hybridfree/eevblog-posts huggingface dataset:
Hameg 203-7, slightly deformed in first half of wave - Page 1
Forum section: electronics / repair

author: Kekke466
author_rank: Newbie
timestamp: October 05, 2020, 05:51:10 pm
content: Hello everyoneI have a really nice Hameg scope 203-7 (20Mhz) on the bench that I have cleaned up. After fixing the dreaded VAR knobs and checking some solder points and calibrating the Y-Gain, I suddenly have a slightly deformed problem in every second half of the wave.You can notice it the most in a saw waveform. I think that this could be calibrated, I have the service manual but don't have a clue where to begin.Go easy on me, this is my first scope that I am restoring (and my first post).Here is a picture that shows the problem. If a kind soul knows what I could do, please share the knowledge.Regards,Kenny

author: Kleinstein
author_rank: Super Contributor
timestamp: October 05, 2020, 07:26:42 pm
content: The HM203-7 should still be an old school analog scope. So there is no calibration or such for corrections.A first point would be to check how the error changes when die curve is shifted up / down and also changing the channel.I see mainly 4 possible sources for the error:1) A problem with the generator2) A cross over error with the output amplifier to drive the tube (so same error for both channels)3) The input amplifier (could be different for the 2 channels), would likely change with continuous variable gain.4) Coupling from the trigger signal to the displayed signal. (could change with trigger settings)

author: Kekke466
author_rank: Newbie
timestamp: October 05, 2020, 09:11:30 pm
content: I actually just got rid of it and I don't exactly know how.I re-adjusted the Y-gain of both channels once more and it just disappearedThis is the situation now, definetly a lot better than before. The sine wave looks as it should be!My timebase (time/div.) is off with just a tiny bit, I guess I can't get it perfect? I have various service manuals but they don't exactly explain if it can be done.Will I have to live with this?

author: shakalnokturn
author_rank: Super Contributor
timestamp: October 05, 2020, 10:44:59 pm
content: It can be adjusted.Allow to warm at least 20min.Start by checking the X amplitude (x1) is right, adjustment is on the lower PCB. Correct length is in the manual ISTR it should be 10.2 div.Then timebase calibration is done with a trim pot for slower sweeps and variable capacitor for faster ones.They're both near the timebase switches.Finish by switching to x10 and adjusting x10 amplitude on lower PCB if needed.

author: Kekke466
author_rank: Newbie
timestamp: October 07, 2020, 05:48:14 pm
content: I was looking around on the PCB, it should be trimpot VR303, I guess that this is the trimmer I have to adjust?Thanks for the help guys!photo host

author: shakalnokturn
author_rank: Super Contributor
timestamp: October 07, 2020, 05:56:33 pm
content: Yes, but only if timebase is out of calibration on the low timebase settings.Ifalsooff on the higher ones start with the horizontal amplitude adjustment.

author: Kekke466
author_rank: Newbie
timestamp: October 07, 2020, 09:26:45 pm
content: A total succes! Timebase correctly calibrated.
HAMEG 303 - 5 horizontal axis troubleshooting - Page 1
Forum section: electronics / repair

author: igbtq
author_rank: Newbie
timestamp: September 14, 2023, 08:32:38 am
content: I have recently acquired an old hameg 303 - 5 in what looked liked perfect condition. After two days of use,the trace was no longer visible on the whole screen. Rather it seems to start a bit to the left of the center,with a bright dot at the beginning of the trace. If i tune the x position, the whole trace doesn't move further to the left, it only shrinks or stretches. It doesnt however stretch or shrink linearly like when using the time/div button. Rather it appears to shrink/stretch more in some parts of the axis than others. The y axisis working perfectly across the whole height?If any of you were to have an idea about what the issue would be it would be very welcome, for i need touse this oscilloscope on a daily basis and all of my work is completely haltet without it.Thank you very much for any answer!

author: Greybeard
author_rank: Frequent Contributor
timestamp: September 14, 2023, 09:55:58 am
content: Old Hameg scopes are known for loose contact on potentiometers and switches, I' ve repaired many...Often helps frequent actuation of those affected pots/switches. Some mild contact cleaner or IPA helps.

author: igbtq
author_rank: Newbie
timestamp: September 16, 2023, 06:12:42 pm
content: Quote from: Greybeard on September 14, 2023, 09:55:58 amThank you for your answer. I thought this was the issue at first as well, but after opening, i sadly discovered, that the contacts are all in perfect order and none of the caps are blown. I believe it must be a horizontal deflection issue. I just don't know where to look.
HAMEG 303-6 O'scope fix - Page 1
Forum section: electronics / repair

author: starkight
author_rank: Newbie
timestamp: March 11, 2020, 12:05:12 am
content: Looking for help in identifying a chip in this scope. Designated as a HAMEG 25D used in the Final Y Amplifier board that drives the CRT drivers. If anyone has the replacement for this chip or know where I can locate one; would be appreciative.
Hameg 303-6 scope - Page 1
Forum section: electronics / repair

author: naleshniki
author_rank: Newbie
timestamp: February 18, 2024, 06:24:52 pm
content: Just picked up a Hameg 303-6 scope. I have found the service manual and schematics for this model EXCEPT the power supply board in my scope is DIFFERENT than anything in the manuals or schematics. Can not find any info /pix of my PS board. It has a component (capacitor) that appears to be cooked; apparently something in the high voltage circuit since my meter goes nuts when I try to read across it. Scope seems to work ok except trace is confined to the upper half of the display; Y position control can bring trace down only to middle of screen. Attached are pix of PS from manual and my PS.Help!

