|
Checking a few things in/around the LVPS of my 465B and noticed that TP4339 checks shorted to ground. I presume that's most likely C4331 or CR4405. Looking at the board, C4331 appears to be a rather large(ish) bulb-like device which I took to be a tantalum; however, the parts list shows that as a 47uF electrolytic. The colors tend to agree with those numbers (e.g. yellow dome, violet middle, etc.) but is that indeed an electrolytic or tantalum?
I can share a picture but this cap hangs out right next to TP4339 (+15V test point). Anyone know?
Thanks,
Barry - N4BUQ
|
Oh, and, I mention CR4405 as I suppose it's possible that's shorted instead of C4331.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "n4buq" <n4buq@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 8:29:11 AM
Subject: [TekScopes] 465B - Question regarding C4331 / CR4405
Checking a few things in/around the LVPS of my 465B and noticed that TP4339
checks shorted to ground. I presume that's most likely C4331 or CR4405.
Looking at the board, C4331 appears to be a rather large(ish) bulb-like
device which I took to be a tantalum; however, the parts list shows that as
a 47uF electrolytic. The colors tend to agree with those numbers (e.g.
yellow dome, violet middle, etc.) but is that indeed an electrolytic or
tantalum?
I can share a picture but this cap hangs out right next to TP4339 (+15V test
point). Anyone know?
Thanks,
Barry - N4BUQ
|
The parts lisitings call tantalum capacitors electrolytics.
That is just a normal dipped looking tantalum capacitor.
Most will suggest that you replace it with the highest voltage tantalum you can find.
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On 5/30/2018 6:29 AM, n4buq wrote: Checking a few things in/around the LVPS of my 465B and noticed that TP4339 checks shorted to ground. I presume that's most likely C4331 or CR4405. Looking at the board, C4331 appears to be a rather large(ish) bulb-like device which I took to be a tantalum; however, the parts list shows that as a 47uF electrolytic. The colors tend to agree with those numbers (e.g. yellow dome, violet middle, etc.) but is that indeed an electrolytic or tantalum?
I can share a picture but this cap hangs out right next to TP4339 (+15V test point). Anyone know?
Thanks,
Barry - N4BUQ
|
On Wed, 30 May 2018 09:29:11 -0400 (EDT), you wrote: Checking a few things in/around the LVPS of my 465B and noticed that TP4339 checks shorted to ground. I presume that's most likely C4331 or CR4405. Looking at the board, C4331 appears to be a rather large(ish) bulb-like device which I took to be a tantalum; however, the parts list shows that as a 47uF electrolytic. The colors tend to agree with those numbers (e.g. yellow dome, violet middle, etc.) but is that indeed an electrolytic or tantalum? I'd go for a dipped tantalum. They're known to fail. Harvey
I can share a picture but this cap hangs out right next to TP4339 (+15V test point). Anyone know?
Thanks,
Barry - N4BUQ
|
I thought I recalled them being listed as electrolytics but wasn't sure.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "tom jobe" <tomjobe@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 8:50:32 AM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405
The parts lisitings call tantalum capacitors electrolytics.
That is just a normal dipped looking tantalum capacitor.
Most will suggest that you replace it with the highest voltage tantalum
you can find.
On 5/30/2018 6:29 AM, n4buq wrote:
Checking a few things in/around the LVPS of my 465B and noticed that TP4339
checks shorted to ground. I presume that's most likely C4331 or CR4405.
Looking at the board, C4331 appears to be a rather large(ish) bulb-like
device which I took to be a tantalum; however, the parts list shows that
as a 47uF electrolytic. The colors tend to agree with those numbers (e.g.
yellow dome, violet middle, etc.) but is that indeed an electrolytic or
tantalum?
I can share a picture but this cap hangs out right next to TP4339 (+15V
test point). Anyone know?
Thanks,
Barry - N4BUQ
|
I thought tantalums were noted for spectacular failure events. If this is indeed my shorted component, it simply failed quietly which I didn't expect. I'll have to lift one side to see if that's the problem (but do suspect it is).
The odd thing is this failure mode was intermittent for a quite a while with failure events lasting a second or so in between long periods of symptom-free performance. I just didn't think tantalums failed that way but maybe so.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "Harvey White" <madyn@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 8:51:16 AM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405
On Wed, 30 May 2018 09:29:11 -0400 (EDT), you wrote:
Checking a few things in/around the LVPS of my 465B and noticed that TP4339
checks shorted to ground. I presume that's most likely C4331 or CR4405.
