Old 'Scope inductor and cap help please

[pfjw@aol.com]

Tabby is dangerous - much as unvaccinated stray cats are dangerous. He loves pissing on the fire.

Peter Wieck
Melrose Park, PA

 

On Wednesday, 9 October 2019 20:40:19 UTC+1, pf...@aol.com wrote:

Tabby is dangerous - much as unvaccinated stray cats are dangerous. He loves pissing on the fire.

Peter Wieck
Melrose Park, PA

ah the usual bullshitters.

 

[Fox's Mercantile]

On 10/9/19 3:29 PM, tabbypurr@gmail.com wrote:

On Wednesday, 9 October 2019 20:40:19 UTC+1, pf...@aol.com wrote:

Tabby is dangerous - much as unvaccinated stray cats are dangerous. He loves pissing on the fire.

Peter Wieck
Melrose Park, PA

ah the usual bullshitters.

Except, you continually prove it. Repeatedly.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Fox's Mercantile]

On 10/9/19 5:56 PM, tabbypurr@gmail.com wrote:
> Lol. Plonk for bullsht overload. Life's too short.

Don't lie to me.
This makes the 4th or 5th time you claim to have kill
filed me.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

On Wednesday, 9 October 2019 23:03:51 UTC+1, Fox's Mercantile wrote:

On 10/9/19 3:29 PM, tabbypurr wrote:
On Wednesday, 9 October 2019 20:40:19 UTC+1, pf...@aol.com wrote:

Tabby is dangerous - much as unvaccinated stray cats are dangerous. He loves pissing on the fire.

Peter Wieck
Melrose Park, PA

ah the usual bullshitters.


Except, you continually prove it. Repeatedly.

Lol. Plonk for bullsht overload. Life's too short.

 

[pfjw@aol.com]

It is a wonder that there are still individuals on this planet that are OK with "doing it over" - and over, and over, and over, and over.

Capacitors made in the days of wax and paper, whatever the casing, cardboard, heavier paper, plastic, ceramic, Bakelite and so forth are of-a-piece. That one or even one hundred may be good does not make them any more reliable, or reduce the need to replace them outright - that is, if one cares about the results.

Sure, if I am repairing a shelf-queen for an individual who states, clearly, that the radio will never, ever, be run more than once per year, and then only for five (5) minutes, if at all, and if that individual will run it only on a bench with a controlled power-supply, MAYBE, I will accept instructions only to do that-which-is-minimally-necessary.

This is a hobby for me, so I do not take payment for anything I might do, and I reserve the right to be arbitrary. In general, I wish anything that leaves my hands to be as "safe and effective" as is reasonably possible, and certainly as reliable as possible. Just as I am not required or restricted to using single-weight, non-detergent oil in a vintage automobile, I am not require or restricted to use vintage parts in a vintage radio. Caps are cheap. Even to a hobbyist at $0.40 an hour, they are far cheaper than "Doing it over". Do them all, and be done with it.

Peter Wieck
Melrose Park, PA

 

[amdx]

On 10/4/2019 6:31 PM, Fox's Mercantile wrote:

On 10/4/19 6:13 PM, etpm@whidbey.com wrote:
On Fri, 4 Oct 2019 14:04:36 -0500, Fox's Mercantile <jdangus@att.net
wrote:

On 10/4/19 12:53 PM, etpm@whidbey.com wrote:
I have not been able to find this style of inductor online. Maybe
I'm not using the correct search terms.  Can anyone point me in the
correct direction? Maybe I could just wind my own. Anybody know what
the permeability of a carbon comp resistor is?

The permeability is zero.
Correction, it's 1.
It's "just a coil form"
Unwind the old one, count the number of turns, measure the wire
size. Wind new turns and replace.
The schematic just shows the inductor in the circuit. It does not show
the inductor as being in parallel with a resistor. And it is described
as 35 uH "ON 10 M". So I'm thinking I either can just replace the
inductor with an off the shelf 35 uH coil and not worry about the
resistor or connect the coil and a 10 meg resistor in parallel.
Eric


You don't need the 10 meg ohm resistor.
This will be fine.
https://www.mouser.com/ProductDetail/API-Delevan/1025-56J?qs=sGAEpiMZZMsg%252By3WlYCkU%2Fuy0w9T3GDQ2AQE7IS6yJE%3D

Know one has mentioned it, but I have a question about the value 33uh.
Unless that is a very large resistor or a very small diameter wire...
I just question the value.
Mikek

 

[Ralph Mowery]

In article <qnnkni$ga9$1@dont-email.me>, nojunk@knology.net says...

Know one has mentioned it, but I have a question about the value 33uh.
Unless that is a very large resistor or a very small diameter wire...
I just question the value.

