My brand new, old HM203-4

[Aldo22]

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. 

[Aldo22]

More photos:

- 1VDC@0.5V/cm
- 1MHz square
- 1MHz square x5
- AM
- XY curve tracer
- XY oscilloscope music

[cte]

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?

Not 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?

[Aldo22]

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?

Not 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.

Thank 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. 

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

Can I look this up somewhere?

[cte]

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

Can I look this up somewhere?

I 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.

[Aldo22]

I 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.

I got mine with the original printed manual.
It is dated 10/82. The accessories sheet is dated 11/83.

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.

In any case, the HM203-4 is in excellent condition for its age.

[bte]

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/detay

The 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.

[Aldo22]

You got yours for CHF18 or something like that if I recall correctly?

At 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.

[JoanBS]

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.

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/detay

Why are you inserting a link to a site that requires registration to access? 

[bdunham7]

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.

You 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.

[bte]

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/detay

Why are you inserting a link to a site that requires registration to access? 

I 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.

[Aldo22]

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.

You 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.

Thank 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. 

[cte]

Thank 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. 

The 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, Berlin has those. But they seem to have high shipping charges to Switzerland...

[Aldo22]

The 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, Berlin has those. But they seem to have high shipping charges to Switzerland...

Many 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. 

[Aldo22]

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.

1000€ 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/

[EvgenyG]

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.

[kripton2035]

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 EUR
don't buy a HM507 for more than 150 EUR IMHO
they are great for the component tester (and XY mode !)

[Aldo22]

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!

[bdunham7]

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?

Do 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.

[David Hess]

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 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.

[egonotto]

Hello,

I don't think the HM203 has a delay line.

Best regards
egonotto

PS: 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.

[Aldo22]

@bdunham7
I 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.

[bdunham7]

I don't think the HM203 has a delay line.

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.

[Aldo22]

Hello,

I don't think the HM203 has a delay line.

Best regards
egonotto

PS: 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.

Thank 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.

[egonotto]

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!

Hello,

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 regards
egonotto