Date   

TDS684A - corroded electrolytic capacitors

Roger Evans
 

I recently bought a TDS684A on eBay, being about the only 1GHz model I had seen at a reasonable cost, bearing in mind shipping from the US to UK and import charges. It arrived OK, channel 2 was working fine as per the eBay description, and it would trigger from all four channels. The digital control functions appear to be OK and there are no signs of corrosion damage to the 'digital' board.

On the acquisition board all the 33uF/10V SMD electrolytics have corroded but the 10uF/35V electrolytics are visually OK. The acquisition board is sparsely populated and there appears to be no damage to other components or to the traces on the visible surface of the board. Rightly or wrongly I followed one of the many suggestions for removing the corroded capacitors - wiggle them back and fore carefully until the work hardened (and corroded) leads break. All the 33uF/10V caps came off easily with no damage to the SMD pads.

The only problem I have met at this stage is that the corroded pads with fragments of corroded leads attached are very resistant to accepting fresh solder. There appears to be a very hard layer produced by the action of the electrolyte on the original copper. On one or two trial pads I have removed the corroded fragments of the old leads, scratched a little of the corroded surface and managed to get just a pinhead of surface wetted with fresh solder.

What suggestions and experiences are there for the preparation of the pads for new components? Do the fibre-glass pens work successfully? Are there any specific suggestions for fluxes? At the moment I just have a generic 'Topnik RF800 SMD NoClean' flux (which I haven't yet tried).

I repaired a corrosion damaged A5 board on my 2465B last year and saw nothing of this sort of surface problem. This particular TDS684A is in excellent condition apart from this limited corrosion and I don't want to inflict further damage in attempting a repair.

Many thanks for any suggestions,

Roger


Re: 465B - Question regarding C4331 / CR4405

Tom Gardner
 

On 01/06/18 15:27, Chuck Harris wrote:
An example where dry slug tantalum capacitors have extremely
long lives are the axially leaded glass hermetically sealed
variety that HP used in large quantities. I have never found
one of them to be bad... never. That variety shows up in
just about every space probe NASA has ever made. There are
tons... ok, pounds (ounces?) of them in Voyager, and it is still
plugging away as it tours the galaxy.
I've see two such caps (or very similar) in a Tektronix 1502
TDR  spew acid across PCB tracks, thus destroying them.

The two culprits were Sprague 109d107030t2 (c6246, c6341),
100uF/30V on a 25V rail.

But that was a seriously odd and irritating PSU :)


Re: 465B - Question regarding C4331 / CR4405

n4buq
 

Those are good things (with, maybe, the exception of #10); however, with maybe the exception of #5, are those critical factors in this application which would preclude using a modern electrolytic? I'm just curious...

Thanks,
Barry - N4BUQ

Whither the tantalum cap?

1) high reliability, no known age failure mechanism (hmmm?)
2) small size for voltage and capacitance.
3) can be built to precise capacitance values.
4) capacitance doesn't change much with voltage or temperature.
5) low ESR (for the era).
6) low inductance.
7) good at high frequencies.
8) very good at high and low temperatures.
9) self healing... up to a point.
10) expensive, gotta love things that are expensive.

Tantalum capacitors are a good thing, but tektronix used the
cheapest variety made. The epoxy dipped dry slug tantalum has
problems with mechanical abuse... when you over stress the
leads, and rip out the epoxy, you let moisture into the
package. Even in good times, the epoxy lets moisture into
the package. Moisture is evil, and contributes to capacitor
failures.

An example where dry slug tantalum capacitors have extremely
long lives are the axially leaded glass hermetically sealed
variety that HP used in large quantities. I have never found
one of them to be bad... never. That variety shows up in
just about every space probe NASA has ever made. There are
tons... ok, pounds (ounces?) of them in Voyager, and it is still
plugging away as it tours the galaxy.

-Chuck Harris

n4buq wrote:
Why are tantalums used here in the first place? I thought it was because
the technology at the time made tantalums a better choice due to their
size but I don't know that to be the reason.

I haven't checked yet, but am wondering if a 47uF@35V electrolytic radial
cap will fit there and if it will work just as good?

Thanks,
Barry - N4BUQ



Re: 465B - Question regarding C4331 / CR4405

Chuck Harris
 

Whither the tantalum cap?

