hybridfree/eevblog-posts huggingface dataset:
Fender Blues Deluxe - Troubleshooting and Repair  - Page 1
Forum section: electronics / repair

author: jcrubin
author_rank: Frequent Contributor
timestamp: March 25, 2019, 12:55:41 pm
content: While I generally do not work on re-pop's or Hybrids, I decided "Why not" so here goes..........This is a Blues Deluxe, a modern amplifier that has tubes in it is the only way to describe it. This is not a pleasant device to work on. Given that the problem was described as a power issue, I will need to go through the caps before anything just to be safe and check the fuse.The meter says nothing has exploded, or at least nothing plans to yet. so a Variac is a safe bet with a current meter. It turns out whatever the problem is, its not a dangerous power issue. Actually, besides the fact that all of the pots are TERRIBLE and the thermistor was worse for wear, the amp works, and it sounds pretty good too!!!!So whats wrong with this thing?Ok Ill test the tubes, tap em too turn the test, see if theres a hidden short.... nothing.....I did take a moment to Deoxit all of the Pots and tube sockets, but I could not find the problem.......that is until it ran for an hour or so.Weirdest thing, plug in the cable makes a noise, puts the amp into standby, replug in the cable does the reverse!!!! Huh???So I noticed that the first stage is not effected by this cutout, and the first stage has a noisy tube... very noisy...Even with the tube replaced , when this event happens it seems everything goes crazy in this amp including LED's and relays. I decided to check an OPAMP for a signal during this event. turns out its dropping power at this time. This power is off a common rail. In that rails power supply a high wattage resistor is found to be the culprit.Furthermore, all of the wire connectors on the harness were reconnected to clean the connections as well. The entire board will need to be disassembled up-top and folded out to replace the components, followed by reassembly.After this a smoke test is conducted on the Variac. Everything sounds great. Finally a new 12AX7 goes in and the cover goes back on...
HP 6960A PSU anyone mains connector? - Page 1
Forum section: electronics / repair

author: Kjelt
author_rank: Super Contributor
timestamp: March 23, 2019, 05:34:14 pm
content: Another salvage from destruction by the iron melters and scrapyard handlers.Am I crazy by saving this or are there more people like me who can't find it in their heart to let something like this just be destroyed ?A HP6960A PSU, so cute, luckily without tubes or I would be lost (no tube experience here).No this puppy has real Bendix B1203 TO3 solid state transistors. Anyone ever heard of Bendix ?My question is does someone has a schematic for this small PSU ?It does not look that difficult so probably will get it back in working condition but it still would be nice to have some paperwork and dates on it.thanks.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 23, 2019, 08:31:11 pm
content: There is no tube in this, its an all transistors psu ?? a 1967 psu in the documenthttps://www.radiomuseum.org/r/hp_power_supply_6960a6960.htmlservice manual you can download it ........ 1.7 meg Hit the green download icon top of the page ...https://www.manualslib.com/manual/703644/Hp-6960a.html?page=1#manual

author: Kjelt
author_rank: Super Contributor
timestamp: March 23, 2019, 10:29:32 pm
content: Thanks that solves the first questions, the thing is almost my ageNow I need one more thing, a fitting mains connector, fitting it with a new IEC connector would be a shame.Also recapping I want to reuse the old cans, they look way to nice to discard.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: March 23, 2019, 11:06:07 pm
content: Wow, what a cutie.Here are some power cords in Germany:https://www.ebay.com/itm/Hewlett-Packard-Netzkabel-Power-Cord-for-old-US-made-test-equipment-Belden/202531165401

author: coromonadalix
author_rank: Super Contributor
timestamp: March 24, 2019, 01:28:33 am
content: If you want to stay vintage and original the ebay link is a good choice
Tektronix DPO3034 rotary encoders - Page 1
Forum section: electronics / repair

author: dzseki
author_rank: Frequent Contributor
timestamp: March 22, 2019, 02:58:47 pm
content: Can anybody tell off-hand what type of rotary encoder is needed in a Tektronix DPO3034 scope? I am going to replace the multifunction and vertical position encoders, I believe they are the same. It would be nice if I would not have to leave the scope gutted until the new encoders are arriving.This scope is at my work, and was rendered to be uneconomical to repair officially (got a 3000€ quote for it!!!), and I figured it might worth a try to replace those few encoders on an otherwise functioning scope...Thanks!

author: coromonadalix
author_rank: Super Contributor
timestamp: March 22, 2019, 08:53:20 pm
content: can you get some numbers on them ?? by slightly dismantling the front panel vs the pcb ??

author: dzseki
author_rank: Frequent Contributor
timestamp: March 23, 2019, 08:19:25 pm
content: I'll look at it on monday. I was just hoping that others probably did similar repair on this particular model family so they would know a suitable replacement.

author: pbarton
author_rank: Frequent Contributor
timestamp: March 23, 2019, 08:36:30 pm
content: Appears to be a common problem, see....The replacement encoder was an Alps EC12E24104A6 available from Farnell:
Low-profile, 2.54mm connection between two boards - Page 1
Forum section: electronics / repair

author: KaneTW
author_rank: Frequent Contributor
timestamp: March 22, 2019, 08:34:28 pm
content: I'm replacing a LCD on a home appliance with a new one. Since the appliance is pretty old, the original LCD is unavailable.The original LCD has a through-hole pin header that mates into a SMD receptacle on the main board, with a total clearance between the two PCBs of about 3-4mm. Increasing that distance would make some buttons on the main PCB unpressable.Now the new LCD also has a 2.54mm pin header footprint (unpopulated), but it's offset by about 5mm vertically. There's not enough space to just shift the entire LCD.Any ideas on how to connect these?Some pictures here (gallery):https://imgur.com/a/oOGxAb0