Looking at the board, C4331 appears to be a rather large(ish) bulb-like
device which I took to be a tantalum; however, the parts list shows that as
a 47uF electrolytic. The colors tend to agree with those numbers (e.g.
yellow dome, violet middle, etc.) but is that indeed an electrolytic or
tantalum? I'd go for a dipped tantalum. They're known to fail.
Harvey
I can share a picture but this cap hangs out right next to TP4339 (+15V test
point). Anyone know?
Thanks,
Barry - N4BUQ
|
Dipped tantalums failing in a complete short without exploding is very ordinary in that vintage of gear.
toggle quoted message
Show quoted text
On 5/30/2018 7:05 AM, n4buq wrote: I thought tantalums were noted for spectacular failure events. If this is indeed my shorted component, it simply failed quietly which I didn't expect. I'll have to lift one side to see if that's the problem (but do suspect it is).
The odd thing is this failure mode was intermittent for a quite a while with failure events lasting a second or so in between long periods of symptom-free performance. I just didn't think tantalums failed that way but maybe so.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Harvey White" <madyn@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 8:51:16 AM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405
On Wed, 30 May 2018 09:29:11 -0400 (EDT), you wrote:
Checking a few things in/around the LVPS of my 465B and noticed that TP4339
checks shorted to ground. I presume that's most likely C4331 or CR4405.
Looking at the board, C4331 appears to be a rather large(ish) bulb-like
device which I took to be a tantalum; however, the parts list shows that as
a 47uF electrolytic. The colors tend to agree with those numbers (e.g.
yellow dome, violet middle, etc.) but is that indeed an electrolytic or
tantalum? I'd go for a dipped tantalum. They're known to fail.
Harvey
I can share a picture but this cap hangs out right next to TP4339 (+15V test
point). Anyone know?
Thanks,
Barry - N4BUQ
|
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.
The way I understand that to be read is 47 x 10^4 and I presume that's pF (470,000pF). That would make it 0.47uF, not 47uF so I must be reading it incorrectly. The last ring, blue, is a voltage code for 20V which agrees with the parts list.
What am I doing wrong?
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "tom jobe" <tomjobe@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 9:10:11 AM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405
Dipped tantalums failing in a complete short without exploding is very
ordinary in that vintage of gear.
On 5/30/2018 7:05 AM, n4buq wrote:
I thought tantalums were noted for spectacular failure events. If this is
indeed my shorted component, it simply failed quietly which I didn't
expect. I'll have to lift one side to see if that's the problem (but do
suspect it is).
The odd thing is this failure mode was intermittent for a quite a while
with failure events lasting a second or so in between long periods of
symptom-free performance. I just didn't think tantalums failed that way
but maybe so.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Harvey White" <madyn@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 8:51:16 AM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405
On Wed, 30 May 2018 09:29:11 -0400 (EDT), you wrote:
Checking a few things in/around the LVPS of my 465B and noticed that
TP4339
checks shorted to ground. I presume that's most likely C4331 or CR4405.
Looking at the board, C4331 appears to be a rather large(ish) bulb-like
device which I took to be a tantalum; however, the parts list shows that
as
a 47uF electrolytic. The colors tend to agree with those numbers (e.g.
yellow dome, violet middle, etc.) but is that indeed an electrolytic or
tantalum? I'd go for a dipped tantalum. They're known to fail.
Harvey
I can share a picture but this cap hangs out right next to TP4339 (+15V
test
point). Anyone know?
Thanks,
Barry - N4BUQ
|
On Wed, 30 May 2018 10:05:56 -0400 (EDT), you wrote: I thought tantalums were noted for spectacular failure events. If this is indeed my shorted component, it simply failed quietly which I didn't expect. I'll have to lift one side to see if that's the problem (but do suspect it is). I've seen some that are, but they can be leaky. I've seen both modes of failure.
The odd thing is this failure mode was intermittent for a quite a while with failure events lasting a second or so in between long periods of symptom-free performance. I just didn't think tantalums failed that way but maybe so.
Probably the most accurate statement that can be made about them is "tantalums fail". The dipped ones from that era fail frequently. They can do a low resistance, but not a dead short. In that case, they may get rather warm. Harvey Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Harvey White" <madyn@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 8:51:16 AM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405
On Wed, 30 May 2018 09:29:11 -0400 (EDT), you wrote:
Checking a few things in/around the LVPS of my 465B and noticed that TP4339
checks shorted to ground. I presume that's most likely C4331 or CR4405.
Looking at the board, C4331 appears to be a rather large(ish) bulb-like
device which I took to be a tantalum; however, the parts list shows that as
a 47uF electrolytic. The colors tend to agree with those numbers (e.g.
yellow dome, violet middle, etc.) but is that indeed an electrolytic or
tantalum? I'd go for a dipped tantalum. They're known to fail.
