Old Calscope

[satdaveuk]

My old Calscope which Ive had since serving my apprenticship is about 35 years old is giving trouble as in cant get nice clear cut wave forms anymore.
Dont know wether to have a go at it or maybe change.
Any pointers to bringing new life back into it would be handy from members here.
Or do I call it a day and replace.

Regards

[Qiaozhi]

My old Calscope which Ive had since serving my apprenticship is about 35 years old is giving trouble as in cant get nice clear cut wave forms anymore.
Dont know wether to have a go at it or maybe change.
Any pointers to bringing new life back into it would be handy from members here.
Or do I call it a day and replace.

Regards

What does it look like?
Do you have a photo?

[satdaveuk]

Hi
Its the super 10 calscope

[Qiaozhi]

Hi
Its the super 10 calscope

I thought so!
You've posted a photo of this before, and it's the same as my old Scopex 4D 10.
Do you need the circuit diagram?

[satdaveuk]

I thought so!
You've posted a photo of this before, and it's the same as my old Scopex 4D 10.
Do you need the circuit diagram?

Yes if its not to much trouble thanks

[Qiaozhi]

Yes if its not to much trouble thanks

It too me a while to find it, but I seemed to remember sending it to someone else in the past.
http://www.geotech1.com/forums/showthread.php?t=17129

Please let us know if you get it working again.

[satdaveuk]

It too me a while to find it, but I seemed to remember sending it to someone else in the past.
http://www.geotech1.com/forums/showthread.php?t=17129

Please let us know if you get it working again.

Thanks Qiaozhi
Ive posted on that thread asking Taliesin if he can remember the fault and remedy he had, although two years ago its worth a shot.
Will have a go at it and let you know, if rectified its worth keeping in the faults log for fucture ref as there a good scope when up and running to spec.
Have you had any faults on this model that you have solved in the past, ive had 2 caps leaky plus dry joint thats it, , did it in one go 4-5 years ago.

Many thanks again

[Qiaozhi]

Thanks Qiaozhi
Ive posted on that thread asking Taliesin if he can remember the fault and remedy he had, although two years ago its worth a shot.
Will have a go at it and let you know, if rectified its worth keeping in the faults log for fucture ref as there a good scope when up and running to spec.
Have you had any faults on this model that you have solved in the past, ive had 2 caps leaky plus dry joint thats it, , did it in one go 4-5 years ago.

Many thanks again

I don't use it these day. Not since first buying a Gould OS 300 and then a GW Instek GDS-1022. Also, it's never gone wrong.

[satdaveuk]

calscope 10 out of focus

Hi
Here is picture that shows symptom of the fault.
As I said previously it wasn't clear cut display but now its gone completely out of focus.
Checked the EHT/HT/LT lines and they seem ok, checked voltage on CRT base which vary a bit when altering the focus control on front panel but makes no difference on display.
Both channels are showing, channel A is showing 50hz via my finger present on probe.
XY and everything else seems to be working ok.

Any tips on this fault would be received gratefully as its in excellent condition and has sentimental value, as dad bought me it from new while I was doing my apprenticeship back in early 70s.

Thanks in advance

[Qiaozhi]

Hi
Here is picture that shows symptom of the fault.
As I said previously it wasn't clear cut display but now its gone completely out of focus.
Checked the EHT/HT/LT lines and they seem ok, checked voltage on CRT base which vary a bit when altering the focus control on front panel but makes no difference on display.
Both channels are showing, channel A is showing 50hz via my finger present on probe.
XY and everything else seems to be working ok.

Any tips on this fault would be received gratefully as its in excellent condition and has sentimental value, as dad bought me it from new while I was doing my apprenticeship back in early 70s.

Thanks in advance[ATTACH]23619[/ATTACH]

Maybe the tube is faulty.
As I mentioned previously, I have a Scopex 4D 10 (in working condition) that looks virtually identical. If you want it, make me an offer. You can use it to compare the two units and then resell it later.

[satdaveuk]

You could be right, what Ive done is checked the 4 electro caps by lifting one end (Discharged before checking) worth keeping in mind as theres charge in these caps long after switching off, anyway they are OK, just need to check the 2.2m resistors theres about 4 or 5 of those and theres about 6 diodes that that are chained for voltage drop which need checking.
Your circuit and board layout although similar are not the same there are certain difference's incl component number IDs but managing to find myself around it.
If I don't have any luck may consider buying yours if its cheap enough, bare in mind postage these days is expensive.

[Qiaozhi]

You could be right, what Ive done is checked the 4 electro caps by lifting one end (Discharged before checking) worth keeping in mind as theres charge in these caps long after switching off, anyway they are OK, just need to check the 2.2m resistors theres about 4 or 5 of those and theres about 6 diodes that that are chained for voltage drop which need checking.
Your circuit and board layout although similar are not the same there are certain difference's incl component number IDs but managing to find myself around it.
If I don't have any luck may consider buying yours if its cheap enough, bare in mind postage these days is expensive.

The scope weighs just under 6kg. It could be shipped to you using Hermes UK Economy for £4.99 + VAT (plus the cost of the scope, of course).

[satdaveuk]

Fult located and cured

Hi
The fault was R614 910k on your circuit and R669 820k on mine, had gone high to 15Mohm.
Its located underneath the CRT shielding.
What a lovely layout these English machines are and easy de-soldering like the old days using leaded solder, components all well spaced out.
The resistor was a half watt high stab 5% and that exactly what I replaced it with from old stock.
Now its apart shall give it a well deserved clean before reassemble

Picture quality as new which you can see by the picture.

Thanks for the offer Qiaozhi
Mine is up and going now so don't require it.
Regards

[Qiaozhi]

Hi
The fault was R614 910k on your circuit and R669 820k on mine, had gone high to 15Mohm.
Its located underneath the CRT shielding.
What a lovely layout these English machines are and easy de-soldering like the old days using leaded solder, components all well spaced out.
The resistor was a half watt high stab 5% and that exactly what I replaced it with from old stock.
Now its apart shall give it a well deserved clean before reassemble

Picture quality as new which you can see by the picture.

Thanks for the offer Qiaozhi
Mine is up and going now so don't require it.
Regards

Well done!
I'm pleased you got it working again.