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 22, 2019, 08:50:48 pm
content: Oh no worries, those are plenty available. Shop for bottom-entry, SMT female headers/sockets.Tim

author: KaneTW
author_rank: Frequent Contributor
timestamp: March 22, 2019, 09:16:23 pm
content: There's already one of those on the main board. The problem is the offset between the existing LCD's header and the new LCD's.

author: LateLesley
author_rank: Frequent Contributor
timestamp: March 22, 2019, 09:20:18 pm
content: I think in that situation, i'd just use ribbon cable, and solder between the two boards, leaving a little extra ribbon for manoeuvrability,, and so you can fold it flat, level with the PCBs. It's about the easiest way I can think of. Maybe others will have a better suggestion.

author: wraper
author_rank: Unknown
timestamp: March 22, 2019, 09:20:28 pm
content: Replace female connector on PCB with male connector. If space allows, solder male connector on LCD as well and connect boards with cable which has female connector on both ends. If space does not allow it, solder cable on LCD end directly to PCB.

author: KaneTW
author_rank: Frequent Contributor
timestamp: March 23, 2019, 12:20:31 am
content: Good idea, and probably what I'll go with. I've been trying to find a low-profile ribbon cable connector (cable -> socket) but the best I found was Samtec ICSD at ~9.5mm height. Probably going to have to make do with that.Most likely will have to solder the cable to the LCD, but that's not too big of a deal.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 23, 2019, 08:56:17 am
content: Oh, so the socket is the main board, and the header is the LCD? Ah, so then the last picture is comparing old and new? (This would've been more obvious with captions..)Yeah, you aren't going to find something commercial to shift the centers. Best bet, interposer board, with SMT pins (could use an SMT header and pry off the plastic body after soldering), and the LCD connections will have to be SMT pads, soldered through the header holes (the solder equivalent of a plug weld joint). Barring that, just wire it one at a time, ribbon cable would be alright, or loose wires. Preferably thinner wires (28ga wire wrap style?) so it doesn't get too in-the-way.Bonus points for wiring to a header, as a top-side plug? Mind the reversed pinout of course.Tim
Fluke 289 battery-tab broke :( - Page 1
Forum section: electronics / repair

author: awallin
author_rank: Frequent Contributor
timestamp: March 22, 2019, 05:05:05 pm
content: my Fluke 289 has batteries in the back cover which make contact with the main body.But now one of the tabs brokehttps://photos.app.goo.gl/YUuxqsTah1TAxEFG6any obvious/simple fixes or spare-part suggestions?? thanks!

author: coppercone2
author_rank: Super Contributor
timestamp: March 22, 2019, 05:06:35 pm
content: I soldered on a sheet of copper covered solder with a walnut husk under it to act as a light springIf you touch it quick with lead solder it will stick to the nickle plating but it won't burn the plastic.Tin both surfaces and flux before you solder the new part on. Maybe I just did a press fit But I think it solders, was a few years ago.Shitty design choice on Flukes part, that tab breaking is a COMMON problem I have seen many times on this forum.

author: LateLesley
author_rank: Frequent Contributor
timestamp: March 22, 2019, 05:15:35 pm
content: Maybe get one of these, and fit it to the metalwork??https://www.ebay.co.uk/sch/i.html?_odkw=keystone+209&_osacat=0&_from=R40&_trksid=m570.l1313&_nkw=keystone+209&_sacat=0

author: Heartbreaker
author_rank: Unknown
timestamp: March 22, 2019, 06:03:22 pm
content: Quote from: LateLesley on March 22, 2019, 05:15:35 pmI came hele to say the same. Battery terminals are solderable springs. Keystone has a lot of different types like the one above.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 22, 2019, 08:37:37 pm
content: why not ask at Fluke ??

author: coromonadalix
author_rank: Super Contributor
timestamp: March 23, 2019, 01:51:29 am
content: saw this on ebayhttps://www.ebay.com/itm/20Pcs-Silver-Tone-Metal-AA-A-CR2-9V-Battery-Positive-Negative-Contact-Plate/322872100874
Need Help With Korean A-One AM-0629 Chassis - Page 1
Forum section: electronics / repair

author: Ookpik
author_rank: Contributor
timestamp: March 18, 2019, 12:20:22 am
content: I am fixing this chassis for a friend and am having trouble. I have deduced that the problem is most likely the voltage regulator however I have no idea which part or parts comprise the voltage regulator.The chassis is the type that was used as a replacement chassis for 1980’s video arcade games. Unfortunately, no documentation seems to exist for this chassis. The closest schematic I have located can be foundHere.A larger image of the chassis can be foundHere.Any help would be greatly appreciated!

author: Ookpik
author_rank: Contributor
timestamp: March 22, 2019, 06:29:46 pm
content: I did a cap kit on the chassis. No change.If anyone else has any suggestions they would be greatly appreciated!

