My brand new, old HM203-4 - Page 1
Forum section: electronics / testgear

author: Aldo22
author_rank: Super Contributor
timestamp: April 06, 2025, 09:32:18 am
content: I bought a beautifully preserved Hameg HM203-4 from a private owner for very little money.It is my first analog scope.It's in an optical condition that could (almost) be used to take advertising photos today.I have not discovered any problems with its functionality so far.I can't imagine that it worked better 40 years ago.So buying an old analog CRO doesn't necessarily have to be frustrating.It complements my cheap DSO perfectly, as this- has no (digital) phospor.- is not particularly good in XY mode or oscilloscope music (like most cheap DSOs).- displays signals with a slight delay, which can be somewhat confusing with audible audio signals, for example.The old Hameg does all this better.You can see some “impressions” below.However, I do have a few questions:There are a few scratches on the CRT cover (How do you call this?). Nothing that would interfere with the function, but because the rest is so nice, I wonder if I could polish them out.Is it acrylic glass?Does that make sense, or is there too much risk of scratching it even more?What is the best way to do this? I don't want to buy any expensive special products for this.I have already polished watch glasses with car polish. That worked really well.The component tester has approx. 9.7Vrms instead of the max. 8.5Vrms specified in the manual.Does this indicate a problem or is it safe?What else would I need to test or maintain? I don't think the scope has ever been opened in 40 years.I'm sure the first capacitors are still in it.I think you can leave it as it is as long as there are no apparent problems, right?Thanks for any tips on this vintage scope.

author: Aldo22
author_rank: Super Contributor
timestamp: April 06, 2025, 09:33:15 am
content: More photos:- 1VDC@0.5V/cm- 1MHz square- 1MHz square x5- AM- XY curve tracer- XY oscilloscope music

author: cte
author_rank: Regular Contributor
timestamp: April 06, 2025, 05:59:19 pm
content: Quote from: Aldo22 on April 06, 2025, 09:32:18 amNot a problem, but check the input voltage selector switch. It will probably be set to 220V. I'd recommend setting it to 240V (or 237V). Not sure if this model already has the voltage selector switch on the back of the device near the IEC socket. If not, it can usually be set internally at the mains transformer.Out of curiosity: Do you know the manufacturing date/year of the device?

author: Aldo22
author_rank: Super Contributor
timestamp: April 06, 2025, 06:29:48 pm
content: Quote from: cte on April 06, 2025, 05:59:19 pmThank you! Good idea.It has the external switch and I have now set it to 240V.Now there are 8.8Vrms at the component tester, which is close enough to the specification.Quote from: cte on April 06, 2025, 05:59:19 pmCan I look this up somewhere?

author: cte
author_rank: Regular Contributor
timestamp: April 06, 2025, 07:19:17 pm
content: Quote from: Aldo22 on April 06, 2025, 06:29:48 pmI found a (service) manual for the 203-4 which is dated 1983. And on the photos you posted above I can see a HEF4013 integrated circuit with a date code of 1983, so we can probably settle on a mfg date of 1983 or 1984.Agewise, this would fit right in the middle of my "collection" of HAMEGs..(1979 and 1990)I still think those were the times where Hameg built pretty solid devices.

author: Aldo22
author_rank: Super Contributor
timestamp: April 06, 2025, 07:56:20 pm
content: Quote from: cte on April 06, 2025, 07:19:17 pmI got mine with the original printed manual.It is dated 10/82. The accessories sheet is dated 11/83.Quote from: cte on April 06, 2025, 07:19:17 pmIn any case, the HM203-4 is in excellent condition for its age.

author: bte
author_rank: Regular Contributor
timestamp: April 06, 2025, 09:04:25 pm
content: Just out of curiosity, I looked at a locally famous site (people and companies sell mostly second-hand items here) to see if I could find such a scope and what the prices would be. I found this:https://www.sahibinden.com/ilan/ikinci-el-ve-sifir-alisveris-teknik-elektronik-test-olcum-cihazi-hameg-analog-dijital-komponent-testerli-osiloskop-1237894972/detayThe seller says it (Hameg HM-507) has less than 2 hours of usage. Asking price is more than 1000 EUR.You got yours for CHF18 or something like that if I recall correctly?EDIT: It looks like the link may require registration for some people. I attached a few pictures of the 1000 EUR Hameg HM-507 to this post.