author: DVM-James
author_rank: Contributor
timestamp: February 21, 2024, 01:12:00 pm
content: That´s curious!If You haven´t done it before, send an E-Mail toinfo@sky-messtechnik.deand attach this picture and one from the bottom-side and from the rear of the 303-6 (-that shows the label with type-nr. , ser-nr. ++) and a picture from that burned capacitor seen from the side (-should desolder it, if possible).regards James
Hameg 605 Y-Out Oddity - Page 1
Forum section: electronics / repair

author: JoergR
author_rank: Contributor
timestamp: June 23, 2022, 10:39:39 pm
content: Hi all,I'm in the process of repairing a Hameg 605 60MHz analog scope. I fixed the usual power supply issues and also some loose soldering pads on a connector and some broken solder joints and everything seems to work fine now - except the Y-Out on the back and I'm out of my wits here how this error can occur at all.I've connected a sine wave to channel 2 and the calibrator square signal to channel 1. Y-out is connected to my second scope in the background.Img 1) When triggering on channel 2 (the sine), it is passed through to the Y-out and displayed on the second scope as expected.Img 2) When triggering on channel 1 (the square) - it is not passed trough to the Y-out and the second scope only sees a 1V DC signal.But that should not be possible, since there is only a single buffer that routes the selected trigger signal to the Y-out and if this works for channel 2, I don't see what this would not work for channel 1. Img 3 shows the block diagram. Triggering works just fine for both channels - so why does the Y-out only work for the signal on channel 2?Y-Out is on the bottom of the block diagram in the lower left corner of the TB Board.Thanks a lot for any insight.Joerg

author: JoergR
author_rank: Contributor
timestamp: June 25, 2022, 07:51:52 am
content: ok, figured it out - note to self: When fixing solder pads on a broken connector, fix all of them! And get new glasses!The trigger signal is routed twice(!) from the Y-Board to the TB Board. Through pins 5 and 6 of the P2-3/1 connector. I'm not sure why this is done, but I suspect it enables the alternate triggering mode.When fixing the broken connector P2-3/1, I had assumed the solder pad on pin 6 (on the right) was still ok, but on the photos you can see (in hindsight), that the connection to the trace is broken. Since I didn't want to remove the entire board again, I fixed it on the components' side. Not pretty, but I guess I'll get another chance to fix it for good at some later time.Now everything is in working order and the Y-Out does output both channels 1 and 2.As a side note, the pin numberings on the component layout schematic are wrong - 1 is 6 and 6 is 1 - in case anyone else runs into the same problem again.
Hameg 7042 PSU , troubleshooting / repair - Page 1
Forum section: electronics / repair

author: Ivanovitch_k
author_rank: Newbie
timestamp: April 19, 2020, 02:32:01 pm
content: Hi,I'm experiencing strange behaviors with myHameg 7042-3bench PSU. It still works but I'm concerned it's on the way out...It started by blowing the AC fuse at "cold" power on (in the morning after being switched off for the night).Did that a few times in a few week span, replacing the fuse fixed it. Cycling power while "hot" doesn't seem to be an issue.After replacing the fuse 4 times, I opened it for inspection, apart a few dust spots which I cleaned, nothing unusual, no puffy caps, no magic smell, no nothing...Now, the center rail (2.7 - 5.5V) exhibits a very strange behavior: when powering the supply on (cold or hot) there is a very slow ramp up (10 seconds+) time to the set voltage.Other channels almost immediately reach their values. This is with the output off.An hint, tweaking the voltage adjustment knob "speed up" and seems to help the channel attain it's set point faster.I'd like to repair it if possible, because other than that it's a very nice PSU, it's an old design but & it's still sold under Rhode & Schwarz name.Couldn't find the service manual for it, if anyone has it...Given those symptoms, any idea of where I should start probing / looking into ?Thanks !

author: aqibi2000
author_rank: Regular Contributor
timestamp: April 19, 2020, 03:27:52 pm
content: One would assume this is related to capacitors. Blowing fuses which not actually fault due to inrush current?

author: kripton2035
author_rank: Super Contributor
timestamp: April 19, 2020, 05:06:14 pm
content: this is for the 7042-5, but there are all the schematics. hope this helps.https://elektrotanya.com/hameg_hm7042-5_power_supply_sm.pdf/download.html

author: JKKDev
author_rank: Regular Contributor
timestamp: April 20, 2020, 05:51:47 am
content: I would also vote for a faulty cap somewhere on that line.

author: xavier60
author_rank: Super Contributor
timestamp: April 20, 2020, 09:10:50 am
content: Page 17 shows an inrush limiting resistor and bypass relay. Would be worth having a close look at.

