Test Equipment Anonymous (TEA) group therapy thread

[Robert763]

Vince
No you are not being silly that is a OK way to check leakage.

however rather than the DMM on current I'd use it on voltage in series with the capacitor and HT. No chance of blowing it up and with 10M input impedance each volt indicated is 0.1uA of leakage.

[Specmaster]

ELECTROTANYA seems to have a service manual.

No it doesn't unless my search is bogus. Sony ICF-5500W

The M refers to Marine Band, the radio itself is identical to yours apart from the wavebands covered, but the all important mechanical construction of the band selector etc is the same and a decent copy of the full manual can be downloaded FOC from here https://archive.org/details/manual_ICF5500M_SONY and this also includes the exploded construction drawings.

[Cerebus]

I just can't hide it any longer....

All those pics of 7000 series scopes and their plugins!  It's just too much.



I want one.

You might as well take up the complementary sport in the meantime. 

I think the alternative Finnish sport of wife carrying would both be more fun and less odiferous.



It certainly looks more fun than carrying a couple of pigs. The downside would be the absence of a huge stack of bacon sarnies at the end of it.

[Vince]

Vince
No you are not being silly that is a OK way to check leakage.

however rather than the DMM on current I'd use it on voltage in series with the capacitor and HT. No chance of blowing it up and with 10M input impedance each volt indicated is 0.1uA of leakage.

Oh yes you are riught that's quite a clever trick, I remember reading about it here recently... thanks for reminding me about it ! 
Will do that.

For now I have pulled one leg of the Mica cap and measured it... at about 75pf for a nominal 56 +/- 10% (according to the parts list).
So that's +30/35% off ! 

Way more than the allowed 10%.

So right there it's suspicious...

Will do the leak test right now, stay tuned ! 

[Neomys Sapiens]

ELECTROTANYA seems to have a service manual.

No it doesn't unless my search is bogus. Sony ICF-5500W

"She" has the ICF-5500M. A quick picture comparison shows the M is a four-band that covers FM, SW, MW and Marine (around 4MHz); while the W is a three-band that has FM, AM and "Marine Weather" / PSB (around 160MHz). Radios look quite the same other wise.

Now I'm confused. Who is "She" ? 

https://elektrotanya.com/sony_icf-5500m_sm.pdf/download.html

[med6753]

ELECTROTANYA seems to have a service manual.

No it doesn't unless my search is bogus. Sony ICF-5500W

The M refers to Marine Band, the radio itself is identical to yours apart from the wavebands covered, but the all important mechanical construction of the band selector etc is the same and a decent copy of the full manual can be downloaded FOC from here https://archive.org/details/manual_ICF5500M_SONY and this also includes the exploded construction drawings.

OK, thanks. Got it. And yes, physical construction is almost identical. Will definitely be a help for the future.

[med6753]

ELECTROTANYA seems to have a service manual.

No it doesn't unless my search is bogus. Sony ICF-5500W

"She" has the ICF-5500M. A quick picture comparison shows the M is a four-band that covers FM, SW, MW and Marine (around 4MHz); while the W is a three-band that has FM, AM and "Marine Weather" / PSB (around 160MHz). Radios look quite the same other wise.

Now I'm confused. Who is "She" ? 

https://elektrotanya.com/sony_icf-5500m_sm.pdf/download.html

Thanks, got it. Spec beat you to it.

[mnementh]

You can call me whatever you like, as long as it's not late to dinner.

You can leave in a huff if you like. If that's too soon you can leave in a minute and a huff. 

Ummm... but then who's going to cook dinner...? 

mnem

[Vince]

Leakage test below, done 

Parts list says that cap is rated at 500 Volts.

In circuit it's not seeing anywhere close to that it looks like, but I wanted to test it as close as to its rated voltage anyway.

Highest voltage rail available is +350V so used that. As I am typing this I am now realizing I could have used that +350V rail in conjunction with the -150V reference rail to get precisely the 500V I needed, bummer, how stupid I am ! 

Anyway, I think 350V is good enough to draw conclusions here.

So here is how it went :

At power up, voltagE/current was rising, steadily/linearly. After a few seconds, 30 or whatever, it settled at 230Volts, hence 23uA.

It stayed there for 2 minutes then started  rising again, very slowly. It got to 260/270Volts.

Then5 minutes later it started climbing again, very slowly. Took the picture below at 304 Votls, but I am checking it right now as I am typing this, and it's already up to 315 Volts now !

No doubt it will reach the full 350V eventually,given enough time...

So that's about 30uA leakage then, eh ?

How good or bad is it ? Have no idea. Do'nt know what is normal / acceptable for cpas in general, never mind for each type of caps, never mind for vintage ones.

However the simple fact that it keeps rising all the time, does not seem right to me. Regardless of what the normal leakage for this type cap is, I would expect it to settle after a few second, not keep rising over the course of an hour...