author: Aldo22
author_rank: Super Contributor
timestamp: April 06, 2025, 09:33:56 pm
content: Quote from: bte on April 06, 2025, 09:04:25 pmAt the end of the auction it was CHF 30.But I was able to pick it up myself (10 minutes from my home) and to test it briefly at the previous owner's house.A good coax BNC cable was also included.The price was very good considering the condition of the device.

author: JoanBS
author_rank: Contributor
timestamp: April 06, 2025, 09:54:56 pm
content: Congratulations! For this price and in this condition, I think it's a real bargain. I had an HM205-3, like the one from cte, which I sold years ago because I needed more bandwidth, but within its limitations, it worked very well.Quote from: bte on April 06, 2025, 09:04:25 pmWhy are you inserting a link to a site that requires registration to access?

author: bdunham7
author_rank: Super Contributor
timestamp: April 06, 2025, 10:05:42 pm
content: Quote from: Aldo22 on April 06, 2025, 09:32:18 amYou have to be really careful not to make it hazy at all because that will disperse your display light. I've seen scope faces that have been "polished" and it usually isn't good. I don't see any signficant scratches or issues there, my first guess is that it is best left alone. If you must do something, take it apart and see if it is clear or tinted. If clear, you can have a new piece cut. If tinted, you'll need to find something similar to have cut.

author: bte
author_rank: Regular Contributor
timestamp: April 06, 2025, 10:12:26 pm
content: Quote from: JoanBS on April 06, 2025, 09:54:56 pmI didn't know that the site would be asking for registration. I can browse freely without any registration. I just checked again and on the latest Firefox on my Windows 7 machine, it asks for registration but on my other older browsers, it doesn't.Apologies for the inconvenience... I edited my previous post to reflect that and added a few pictures of the item on offer.

author: Aldo22
author_rank: Super Contributor
timestamp: April 06, 2025, 10:29:46 pm
content: Quote from: bdunham7 on April 06, 2025, 10:05:42 pmThank you!I tried it with car polish and a soft cloth. It looks good now.It wasn't really a problem anyway, I just wanted to know if I could make it look even better.

author: cte
author_rank: Regular Contributor
timestamp: April 07, 2025, 07:20:13 am
content: Quote from: Aldo22 on April 06, 2025, 10:29:46 pmThe grid should already be inside the tube for this model. So, with a little DIY skill, you'll be able to replace the scratched protective screen with a screen made of PMMA ("Plexiglas").Modulor, Berlinhas those. But they seem to have high shipping charges to Switzerland...

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 07:55:26 am
content: Quote from: cte on April 07, 2025, 07:20:13 amMany thanks for the tip!After the treatment with the car polish, my “Leidensdruck” is gone.The scope looks good to me now.After all, one shouldn't overdo it.

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 08:02:29 am
content: Quote from: bte on April 06, 2025, 09:04:25 pm1000€ is a lot.Here, the ones over CHF 100 don't sell well anymore, afaics.Tomorrow another auction ends for an HM205 (currently at 37.-) and an HM605 (currently at 57.-).The price will certainly go up a bit, but I don't think they will go far above 100.-https://www.ricardo.ch/de/s/messger%C3%A4te%20elektronik%20hameg/

author: EvgenyG
author_rank: Regular Contributor
timestamp: April 07, 2025, 08:22:32 am
content: Have you tried asking Sky Messtechnik? They used to sell old Hameg scopes for reasonable prices. They also stock replacement encoders and other parts.https://www.sky-messtechnik.de/produkte/gebrauchte-messgeraete/oszilloskop-analog/89-hm1507-3-150mhz-100msa-sOn a side note, HM507 is a nice scope but it is not worth 1000 EUR.

author: kripton2035
author_rank: Super Contributor
timestamp: April 07, 2025, 09:32:30 am
content: the HM507 is a combo 50MHz analog-digital model. it is more $$$ than the HM203 that is 20MHz analog only.but 1000 EUR is too much.I've got a HM407 a few years back for 120 EURdon't buy a HM507 for more than 150 EUR IMHOthey are great for the component tester (and XY mode !)