author: WirelessESD
author_rank: Newbie
timestamp: April 20, 2020, 06:01:04 pm
content: I would check VDR1 as well I had a varistor intermittently fail closed on a power supply once.
hameg hm 1507 display problem - Page 1
Forum section: electronics / repair

author: icomdealer.ir@gmail.com
author_rank: Newbie
timestamp: October 25, 2020, 09:08:51 am
content: -Hcan any one help me solve the problem with my hameg 1507-3 osiloscope display ?it works and show the waveforms but digital system does not work and frequency and amplitude dont displayed any more .also the the cursor lines are not displayed too ..please tell me what to do if you know how to solve this problem ...regards

author: akimpowerscr
author_rank: Regular Contributor
timestamp: October 26, 2020, 11:28:00 am
content: First you will need the HM1507 service manual.You can try to obtain it by contactingHAMEG.https://allice.de/hameg/RHODE and SCHWARTZhttps://www.rohde-schwarz.com/lt/products/test-and-measurement/oscilloscopes/overview_63663.htmlOtherwise, contact me by email.NB: I must warn you, it is a very complicated device like all combiscopes in general.If you are not a really very skilled technician, I would advise against trying to fix it, you can damage it even more than it is.In this case, I recommend that you continue to use it as a simple analog oscilloscope.
HAMEG HM 305-2 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 08, 2022, 01:35:08 pm
content: Good morning all! I am still asking you because my HAMEG HM 305-2 oscilloscope is out of order; here is its strange behavior in detail: at startup it displays: "error keyboard", and all buttons and manipulations are blocked, except the focus adjustment...... Does anyone have an idea?? Thank you for you precious help!
Hameg HM 404-2 pixelated letters - Page 1
Forum section: electronics / repair

author: Psychodad49
author_rank: Newbie
timestamp: December 26, 2024, 08:10:14 am
content: Hello,I purchased a Hameg 404-2. It works normally as an analog scope. But what doesn't work is the display of the numbers and letters on the screen. These are pixelated. I have restored several vintage scopes (Hameg, Tektronix, Leader) but have no experience with this type of scope. Where can I suspect the error, which module is in question? What is the procedure? There is a circuit diagram, but it doesn't really help me. I checked the supply voltages and everything was spot on. Can someone help me? Thank you.

author: cte
author_rank: Regular Contributor
timestamp: December 26, 2024, 10:00:13 am
content: The numbers and letters on the screen are called "readout" in Hameg's terminology. So I would suggest to inspect the Readout Board (page 23).I'm a former owner of this model and I've added a few pictures for reference on how the screen should look like. On power-up, there should be a Hames logo visible while the self test is running.Can say I had lots of trouble with this model. Had to sent it for repair to Hameg service multiple times.
Hameg HM1008 Scope - Page 1
Forum section: electronics / repair

author: Yamin
author_rank: Frequent Contributor
timestamp: November 08, 2018, 04:17:32 am
content: Hi, I have got 4 units of Hameg HM1008 all with the same capacitor blown on the power supply. Has anyone else come across this problem?What could be the possible reason - all the units are maybe 6 years old. I haven't removed the pcb yet so don't know the function of the cap for sure but I'm assuming it used to filter out the main AC in.Can you please help me to identify the make of this capacitorThanks in advance

author: tautech
author_rank: Super Contributor
timestamp: November 08, 2018, 04:42:20 am
content: Quote from: Yamin on November 08, 2018, 04:17:32 amYep, exactly that.They're one of the X or Y class of caps and not necessary for operation.Replace with non-translucent case varieties.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 08, 2018, 09:59:48 am
content: The capacitor is in the line filter section before the bridge rectifier, if i recall this capacitor can crack on the casing and fail ?

author: Glare
author_rank: Newbie
timestamp: November 17, 2022, 09:32:45 pm
content: This is a WIMA MP 3-X2. Try a comparable MKP-X- or Y-type as a replacement. From a safety perspective, however, the MP-types would be more favorable.

author: Hamelec
author_rank: Regular Contributor
timestamp: November 18, 2022, 08:00:57 am
content: a well known issue of these RIFA caps / exploders..change it erverywhere you will find it.

author: George Edmonds
author_rank: Frequent Contributor
timestamp: November 18, 2022, 10:06:05 am
content: HiPlease note, X an Y capacitors are NOT interchangeable.X capacitors should ONLY be used phase to neutral or phase to phase, NEVER to Earth / Ground / or whatever it is called where you are.Y capacitors can be used phase or neutral to Earth / Ground / or whatever it is called where you are.The reason for this is one of safety, Y capacitors MUST fail open circuit to avoid any possibility of making the equipment case live following a failure, whereas X capacitors need not fail open.G Edmonds
Hameg HM103 unblanking, semis OK, 68 pF caps? - Page 1
Forum section: electronics / repair

author: jonpaul
author_rank: Super Contributor
timestamp: October 05, 2020, 08:53:17 am
content: Bonjour a tous:For the Hameg HM103 scope with dead unblanking circuit continued saga from September post asking for parts....I have replaced the optocoupler, NPN, PNP BF199 BF440, and checked all resistors and trimpot, all are fine.Blanking logic input pulse is fine, so quite a puzzle.Last possibility: leaky coupling caps 68pF/2kV, I have seen many posts referring to their failure.I have no way to test caps here. I have only a variac, VOM and soldering iron!I ask the Hameg veterans to please inform me:Could a failed cap just kill blanking, but scope works fine and traces is good otherwise?How to diagnose if a cap has failed?Will a failed 68 pF/2kV kill the semiconductors?where else to look for the problem?Your assistance is greatly appreciated!Jon
Hameg HM1507-2 repiar - Page 1
Forum section: electronics / repair