author: coromonadalix
author_rank: Super Contributor
timestamp: March 22, 2019, 08:43:12 pm
content: hum check on the aluminum plate, i think the Q05 is a regulator or the flyback driver, do i see some U02 near the plateyour closest schematics is for speakers not for an monitor
Cheap Dmm glitch - Page 1
Forum section: electronics / repair

author: X13
author_rank: Newbie
timestamp: March 22, 2019, 08:11:57 am
content: After seeing Dave being impressed with the aneng 8008, I ordered one on bangood .After a long trip from China the meter arrived, I started using it and within a few months I blew up the current range fuse. While checking the fuses on both the current and voltage ranges I realized that even the voltage range fuse was blown.I removed both the fuses but miraculously the voltage and resistance functions still work.(the current range doesnt work but thats expected anyway) What's the point of fusing the voltage range when the meter can still measure voltages without it? I this a common thing or am I mistaken or did I get a faulty meter?(Ps the fuse contacts on the voltage range are not shorted)

author: martin1454
author_rank: Regular Contributor
timestamp: March 22, 2019, 08:54:04 am
content: the 2 fuses are not connected to the voltage range / resistance range - The 2 fuses are only used in current measurement, and there is 2 different fuses to the different ranges of current measurement.
F27 resistor value - Page 1
Forum section: electronics / repair

author: montarbo
author_rank: Contributor
timestamp: March 17, 2019, 08:24:18 pm
content: Hello,Thanks a head for help with SMD resistor value. A code F27 on the resistor itself.

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 18, 2019, 08:10:48 am
content: Size, circuit context and maybe a photo would be helpful.Any way it could be a fuse?

author: montarbo
author_rank: Contributor
timestamp: March 18, 2019, 11:41:06 am
content: 1812 package and its in PSU mains input to an industrial LED light, there are two of these in series with a TH (green, black, silver, gold, blue), ieF27--TH as above--F27. Both the F27 are fried.

author: montarbo
author_rank: Contributor
timestamp: March 20, 2019, 07:35:45 pm
content: Any ideas???

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 21, 2019, 06:28:58 pm
content: Check if there is a fuse anywhere else.Is TH a NTC thermistor? What power is the light?With no better clues I'd throw in a couple of 27fusible resistors.

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 21, 2019, 08:28:16 pm
content: If this is indeed a resistor, this should be a 12Mohm, +/-5% resistor.See here for SMD resistor marking:http://www.marsport.org.uk/smd/res.htm

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 21, 2019, 11:52:21 pm
content: 12Mon the power input that's not going to fit...Maybe TH is trough-hole, in that case the TH would be an inductor.An inductor and series resistor is a common setup on the input of cheap SMPSs. I'd still stick to 2x 27but check power consumption and size of bulk capacitor.
Removing a "glued on" encoder disc on a BLDC motor - Page 1
Forum section: electronics / repair

author: chris_leyson
author_rank: Super Contributor
timestamp: March 20, 2019, 09:45:35 pm
content: Today I managed to kill a Hall sensor output on a small BLDC motor, one output is stuck at 4.5V. Should have insulated the bare wire ends, that will teach meIt's probably an easy fix, just remove the rear PCB and replace the broken sensor. Trouble is the encoder hub is glued onto the rear shaft and I can't get the PCB out. Heating the encoder hub to soften the glue is not going be an option because of too much thermal mass.The encoder sensor is a Avago part and the 250 line encoder disc might also be an Avago part but there is no grub screw to mount it onto the shaft, it's glued on, how dumb is that. It probably takes more assembly effort messing around with glue than simply tightening up a grub screwI'm starting to wonder if this was a deliberate design choice to make the motor non-repairable or maybe it was a cost down to save the cost of a grub screw who knows but it's poor design. BTW motor is Hurst DMA0204024B101 aka Microchip AC300022. Made in America, nice motor but shame about the electronics interface.

author: chris_leyson
author_rank: Super Contributor
timestamp: March 20, 2019, 10:53:42 pm
content: Forgot to post a picture. There is no way that encoder disc is coming off and that is before I've even had a chance to find out what Hall sensors they are using. There is no diode protection built in, not that I can see so more cost down. It's a good motor but a shame about the poor electronics design.

author: amyk
author_rank: Super Contributor
timestamp: March 21, 2019, 12:03:26 am
content: Solvent might work... depends on the material.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 21, 2019, 02:25:08 am
content: Are you sure it is glued - could it just be a press fit?E.g. they could have heated up the aluminum wheel to expand it and then press it on the steel shaft.

author: chris_leyson
author_rank: Super Contributor
timestamp: March 21, 2019, 04:53:28 pm
content: I initially thought the encoder was glued on because there is a soft silicone like adhesive on the top and bottom of the encoder disc, I assume this is holding the disc onto the hub. I think a press fit is quite likely as there is a machined recess in the hub and also Hurst Manufacturing got back to me and said I need a special tool to remove the encoder. Given that the shaft diameter is 7.6mm I don't think I'm going to find a replacement any time soon so the encoder is staying put. At least I've still got two Hall sensors working as well as the encoder so I've got information to get rotor position.
[SOLVED] Hantek MSO5074FG - stuck at self-cal step 34/66 - Page 1
Forum section: electronics / repair

author: aandrew
author_rank: Frequent Contributor
timestamp: March 19, 2019, 04:43:09 pm
content: I have one of these and while doing some small-signal measurements (power supply ripple) I've noticed that the scope seems to have a ~80mV offset at the 50mV/div scale. This offset is present on AC or DC coupling (not when the coupling is set to GND).I thought perhaps I should run a self-cal so I disconnected everything from the front panel and ran it, but it got stuck at step 34. Hantek says it should take about a half hour but even after running it overnight it's still stuck at the same step. They are unwilling to give me any information to try to resolve this on my own but I know there are some people here with a lot of experience with hacking this device so perhaps some of this info might be floating around eevblog...Does anyone here know what the various self-cal steps are or more specifically how to get past step 34?