1) high reliability, no known age failure mechanism (hmmm?)
2) small size for voltage and capacitance.
3) can be built to precise capacitance values.
4) capacitance doesn't change much with voltage or temperature.
5) low ESR (for the era).
6) low inductance.
7) good at high frequencies.
8) very good at high and low temperatures.
9) self healing... up to a point.
10) expensive, gotta love things that are expensive.

Tantalum capacitors are a good thing, but tektronix used the
cheapest variety made. The epoxy dipped dry slug tantalum has
problems with mechanical abuse... when you over stress the
leads, and rip out the epoxy, you let moisture into the
package. Even in good times, the epoxy lets moisture into
the package. Moisture is evil, and contributes to capacitor
failures.

An example where dry slug tantalum capacitors have extremely
long lives are the axially leaded glass hermetically sealed
variety that HP used in large quantities. I have never found
one of them to be bad... never. That variety shows up in
just about every space probe NASA has ever made. There are
tons... ok, pounds (ounces?) of them in Voyager, and it is still
plugging away as it tours the galaxy.

-Chuck Harris

n4buq wrote:

Why are tantalums used here in the first place? I thought it was because the technology at the time made tantalums a better choice due to their size but I don't know that to be the reason.

I haven't checked yet, but am wondering if a 47uF@35V electrolytic radial cap will fit there and if it will work just as good?

Thanks,
Barry - N4BUQ


Re: ARRL Handbooks for sale

Dave Daniel
 

All,

The handbooks have been spoken for.

Dave

On 6/1/2018 6:02 AM, Dave Daniel wrote:
All,

I am sending this email to multiple forums.

I am in the process of moving from Colorado to Florida and am cleaning out the lab/shack. I have available for the price of shipping two ARRL handbooks, one from 2005 and one from 2008. Both are hardback editions with mylar dust jacket protectors and both are in pristine condition. I'd prefer to send these to people who can use them rather than just toss them.

If you are interested, please contact me at kc0wjn at gmail dot com OFF-LIST (I will not respond to emails sent to the list). Payment would be by personal check mailed to me or (preferably) PayPal.

Dave

KC0WJN


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: 465B - Question regarding C4331 / CR4405

n4buq
 

Why are tantalums used here in the first place? I thought it was because the technology at the time made tantalums a better choice due to their size but I don't know that to be the reason.

I haven't checked yet, but am wondering if a 47uF@35V electrolytic radial cap will fit there and if it will work just as good?

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "tom jobe" <tomjobe@gmail.com>
To: TekScopes@groups.io
Sent: Friday, June 1, 2018 8:00:45 AM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

Now that you understand this aspect of the dipped tantalum situation,
change the few dipped tantalums you find on the 465B and go up on the
voltage rating of each one as much as you can. 35 volts is a common
voltage rating that's usually available, and that should work fine for
all of them, but there are a few 50 volt tantalum caps available in the
10 to 47uF range these will all be in. Tantalum caps below 10uF don't
seem to be a problem in my limited experience, plus I don't know if the
465B even uses any dipped tantalums below 10uF.



On 6/1/2018 5:27 AM, n4buq wrote:
Pulled the tantalum and it is, indeed, fully shorted (measures under 0.1
ohms). Wish I'd seen that before I pulled all the electrolytic filter
cans. Oh well, at least those will get a new lease on life.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Barry" <n4buq@knology.net>
To: TekScopes@groups.io
Sent: Wednesday, May 30, 2018 4:09:10 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

And that agrees exactly with that page that Fabio referenced. When I saw
the
blue band, I was thinking that would be the logical multiplier but the
references I was seeing on the web stated that was the voltage code.
Mystery solved.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "tmillermdems" <tmiller11147@verizon.net>
To: TekScopes@groups.io
Sent: Wednesday, May 30, 2018 4:07:35 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

Looking at the 465B manual shows it to be a 47 uF, 20 volt dipped tant.
The
yellow dot is the voltage and is the positive lead. The bottom blue band
is
a 10^6 multiplier.


----- Original Message -----
From: "Glenn Little" <glennmaillist@bellsouth.net>
To: <TekScopes@groups.io>
Sent: Wednesday, May 30, 2018 4:53 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405


Maybe a dipped tantalum is assumed to be in microfarads for the base?
I have never seen a tantalum in the pF range. The smallest I think that
I
have seen is 0.1 uF.