author: jackie.cen
author_rank: Newbie
timestamp: October 26, 2018, 07:07:17 am
content: hi there,i got a hameg hm1507-2 scope.it did not display anything.so i repair it.it did not have the HV voltage.i change the voltage multiplier,it made by myself.so it displayed.but the screen did not display the whole image ,only about 1/4 image.i change the all of the potentiometers,it did not work as expect.does someone have the schematics for this model?Best regards,jackie

author: jackie.cen
author_rank: Newbie
timestamp: October 26, 2018, 07:13:13 am
content: the Follow

author: jackie.cen
author_rank: Newbie
timestamp: October 26, 2018, 07:14:47 am
content: the follow

author: ElecSeb
author_rank: Regular Contributor
timestamp: October 26, 2018, 07:16:18 am
content: https://www.eevblog.com/forum/repair/hm1507/msg1565743/#msg1565743

author: jackie.cen
author_rank: Newbie
timestamp: October 28, 2018, 01:22:03 am
content: thank you!i fix it,now it's ok!

author: jackie.cen
author_rank: Newbie
timestamp: October 28, 2018, 01:35:26 am
content: first i find the voltage multiplier is dead,so i made one by hand.it's about 85:8:800,65v 75% square singal input.

author: jackie.cen
author_rank: Newbie
timestamp: October 28, 2018, 01:39:09 am
content: after the new voltage multiplier,the screen is still blank.i change the resistances,the screen is work,but image is out of the screen.

author: jackie.cen
author_rank: Newbie
timestamp: October 28, 2018, 01:47:41 am
content: the image is bigger than screen,because the amplitude of x and y singal is big.my plan is reduce the amplitude of x and y singal.change 3 resistances ,about half of them.

author: jackie.cen
author_rank: Newbie
timestamp: October 28, 2018, 01:51:19 am
content: now the image is ok,but image is not clean,the text can't read.change the potentiometer and focus on the front panel.it would be ok.

author: carlitos
author_rank: Contributor
timestamp: June 09, 2020, 10:19:26 pm
content: Quote from: jackie.cen on October 28, 2018, 01:35:26 amHi,sorry bother you, but I have same oscilloscope and I am repairing it.Unfortunately the high voltage transformer was lost in transportation to a rewind shop to repair it.Is it possible to send some details how you rewind this transformer, like how many turns, wire diameter, wire orientation and pinout connection.Thanks a lot.Best regards,Carlos
Hameg HM1507-3 time base encoder? - Page 1
Forum section: electronics / repair

author: Systemtek
author_rank: Contributor
timestamp: December 11, 2018, 05:45:57 pm
content: Hi,I have an HM1507-3 that when the time base is adjusted beeps to indicate the limits have been reached and/or jumps around erratically in time base value.What are your suggestions? Is it sensible to say its almost definitely the encoder? can anyone help me find a replacement if so?I have another HM1507 that was given to me by my dad as when we turned on the scope with a x10 probe setting it had broken since he last used it. So I have a working HM1507 without the x10 setting but I don't really want to take the encoder from the working scope and risk having no working scopes.Thanks for any repliesHan

author: shakalnokturn
author_rank: Super Contributor
timestamp: December 11, 2018, 10:48:42 pm
content: The encoder is a likely culprit for your symptoms, have you tried giving it a spray?As you have another working scope you could probe the encoder outputs on the defective one and make sure yourself.

author: Systemtek
author_rank: Contributor
timestamp: December 13, 2018, 12:26:43 pm
content: Thanks. I will try that.

author: Systemtek
author_rank: Contributor
timestamp: June 01, 2019, 09:02:30 pm
content: I successfully dismantled and cleaned the rotary encoder.(finally) I reassembled the unit it passes self tests but the trace is nowhere to be seen. Although there is a glow at the top of the screen on high intensity settings as there is when the trace has gone off screen. Auto set and vertical position are no help though.The canned board with the b&cs had to be disconnected and I haven't tried re plugging the ribbons yet.The cal sticker was right alright. Its definitely voidTIA

author: Systemtek
author_rank: Contributor
timestamp: June 02, 2019, 08:50:21 am
content: I think I have fixed it.
Hameg Hm203-4 oscilloscope y axis issue - Page 1
Forum section: electronics / repair

author: sahko123
author_rank: Frequent Contributor
timestamp: March 24, 2020, 03:58:07 am
content: ive got a Hameg oscilloscope from whenever ago and i like an idiot decided to assemble it months after having taken it apart. So i put it back together turned it on and.. Yay! it displays a trace..."hmm lets plug a signal into it. Ok that displays fine. Its a bit high up lets move it down. WTF". in more proper terms the y axis range is limited to about a third the way up the screen and to the top. does anyone know what can be wrong and have they encountered this sort of issue before? Thanks

author: sahko123
author_rank: Frequent Contributor
timestamp: March 24, 2020, 03:36:06 pm
content: wanna die... 20 hours and it all came down to one of the crt wires hanging loose..........