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 03:21:51 pm
content: I have a question.This is my first analog oscilloscope. So I am used to a DSO.I have a square wave signal of 20kHz.At 0.5ms/div I see the edge in the middle of the screen. The triggering is correct.However, when I go to 0.2ms/div, I only see a horizontal line.Turning the X-Pos control doesn't help much either.Why is it not triggered in the center?Is this normal or a fault with my device?How can I determine the rise time, for example?Thank you!

author: bdunham7
author_rank: Super Contributor
timestamp: April 07, 2025, 03:53:36 pm
content: Quote from: Aldo22 on April 07, 2025, 03:21:51 pmDo you have the trigger set for a positive or negative slope?A DSO is continuously (mostly) recording and thus can show you both the data before and after the trigger event. An analog scope isn't recording anything (with a small exception which we'll get to) so how could it possibly show you anything before the trigger?I think you have the trigger set on the rising slope which means your trigger event is actually a bit off of the left side of the screen. The sweep rate just happens to be just right so that the falling edge is near the center and you've helpfully dialed it in using the HPOS control. Right? If you increase the sweep speed, then it gets all the way across the screen before the falling edge happens. Now if you adjust the HPOS to the right so that you can see that rising edge at the left side of the screen, you'll be able to see the actual trigger point. But you'll also be able to see a small bit of signal from before the trigger! How can that happen?The answer there is that there is a coil of special cable in the vertical amplifier circuit that serves as a delay line. It takes a few hundred ns (typically) for the signal to propagate through this and the resulting delay gives the trigger and horizontal sweep circuits just enough time to start up and begin the horizontal trace. That's the tiny bit of signal that the analog scope "records".Edit: That's all assuming the HM203-4 actually has a vertical delay line. I actually don't see one in your photos...and without it you won't be able to see rise time without some trickery.

author: David Hess
author_rank: Super Contributor
timestamp: April 07, 2025, 04:03:53 pm
content: Quote from: Aldo22 on April 06, 2025, 09:32:18 amThe plastic CRT cover is acrylic or polycarbonate and also serves as protection in case the CRT implodes. It can be polished, however if the scratches are deep enough to feel, then it will take a lot of polishing to remove them.A car headlight polishing kit would not be a bad place to start. I might just get a set of buffing pads for my die grinder and polishing compound.

author: egonotto
author_rank: Super Contributor
timestamp: April 07, 2025, 04:14:30 pm
content: Hello,I don't think the HM203 has a delay line.Best regardsegonottoPS: you can't see the first 50 ns or so after the trigger event because the trigger circuit needs time.That's why more expensive analog scopes have a delay line so that you can still see the trigger event. This is not a memory, but delays the signal longer than the trigger circuit.

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 04:16:34 pm
content: @bdunham7I understand, the leftmost point is the trigger point.But I only get to see the whole edge with a combination of the Trigger:Norm setting and manual level setting as well as Trigger Selector: HF.Then I get the picture below and can roughly determine the rise time.I don't quite understand why this is the case (HF).Thank you.P.S. egonotto is right with the delay line.

author: bdunham7
author_rank: Super Contributor
timestamp: April 07, 2025, 04:33:25 pm
content: Quote from: egonotto on April 07, 2025, 04:14:30 pmI certainly don't see one either physically or in the schematic as something other than a cable. However, the XY performance specs for BW and phase shift are similar to models that do have delay line. But it's easy enough to check by shifting over the trace to the right and seeing if he gets the rising edge or not.

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 04:34:27 pm
content: Quote from: egonotto on April 07, 2025, 04:14:30 pmThank you.Yes, that's probably not the strong point of the HM203.But that's not why I bought it. My Hantek is better at this and shows me the rise time straight away.I'm just trying to get to know the HM203 and explore its limits.

author: egonotto
author_rank: Super Contributor
timestamp: April 07, 2025, 04:36:23 pm
content: Quote from: Aldo22 on April 07, 2025, 03:21:51 pmHello,there must be a mistake, the frequency in the first picture is not higher than 200 Hz. Because you can see at most one period, which is therefore not shorter than 5 ms.Best regardsegonotto

author: bdunham7
author_rank: Super Contributor
timestamp: April 07, 2025, 04:37:45 pm
content: Quote from: Aldo22 on April 07, 2025, 04:16:34 pmWhat is the sweep rate in that photo?

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 04:38:26 pm
content: Quote from: bdunham7 on April 07, 2025, 04:33:25 pmThis one has a delay line:https://www.ricardo.ch/de/a/hameg-oszilloskop-hm605-mit-zubehoer-1285416010/The auction ends tomorrow.

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 04:41:33 pm
content: Quote from: bdunham7 on April 07, 2025, 04:37:45 pmMax: 500ns, but no X-Magn.