Also, in the RC network, the 'R' is several Mega-ohms( fixed 2M resistor in series with 5M pot), so 30uA leakage does translate to quite a bit of voltage...


EDIT : just re-did the test, this time under 500V using the -150V rail instead of chassis ground.... Result : immediately upon turning on the power, it jumps to 400Volts. 2 minutes later still at 400V.
So looks like it leaks 40uA then. Oh no wait, it's rising again, now at 420 Volts !! 

My first leakage test on vintage caps, cooooool   
It's so easy, no need for fancy expensive bulky vintage tester, just use the instrument itself as a power source, test leads and a DMM / voltmeter, and you're in business !!! 

[Vince]

EDIT #2 :would you believe it, I am in luck : I checked my drawer, have some random ceramic disc caps... can't believe it, I got a big one that's exactly the value I need, 56pF, and is super HV : 6kV, should do it !! 

I measured its value, spot on 56pF, yeah !

Then I did (still running) a leakage test at 350V, if just to compare it to the old MIca cap, so I learn something.

Result : upon firing power : ZERO volts, 0.000V !

10 minutes later now :still dead ZERO ! 

OK... so that Mica cap is bad eh, what do you think ?

Will put the ceramic cap in the instrument to see if that improves things or not, stay tuned....   

[Cerebus]

You can call me whatever you like, as long as it's not late to dinner.

You can leave in a huff if you like. If that's too soon you can leave in a minute and a huff. 

Ummm... but then who's going to cook dinner...? 

Someone could always open a tin of soup. Duck soup perhaps? 

[Vince]

OK I put that ceramic disc cap instead of the Mica, fired up..... VICTORY !!!!! 

That 100us stage now works perfectly, trim pot now is operational again and I can adjust the time interval just fine, it can adjust it to 100us, 150 or 200us.

Stage is fixed 100%, yes !!!   

OK so now need to replace the cap in the two following stages, which don't work either and also use a mica cap.

These 2 stages both use a 250pF cap, don't have that sadly. Will visit my local electronics shop tomorrow to get some ceramic disc caps.
Small shop so no website, but I have his catalogue in PDF format here. I see the closest he has is 220pF, a bit out of tolerance to replace a 250pF 10%... but should do it. Hell with some luck it will read a bit high and will therefore be in tolerance for what I need.
Or.. I see he has some 120pF ones. I could put two of those in // and that would be good. But they are expensive at 1.6 Euro a pop, and I would need 4 in them total..
The 220pF is discounted at only 86 cents, and I need only two not 4. Hmm... choices choices ! 


So that was interesting....it was so easy to blame all these ancient tubes, and in the end it was the most Unlikely part that failed, a freaking Domino Mica cap !
And only detectable with a proper HV leakage test at that, because it tests OK with a DMM, not low impedance not silly capacitance value... you do need a proper leakage test to detect the problem...

00h00 here, going to bed happy, fixed the thing, learned some interesting stuff, did a cool leakage test, life is good ! 

[Neomys Sapiens]

You can call me whatever you like, as long as it's not late to dinner.

You can leave in a huff if you like. If that's too soon you can leave in a minute and a huff. 

Ummm... but then who's going to cook dinner...? 

Someone could always open a tin of soup. Duck soup perhaps? 

When my employer was taken over by our current Austrian parent corporation, they brought along their ugly and (to me) not very appealing mascot - a blue rubber duck. I mean, fly with the eagles or waddle with the ducks, you know...
I could not help but abusing the thing for several vile & funny montages, among which was the one shown below. So 'duck soup' did connect to that right away - I think I have to come up with some new ones!

[mnementh]

You can call me whatever you like, as long as it's not late to dinner.

You can leave in a huff if you like. If that's too soon you can leave in a minute and a huff. 

Ummm... but then who's going to cook dinner...? 

Someone could always open a tin of soup. Duck soup perhaps? 

mnem
"...on second thought, I'd rather dance with the cows til you come home."

[BU508A]

Will somebody visit one of those events?

HAM Radio in Friedrichshafen - 24.6. - 26.6.2022

UKW Tagung in Weilheim - not sure, if this event will take place. I haven't found any information about the UKW Tagung in 2022.

I think, I'll visit the HAM Radio on Friday, perhaps we can do there a little TEA meeting? 

[med6753]

OK I put that ceramic disc cap instead of the Mica, fired up..... VICTORY !!!!! 

That 100us stage now works perfectly, trim pot now is operational again and I can adjust the time interval just fine, it can adjust it to 100us, 150 or 200us.

Stage is fixed 100%, yes !!!   

OK so now need to replace the cap in the two following stages, which don't work either and also use a mica cap.