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 24, 2020, 05:24:30 pm
content: If you're not suicidal, at least it's a happy end.
Hameg HM203-6 blanking glitch - Page 1
Forum section: electronics / repair

author: shakalnokturn
author_rank: Super Contributor
timestamp: May 25, 2019, 01:41:23 pm
content: I'm trying to get this old scope back to normal. (Normal should be enough, not new...)When I picked it up it had no display due to lack of -12V (R761 burnt on "XY" board.)Since replacing this resistor, scope is mostly working as intended, the only problem found so far is what looks like a small timing issue with the blanking control. (This model has no Z mod. input)On lowest timebase the brief flash of the retrace can actually be seen on the CRT, followed by a bright spot on the left, the rest of the scan is normal.On most of the timebase settings the traces appear with a bright spot to the left followed by a slightly dim start of scan, the remaining scan being normal.On highest timebases the trace loses the bright spot to the left and the beginning of the scan, the trace fades-in on the first 1/3 of the CRT.I've probed at it with another identical scope, looking at blanking control at anode (Pin 1) of optocoupler and ramp output at "TP" (R559 on timebase), on the fastest timebase I can make sense of what's probed and what's displayed on the sick scope. (Without understanding the cause however.)On the lower speeds it just doesn't seem obvious... What am I missing? A couple of ns?

author: shakalnokturn
author_rank: Super Contributor
timestamp: August 27, 2019, 10:05:11 pm
content: Got back to working on this one again yesterday.After looking at the schematics long enough I decided to replace some decoupling capacitors in the timebase. The ones that seemed to make the most sense were C540, C541.No luck, they were good enough nothing better after.Then replaced C517 and C530, C530 was totally gone, nothing left to measure (over 40Mresistance and no capacitance), still no effect on my blanking problem.Nothing related but I also stumbled across C750 in the final stage of the X amp that had never even been fitted.My problem turned out to be T501 (BF199) in the blanking section. The transistor had more or less evaporated, all the AVR tester can make of it is a 30pF cap between B-E.Happy end, thanks for all your input.

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 16, 2020, 11:27:26 pm
content: As a follow-up to this repair:This scope was sold end of last year as study equipment to a young "digital artist" teaching in a Swiss art school.You can catch a couple of glimpses of it in their commercial demo video here:
hameg hm203-6 x axis not working - Page 1
Forum section: electronics / repair

author: quentin
author_rank: Newbie
timestamp: November 07, 2020, 09:51:40 pm
content: I am trying to repair a hameg 203-6 oscilloscope and i have cheched almost all chips and found no broken components and the only way to make it half work is to take the time knob an move it between specific channels. And even like that i have only manage to make the y axis work.Does anybody have a idea to what is causing this problem?also i tried cleaning the time knob but it made no changes and when i probe the adjustment channel it shows me the right voltagei appologise if my english is badthanks

author: akimpowerscr
author_rank: Regular Contributor
timestamp: November 07, 2020, 10:53:41 pm
content: First of all, welcome to the forum....If I understood correctly, the time base of your HM203-6 does not seem to be working.Could you apply a signal to both channels at the same time (preferably low frequency sinusoidal) and tell me what you see on the screen when you press the xy button?

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 08, 2020, 02:21:58 pm
content: As akimpowerscr said.Also does the X-Pos. control work?My first scope (that I still have since '98) is a HM203-6, it's going the same way as yours, the timebase is intermittent, I know it's a contact problem because I can stop/start the problem pushing down on the Trig./ Timebase PCB.If ever you need a second HM203-6 to repair yours I have a working one to sell

author: IRmska
author_rank: Newbie
timestamp: November 10, 2020, 06:27:18 pm
content: I have a working HM203-7, (its a close model, I guess it shares most of the internals), I can check some lines or specific parts, whatever you might need to check on a working one, just let me know!

author: quentin
author_rank: Newbie
timestamp: May 14, 2021, 08:10:22 pm
content: Excuse me for my absence, i was bored about the scope and totally forgot that i posted this-using the calibration pins on the oscilloscope (square signal of 2v) i can make the vacuum tube display the voltage but not the time (sorry, i couldn't use sin wave sadly my frequencygenerator is broken too)-using both channels with the x-y button makes a sideways line with the square signal of 2v (see in the picture)-since the timebase is not working and it could be the contact fault on the time base knob, what can i use to clean it ?-the trig does not light up so it may be due to the poor contact or an other problemchecking directly on an other oscilloscope is not necessary, just responding to my questions is enough, you are already wasting too much time for meThanks to all of you for responding to my questions, i greatly appreciate it
HAMEG HM303-4 OSCILLOSCOPE FAULT - Page 1
Forum section: electronics / repair

author: giorgos0101
author_rank: Newbie
timestamp: September 16, 2025, 09:26:09 am
content: Hello everybody.I have an oscilloscope HAMEG HM303-4and I have noticed a problem.When I am turning the X position knob to the right, in order to see the left edge of beam,I see a dot in left edge of beam.(PHOTO 1)By applying a 1 khz square test signal , it appears two dots on the rise side of first pulse, on bottom and top.(PHOTO 2)If I deselect auto trigger and turn its knob, in order to dissapear waveform, the two dots an left sre still remaining.(PHOTO 3)Also If I apply 1 mhz square test signal , it apperas blanking lines too .(PHOTO 4)Any suggestions please?see attached.