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 04:42:57 pm
content: Quote from: egonotto on April 07, 2025, 04:36:23 pmIt could be that I had set X-Magn (x5). However, this had no effect on the problem.

author: bdunham7
author_rank: Super Contributor
timestamp: April 07, 2025, 04:48:16 pm
content: Quote from: Aldo22 on April 07, 2025, 04:41:33 pmOK, so the HF trigger reacts the quickest and I'll assume you've set the trigger level to the very bottom of the rising edge. Thus you only miss the very beginning (50-100ns) and since it isn't a very fast signal (or scope), you see most of the rising edge.It's been a while since I've seen a scope without a delay line but I suppose this really is one of the ultra-budget models of its time.QuoteAnd it begins!

author: egonotto
author_rank: Super Contributor
timestamp: April 07, 2025, 04:54:55 pm
content: Quote from: Aldo22 on April 07, 2025, 04:42:57 pmHello,then one period would be at least 1 ms. A 20 kHz signal has a period of 0.05 ms.Best regardsegonotto

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 05:00:36 pm
content: Quote from: bdunham7 on April 07, 2025, 04:48:16 pmThanks for the explanation with HF.Yes, I took a lame rise time so that I can see something on the Hameg.It is about 20kHz and 130ns rise time (according to the Hantek DSO2000, Screenshot also at 500ns/div).

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 05:11:52 pm
content: Quote from: egonotto on April 07, 2025, 04:54:55 pmHmm, I probably confused ms with µs on the setting knob?I think it was 5µs.It's all still unfamiliar to me...

author: Greybeard
author_rank: Frequent Contributor
timestamp: April 07, 2025, 07:06:57 pm
content: Quote from: Aldo22 on April 06, 2025, 06:29:48 pmThe manufacturing date is printed on the label on the CRT shield (the same label should also be on the back of the oscilloscope case):

author: bdunham7
author_rank: Super Contributor
timestamp: April 07, 2025, 07:15:45 pm
content: Quote from: Aldo22 on April 07, 2025, 05:00:36 pmSo, after some more coffee and clearing some cobwebs from my brain, it occurred to me that at the relatively slow maximum sweep rates here the delay line doesn't really get you a whole lot. I set up a similar signal at the same sweep rate as your scope and you can see what I get at 500ns/div and then expanded to 50ns/div. The trigger is set right at the end of the first division, between the lower dotted horizontal line and the division line directly above it. The delay is more relevant to faster signals like the third photo (8.4ns rise time) with the trigger set a zero and the center of the screen.Obviously you see the tremendous advantage of DSOs for this application. Curve tracing and XY are better uses of your CRO. And perhaps a scope-clock project.

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 07:28:18 pm
content: Quote from: Greybeard on April 07, 2025, 07:06:57 pmI see! Once you know, it's really simple.But it doesn't have anything like that on the back.

author: Phil1977
author_rank: Frequent Contributor
timestamp: April 07, 2025, 07:34:18 pm
content: Quote from: Aldo22 on April 06, 2025, 09:32:18 amI´ve got the older version of the HM203 without the integrated component tester feature. It´s perfectly functional, and I checked all capacitors with a thermal imager after some time of usage. I did not find any indication of a problem at my unit, but I can only recommend to do the same test.Be aware of the HV at and around the beam intensity / focus potentiometers while operating the scope without its housing.

author: Aldo22
author_rank: Super Contributor
timestamp: April 07, 2025, 07:35:04 pm
content: Quote from: bdunham7 on April 07, 2025, 07:15:45 pmYes, that's why I bought it (plus real-time view of audio signals and the component tester).And that's why I don't need any special features.I just wanted a well-preserved analog oscilloscope with proven, relatively simple technology.

author: bte
author_rank: Regular Contributor
timestamp: April 08, 2025, 12:47:32 am
content: Quote from: EvgenyG on April 07, 2025, 08:22:32 amI think this reply is addressing me. Thank you for the hint and apologies for late reply. Unfortunately, as of last week, we (residents of Turkey) can no longer buy internationally unless the international company has a local branch/representative. The previous customs regulations "update" before that had decreased our allowance to 30 EUR including shipping. Both of these combined has practically killed international shopping for us.

author: Aldo22
author_rank: Super Contributor
timestamp: April 08, 2025, 09:38:52 am
content: Quote from: Phil1977 on April 07, 2025, 07:34:18 pmI do not have a thermal imager only a pyrometer.I took a look at the large electrolytic capacitors after half an hour.The warmest was the 1000µF/40V with approx. 55°C.I think that's still normal, isn't it?