Harvey
I can share a picture but this cap hangs out right next to TP4339 (+15V test
point). Anyone know?
Thanks,
Barry - N4BUQ
|
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.
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Show quoted text
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.
--
Richard Knoppow
dickburk@...
WB6KBL
|
Hello Richard,
As soon as I read about your doubt on the color coding of the dipped tantalum caps that Tek used, I recalled having seen the color coding scheme on some Tektronix service manual.
At first, I confessed I dismissed your doubt and thought... Heck Richard, R.T.F.M.! It's in all manuals...!
But then my better self came in and I went on looking for it in the first manual I could grab my hands on, of my own Tek 464, and to my surprise, it wasn't there... After all, It was good that I didn't RTFM you.
Then I thought that Tektronix used to be more zealous about their documentation of the earlier scopes and opened my pdf copy of the 454 (the oldest manual I had at hand) and then my copy of the 454a, a little newer... and, although I found references to color coding, both of resistors and tubular ceramic caps, there wasn't any for dipped tantalums...
But I was sure I had seen it, so I kept searching and bingo.
I found it on the Tek 465 service manual, on this version you can get from Electrotanya...:
The same scan (and the link to electrotanya) is also referenced on the TekWiki pages of the 465, under the title "Tektronix 465 Manual (PDF) (better scan)".
There, on the maintenance chapter, page 4.4. it's the color coding for the dipped tantalum.
Rgrds,
Fabio
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On Wed, May 30, 2018 at 01:27 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.
--
Richard Knoppow
dickburk@...
WB6KBL
|
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
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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@... 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"
|
Richard's not the one who needs the admonition. That would be me; however, I'm not finding that info in the 465B manual. I'll have to look at the 465 manual.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "Fabio Trevisan" <fabio.tr3visan@...>
To: [email protected]
Sent: Wednesday, May 30, 2018 3:48:04 PM
Subject: Re: [TekScopes] 465B - Question regarding C4331 / CR4405
Hello Richard,
As soon as I read about your doubt on the color coding of the dipped tantalum
caps that Tek used, I recalled having seen the color coding scheme on some
Tektronix service manual.
At first, I confessed I dismissed your doubt and thought... Heck Richard,
R.T.F.M.! It's in all manuals...!
But then my better self came in and I went on looking for it in the first
manual I could grab my hands on, of my own Tek 464, and to my surprise, it
wasn't there... After all, It was good that I didn't RTFM you.
Then I thought that Tektronix used to be more zealous about their
documentation of the earlier scopes and opened my pdf copy of the 454 (the
oldest manual I had at hand) and then my copy of the 454a, a little newer...
and, although I found references to color coding, both of resistors and
tubular ceramic caps, there wasn't any for dipped tantalums...
But I was sure I had seen it, so I kept searching and bingo.
I found it on the Tek 465 service manual, on this version you can get from
Electrotanya...:
The same scan (and the link to electrotanya) is also referenced on the
TekWiki pages of the 465, under the title "Tektronix 465 Manual (PDF)
(better scan)".
There, on the maintenance chapter, page 4.4. it's the color coding for the
dipped tantalum.
Rgrds,
Fabio
On Wed, May 30, 2018 at 01:27 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.
--
Richard Knoppow
dickburk@...
WB6KBL
|
Glen,
I have a different perception of the dipped tantalum markings being always in uF.
Apart from the odd color coded ones from Tek, from all others that are marked with numbers, I would say half of them have the markings in uF (2 digits only, or digit dot digit), and the other half would carry the now ubiquitous 3 number "power of ten" notation, e.g. 105 for 1uF (1Meg pF).
Rgrds,
Fabio
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On Wed, May 30, 2018 at 01:53 pm, Glenn Little wrote:
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@... 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"
|
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.
toggle quoted message
Show quoted text
----- Original Message ----- From: "Glenn Little" <glennmaillist@...> To: < [email protected]> 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@... 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"
|
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
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----- Original Message ----- From: "tmillermdems" <tmiller11147@...>
To: [email protected]
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@...>
To: <[email protected]>
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@... 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"
|
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
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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@...>
To: <[email protected]>
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@... 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"
|
Sure, picofarads x 10^6 is microfarads. It's correct.
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----- Original Message ----- From: "Fabio Trevisan" <fabio.tr3visan@...> To: < [email protected]> 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
|
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
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----- Original Message ----- From: "Barry" <n4buq@...>
To: [email protected]
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@...>
To: [email protected]
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@...>
To: <[email protected]>
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@... 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"
|
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.
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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@...>
To: [email protected]
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@...>
To: [email protected]
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@...>
To: <[email protected]>
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@... 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"
|
Fabio Trevisan