author: jonpaul
author_rank: Super Contributor
timestamp: September 16, 2025, 09:29:19 am
content: Try at much faster and slower HOR time/div.Usual Hameg analog 1980s scopes: Blanking Z axis failure.underrated HV ceramic caps and bad optocoupler.See schematic and serv manual.Jon

author: giorgos0101
author_rank: Newbie
timestamp: September 16, 2025, 11:32:49 am
content: Thank you for response.The problem exists in all positions of time /div selector.

author: giorgos0101
author_rank: Newbie
timestamp: September 18, 2025, 06:13:43 am
content: I replaced the optocoupler and three 3kV ceramic capacitors on crt board.Unfortuantely the problem remains same as before.Any other idea please?

author: Greybeard
author_rank: Frequent Contributor
timestamp: September 19, 2025, 07:21:04 pm
content: T6011, T6012?Older Hameg oscilloscopes often fail with BF199 or BF440.

author: Zenith
author_rank: Frequent Contributor
timestamp: September 19, 2025, 09:49:32 pm
content: It looks to me as if flyback suppression (Z blanking) isn't working. On some Hameg scopes there was a potentiometer to adjust it. They gave a waveform to aim for, but it could be done by eye. There doesn't seem to be an adjustment on this model.I'd be inclined to use another scope to check that the input to the optoisolator looks right. R6003 looks to be a select on test component, which suggests it's critical. There's what looks to be a waveform/voltage levels for the Z blanking, which is -1960V and -1930V. The problem with that part of the circuit is that it's at around -1900V, so obviously, care is needed.Have you checked that all supply lines are the expected voltage and have no ripple? If they are not, other fault finding is likely to be a waste of time. The reservoir capacitors in the power supplies are often a problem in Hameg scopes.

author: giorgos0101
author_rank: Newbie
timestamp: September 22, 2025, 12:25:00 pm
content: Thanks for your answers.On schematic T6011, T6012 are BF824 , BFS20.Anyway I will check that transistors.Regarding power supply, I have already replace all electrolytic capacitors.I will check capacitors on High voltage section too and I wil let you know.
Hameg HM303-6 K Rotary Switch reassembly and how to purchase. - Page 1
Forum section: electronics / repair

author: youngwug
author_rank: Contributor
timestamp: September 29, 2020, 05:39:45 pm
content: Attached photo is Hameg HM303-6K.During repairs a long time ago, the Volts/Div Rotary switches of Ch. 1 & 2 of the front panel were loosened.I spent a lot of time trying to reassemble it, but it was impossible.If anyone disassembles and assembles this switch, please link to a photo or video.One had to be reassembled and the other had a broken shaft.Please also link to where you can purchase.

author: youngwug
author_rank: Contributor
timestamp: September 30, 2020, 05:00:04 am
content: Each of the 1st and 2nd springs and balls must be fully installed in order.And it's easy to reassemble.However, I've wasted a lot of time trying to insert it using the "?(Why)" hole.If you use the "? (why)" hole, you can insert one, but the second is impossible.I think this hole is the Grease injection hole.So one was reassembled.The remaining one rotary switch has to be purchased because the shaft is broken.Please tell me where to buy.
Hameg HM512 scope CRT earth wire  - Page 1
Forum section: electronics / repair

author: tallnutt
author_rank: Newbie
timestamp: June 14, 2020, 03:32:08 am
content: Good day to you all,I have just bought my first scope, a 1972 Hameg HM512, dual channel, 20 MHz, for audio work. Despite its age, I'm very happy with it. Everything seems to work well, except perhaps the V/Div DC calibration seems to go out when it is turned off. I followed the DC adjust procedure in the manual, but every time it's turned on the V/Div fine adjust will cause a y-shift. This was asked by another user here for a similar scope but there was no conclusion posted. However it is not a major problem for me as I do not normally need to use the fine adjust.My main question is, when I opened it to clean the switches and pots (it actually looked very clean inside already), I noticed a yellow wire hanging loose - connected to the top of the case with a connector that looks like it should be on the back CRT terminals - see picture. This wire is not marked on the manual diagrams and the manual is in German so I'm not sure if it mentions it.Does anyone know if this wire should be connected and if so, where? Either way, I do not think it should have been hanging lose like that - I could just tape it up and leave it since it seems to be working OK, although it could be a safety issue?Thanks for any help,Theo

author: shakalnokturn
author_rank: Super Contributor
timestamp: June 14, 2020, 07:50:10 am
content: Any chances it should attatch to the rear cover - the one that you removed?Can you spot a small spade tab anywhere on it?

author: tallnutt
author_rank: Newbie
timestamp: June 14, 2020, 07:51:30 am
content: Quote from: shakalnokturn on June 14, 2020, 07:50:10 amHmmm.. good idea, maybe it did. I'll check.