author: Phil1977
author_rank: Frequent Contributor
timestamp: April 08, 2025, 10:16:08 am
content: Quote from: Aldo22 on April 08, 2025, 09:38:52 amIt always depends on where the heat comes from. If a 1000uF cap heats up by itself in a classic non-switching power supply then it´s a clear indication of a high ESR - probably because of dried electrolyte. If it´s next to any other heat source and nearby components have similar temperatures, then it´s okay.If it´s just one suspicious cap then I would test it out-of-circuit.

author: Aldo22
author_rank: Super Contributor
timestamp: April 08, 2025, 10:40:02 am
content: Quote from: Phil1977 on April 08, 2025, 10:16:08 amThank you.It's the one in the middle of the five big ones on the right in this photo:https://www.eevblog.com/forum/testgear/my-brand-new-old-hm203-4/?action=dlattach;attach=2539560;imageIf I want to test it, I'll probably have to remove the whole board with all the mechanical parts, right?...

author: madires
author_rank: Super Contributor
timestamp: April 08, 2025, 11:31:50 am
content: Quote from: EvgenyG on April 07, 2025, 08:22:32 amThe used scope offered is an HM1507-3, a combiscope (analog scope and DSO), not a HM507. Still, to ask 1000 Euros for that one is too much. For comparison, the later HM1508-2 with 1 GSa/s and USB was about 2000 Euros new, IIRC.

author: Aldo22
author_rank: Super Contributor
timestamp: April 08, 2025, 12:45:49 pm
content: Quote from: Phil1977 on April 08, 2025, 10:16:08 amI was able to measure the electrolytic capacitor in-circuit.It looks good, doesn't it?965μF64.3mΩ

author: Aldo22
author_rank: Super Contributor
timestamp: April 14, 2025, 11:54:10 am
content: Can someone with experience tell me whether these measured values are within the tolerance range?Is #7 too high?I don't understand #4 at all.Everything measured against ground.In any case, the scope works quite well.1: -11.87V (-12V)2: 4.97V (5V)3: 23.83V (24V)4: -8.81 (+3.1V / -12 antipole)5: 261.6V (260V)6: 140.2V (140V)7: 3.91V (3.75V)

author: bdunham7
author_rank: Super Contributor
timestamp: April 14, 2025, 02:28:16 pm
content: The 3.75V circuit is not mentioned as one of the regulated supplies, but even if it were your measurement would be within the 5% tolerance that the manual mentions for the other fixed supplies. IDK exactly what the 3.75V supply is for so you'd have to figure that out if you really want to know whether to worry about it."Antipole" is an extremely shortened or translated (or both) designation meaning you should put the negative test lead on the -12V point rather than ground to take this reading. Alternatively you can just do the math and you'll get 3.06V.

author: Aldo22
author_rank: Super Contributor
timestamp: April 14, 2025, 02:46:23 pm
content: Quote from: bdunham7 on April 14, 2025, 02:28:16 pmThank you very much!The 3.75V obviously plays a role with the DC level (See attachment).I have too little knowledge to judge whether this is OK.As I said, the scope actually works well. It could be a bit more accurate in the amplitude measurement, but it's not really a problem.That's what I have the DSO for.

author: bdunham7
author_rank: Super Contributor
timestamp: April 14, 2025, 04:05:26 pm
content: Quote from: Aldo22 on April 14, 2025, 02:46:23 pmI don't have the service manual for this--did you find it online or do you have the paper copy?For your DC level check, set the scope to 1V/div with open inputs and auto trigger, then adjust the vertical position to the exact center. Now decrease the V/div one increment at a time and see where the trace is at each step. If it stays near the center, your DC level is OK. At least that's how I think it should work based on other scopes, but I could be misinterpreting the term so don't adjust anything based on what I say. The amplitude error would be a vertical (Y) gain issue, not DC level.My guess is that it is all OK.

author: Aldo22
author_rank: Super Contributor
timestamp: April 14, 2025, 04:39:25 pm
content: Quote from: bdunham7 on April 14, 2025, 04:05:26 pmI have both, paper and PDF.I have attached the PDFs (Service and Manual), in case anyone is interested.My model is HM203-4AQuote from: bdunham7 on April 14, 2025, 04:05:26 pmThank you.I did the check. Yes, it looks good.P.S. In general, it seems to be in very good condition after more than 40 years.It can handle 57MHz.