author: aandrew
author_rank: Frequent Contributor
timestamp: March 21, 2019, 09:05:22 pm
content: So I opened up the scope just to poke around and immediately found a problem:After replacing all the caps in that section (the electrolytics sprinkled around the rest of the board all looked fine) the unit powered up and I did a self-cal which completed successfully! I guess whatever is going on around step 34 was waiting for the supply to be quiet and with those toasted, bloated caps it could never get there.So I did the natural thing next: I replaced the HEF4052s with CD74HC5052s from TI (better analog bandwidth), installed the missing ethernet components and added the JTAG headers.
Racal-Dana 5004 multimeter (was display segments, now on to others probs)  - Page 1
Forum section: electronics / repair

author: valley001
author_rank: Frequent Contributor
timestamp: March 15, 2019, 10:36:36 pm
content: Hello all,I got a Racal-Dana 5004 multi meter incoming for what I think is a decent price. One thing I know is wrong with it is one segment on each display digit does not light. It appears it may be the same segment on each digit. I am wondering if anyone has had experience with this fault in the past, and what I should look at when it arrives. Is this a multiplexing fault of some type?

author: coromonadalix
author_rank: Super Contributor
timestamp: March 15, 2019, 11:29:27 pm
content: Most display instruments are somewhat multiplexed, that way you can save on many pcb space, data lines etc ...If the same segment is off on many displays, you know its multiplexed in a way, you'll have to find the schematics or try to decipher how your display is working, drivers ic's etc ... maybe a bad solder, a broken trace, failed driver ...I only found out a 5001 model ??

author: valley001
author_rank: Frequent Contributor
timestamp: March 20, 2019, 10:37:43 pm
content: So it turns out the display is just fine, all segments operating normally.I assumed the internal calibration factors would have been lost due to the age of the 3v lithium batt, but they are intact. The batt looks sort of like a cr123, I wonder if I could simply replace the original with a fresh cr123? Amazingly it still shows 3v on my DMM.I bought this because it was cheap and in very nice cosmetic condition, but also to use as an additional comparison for my Fluke 332D. With the 332D set to 1v the Dana 5004 dithers 20-40 counts above and below 1.00000 but it never settles. I am wondering if this could be a fault with the meter. I have been browsing the manual and it appears it should be able to display a stable reading.If this is indeed a problem, does anyone have advice on where to look first?I did notice three large electrolytic caps (C82, C80, and C77) on the mother board show evidence of heating, their outer plastic shrink wrap coating has melted through in spots. I checked them in circuit with my component tester and they test in spec with low ESR. So? I think these are PSU filter caps so could ripple impact the stability of the meter?Edit: I checked the output of the 332D on my scope I am seeing around 16-20mv p-p ripple.

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 21, 2019, 08:38:18 am
content: H?I would definitely have a look at your 332D's bookwork again – 15–20mV on a calibration source is definitely a bit much for that type of instrument and may well be enough to cause the LSD on the display to jitter – especially with modern a/d converters!Are you sure the 15–20mV p–p isn't simply "grass" from the oscilloscope amplifier itself that you monitored the calibrator's output with?Chris Williams
YAMAHA RX-V675 - PS2 PROBLEM - Page 1
Forum section: electronics / repair

author: nbrezovec
author_rank: Newbie
timestamp: March 19, 2019, 08:46:10 pm
content: Hello,The Yamaha rx-v675 comes off after 5 minutes with a loud noise in the speakers! After it goes off, it may turn on normal. The error is PS 158The error does not occur immediately. After 5 minutes the PS2 voltage is not stable. It's obviously overwhelming, and I do not know what ...Sorry for my bad EnglishPlease help

author: PKTKS
author_rank: Super Contributor
timestamp: March 20, 2019, 02:02:49 pm
content: PS stands for PowerSupply - other codes indicate last readingsand sometimes a good hint where the fault may be,but YAMAHA gear is anything but simple to dealfar too much details and too much stuff crammed together.Download the manual and start a tracking down procedure fromthe PSU mains which needs to be carefully examinedPaul

author: nbrezovec
author_rank: Newbie
timestamp: March 20, 2019, 09:53:39 pm
content: The problem was in IC 7912. Receiver is repaired.
Tektronix 7313 repair - Page 1
Forum section: electronics / repair

author: psykok
author_rank: Frequent Contributor
timestamp: March 05, 2019, 10:15:27 am
content: Hi,Just bought a some instruments and got this Tektronix 7313.The scope is turning on but the screen get totally green after a few seconds.If I install the 7b53an module in any of the 3 places, the scope is loosing the 5v rail (the plug-in is working, no issue with it)Installing a vertical module like the 7a15 is not disturbing the 5v.Any idea what could cause this issue?I will sign the PSU tomorrow to check if something is bad there.Alex

author: David Hess
author_rank: Super Contributor
timestamp: March 05, 2019, 11:21:35 am
content: The 7313 is an analog storage scope so the CRT includes a flood gun which illuminates the entire CRT depending on operating mode. So what you are seeing is normal depending on the settings.