author: tallnutt
author_rank: Newbie
timestamp: June 14, 2020, 08:19:41 am
content: Quote from: tallnutt on June 14, 2020, 07:51:30 amFound it! It clips onto a ground pin on the top right of the rear circuit board.Thanks.
Hameg HM604-2 Oscilloscope: Help: Trig level very temp dependent and unstable - Page 1
Forum section: electronics / repair

author: geekyoyd
author_rank: Contributor
timestamp: August 16, 2021, 01:51:05 pm
content: HiyaI have been working on this fault on my HM604-2 Oscilloscope for a while without success so I thought I'd swallow my pride and ask for help!The symptoms are that the trigger level (set on auto or manual) takes a while to settle down after switch on and varies over a wide range as the scope warms up. When it has warmed up, the trace is not very stable which is due to noise on the trigger signal which I can see with another scope connected to IC304 output on pin 1 or [trig out to NE529 comparator]. I am guessing the faulty part will be in the analog section of the timebase triggering circuits, the filters or the amp. I am hoping that an expert tinkerer on here will be able to suggest a stressed component or two that are likely candidates for failure. It is difficult to diagnose a circuit like this with many stages within a feedback loop.Thanks in advance.Dan

author: Ringmodulator
author_rank: Regular Contributor
timestamp: August 19, 2021, 05:17:48 pm
content: Hi Dan,I can only offer some generic hints. I own a HM 705, which is somewhat older.At fist, I would check the power supply lines with another scope. Problems with the rectifiers and electrolytic caps are quite common. I have experienced also problems with microcracks at solderjoints at leads that interconnect boards giving strange problems, that looked like temperature dependent.Next, I suggest using a plasic toothbrush to brush around to locate the area of the problem.Next step is using freezing spray on single components.Use of an isolation transformer should be mandatory.Good luck,Chris

author: bd139
author_rank: Super Contributor
timestamp: August 19, 2021, 06:31:52 pm
content: Agree with Ringmodulator.Almost all the problems I've had with Hameg scopes are either the electrolytic capacitors giving up (and leaking), IC sockets or dry joints.

author: BFX
author_rank: Frequent Contributor
timestamp: August 20, 2021, 06:19:02 am
content: Do not forget to cleanup switches, pots and check discoloration of resistors.
Hameg HM604-3 problem - Page 1
Forum section: electronics / repair

author: Davey
author_rank: Newbie
timestamp: September 23, 2023, 03:52:14 pm
content: There is a problem with this scope of no control of brilliance. I have checked the internet for a circuit, but although there are circuits, they are not the version I want. The scope I have has a switched mode PSU and the circuits I have found have a linear PSU. If someone can point to a link to a circuit, or a known solution, it would be most welcome. Thanks

author: Zenith
author_rank: Frequent Contributor
timestamp: September 23, 2023, 04:28:27 pm
content: I can't help with the manual.I'd guess that most of the circuitry is similar to HM604 scopes with linear power supplies. A common cause of problems with brilliance in scopes is that the pot that controls brilliance is in the centre of a chain of resistors which have a high voltage across them and one of the resistors is open circuit. The resistors have values of several megohms. Check them and if they are bad, replace them with resistors with a suitable high voltage rating, which are available from Farnell etc.It's also possible that the pot is faulty, but that seems to happen less often.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: September 23, 2023, 04:46:19 pm
content: https://www.eevblog.com/forum/repair/hameg-303-5-horizontal-axis-troubleshooting/msg5059750/#msg5059750Perhaps read this
Hameg HM604 pot shaft coupling - Page 1
Forum section: electronics / repair

author: JuanGg
author_rank: Regular Contributor
timestamp: September 05, 2019, 07:29:58 pm
content: The plastic coupling connecting the delayed sweep knob with its potentiometer was cracked, and after trying to glue it (it refuses, seems to be some kind of polyethylene), I just 3d printed a replacement. Just an example on how 3d printing may come in handy when restoring equipment.Juan

author: Chriss
author_rank: Frequent Contributor
timestamp: September 05, 2019, 08:08:11 pm
content: Well done job.I like how you solved the problem.3D printer is something "must have " nowadays...Sent from my SM-J500F using Tapatalk

author: shakalnokturn
author_rank: Super Contributor
timestamp: September 08, 2019, 12:35:20 am
content: Although I keep looking into it I still don't own a 3D printer. My fix is to wrap a few turns of single stranded copper wire around the cracked section and glue that in place. Not as neat but usually does the job.

author: JuanGg
author_rank: Regular Contributor
timestamp: September 08, 2019, 09:51:54 am
content: Quote from: shakalnokturn on September 08, 2019, 12:35:20 amI originally did something along those lines, and while it lasted for some time, the shaft kept slipping and I had to open up the scope every once in a while to re-tighten the screws. Hopefully, no need to do that again.Also, as the saying goes "To a man with a hammer, everything looks like a nail. This could have been hand made out of wood/plastic in less time than it took to print it.Juan
Hameg HM705 Repair - Page 1
Forum section: electronics / repair