Glenn


On 5/30/2018 4:26 PM, Richard Knoppow wrote:
This is even more puzzling. I looked up the color code for tantalum
caps,
I found several sites. Top is first significant digit, ring is second
significant digit, dot is multiplier, all as you say.� However, the
charts I found show multipliers only up to three, no yellow, which
would
be four. Nor do they state specifically what the base value that is
being
multiplied is. Info may be on some site I didn't look at.
�� The traditional color code for caps is based on the uuF or
pico-farad as the base value. Assuming this your cap would be .047uF.
If
this is a dipped tantalum or
type J, the blue stripe indicates a voltage rating of 34V. There should
also be a mark to indicate polarity, usually a plus sign near one lead.
��� The fact that the charts I found do not show a multiplier
greater than 1000 suggests that this might not be a dipped tantalum.
Maybe old information hiding on the web.

On 5/30/2018 11:32 AM, n4buq wrote:
Still curious regarding the color scheme. The top is yellow, the ring
just below that is violet, and there's a yellow dot (more like a
splotch
but still...).� The last color (bottom where the leads are) is blue.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"










Re: 465B - Question regarding C4331 / CR4405

tom jobe <tomjobe@...>
 

Now that you understand this aspect of the dipped tantalum situation, change the few dipped tantalums you find on the 465B and go up on the voltage rating of each one as much as you can. 35 volts is a common voltage rating that's usually available, and that should work fine for all of them, but there are a few 50 volt tantalum caps available in the 10 to 47uF range these will all be in. Tantalum caps below 10uF don't seem to be a problem in my limited experience, plus I don't know if the 465B even uses any dipped tantalums below 10uF.

On 6/1/2018 5:27 AM, n4buq wrote:
Pulled the tantalum and it is, indeed, fully shorted (measures under 0.1 ohms). Wish I'd seen that before I pulled all the electrolytic filter cans. Oh well, at least those will get a new lease on life.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Barry" <n4buq@knology.net>
To: TekScopes@groups.io
Sent: Wednesday, May 30, 2018 4:09:10 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

And that agrees exactly with that page that Fabio referenced. When I saw the
blue band, I was thinking that would be the logical multiplier but the
references I was seeing on the web stated that was the voltage code.
Mystery solved.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "tmillermdems" <tmiller11147@verizon.net>
To: TekScopes@groups.io
Sent: Wednesday, May 30, 2018 4:07:35 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

Looking at the 465B manual shows it to be a 47 uF, 20 volt dipped tant. The
yellow dot is the voltage and is the positive lead. The bottom blue band is
a 10^6 multiplier.


----- Original Message -----
From: "Glenn Little" <glennmaillist@bellsouth.net>
To: <TekScopes@groups.io>
Sent: Wednesday, May 30, 2018 4:53 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405


Maybe a dipped tantalum is assumed to be in microfarads for the base?
I have never seen a tantalum in the pF range. The smallest I think that I
have seen is 0.1 uF.

Glenn


On 5/30/2018 4:26 PM, Richard Knoppow wrote:
This is even more puzzling. I looked up the color code for tantalum
caps,
I found several sites. Top is first significant digit, ring is second
significant digit, dot is multiplier, all as you say.� However, the
charts I found show multipliers only up to three, no yellow, which would
be four. Nor do they state specifically what the base value that is
being
multiplied is. Info may be on some site I didn't look at.
�� The traditional color code for caps is based on the uuF or
pico-farad as the base value. Assuming this your cap would be .047uF. If
this is a dipped tantalum or
type J, the blue stripe indicates a voltage rating of 34V. There should
also be a mark to indicate polarity, usually a plus sign near one lead.
��� The fact that the charts I found do not show a multiplier
greater than 1000 suggests that this might not be a dipped tantalum.
Maybe old information hiding on the web.

On 5/30/2018 11:32 AM, n4buq wrote:
Still curious regarding the color scheme. The top is yellow, the ring
just below that is violet, and there's a yellow dot (more like a
splotch
but still...).� The last color (bottom where the leads are) is blue.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"







Re: 465B - Question regarding C4331 / CR4405

n4buq
 

Pulled the tantalum and it is, indeed, fully shorted (measures under 0.1 ohms). Wish I'd seen that before I pulled all the electrolytic filter cans. Oh well, at least those will get a new lease on life.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Barry" <n4buq@knology.net>
To: TekScopes@groups.io
Sent: Wednesday, May 30, 2018 4:09:10 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

And that agrees exactly with that page that Fabio referenced. When I saw the
blue band, I was thinking that would be the logical multiplier but the
references I was seeing on the web stated that was the voltage code.
Mystery solved.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "tmillermdems" <tmiller11147@verizon.net>
To: TekScopes@groups.io
Sent: Wednesday, May 30, 2018 4:07:35 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

Looking at the 465B manual shows it to be a 47 uF, 20 volt dipped tant. The
yellow dot is the voltage and is the positive lead. The bottom blue band is
a 10^6 multiplier.