I ran some numbers a while back and nothing reasonable for 33 uH came
out for an air wound coil that would fit on a 1/2 to 1 watt resistor.
Maybe it was .33 uh.

 

On Thu, 10 Oct 2019 06:08:38 -0700 (PDT), "pfjw@aol.com"
<peterwieck33@gmail.com> wrote:

It is a wonder that there are still individuals on this planet that are OK with "doing it over" - and over, and over, and over, and over.

Capacitors made in the days of wax and paper, whatever the casing, cardboard, heavier paper, plastic, ceramic, Bakelite and so forth are of-a-piece. That one or even one hundred may be good does not make them any more reliable, or reduce the need to replace them outright - that is, if one cares about the results.

Sure, if I am repairing a shelf-queen for an individual who states, clearly, that the radio will never, ever, be run more than once per year, and then only for five (5) minutes, if at all, and if that individual will run it only on a bench with a controlled power-supply, MAYBE, I will accept instructions only to do that-which-is-minimally-necessary.

This is a hobby for me, so I do not take payment for anything I might do, and I reserve the right to be arbitrary. In general, I wish anything that leaves my hands to be as "safe and effective" as is reasonably possible, and certainly as reliable as possible. Just as I am not required or restricted to using single-weight, non-detergent oil in a vintage automobile, I am not require or restricted to use vintage parts in a vintage radio. Caps are cheap. Even to a hobbyist at $0.40 an hour, they are far cheaper than "Doing it over". Do them all, and be done with it.

Peter Wieck
Melrose Park, PA

The caps were pretty cheap, even the 450 volt electrolytics. So
they are all getting replaced. Aside from probably being a good idea I
really don't want a cap to go short down the road and ruin the power
xmfr. The only caps I am not replacing are the little disc ceramic
ones.
I don't know yet what shape the tubes are in but since the scope
does work now I think they are probably in good shape. The nearest
tube tester to me that I know of is 80 miles away sso I can't test
them except to see ho well the scope functions.
I bet I can find a Ham that has a tube tester closer to me if I
really want to test tubes. Might just be cheaper to find some new ones
on eBay.
Eric

 

On Thursday, 10 October 2019 14:08:42 UTC+1, pf...@aol.com wrote:

It is a wonder that there are still individuals on this planet that are OK with "doing it over" - and over, and over, and over, and over.

Capacitors made in the days of wax and paper, whatever the casing, cardboard, heavier paper, plastic, ceramic, Bakelite and so forth are of-a-piece. That one or even one hundred may be good does not make them any more reliable, or reduce the need to replace them outright - that is, if one cares about the results.

Sure, if I am repairing a shelf-queen for an individual who states, clearly, that the radio will never, ever, be run more than once per year, and then only for five (5) minutes, if at all, and if that individual will run it only on a bench with a controlled power-supply, MAYBE, I will accept instructions only to do that-which-is-minimally-necessary.

This is a hobby for me, so I do not take payment for anything I might do, and I reserve the right to be arbitrary. In general, I wish anything that leaves my hands to be as "safe and effective" as is reasonably possible, and certainly as reliable as possible. Just as I am not required or restricted to using single-weight, non-detergent oil in a vintage automobile, I am not require or restricted to use vintage parts in a vintage radio. Caps are cheap. Even to a hobbyist at $0.40 an hour, they are far cheaper than "Doing it over". Do them all, and be done with it.

Peter Wieck
Melrose Park, PA

With paper caps I tend to agree. Electolytics are a mix, some are fine and will outlast whatever you would replace them with. Other types of old cap are usually reliable.


NT

 

[Fox's Mercantile]

On 10/10/19 12:27 PM, etpm@whidbey.com wrote:

The caps were pretty cheap, even the 450 volt electrolytics. So
they are all getting replaced. Aside from probably being a good idea I
really don't want a cap to go short down the road and ruin the power
xmfr. The only caps I am not replacing are the little disc ceramic
ones.

Like I said, collateral damage that is avoidable.

I don't know yet what shape the tubes are in but since the scope
does work now I think they are probably in good shape. The nearest
tube tester to me that I know of is 80 miles away sso I can't test
them except to see ho well the scope functions.

Once you've fixed all the cheap things, capacitors and way out of\
tolerance resistors, then you can worry about the tubes. Which I've
found are usual still good.

I bet I can find a Ham that has a tube tester closer to me if I
really want to test tubes. Might just be cheaper to find some new ones
on eBay.
Eric

Be careful, they'll try and teach you Morse code.



--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[pfjw@aol.com]

No idea where you are, but if you are near Philadelphia, I can help with testing tubes. Between the big Hickok, which can match, or the little Simpson, I would have you covered.

Peter Wieck
Melrose Park, PA

 

[amdx]

On 10/10/2019 12:09 PM, Ralph Mowery wrote:

In article <qnnkni$ga9$1@dont-email.me>, nojunk@knology.net says...