author: Nicholas1
author_rank: Newbie
timestamp: August 07, 2022, 12:55:00 pm
content: Greetings,I am in the process of repairing a Hameg HM705 oscilloscope. I repainted the case as the old paintwork was chipped and had rust underneath. After blowing out the insides with high-pressure air, I realised that that wasn't such a good idea. One of the wipers on the potentiometer was blown off. I did fix it, though, by repurposing a wiper from another potentiometer of different value. The high-pressure air didn't remove much grease or dust at all, so I bought someelectronic cleaning solventto try instead.Now I want to replace fragile and cracked polyester film capacitors on the circuit boards (after not applying much force with a pair of pliers, I accidentally pulled the capacitor body from its legs while desoldering it. Oops.). I saw a video Mr. Dave Jones posted on YouTube a while ago,about film capacitors. After finding out that moisture ingression can cause issues, and with the scope's age in mind, I decided that I want to try replace every film capacitor possible.I have a few questions regarding capacitors and the repair process in general:On the boards, there are some Phillips "MKT" capacitors. I found out that they are polyester film capacitors. However, to the right of their printed values are some extra markings, whose meanings I don't know. E.g.:0.1M0.1/200.022KAre these some sort of tolerances?Should I also replace the other capacitors while I'm replacing the poly film capacitors (e.g. ceramic and electrolytic)? I envisage that this will be a big job as there is a lot of disassembling I must do to first before I can replace the capacitors, so I might as well do as much as I can in one go.Are there any disadvantages of replacing capacitors with ones that have higher voltage ratings while everything else remains the same? E.g. 0.022uF 400V vs. 0.022uF 630V.What else do you recommend I do during this repair process?Before I start desoldering and putting new capacitors in, I will first wait patiently for some advice.Thank you for reading,Nicholas.
Hameg hm8001 low output voltage - Page 1
Forum section: electronics / repair

author: RolandK
author_rank: Regular Contributor
timestamp: August 24, 2022, 10:14:08 am
content: On one hameg hm8001 i had a seldom behavior. It was working with 8011-3 and 8040, but not with a function generator 8030-5.First i thought it is the l200h regulator. So i changed that one. But no success, so after the rapair went the original L200h back inside. After more investigation there was a 50 Ohm resistance in the connection cable beween the power supply board and the backplane. Just gave this some 15 Volts from another supply and the resistance was gone. I think it was in the female connector. They have no solid separation between the contacts and it is the only position where it could be.

author: TaylorD93
author_rank: Regular Contributor
timestamp: August 24, 2022, 11:25:53 am
content: The Edge connector within the Plug in module (say 8030 etc) has links/resistors to tell the L200 within the Chassis, what it should regulate too.Id check that path on the Plugin module is ok. buzz out the edge connector within the module, they tend to have a bespoke PCB with the gold fingers then a certain routing to loop back.It could also be that the other modules do not use a particular tap/pins on the Edge connector socket within the chassis, so it would be worth buzzing that out too.
hameg HM8011-3 input resistors - Page 1
Forum section: electronics / repair

author: tamba
author_rank: Newbie
timestamp: September 03, 2025, 06:06:03 pm
content: hi allI have decided to build a fairly accurate multimeter. For this I chose the Hameg HM8011-3The reason for this was that I had most of the parts.Almost complete information is available about this device.I just have one question for the owners of this device.In the ohm and volt input section, there are two 2-watt resistors with values ​​of 100 kilohms and 1 kilohms, which are marked as R101 and R102 in the device schematic.In the photos I found here, the resistors are not installed. You can find them under the fourth blue button from the top.https://www.radio-bastler.de/forum/index.php?thread/26551-hameg-hm8011-3-multimeter-buzzer-summer-gibt-keinen-ton-aus/schematic is herehttps://www.radiomuseum.org/r/hameg_digital_multimeter_hm8011_2.htmlThe interesting thing is that on the device's PCB, the location of the desired resistors is marked with dotted lines, Maybe the dots mean that they are not necessary to install.but by studying the device's schematic, we realize that if they are not installed, the connection between the volt and ohm probes is completely disconnected from the device.My request to device owners is to check the condition of these resistors on their devices.If possible, please post a clear picture of the device board here.will be thankful for the time you spend for me

author: tamba
author_rank: Newbie
timestamp: September 03, 2025, 06:12:41 pm
content: The location of resistors R101 and R102 in the pcb are clearly visible here. The schematic of the device is also visible on the following pages.https://www.manualslib.com/manual/1594856/Hameg-Hm8011-3.html?page=7#manual
Hameg HM8030-6: Decade buttons not working on STOP frequency: fault or feature? - Page 1
Forum section: electronics / repair

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: December 23, 2019, 06:56:18 pm
content: Hello there,can anyone out there with a Hameg 8030-6 (5 will probably do as well) confirm that the decade buttons (50mHz <- ->10MHz) only work when START is selected, but not on the STOP frequency?Thanks in advance and merry Christmas.
Hameg HMS3010 / HMS-X Spectrum Analyzer - Page 1
Forum section: electronics / repair

author: szymon019
author_rank: Contributor
timestamp: November 16, 2022, 08:59:49 pm
content: Hi Team,Does anyone have service manual for Hameg HMS-3010 / R&S HMS-X? It worked fine till one day when after powering up it lost TG and sensitivity.Tracking generator generates lower half of sinusoidal waveforms, receiver sensitivity is also affected, preamplifier looks like also not working. At the beginning I expected that positive supply rail died but now it looks like maybe some other IC?Thank you for suggestions.

author: szymon019
author_rank: Contributor
timestamp: November 20, 2022, 09:03:49 am
content: Hi All,Does anyone has HMS-X HMS 3010 analyser with tracking generator and would be able to measure how TG output, looks like?I would expect sinusoidal waveform but now in user manual I see it is not needed.Scope time waveform, power measured by another Spectrum Analyser -20,8dBm when setting output to -20dBm. Signal is distorted in 2 stage BF520 based RF amplifiers. It see proper sine waveform.Voltage for TG block is enabled on screen and controlled by R103G33 LDO. LDO output voltage in tollerance 3.2... sth so should be fine. Thermal image does not lead to part which would be overheated.