----- Original Message -----
From: "Glenn Little" <glennmaillist@bellsouth.net>
To: <TekScopes@groups.io>
Sent: Wednesday, May 30, 2018 4:53 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405


Maybe a dipped tantalum is assumed to be in microfarads for the base?
I have never seen a tantalum in the pF range. The smallest I think that I
have seen is 0.1 uF.

Glenn


On 5/30/2018 4:26 PM, Richard Knoppow wrote:
This is even more puzzling. I looked up the color code for tantalum
caps,
I found several sites. Top is first significant digit, ring is second
significant digit, dot is multiplier, all as you say.� However, the
charts I found show multipliers only up to three, no yellow, which would
be four. Nor do they state specifically what the base value that is
being
multiplied is. Info may be on some site I didn't look at.
�� The traditional color code for caps is based on the uuF or
pico-farad as the base value. Assuming this your cap would be .047uF. If
this is a dipped tantalum or
type J, the blue stripe indicates a voltage rating of 34V. There should
also be a mark to indicate polarity, usually a plus sign near one lead.
��� The fact that the charts I found do not show a multiplier
greater than 1000 suggests that this might not be a dipped tantalum.
Maybe old information hiding on the web.

On 5/30/2018 11:32 AM, n4buq wrote:
Still curious regarding the color scheme. The top is yellow, the ring
just below that is violet, and there's a yellow dot (more like a
splotch
but still...).� The last color (bottom where the leads are) is blue.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"








ARRL Handbooks for sale

Dave Daniel
 

All,

I am sending this email to multiple forums.

I am in the process of moving from Colorado to Florida and am cleaning out the lab/shack. I have available for the price of shipping two ARRL handbooks, one from 2005 and one from 2008. Both are hardback editions with mylar dust jacket protectors and both are in pristine condition. I'd prefer to send these to people who can use them rather than just toss them.

If you are interested, please contact me at kc0wjn at gmail dot com OFF-LIST (I will not respond to emails sent to the list). Payment would be by personal check mailed to me or (preferably) PayPal.

Dave

KC0WJN


Re: TG501 No 1ns output, repairs underway

 

On Thu, May 31, 2018 at 10:47 am, satbeginner wrote:


Hi Raymond & Albert,
Thanks for your response and info, Leo.
Please let us know how the Chinese reed tubes are performing.

Raymond


Re: TG501 No 1ns output, repairs underway

satbeginner
 

Hi Raymond & Albert,

My assumption ;-) was that the relay would switch between 1ns and 2ns, but you are right, it works differently.
For now I put a small wire in place of the relay, so now it will do only 1ns and 2ns.

Funny, but of course the centre pin Peltola of the 1ns BNC appeared to be off centre... ;-) that helped a lot to get at least some signal on the 1ns output.

(Leo's law nr3 again: "When troubleshooting something, there is always more than one item broken...."

To see the markers I use a TDS540B, and it is perfectly OK for the 2ns markers.
When I repaired this TDS540B the DAC of CH2 was broken (one stuck data bit) but there were problems with the input attenuator too.
I replaced the DAC, and I also got hold of a TDS784 input board, so I got the input attenuator from that board to put in CH2.

(Off Topic: I think these scopes develop problems when they come from a 19" rack-mount and people start using them without feet installed. This blocks the airflow, so especially the DAC's will get too hot.)

The scope has obvious level issues with the 1ns markers, but at least I can see the 1ns markers, both the timing and the level being around 110mV.

The repetition rate of the markers I check using a 1GHz counter (PM6672 with a build-in OCXO) that I calibrated against a GPS controlled 10MHz generator.

I will put-up some pictures in this album again: https://groups.io/g/TekScopes/album?id=53435

Thanks for all the tips,

to be continued,

Leo


OT: need ultraviolet-transmitting filter glass?