author: anotherlin
author_rank: Frequent Contributor
timestamp: March 20, 2019, 07:31:13 pm
content: Can you update us on the repair?I just bought a 7313 from ebay.com but it arrived broken!I will soon start the repair process.
HP 8590L No display - Page 1
Forum section: electronics / repair

author: moonbouncer
author_rank: Newbie
timestamp: December 29, 2018, 11:06:47 pm
content: HiI have a faulty HP8590LIt has Omni vision CRT LPOE3Y, I also have a TR60S1A available from a HP8591On what i found both CRT's have different Sync frequencys ?I noticed that on the 5 pin connector J8 comming from the mainboard the +12V is missing, also the GND is not really chassis GndSo maybe something is wrong on the mainboardCan anyone point me to a PDF servicemanual somewhere ?Thanks

author: pbarton
author_rank: Frequent Contributor
timestamp: December 30, 2018, 03:07:12 pm
content: http://oz1db.dk/hp/omnivision_man_lp06xx_rev0_0611.pdfhttp://ftb.ko4bb.com/manuals/86.153.160.39/HP_8595X_Video_section_TR-60S1A_from_Panasonic_Operator_Manual-HP859X_module_video_panasonic_SM.pdfhttps://community.keysight.com/thread/24266https://community.keysight.com/thread/5339"Panasonic and Omni Vision displays use different CRT's - same size - different pinouts. They don't interchange."https://community.keysight.com/thread/5121https://community.keysight.com/thread/1808The HP 8590 Series Service Guide says "If the display is blank, verify the MONITOR OUTPUT BNC on the rear panel by connecting an external monitor" or just scope it, to verify the presence of a video signal.Simple way to verify that +12V is present on the monitor:- In low light conditions you should be able to see a 'glow' from the heater, at the back, of the CRT neck. (the monitor outer cover needs to be removed).I'm aware that you have an OmniVision LPOE3Y monitor, however a common fault on the OmniVision LP0615E3Y monitor, is C14 4.7uF 50v.If the FOCUS control is not having much effect, you need to measure R27 which should be 2M, but often drifts to 20M ohm.OmniVision LP0615E3Y = 6" CRT and 15KHz sync.OmniVision LP0619E3Y = 6" CRT and 19KHz sync.I seem to remember that the monitor has three bunches of cables coming out of the back orifice. One goes to J8 on the main board. One goes to the front panel intensity/brightness control. A third single lead (possibly purple) goes into a 'difficult to see' connection, directly into the side of the 8590 power supply. I assume that there are all there? I'm thinking that the monitor does not bother to source +12V from the J8 connector, but receives +12V directly from the power supply side connector.Power supply drawings are not available.HP 8590 Component Level Information Package (CLIP) available fromftp://ftp.agilent.com/manuals/5963-2591%208590A%20Series%20Component%20Level%20Info%20Package%20July97.pdfThe two J8 drawing shown below, were both taken from .pdf page 388 of 418.I don't think that you should be expecting +12V to be coming out of J8. The monitor gets +12V from a different place.Good Luck.

author: carl_lab
author_rank: Frequent Contributor
timestamp: February 18, 2019, 03:28:37 pm
content: Moonbouncer,could you solve the problem?

author: xwarp
author_rank: Frequent Contributor
timestamp: March 19, 2019, 11:12:56 am
content: Tag for future use.
Anritsu MS4662A VNA - Page 1
Forum section: electronics / repair

author: Eugene1970
author_rank: Newbie
timestamp: March 18, 2019, 09:50:55 pm
content: My Anritsu MS4662A does not booting. Hangs on self test procedure.Presumably because of a firmware error.I tryed get firmware files from Anritsu, they answered the request:We no longer support this instrument manufactured in 1999 or 2000 and do not have the firmware files.Are there any Anritsu MS4662A owners on the forum? Any help or advice.
Help with Silicon Caps Needed! - Page 1
Forum section: electronics / repair

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 18, 2019, 12:39:22 pm
content: Hi!Does anybody recognise these Silicon caps used on a surface-mount white plastic switch please?I found the switches themselves made by C & K but an email from C & K Technical Support said they appear to be "third party made" and they were unable to supply replacements - they sent this picture to me so obviously they knew what I was looking for!If anyone can recognise these caps/switches from another maker who can supply the silicone caps I'd be ever so grateful - I'm stuck with a job at work missing one of these!!!Chris Williams

author: PedroDaGr8
author_rank: Super Contributor
timestamp: March 18, 2019, 07:35:54 pm
content: Note: This is silicone (flexible polymer of alkyl silanes) not silicon (brittle metalloid semiconductor).Otherwise, they might be proprietary and very hard to find. I have seen these called "switch boots" and "switch caps" but can't seem to find any that look exactly like what you have.
Super Mario Bros 3 busted CHR ROM  - Page 1
Forum section: electronics / repair

author: Lolucoca
author_rank: Contributor
timestamp: June 15, 2018, 06:49:45 am
content: Hi! I just got a Super Mario Bros 3 cartiridge for the NES from a friend of mine and it seems to have a busted CHR ROM. It seems to be some Sharp Mask ROM with a kind of custom pinout. However, I can (hopefully) adapt it to use a standard EPROM. The thing is, I can't find any dumps of just the CHR ROM alone. Do you guys have one by any chance?