No one has mentioned it, but I have a question about the value 33uh.
Unless that is a very large resistor or a very small diameter wire...
I just question the value.



I ran some numbers a while back and nothing reasonable for 33 uH came
out for an air wound coil that would fit on a 1/2 to 1 watt resistor.
Maybe it was .33 uh.

Ya, I didn't run any numbers, I have wound quite a few air coils and
33uh seems like it would be kind off large, compared to a resistor*. So,
it just doesn't seem right.

Mikek


*I know, how big is a resistor

 

On Thu, 10 Oct 2019 12:16:10 -0700 (PDT), "pfjw@aol.com"
<peterwieck33@gmail.com> wrote:

No idea where you are, but if you are near Philadelphia, I can help with testing tubes. Between the big Hickok, which can match, or the little Simpson, I would have you covered.

Peter Wieck
Melrose Park, PA

I'm north of Seattle. On an island.
Eric

 

On Thursday, 10 October 2019 18:22:14 UTC+1, et...@whidbey.com wrote:

The caps were pretty cheap, even the 450 volt electrolytics. So
they are all getting replaced. Aside from probably being a good idea I
really don't want a cap to go short down the road and ruin the power
xmfr. The only caps I am not replacing are the little disc ceramic
ones.
I don't know yet what shape the tubes are in but since the scope
does work now I think they are probably in good shape. The nearest
tube tester to me that I know of is 80 miles away sso I can't test
them except to see ho well the scope functions.
I bet I can find a Ham that has a tube tester closer to me if I
really want to test tubes. Might just be cheaper to find some new ones
on eBay.
Eric

Easiest way to test tubes is to check the anode/cathode current in situ. The great majority of bad tubes aren't able to pass enough current, though other faults can exist.


NT

 

[Fox's Mercantile]

On 10/11/19 6:46 AM, tabbypurr@gmail.com wrote:

Easiest way to test tubes is to check the anode/cathode
current in situ. The great majority of bad tubes aren't
able to pass enough current, though other faults can exist.

More useless advice.

While this may be true with television sweep tubes used as
RF final amplifiers, the proper way to test tubes "in situ"
is to know what they're supposed to do and see if they do.
Most faults can be zeroed in on by simply seeing if a
function does what it's supposed to do.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[pfjw@aol.com]

It is always the device itself that is the best tester of tubes. But for:

Thermal faults - mostly shorts, sometimes going open. A thermal short (or open) will not show up with a VOM when the tube is cold. Further, a rectifier short, for instance, could destroy a power transformer in very short order if not caught immediately, especially if the device is poorly fused (most are). This can be deadly to vintage equipment.

Cascade effects - this tube is a bit weak, and that tube is a bit weak, and yet a third tube is a bit weak. Now, the entire device is 'not quite right' but no singled tube would explain it. And, in the real world, it is this cascade issue that is most common. And, often, why otherwise salvageable devices find their way onto a shelf or into landfill. Sad.

Generally, a thermal fault would have been screened out of the device at some point, one hopes. But not always. And, generally, thermal faults while not immediate are usually quick enough that they would be caught in the initial testing. But not always.

Leads to a tiny rant on how to test a tube. Guys and Gals! Proper tube testing, even on an emissions-only tester, takes _AT LEAST_ ten (10) minutes per tube. First, the set-up and initial screen for shorts and gas. Then the (so-called) "Quality" test. Then, minutes 2 - 10, watch that meter and see what the tube does as it warms up and equalizes. And, at the end of it all, repeat the shorts/gas screening. Only now, do you have useful information.

NOTE 1: Some cheap testers are not capable of holding a heavy output tube for extended periods as the on-board power-supply is inadequate. Be cautious..

Note 2: A tube tester, even the finest Hickok or AVO tests a tube RELATIVE to an established norm or average. A tube may still function perfectly adequately even if all it does is barely lift the meter.

Note 3: Rectifier tubes are the exception to Note 2. They *must* be 'in the zone', or they will be either passing too much AC, or not enough DC, or both.

Note 4: Which leads to being at least aware that the tester in use needs calibration - if possible, or at least pre-testing with known-good tubes to see where the meter falls. Then, compare the others to that.

Tube testers are screening devices. They will indicate dangerous faults (shorts and gas) not possible by any other means other than possible damage to the "home" unit. And they will indicate absolute faults such as an open filament. And for those heavily into Audio, a vanishingly few will allow actual proper matching. After which, it is the "home unit".