Brad Thompson <brad.thompson@...>
 

Hello--

Please contact me off list for availability of NOS Schott UG-1
ultraviolet-transmitting glass. The material blocks visible light
and transmits 360 nm (peak).

Specs are available at...

http://www.uqgoptics.com/materials_filters_schott_uvTransmitting_UG1.aspx

Questions welcomed--

Thanks, and 73--

Brad AA1IP


Re: TG501 No 1ns output, repairs underway

Albert Otten
 

May I add that if the 1 ns out is not working then also check the center pins of the Peltola connectors. It's easy to bent these pins away from the receptacle when not inserted properly. I am not the only one who has seen such a failure.

Albert


Re: TG501 No 1ns output, repairs underway

 

I trust that you checked whether the 1 ns output works while the relay is missing?
Reason I'm asking is that the relay is in one position for all times of 5 ns and up and in the other position for 1 ns *and* 2 ns and you're writing that all times 2 ns and up were ok.

What 'scope model are you using to watch the 1 ns "marker"?

Raymond


Re: TG501 No 1ns output, repairs underway

 

Hi Leo,
I trust that you checked whether the 1 ns output works while the relay is missing? It would be the only functioning output without the relay.

Raymond


TG501 No 1ns output, repairs underway

satbeginner
 

Hi all,

I was toying around with some of my Tek-Stuff and found there was no output at all in the 1ns setting of my TG501, while the 2ns was working perfectly.
When looking at the schematics I found there is happening nothing dramatic in between the 2ns and the 1ns signals.
The 2ns just 'kicks' a ringing circuit tuned for 1ns, and that's it.

It turned out the (very) small reed-relay that switches the 1ns output was not working any more.
When touching the connections to measure the signals I saw it moved when touching?

When I de-soldered the side with the one connection, 2/3 of the reed-rely came out, so it was obviously broken.

The good news: It looks like it is just the glass part that is broken, not the coil, that part is positioned loosely inside the actuator-coil, so replacement should be easy.
I found these reed-switches for cheap on AliExpress, so repair will be continued in some weeks, usually shipping from China to rural Spain is 3-4 weeks... ;-)

Pictures of the relay can be found here: https://groups.io/g/TekScopes/album?id=53435

To be continued,

Leo


Re: 465B - Question regarding C4331 / CR4405

 

Sure, picofarads x 10^6 is microfarads. It's correct.

----- Original Message -----
From: "Fabio Trevisan" <fabio.tr3visan@gmail.com>
To: <TekScopes@groups.io>
Sent: Wednesday, May 30, 2018 5:49 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405


Hello tmillermdems...
Indeed... but curiously enough, on page 4.5. continuing the explanation on the color coding, the manual provides an inconsistent information that the units of the dipped tantalum caps are in "microfarads".
I think it's a mistake and either they meant micro-microfarads, or someone simply screwed up in their own thinking.
Rgrds,
Fabio


Re: 465B - Question regarding C4331 / CR4405

Fabio Trevisan
 

Hello tmillermdems...
Indeed... but curiously enough, on page 4.5. continuing the explanation on the color coding, the manual provides an inconsistent information that the units of the dipped tantalum caps are in "microfarads".
I think it's a mistake and either they meant micro-microfarads, or someone simply screwed up in their own thinking.
Rgrds,
Fabio

On Wed, May 30, 2018 at 02:05 pm, tmillermdems wrote:


Looking at the 465B manual shows it to be a 47 uF, 20 volt dipped tant. The
yellow dot is the voltage and is the positive lead. The bottom blue band is
a 10^6 multiplier.


----- Original Message -----
From: "Glenn Little" <glennmaillist@bellsouth.net>
To: <TekScopes@groups.io>
Sent: Wednesday, May 30, 2018 4:53 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405


Maybe a dipped tantalum is assumed to be in microfarads for the base?
I have never seen a tantalum in the pF range. The smallest I think that I
have seen is 0.1 uF.

Glenn


On 5/30/2018 4:26 PM, Richard Knoppow wrote:
This is even more puzzling. I looked up the color code for tantalum caps,
I found several sites. Top is first significant digit, ring is second
significant digit, dot is multiplier, all as you say.� However, the
charts I found show multipliers only up to three, no yellow, which would
be four. Nor do they state specifically what the base value that is being
multiplied is. Info may be on some site I didn't look at.
�� The traditional color code for caps is based on the uuF or
pico-farad as the base value. Assuming this your cap would be .047uF. If
this is a dipped tantalum or
type J, the blue stripe indicates a voltage rating of 34V. There should
also be a mark to indicate polarity, usually a plus sign near one lead.
��� The fact that the charts I found do not show a
multiplier
greater than 1000 suggests that this might not be a dipped tantalum.
Maybe old information hiding on the web.

