at all. I had to "massage" each key until it started to work. Cleaning conductive pads with alcohol, using soft cloth, helped not so much.
Mechanical Repair HP 5255A (plug in for 5245L) 'Frozen' Dial - Page 1
Forum section: electronics / repair

author: VK5RC
author_rank: Unknown
timestamp: September 02, 2017, 01:16:36 pm
content: Having repaired my 5245Lhttps://www.eevblog.com/forum/repair/repair-of-hp-5245l-nixie-frequency-counter/- a lovely beast - I am slowly getting some of the many plug ins that are available (and some other 1960s counters).The 5255A is a heterodyne type frequency converter that takes the 1MHz reference signal from the main counter, multiplies it many times (to 200MHZ first) then mixes it with the signal to be measured (3-12GHz),mixing it down into the 50MHz bandwidth of the 5245L.The 5255A uses a tuned cavity to select the Nth harmonic of the 200MHz derived from the 5245Ls reference, the harmonic frequency selected is determined by the mechanics of the cavity, controlled by some lovely gears. See HP Journalhttp://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1964-06.pdfMy unit had a problem in that the 'Knob' would turn freely - and would appear to reach end stops - but the 'Dial' (indicating the approximate harmonic being tuned) would not move at all. See Front Photo.A manual is available from Keysight (Thanks guys!) but isn't a lot of help with the mechanics.http://literature.cdn.keysight.com/litweb/pdf/05255-9031.pdf?id=1869245After quite a bit of experimentation, access to the area requires removal of the entire bottom aluminium plate - see photo Access.The front Knob is removed by an imperial Allen key, and the Dial by Phillips screws. Also removal of other screws holding on the front cover is required. The front cover can then be moved forward little to gain access. See Photo GearsThere is a shaft - labelled A in the below photos, and the gears B and C are swaged together, and D and E should be swaged together but weren't in my unit. The lubricant between the shaft A and gear E had dried - fixing gear E (and the Dial that it drives eventually) very firmly to the chassis . gear D was being driven very nicely and rotating around the swaged area. With apologies to robrenz (a mechanical genius) a few well punched divetts again linked gears D and E. See photo gears 2.Hope this is of some help to others.Now on to the electrical fix!
PCB warmer/rework station - Page 1
Forum section: electronics / repair

author: sunspots
author_rank: Contributor
timestamp: September 05, 2017, 11:54:41 pm
content: I was wondering if someone could point me towards (or just list models of) some decent Hakko rework stations/board heaters.What I'm looking for is something that will accurately warm the PCB underneath, as well as something that can hold the board in place (preferably the size of a motherboard ATX minimum). And what would be cool in addition would be something that could hold a Hakko 852 hot air rework tool, like a drill press.I've been going with used/old models to save thousands of dollars, I'd like to continue down that path if possible.Thanks!
Fixing a DiabloSport Tuner, Cap replacement? - Page 1
Forum section: electronics / repair

author: Cljnco
author_rank: Newbie
timestamp: August 26, 2017, 04:20:19 am
content: Hello folks, I was givin a dead tuner. I popped it open and found this. I think is a 220uF 6.3V Tantalum cap? You know the blown one next to the TDA7052A audio amp chip. But I can't figure out how to find a replacement for it. Anyone help me out?

author: Morten
author_rank: Newbie
timestamp: August 29, 2017, 09:32:30 pm
content: Hi there.Heve you tryed RS-Online, they have lots of suitable replavements.Alternatively, if the space allow it, use a electrolytic capacitor, and give it a blob of hotmeld to keep it in place.GreatingsMorten

author: A@ron
author_rank: Contributor
timestamp: August 30, 2017, 01:41:30 am
content: 220uF 6.3V Vishay brand cap with a D case code would be my guesshttp://www.mouser.com/ProductDetail/Vishay-Sprague/293D227X96R3D2TE3/?qs=sGAEpiMZZMuEN2agSAc2ppeu9zLjpAvsTIxfmapjqF0%3d

author: Cljnco
author_rank: Newbie
timestamp: September 02, 2017, 05:19:08 am
content: Thank you. Ordered and worked great. I was under the obviously incorrect assumption the markings would be same, please be gentle, I am still learning. This cap wasn't marked in any way the same, however once I replaced it among couple other things everything seems to be functioning well.I actually thought of that however I didn't want to use an Electrolytic to replace it because I was unsure how why they used a tantalum cap in the first place. Also would electrolytic need a different value?Anyways, thank you for the help, I really appreciate it.
SONY EVI-D70 PTZ camera (SOLVED) - Page 1
Forum section: electronics / repair

author: BFX
author_rank: Frequent Contributor
timestamp: March 17, 2017, 01:07:18 pm
content: Hi all,I have here on the bench broken SONY EVI-D70 PTZ camera.I'm looking for service manual.I found few web sites but all is paid.

author: BFX
author_rank: Frequent Contributor
timestamp: March 26, 2017, 10:40:37 pm
content: Somebody to identify this guy? (looks like some main MCU, or DSP)I can't find any information.

