My brand new, old HM203-4

[bdunham7]

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).

What is the sweep rate in that photo? 

[Aldo22]

I 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.

This one has a delay line:
https://www.ricardo.ch/de/a/hameg-oszilloskop-hm605-mit-zubehoer-1285416010/
The auction ends tomorrow. 

[Aldo22]

What is the sweep rate in that photo?

Max: 500ns, but no X-Magn.

[Aldo22]

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.

It could be that I had set X-Magn (x5). However, this had no effect on the problem.

[bdunham7]

Max: 500ns, but no X-Magn.

OK, 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.

This one has a delay line:
https://www.ricardo.ch/de/a/hameg-oszilloskop-hm605-mit-zubehoer-1285416010/
The auction ends tomorrow. 

And it begins!

[egonotto]

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.

It could be that I had set X-Magn (x5). However, this had no effect on the problem.

Hello,

then one period would be at least 1 ms. A 20 kHz signal has a period of 0.05 ms.

Best regards
egonotto

[Aldo22]

OK, 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.

Thanks 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).

[Aldo22]

then one period would be at least 1 ms. A 20 kHz signal has a period of 0.05 ms.

Hmm, I probably confused ms with µs on the setting knob?
I think it was 5µs.
It's all still unfamiliar to me... 

[Greybeard]

Out of curiosity: Do you know the manufacturing date/year of the device?

Can I look this up somewhere?

The manufacturing date is printed on the label on the CRT shield (the same label should also be on the back of the oscilloscope case):

[bdunham7]

It is about 20kHz and 130ns rise time (according to the Hantek DSO2000, Screenshot also at 500ns/div).

So, 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.

[Aldo22]

The manufacturing date is printed on the label on the CRT shield (the same label should also be on the back of the oscilloscope case):

I see! Once you know, it's really simple.   
But it doesn't have anything like that on the back.

[Phil1977]

I'm sure the first capacitors are still in it.

I´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.

[Aldo22]

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.

Yes, 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.

[bte]

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-s

On a side note, HM507 is a nice scope but it is not worth 1000 EUR.

I 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.

[Aldo22]

I´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.

I 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?

[Phil1977]

I 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?

It 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.

[Aldo22]

It 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.

Thank 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;image

If I want to test it, I'll probably have to remove the whole board with all the mechanical parts, right?... 

[madires]

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-s

On a side note, HM507 is a nice scope but it is not worth 1000 EUR.

The 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.

[Aldo22]

If it´s just one suspicious cap then I would test it out-of-circuit.

I was able to measure the electrolytic capacitor in-circuit.
It looks good, doesn't it?
965μF
64.3mΩ

[Aldo22]

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)

[bdunham7]

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.

[Aldo22]

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. 

Thank 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.

[bdunham7]

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.

I 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.

[Aldo22]

I don't have the service manual for this--did you find it online or do you have the paper copy?

I have both, paper and PDF.
I have attached the PDFs (Service and Manual), in case anyone is interested.
My model is HM203-4A

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.

Thank 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.