author: Rasz
author_rank: Super Contributor
timestamp: June 15, 2018, 02:19:48 pm
content: one of the most popular games ever, worth ~$5, probably less than replacement eprom

author: Bashstreet
author_rank: Frequent Contributor
timestamp: June 19, 2018, 05:28:00 pm
content: Quote from: Rasz on June 15, 2018, 02:19:48 pm10$

author: CZroe
author_rank: Contributor
timestamp: March 18, 2019, 07:28:37 pm
content: I’ve probably got 20 copies of this game and I value it closer to $15. That said, I do have one with a non-standard CHR ROM that I plan to fix one day. Perhaps I’ll whip up a second chip for yours.What you need is an NES ROM splitter that looks at the iNES header to split the ROM into Header, CHR, and PRG, or whichever specific ones you want. There are a number of these out there. Use whatever NESDev recommends. They also have the info for reading the header and doing it yourself with a HEX editor.
HP 6830 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 18, 2019, 03:18:43 pm
content: Hello everyone! I bought a new printer HP 6830, the former owner gave it to me because it was down on the print. At startup, it indicates that the head has a problem. I took the head off, and I replaced it (by the same and an original), and I always have the same error message. 3 cartridges are set up and the black cartridge is a high capacity model. Do you need to install 4 cartridges set up to initialize the new head ?? And where to buy these special cartridges (because hp do not market them) ?? The printer is no longer under warranty. Thank you for you precious help
need socket for DS1230AB-120 NVRAM - Page 1
Forum section: electronics / repair

author: cncjerry
author_rank: Unknown
timestamp: March 18, 2019, 01:04:41 am
content: I'm replacing the NVRAMs on a scope with DS1230AB-120 and need the correct socket. Are those chips standard 28pin size?Thanks.Jerry

author: ChuckDarwin
author_rank: Regular Contributor
timestamp: March 18, 2019, 09:40:36 pm
content: Yes, common 28 pin 600 mil (aka wide) DIP socket for the DS1230AB EDIP version.
Lowish resistance between transformer windings - Page 1
Forum section: electronics / repair

author: atw58
author_rank: Newbie
timestamp: March 17, 2019, 04:44:46 pm
content: I'm trying to find the cause of severe ringing on a switching power supply, the transformer has four sets of windings. Resistance is OL between all sets but one (primary to one of the secondary) which reads 1.2M. I've read 1M per 1000V should be the min insulation resistance of wire for motors etc. The max transformer voltage is 400V pp. The rest of the components look good; cap esrs are fine, diodes ok, resistors ok.Should I disassemble the transformer and fix the low resistance.

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 17, 2019, 08:09:38 pm
content: Was that measured in circuit or off PCB?
lm317 low output rock ola 6000 - Page 1
Forum section: electronics / repair

author: nus
author_rank: Contributor
timestamp: March 17, 2019, 01:48:32 pm
content: so trying to get this psu for a rock ola6000 working, 26v rail is only outputting 2.76v.So originally the lm317 output was short to ground, it took out he 10ohm 5w resistor on the input, this is all fixed now.checked the resistors on the output they seem fine, get 2.76v, not sure what to check now, none of the caps seem to be short either.

author: nus
author_rank: Contributor
timestamp: March 17, 2019, 01:51:30 pm
content: schematic

author: nus
author_rank: Contributor
timestamp: March 17, 2019, 02:00:37 pm
content: MPSA06 is the Transistors

author: nus
author_rank: Contributor
timestamp: March 17, 2019, 03:51:39 pm
content: there is only .6v on the base, nothing on the collector.resistance is about 5.7k between emitter and collector, when off, in circuit.i plugged the the 4.7k and and 5.7k in to the lm317 calc, and i get 2.7659, measured and i get 2.76v on the output.don't really know how transistors work, not sure what i need to do.

author: nus
author_rank: Contributor
timestamp: March 17, 2019, 03:56:04 pm
content: never mind, im dumb. needs base 0v to work
Popped a FET in PWM Solar Controller - Page 1
Forum section: electronics / repair

author: metrologist
author_rank: Super Contributor
timestamp: March 16, 2019, 07:17:57 pm
content: In a cheap PWM solar charge controller - I reverse poll'd itThere are a pair in common positive with switched negative. One popped, but no marking except for an embossedD005in a tiny circle.This is for 24V solar system and rated 20A, so each is probably a 10A FET. I removed the shorted one and it works fine now, but I'd like to get a new pair ().I wanted to clarify that common positive is for solar panel, battery, and output. I was looking at this topic and see they might be in series, so now I'm not sure.https://electronics.stackexchange.com/questions/306836/pwm-solar-charge-controller-mosfet/306843Any recommends or should I measure the gate pin?

author: fzabkar
author_rank: Super Contributor
timestamp: March 16, 2019, 09:08:52 pm
content: AIUI, the usual case is that the first MOSFET is configured as an ideal blocking diode (to prevent the battery from discharging into the panel). The second MOSFET charges the battery via PWM, while the third MOSFET is the load switch.Could you upload photos of your PCB?

author: metrologist
author_rank: Super Contributor
timestamp: March 17, 2019, 12:49:16 am
content: I am not sure if that block diagram is the same as this one. I know there is a 10A and 20A version. I figured there is a reference design that everyone copied.This is removed fet and bottom trace is common positive.I reversed the battery. The trace side has output on left side, panel on right, and battery center.