These 2 stages both use a 250pF cap, don't have that sadly. Will visit my local electronics shop tomorrow to get some ceramic disc caps.
Small shop so no website, but I have his catalogue in PDF format here. I see the closest he has is 220pF, a bit out of tolerance to replace a 250pF 10%... but should do it. Hell with some luck it will read a bit high and will therefore be in tolerance for what I need.
Or.. I see he has some 120pF ones. I could put two of those in // and that would be good. But they are expensive at 1.6 Euro a pop, and I would need 4 in them total..
The 220pF is discounted at only 86 cents, and I need only two not 4. Hmm... choices choices ! 


So that was interesting....it was so easy to blame all these ancient tubes, and in the end it was the most Unlikely part that failed, a freaking Domino Mica cap !
And only detectable with a proper HV leakage test at that, because it tests OK with a DMM, not low impedance not silly capacitance value... you do need a proper leakage test to detect the problem...

00h00 here, going to bed happy, fixed the thing, learned some interesting stuff, did a cool leakage test, life is good ! 

Vince, you should replace with mica, not ceramic. Ceramic capacitors tend to drift too much. Mica capacitors are much more stable and that is needed in those critical circuits.

See this...

https://www.westfloridacomponents.com/blog/mica-capacitors-use/

[Brumby]

I just can't hide it any longer... All those pics of 7000 series scopes and their plugins!  It's just too much.

I want one.

What do you want? A scope mainframe?   A plugin?   Both?   Which model?   Which module(s)?

Questions over questions ... 

You should be a little more specific if you want us to advise enable you adequately.   

  There... FTFY.   

mnem
 

I didn't want to make it that obvious. 

This is the TEA thread.

Obvious doesn't matter.

[Brumby]

As for the boat anchor rating ... it doesn't scare me,  but I do respect it.

 I will take appropriate precautions  (if the opportunity should ever present itself).

[Vince]

OK I put that ceramic disc cap instead of the Mica, fired up..... VICTORY !!!!! 

That 100us stage now works perfectly, trim pot now is operational again and I can adjust the time interval just fine, it can adjust it to 100us, 150 or 200us.

Stage is fixed 100%, yes !!!   

OK so now need to replace the cap in the two following stages, which don't work either and also use a mica cap.

These 2 stages both use a 250pF cap, don't have that sadly. Will visit my local electronics shop tomorrow to get some ceramic disc caps.
Small shop so no website, but I have his catalogue in PDF format here. I see the closest he has is 220pF, a bit out of tolerance to replace a 250pF 10%... but should do it. Hell with some luck it will read a bit high and will therefore be in tolerance for what I need.
Or.. I see he has some 120pF ones. I could put two of those in // and that would be good. But they are expensive at 1.6 Euro a pop, and I would need 4 in them total..
The 220pF is discounted at only 86 cents, and I need only two not 4. Hmm... choices choices ! 


So that was interesting....it was so easy to blame all these ancient tubes, and in the end it was the most Unlikely part that failed, a freaking Domino Mica cap !
And only detectable with a proper HV leakage test at that, because it tests OK with a DMM, not low impedance not silly capacitance value... you do need a proper leakage test to detect the problem...

00h00 here, going to bed happy, fixed the thing, learned some interesting stuff, did a cool leakage test, life is good ! 

Vince, you should replace with mica, not ceramic. Ceramic capacitors tend to drift too much. Mica capacitors are much more stable and that is needed in those critical circuits.

See this...

https://www.westfloridacomponents.com/blog/mica-capacitors-use/

Yes I was wondering about that, but didn't post about it, one thing at a time I thought ! 
For now the purpose was to debug the thing.

But now that it's clear the Mica caps were the problem, yes I can now try to find a good replacement.
Problem is... I though Mica caps don't exist anymore these days ?! 

I don't know enough about the specs of mica o know what modern / readily available cap technology would be a good replacement.

Hopefully there are cap experts here... someone... somewhere... don't be shy.

Until a good replacement is determined, will get disc caps locally tomorrow to keep me going in the debugging department.

EDIT : the article you linked to kinda implies that Mica caps might still be available today. Will look on the usual websites, see what they might have...

[med6753]

OK I put that ceramic disc cap instead of the Mica, fired up..... VICTORY !!!!! 

That 100us stage now works perfectly, trim pot now is operational again and I can adjust the time interval just fine, it can adjust it to 100us, 150 or 200us.

Stage is fixed 100%, yes !!!   

OK so now need to replace the cap in the two following stages, which don't work either and also use a mica cap.

These 2 stages both use a 250pF cap, don't have that sadly. Will visit my local electronics shop tomorrow to get some ceramic disc caps.
Small shop so no website, but I have his catalogue in PDF format here. I see the closest he has is 220pF, a bit out of tolerance to replace a 250pF 10%... but should do it. Hell with some luck it will read a bit high and will therefore be in tolerance for what I need.
Or.. I see he has some 120pF ones. I could put two of those in // and that would be good. But they are expensive at 1.6 Euro a pop, and I would need 4 in them total..
The 220pF is discounted at only 86 cents, and I need only two not 4. Hmm... choices choices ! 