A decent emissions-only tester is a handy device for anyone dabbling seriously in tube equipment. IT *may* (not necessarily will) save a bunch of time if used properly. And, a decent emissions tester will not break the bank, either. Leading, again, to:

Note 5: (Heresy Warning!) The step between a decent emissions-only tester and one that will actually convey enough additional information to be useful is considerable in complexity and in cost. A Heath TC3 for 99-44% of general hobby purposes is as good as any but the very top-of-the-line GM testers.. That includes the TV-7 military tester and all its clones. The next step up are those capable of matching - or the modern computerized testers that will plot curves and so forth. So, from roughly $80 - $200 for a good, clean TC3 or-equal, to the $900 - $2,500-and-up for a properly calibrated Hickok 539 series, AVO or Card-Matic, don't bother with the in-between.

Peter Wieck
Melrose Park, PA

 

[Jeff Urban]

Understand electronics much ? Or just what "someone wrote" ?

If you got a coil and cap like that, if the coil is not open it cannot make the trace disappear. It may not have quite the frequency response but it will still work.

There is nothing in a scope that old and limited that would suffer much from the opening up of a resistor that is bridged by a coil. Measure it, if it is not open move on and find the real problem. This ain't it.

 

[Jeff Urban]

>I will be replacing practucally every cap.

You should not until you get the trace to respond to a signal. UNLESS the scope is so old it does not have DC coupling it is not a capacitor.

 

On Friday, 11 October 2019 15:38:09 UTC+1, pf...@aol.com wrote:

It is always the device itself that is the best tester of tubes. But for:

Thermal faults - mostly shorts, sometimes going open. A thermal short (or open) will not show up with a VOM when the tube is cold. Further, a rectifier short, for instance, could destroy a power transformer in very short order if not caught immediately, especially if the device is poorly fused (most are). This can be deadly to vintage equipment.

Cascade effects - this tube is a bit weak, and that tube is a bit weak, and yet a third tube is a bit weak. Now, the entire device is 'not quite right' but no singled tube would explain it. And, in the real world, it is this cascade issue that is most common. And, often, why otherwise salvageable devices find their way onto a shelf or into landfill. Sad.

Generally, a thermal fault would have been screened out of the device at some point, one hopes. But not always. And, generally, thermal faults while not immediate are usually quick enough that they would be caught in the initial testing. But not always.

Leads to a tiny rant on how to test a tube. Guys and Gals! Proper tube testing, even on an emissions-only tester, takes _AT LEAST_ ten (10) minutes per tube. First, the set-up and initial screen for shorts and gas. Then the (so-called) "Quality" test. Then, minutes 2 - 10, watch that meter and see what the tube does as it warms up and equalizes. And, at the end of it all, repeat the shorts/gas screening. Only now, do you have useful information..

NOTE 1: Some cheap testers are not capable of holding a heavy output tube for extended periods as the on-board power-supply is inadequate. Be cautious.

Note 2: A tube tester, even the finest Hickok or AVO tests a tube RELATIVE to an established norm or average. A tube may still function perfectly adequately even if all it does is barely lift the meter.

Note 3: Rectifier tubes are the exception to Note 2. They *must* be 'in the zone', or they will be either passing too much AC, or not enough DC, or both.

Note 4: Which leads to being at least aware that the tester in use needs calibration - if possible, or at least pre-testing with known-good tubes to see where the meter falls. Then, compare the others to that.

Tube testers are screening devices. They will indicate dangerous faults (shorts and gas) not possible by any other means other than possible damage to the "home" unit. And they will indicate absolute faults such as an open filament. And for those heavily into Audio, a vanishingly few will allow actual proper matching. After which, it is the "home unit".

A decent emissions-only tester is a handy device for anyone dabbling seriously in tube equipment. IT *may* (not necessarily will) save a bunch of time if used properly. And, a decent emissions tester will not break the bank, either. Leading, again, to:

Note 5: (Heresy Warning!) The step between a decent emissions-only tester and one that will actually convey enough additional information to be useful is considerable in complexity and in cost. A Heath TC3 for 99-44% of general hobby purposes is as good as any but the very top-of-the-line GM testers. That includes the TV-7 military tester and all its clones. The next step up are those capable of matching - or the modern computerized testers that will plot curves and so forth. So, from roughly $80 - $200 for a good, clean TC3 or-equal, to the $900 - $2,500-and-up for a properly calibrated Hickok 539 series, AVO or Card-Matic, don't bother with the in-between.

Peter Wieck
Melrose Park, PA

Good advice when being thorough, but time consuming. Just checking Ia or Ik is correct is the quick 'is the stage working' check that gets the job done quickly in most cases. If not obviously you then need to check electrode voltages, Rs Cs etc to determine valve or component failure.

Valves declared fauly by a tester sometimes still work. Grid shorts can make little difference when Rfault is higher than Rin, eg when the valve is transformer fed. And valves sometimes pass on a tester but won't work in the circuit. A tester is very useful but not the ultimate decider.


NT