author: fzabkar
author_rank: Super Contributor
timestamp: March 17, 2019, 02:03:26 am
content: ISTM that there are 4 parallel MOSFETs for charging the battery, 2 parallel MOSFETs for supplying the load, and a single MOSFET configured as an ideal blocking diode. The really cheap (AU$10 - $20) PWM controllers have only a single MOSFET for each function.That said, I'm wondering how the circuit manages to share the current equally between the parallel connected MOSFETs. Could the failure have been due to unequal current sharing? It would be interesting to measure the RDSon in charge mode. You could do this by measuring the voltage drop across the current sense resistor pairs (R005) and the voltage between drain and source.

author: floobydust
author_rank: Super Contributor
timestamp: March 17, 2019, 02:20:06 am
content: Q1, Q2 are in parallel, I think the drain goes to the load (-) and assume they are N-ch and for the the load switch.I see four MOSFETs are in parallel Q3, Q4, Q5, Q10 with the drain going to panel (-) and assume they are N-ch and for the PWM and backfeed diode.You could check the gate-drive Q9 and DZ2.Is it working or still shorted with Q5? pulled

author: metrologist
author_rank: Super Contributor
timestamp: March 17, 2019, 02:38:46 am
content: With the shorted part, it was dumping panel voltage to the battery (measured), and the charger indicated that voltage. Removed, the system showed battery voltage and seemed to function, but I really did not test much.The panel terminals measure +1M or 45K ohm depending on polarity.
Got a fluke 36 in garage for sale - what is a safe lube fro the plastic buttons? - Page 1
Forum section: electronics / repair

author: alank2
author_rank: Super Contributor
timestamp: March 16, 2019, 06:35:14 pm
content: For $15. The two buttons are push in/push out and they have some friction between the button and the case even after I wipe them down. Is there a safe light lube I can use on them? I've got 3 in 1 gun oil, some white grease (not sure what kind), etc. I am thinking just the lightest coat of something to reduce the friction, but I don't want it to damage the plastic...

author: Axtman
author_rank: Regular Contributor
timestamp: March 16, 2019, 08:51:51 pm
content: I recommend opening the meter up and giving it a thorough cleaning. Usually grime prevents buttons from operating smoothly. I then recommend a very small amount of petroleum jelly (Vasoline) on the rotary dial and buttons. This is what I did to my Fluke 32 and it worked great.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 16, 2019, 10:41:50 pm
content: I would not use any petroleum based solvant or lubricant or any silliconed ones, use teflon lubeThe petroleum / sillicon may damage some plastics or render the brittle ...
Backlight works, data doesn't. - Page 1
Forum section: electronics / repair

author: D148xZ
author_rank: Newbie
timestamp: March 15, 2019, 06:46:25 pm
content: Two days ago I bought a Sony A7R II from the dutch equivalent of ebay knowing it had a broken lcd.The evf still works but I'd like to fix the main screen. The main lcd shows a black screen, the backlight works but the data feed looks like it doesn't. The seller told me that he spilled drinking water over it.I have taken the screen apart and found that the cables seem fine, no corrosion or anything. The lcd driver board looks fine too, no blown capacitors or cracked traces, there was what seemed like a little bit of corrosion on the outside of the board. Now I'm wondering what the issue is, could it be due to the lcd display itself, something inside the camera body or the lcd driver board. Remember, the evf works fine, it displays everything without problems.Here's some images:https://imgur.com/a/AW5FwqmThanks
SWISSONE Mobile Telephone - Page 1
Forum section: electronics / repair

author: German_EE
author_rank: Super Contributor
timestamp: March 15, 2019, 02:33:58 pm
content: <sigh> OK, not a repair but you might enjoy the story.My girlfriend bought a new (cheap) phone a few weeks ago and reported that it looked nice but the battery life was really poor, averaging a day before it needed recharging. So, last night I agreed to look at it for her.Switched off the phone, removed the back, removed the battery and cleaned all the contacts, then reassembled everything and put the phone on charge so I could do some tests. As I walked out of the workshop and turned off the lights I saw something glowing white in the darkness, bright enough to read by.Bright as a torch perhaps?Yes, this model of phone comes with a torch but you can't see that it's on when the mobile phone is held in the cover as the LED is obscured. Well, at least we know that on a fully charged phone you can run the torch for 24 hours before the battery needs charging again. The surprise was that the phone would remember its ON setting even when the battery was removed and replaced.
Small pozi screws - Page 1
Forum section: electronics / repair

author: MattyT
author_rank: Newbie
timestamp: March 15, 2019, 11:47:32 am
content: What is the smallest pozi sizes? Anyone know where I can find a drive that is compatible with pozi M1 screw?What is actually is meant by size 0 pozi drive? Thanks.

author: tooki
author_rank: Super Contributor
timestamp: March 15, 2019, 11:58:29 am
content: Most screw drive systems use numbered sizes, which are defined in the standards. So a "size 0" Pozidriv screwdriver is a specific size, and that's the smallest one, as it happens. (Phillips, for example, goes much smaller.)An M1 screw is tiny, so my hunch is that it's not Pozidriv at all, but rather Phillips or JIS (the old Japanese standard), because PZ0 would be way too big for an M1.