author: BFX
author_rank: Frequent Contributor
timestamp: September 01, 2017, 12:08:14 pm
content: Ok guys so let's get back to repairing this cameraAfter little hard communication with Sony I've got the service manual(I'm so sorry Sony I had to be a bit rude in case your official service was not able to repair this camera)But it was not so useful as I thought, but it was enough useful to repair the cameraFirst of all in the service manual there is nothing mentioned about the state what I observe (when power LED and state LED is blinking together and camera don't respond on any command from IR or serial interface).But when you have schematic, is more easier to investigate problem.And problem was so obvious. There was missing communication between main MCU and camera video module. Yes bad connection between FCC cable and camera module connector.After take a part cleaning and put it together all is working like a charm.Conclusion:It's great product and we have tens of those PTZ cameras worked years in the field, but service and support is big fail
Tektronix 465B Unstable Trigger - Page 1
Forum section: electronics / repair

author: cjs2pc
author_rank: Newbie
timestamp: August 30, 2017, 07:06:00 pm
content: Hi guys,My Tek 465B scope has some issues triggering when the source is set to Norm under certain circumstances.The trigger light comes on, but the waveform display is not stable and walks across the screen. Sometimes one channel is stable, but the other is not. Often neither is stable.I want to use the Norm setting so I can get a view of two channels at once.Example Setup: 1 KHz square wave calibration signal, 2 channels active and trigger level adjusted so the trigger light is lit for triggered.It will stablize fine on some time divisions and not othersAdjusting the trigger holdoff slightly from centered will sometimes cause the display to stabilizeSwitching from AC trigger coupling to LF Reject will often cause it to stabilizeSetting source from Norm to Channel 1 or 2 works just fine for that channelLeaving it on Norm and turning off channel 2 will cause channel 1 to stabilizeSometimes the trigger light pulses very rapidlyI don't have experience with analog scopes and this one is new to me. Is this a normal thing, or do I maybe have some issues with my triggering board?I absolutely love this scope and want to fix it if I can.Thanks,

author: oldway
author_rank: Super Contributor
timestamp: August 31, 2017, 07:26:43 am
content: It looks like a bad contact problem.The semiconductors are mounted on sockets. Stir the transistors and tunnel diodes from trigger and base time circuits in their socket (with power switched off)Clean the contacts.Also check the power supplies, especially the ripple.If it does not solve the problem, you will have to have another oscilloscope to probe this one.

author: cjs2pc
author_rank: Newbie
timestamp: August 31, 2017, 12:01:09 pm
content: Thank you, I shall give that a try. I do have another oscilloscope if needed.

author: KWKolb
author_rank: Contributor
timestamp: August 31, 2017, 10:49:11 pm
content: It may be operating correctly. According to the Tek 468 operator's manual, page 18, "Source Switch:" "The waveform displayed on the CRT is the source of a composite trigger signal. Stable triggering of non-time related signals usually can be obtained by setting VERT MODE to ALT, SOURCE to NORM, COUPLING to LF REJ (high frequency signals only) and adjusting thru Trigger LEVEL control for a stable display. Time relationship between the Channel 1 signal and Channel 2 signal is not indicated on the display."A case of only having one trigger level for two sources. LF REJ or AC Coupling removes any DC bias between the Channel 1 and Channel 2 signals, allowing a single trigger level to be used for non-overlapping signals. "A trap for the younger players, there."I believe the Tek 465B is similar, although I could not find a similar reference in the Tek 465B manual.VR,Kevin
PRINTER EPSON 1430W - Page 1
Forum section: electronics / repair

author: quinoara
author_rank: Contributor
timestamp: September 06, 2017, 04:18:35 am
content: Greetings to the Foristas gentlemen:I have the modified reference printer on Flat bed working with sublimation inks.I want to make a modification to put LED UV, but I have the disadvantage that in the bottom of the CARTRIDGE DOOR carries a PW sensor, which prevents me from placing the LED there. I want to ask the foristas community if it is possible to locate it in another site since it seems that only mind works as a sensor paper and with the tray to print CD-ROMS. Do you think, what observation should I have?Thanks for your comments.Attached photos
Tektronix 2235 Horizontal problem - Page 1
Forum section: electronics / repair

author: buck converter
author_rank: Regular Contributor
timestamp: August 31, 2017, 09:48:09 pm
content: Recently acquired a tektronix 2235 from a local university. I am not sure if what I recorded is normal.In these two videos I recorded the edge of the probe compensation square wave. I. The first one the x10 mag is activated.https://youtu.be/v6NTnEvhzTMhttps://youtu.be/DcQEsyPuBJYHere is XY mode. I can only adjust the x position a little bit but y goes across the screen.https://youtu.be/lmHDz2LqZu4I have a proper soldering iron and another analog oscilloscope that could be used to fix this but I do not have an isolation transformer, nor do I have any formal EE education (I'm in high school), so I probably can't do more than to tune knobs, check power supply voltages and replace capacitors.

author: Armadillo
author_rank: Super Contributor
timestamp: August 31, 2017, 10:11:01 pm
content: You need to have input on both X and Y. Read the manual.
diode N44K - Page 1
Forum section: electronics / repair

author: spdf
author_rank: Contributor
timestamp: August 31, 2017, 06:51:42 am
content: Hello, I pulled a diode from TV's smps and it says n44k on it. Does that mean 1n4400? 6.8V Zener? Looks like an ordinary silicon diode though.Cheers.

author: Zucca
author_rank: Unknown
timestamp: August 31, 2017, 12:22:22 pm
content: Well, a power supply, a few R and DMM can do miracles sometime.

author: keymaster
author_rank: Regular Contributor
timestamp: August 31, 2017, 12:49:30 pm
content: give us some photos of the board ( both sides ) and the "diode"

author: spdf
author_rank: Contributor
timestamp: August 31, 2017, 01:40:43 pm
content: https://drive.google.com/file/d/0B8KUNmX2TYSUbjFxN29jdkRLU1k/view?usp=sharinghttps://drive.google.com/file/d/0B8KUNmX2TYSUV3FJMmlJeDVnLUk/view?usp=sharinghttps://drive.google.com/file/d/0B8KUNmX2TYSUNEZwSS1rMzEzYTA/view?usp=sharinghttps://drive.google.com/file/d/0B8KUNmX2TYSUMnhuNjZ3Zzk3X3M/view?usp=sharingdiode D202