On 5/30/2018 11:32 AM, n4buq wrote:
Still curious regarding the color scheme. The top is yellow, the ring
just below that is violet, and there's a yellow dot (more like a splotch
but still...).� The last color (bottom where the leads are) is blue.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"





Re: 465B - Question regarding C4331 / CR4405

n4buq
 

And that agrees exactly with that page that Fabio referenced. When I saw the blue band, I was thinking that would be the logical multiplier but the references I was seeing on the web stated that was the voltage code. Mystery solved.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "tmillermdems" <tmiller11147@verizon.net>
To: TekScopes@groups.io
Sent: Wednesday, May 30, 2018 4:07:35 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405

Looking at the 465B manual shows it to be a 47 uF, 20 volt dipped tant. The
yellow dot is the voltage and is the positive lead. The bottom blue band is
a 10^6 multiplier.


----- Original Message -----
From: "Glenn Little" <glennmaillist@bellsouth.net>
To: <TekScopes@groups.io>
Sent: Wednesday, May 30, 2018 4:53 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405


Maybe a dipped tantalum is assumed to be in microfarads for the base?
I have never seen a tantalum in the pF range. The smallest I think that I
have seen is 0.1 uF.

Glenn


On 5/30/2018 4:26 PM, Richard Knoppow wrote:
This is even more puzzling. I looked up the color code for tantalum caps,
I found several sites. Top is first significant digit, ring is second
significant digit, dot is multiplier, all as you say.� However, the
charts I found show multipliers only up to three, no yellow, which would
be four. Nor do they state specifically what the base value that is being
multiplied is. Info may be on some site I didn't look at.
�� The traditional color code for caps is based on the uuF or
pico-farad as the base value. Assuming this your cap would be .047uF. If
this is a dipped tantalum or
type J, the blue stripe indicates a voltage rating of 34V. There should
also be a mark to indicate polarity, usually a plus sign near one lead.
��� The fact that the charts I found do not show a multiplier
greater than 1000 suggests that this might not be a dipped tantalum.
Maybe old information hiding on the web.

On 5/30/2018 11:32 AM, n4buq wrote:
Still curious regarding the color scheme. The top is yellow, the ring
just below that is violet, and there's a yellow dot (more like a splotch
but still...).� The last color (bottom where the leads are) is blue.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"








Re: 465B - Question regarding C4331 / CR4405

 

Looking at the 465B manual shows it to be a 47 uF, 20 volt dipped tant. The yellow dot is the voltage and is the positive lead. The bottom blue band is a 10^6 multiplier.

----- Original Message -----
From: "Glenn Little" <glennmaillist@bellsouth.net>
To: <TekScopes@groups.io>
Sent: Wednesday, May 30, 2018 4:53 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405


Maybe a dipped tantalum is assumed to be in microfarads for the base?
I have never seen a tantalum in the pF range. The smallest I think that I have seen is 0.1 uF.

Glenn


On 5/30/2018 4:26 PM, Richard Knoppow wrote:
This is even more puzzling. I looked up the color code for tantalum caps, I found several sites. Top is first significant digit, ring is second significant digit, dot is multiplier, all as you say.� However, the charts I found show multipliers only up to three, no yellow, which would be four. Nor do they state specifically what the base value that is being multiplied is. Info may be on some site I didn't look at.
�� The traditional color code for caps is based on the uuF or pico-farad as the base value. Assuming this your cap would be .047uF. If this is a dipped tantalum or
type J, the blue stripe indicates a voltage rating of 34V. There should also be a mark to indicate polarity, usually a plus sign near one lead.
��� The fact that the charts I found do not show a multiplier greater than 1000 suggests that this might not be a dipped tantalum. Maybe old information hiding on the web.

On 5/30/2018 11:32 AM, n4buq wrote:
Still curious regarding the color scheme. The top is yellow, the ring just below that is violet, and there's a yellow dot (more like a splotch but still...).� The last color (bottom where the leads are) is blue.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"



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