author: TheNewLab
author_rank: Frequent Contributor
timestamp: March 15, 2019, 12:17:17 pm
content: Quote from: tooki on March 15, 2019, 11:58:29 amAnd if it is the older JIS..in my experience, required a "cross head" screw driver. standard phillips is beveled and may strip the the head, if tightly screwed in

author: tooki
author_rank: Super Contributor
timestamp: March 15, 2019, 12:34:57 pm
content: Yup. What's super annoying is that apparently, the JIS standard was actually withdrawn some years ago, so many tool manufacturers quit making JIS drivers, despite the fact that probably billions of products were made using JIS screws over the years, and some of those will need servicing.So if you go to buy JIS drivers now, you see some reviews indicating that they may not actually be true JIS after all…(I've been wanting to get a set.)

author: MattyT
author_rank: Newbie
timestamp: March 15, 2019, 02:06:07 pm
content: You were right, it was a JIS. Thanks for your help
TG1010A dead output channel - Page 1
Forum section: electronics / repair

author: tom66
author_rank: Super Contributor
timestamp: March 08, 2019, 09:31:36 am
content: The local hackspace has been donated a TTi TG1010A DDS generator. I want to repair it, as the output channel is dead. Unit powers on but no output and no relay click.Checked some rails, +24V, +15V and -15V all dead. Two 500mA fuses blown so replaced those which restored relay function and the rails. Output now stuck at -12V.Checked the output board (it's on a separate card for some reason) and two opamps/drivers have two rather nice holes in them, so I suspect someone has forced a few too many volts up the output and killed these. Checking the signal into the output board shows it is present, so best guess is that section is working OK and just the output opamps are dead.Problem is I can't identify the parts. They are in MSOP8, capable of 10MHz output into 50 ohms, and operate from a +/-15V supply. Output saturated to -12V in fault condition, which MAY be a sign that they are not rail to rail, but could also be an artefact of the damage. Best guess is Linear Tech from their package as LT are fond of MSOP8. However only matching part is a current feedback amp (LT1396), which has an inadequate supply rating so seems unlikely. Moving away from LT, pinout roughly appears to match THS3110 (Vs+, Vs-, output and input on correct side) again current feedback amp so unsure if this is the correct type of amp for this circuit.There's also an LM6181 amplifier on the board. This appears intact. It is a CFA as well.Have asked TTi for a schematic but no reply yet. Anyone have a schematic for this unit? It is not the same as the TG1010, but there appears to be a bit of commonality.Any ideas? Thanks

author: tom66
author_rank: Super Contributor
timestamp: March 11, 2019, 09:23:47 pm
content: Anyone wondering I asked TTi and they provided the service manual. Uploaded below.The part is THS3001.

author: scopeman
author_rank: Frequent Contributor
timestamp: March 14, 2019, 12:41:43 am
content: Quote from: tom66 on March 08, 2019, 09:31:36 amDid you get the unit fixed? It is a great generator. I hope you get it working.It is the same as a Wavetek 29 IIRC. You can get a great waveform creation software from TTI's website that can upload data from scopes and then upload them to the generator. You can also draw waveforms freehand with the mouse or create them from mathematical equations.You can find it here:http://resources.aimtti.com/software/waveform_manager_plus_v4.13.zipI would look onwww.ko4bb.comwhere you will find firmware that I uploaded some time back.Good Luck!SamW3OHM

author: tom66
author_rank: Super Contributor
timestamp: March 15, 2019, 11:40:29 am
content: Still working on it, awaiting parts from Digikey which should be here by Monday hopefully.
broken fob button - Page 1
Forum section: electronics / repair

author: LC
author_rank: Newbie
timestamp: March 10, 2019, 04:05:25 am
content: I have a garage gate fob (DKS brand) that opens 2 gates, one of the buttons (micro tactile switch) isn't working. I gently pried off the non-functioning button and soldered on a new one, thinking that would fix it, but no. Could it be something with the soldering job, or is it more likely to be a different problem? The original fobs for the building are about a decade old now, and other people here are having the same issue.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: March 11, 2019, 06:57:58 pm
content: My guess is the fob battery has finally drained flat. You should petition the building rental office/managers to organize new ones for you and everybody else.

author: Nusa
author_rank: Super Contributor
timestamp: March 11, 2019, 09:48:57 pm
content: You can presumably test the low battery theory, if you haven't already.The other possibility, especially if others are experiencing the same problem with the same gate, is that the problem is on the receiving side, not a fob problem at all.

author: wilfred
author_rank: Super Contributor
timestamp: March 12, 2019, 01:14:54 am
content: If it is a multi button fob then if other functions work it isn't the battery. I have one (ATA PTX-4) for which non-genuine replacements are as cheap as dirt on Ebay. However the one I had was affected by corrosion internally. Perhaps it got rained on once too often. I tried resoldering a new switch and that didn't work but tracing out the PCB and shorting two other points did work so I put it aside assuming somewhere a trace was broken. Bought a new one.10 years is about the life of these things in daily use. The translucent blue plastic on the ones we have is prone to getting brittle and the rubber over the buttons also gets stiff.If it has a button for a little used function you can do without then reprogram it to the function you lost.

author: Clint_dk
author_rank: Newbie
timestamp: March 15, 2019, 04:49:27 am
content: Make sure that you soldered the new switch in correctly, especially if its those small square ones. Turn it another 90 degrees and try again.