So that was interesting....it was so easy to blame all these ancient tubes, and in the end it was the most Unlikely part that failed, a freaking Domino Mica cap !
And only detectable with a proper HV leakage test at that, because it tests OK with a DMM, not low impedance not silly capacitance value... you do need a proper leakage test to detect the problem...

00h00 here, going to bed happy, fixed the thing, learned some interesting stuff, did a cool leakage test, life is good ! 

Vince, you should replace with mica, not ceramic. Ceramic capacitors tend to drift too much. Mica capacitors are much more stable and that is needed in those critical circuits.

See this...

https://www.westfloridacomponents.com/blog/mica-capacitors-use/

Yes I was wondering about that, but didn't post about it, one thing at a time I thought ! 
For now the purpose was to debug the thing.

But now that it's clear the Mica caps were the problem, yes I can now try to find a good replacement.
Problem is... I though Mica caps don't exist anymore these days ?! 

I don't know enough about the specs of mica o know what modern / readily available cap technology would be a good replacement.

Hopefully there are cap experts here... someone... somewhere... don't be shy.

Until a good replacement is determined, will get disc caps locally tomorrow to keep me going in the debugging department.

EDIT : the article you linked to kinda implies that Mica caps might still be available today. Will look on the usual websites, see what they might have...

Still made and required in many modern applications.

[Vince]

Yeah long live Mouser, many of them there, 8,500 !    Lucky you US bastards !

Here on Farnell MUCH less choice, only 174 references, and 90% of them aren't really available : not in their European stock / warehouses, US only, they charge 18 Euros to get them here ! 

Luckily out of the handful that can be bought locally, they happen to have the two values I need, 56pF and 250pF, yeah ! Exact same voltage rating as well, 500V, cool.

They are precision caps at that : 1% for one, 5% for the other, vs 10% for the old one. Should do it 

Bloody expensive at 5 Euros a pop ! Glad I only need 3 of them. So 15 Euros + 10 Euros shipping, 25 Euros for 3 tiny caps, wow.... 

[srb1954]

Yes I was wondering about that, but didn't post about it, one thing at a time I thought ! 
For now the purpose was to debug the thing.

But now that it's clear the Mica caps were the problem, yes I can now try to find a good replacement.
Problem is... I though Mica caps don't exist anymore these days ?! 

I don't know enough about the specs of mica o know what modern / readily available cap technology would be a good replacement.

A modern C0G/NP0 dielectric ceramic cap would also be a suitable substitute for mica in a circuit like this. These have adequate performance to match or exceed the mica caps in terms of tolerance, low loss and temperature stability.

SMD versions of C0G/NP0 caps are readily available from the usual suppliers but finding a supplier with a good range of leaded C0G/NP0 parts may be more difficult.

[BU508A]

As for the mica capacitors (German: Glimmerkondensator or Glimmer Kondensator):

BTB electronics has some of them:
https://btb-elektronik.de/en/products/4410/silver-mica-capacitor/

They can also be found on ebay, search term "silver mica".
In the German ebay section there are some listed:

https://www.ebay.de/sch/i.html?_from=R40&_trksid=p2553889.m570.l1311&_nkw=glimmer+kondensator&_sacat=0

If you need help with ordering etc. I can assist. I can also order and send them to you if you want.


Edit:
another source: https://www.box73.de/index.php?cPath=82_174_272
and another: https://www.mos-electronic-shop.de/glimmerk-250v-500v-c-84_114.html

[Cerebus]

Well, it's the 1st April - technically the second month of spring - and the temperature outside my window at the moment is 0.3ºC, the sky's clearing so it'll go colder before the night's over, and we've got snow warnings for points east of me. Is this supposed to be some sort of April Fool's joke?

Last week it hit 20ºC or more, was sunny, and I was wandering around outside in a T-shirt feeling that spring had really arrived.   

[Specmaster]

Yeah long live Mouser, many of them there, 8,500 !    Lucky you US bastards !

Here on Farnell MUCH less choice, only 174 references, and 90% of them aren't really available : not in their European stock / warehouses, US only, they charge 18 Euros to get them here ! 

Luckily out of the handful that can be bought locally, they happen to have the two values I need, 56pF and 250pF, yeah ! Exact same voltage rating as well, 500V, cool.

They are precision caps at that : 1% for one, 5% for the other, vs 10% for the old one. Should do it 

Bloody expensive at 5 Euros a pop ! Glad I only need 3 of them. So 15 Euros + 10 Euros shipping, 25 Euros for 3 tiny caps, wow.... 

Oh come on, you are joking, there must loads of suppliers in France who can supply these, you just have to use the search engines better.