Add group to favorites
Back to post list
Send new message to group Search:
Post Subject:
Amplifier Problem - ***SOLVED***
Amplifier Problem - ***SOLVED***
Good News!
This headphone amplifier has been REPAIRED and is now working
perfectly.
Here's what happened:
I have been taking parallel measurements between the "good" and "bad"
channels since the beginning.
I took voltage measurements, resistance measurements, tested ALL
capacitors, and tested ALL transistors.
But someone in my original thread (I can't remember who offhand --
sorry) did mention checking the circuit board traces.
"No need," I thought. "The circuit board and all solder joints look
fine to me."
But in a fit of desperation, I nonetheless decided to whip out a
tester I hadn't used yet: my magnifying glass.
That's when I found it -- a *microscopic* crack in the trace between
the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
so incredibly tiny that I easily overlooked it--repeatedly.
I took one of my jumper leads and clipped one end of it to Q208's
emitter and the other end of it to the 3.3 ohm resistor.
I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
Q205's collector now measures +7.09V, and Q206 now has the following
measurements:
B: +6.51V
C: +7.08V
E: +5.84V
I was able to bridge the crack with a well-placed solder trail, and
the headphone amp now sounds great.
A BIG "THANK YOU" TO EVERYONE WHO HELPED ME OUT! I OWE YOU BIG TIME.
Good News!
This headphone amplifier has been REPAIRED and is now working
perfectly.
Here's what happened:
I have been taking parallel measurements between the "good" and "bad"
channels since the beginning.
I took voltage measurements, resistance measurements, tested ALL
capacitors, and tested ALL transistors.
But someone in my original thread (I can't remember who offhand --
sorry) did mention checking the circuit board traces.
"No need," I thought. "The circuit board and all solder joints look
fine to me."
But in a fit of desperation, I nonetheless decided to whip out a
tester I hadn't used yet: my magnifying glass.
That's when I found it -- a *microscopic* crack in the trace between
the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
so incredibly tiny that I easily overlooked it--repeatedly.
I took one of my jumper leads and clipped one end of it to Q208's
emitter and the other end of it to the 3.3 ohm resistor.
I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
Q205's collector now measures +7.09V, and Q206 now has the following
measurements:
B: +6.51V
C: +7.08V
E: +5.84V
I was able to bridge the crack with a well-placed solder trail, and
the headphone amp now sounds great.
A BIG "THANK YOU" TO EVERYONE WHO HELPED ME OUT! I OWE YOU BIG TIME.
Re: Amplifier Problem - ***SOLVED***
"EADGBE" wrote ...
> That's when I found it -- a *microscopic* crack in the trace between
> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
> so incredibly tiny that I easily overlooked it--repeatedly.
>
> I took one of my jumper leads and clipped one end of it to Q208's
> emitter and the other end of it to the 3.3 ohm resistor.
>
> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
Its hard to imagine how the output node (where the two
3.3 ohm resistors join) could be correct (6.4V) without
the path through the lower 3.3 ohm resistor and Q208?
But at least you got it working. Good for you. Trouble-
shooting ("fault-finding" as they call it in the UK) discrete
circuits is rapidly becoming a lost art.
"EADGBE" wrote ...
> That's when I found it -- a *microscopic* crack in the trace between
> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
> so incredibly tiny that I easily overlooked it--repeatedly.
>
> I took one of my jumper leads and clipped one end of it to Q208's
> emitter and the other end of it to the 3.3 ohm resistor.
>
> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
Its hard to imagine how the output node (where the two
3.3 ohm resistors join) could be correct (6.4V) without
the path through the lower 3.3 ohm resistor and Q208?
But at least you got it working. Good for you. Trouble-
shooting ("fault-finding" as they call it in the UK) discrete
circuits is rapidly becoming a lost art.
Re: Amplifier Problem - ***SOLVED***
On Tue, 22 Apr 2008 12:38:19 -0700, "Richard Crowley"
<rcrowley@xp7rt . net > wrote:
>"EADGBE" wrote ...
>> That's when I found it -- a *microscopic* crack in the trace between
>> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
>> so incredibly tiny that I easily overlooked it--repeatedly.
>>
>> I took one of my jumper leads and clipped one end of it to Q208's
>> emitter and the other end of it to the 3.3 ohm resistor.
>>
>> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>
>Its hard to imagine how the output node (where the two
>3.3 ohm resistors join) could be correct (6.4V) without
>the path through the lower 3.3 ohm resistor and Q208?
>
Pure coincidence - it was the breakdown voltage of the reverse biased
base-emitter of Q207.
>But at least you got it working. Good for you. Trouble-
>shooting ("fault-finding" as they call it in the UK) discrete
>circuits is rapidly becoming a lost art.
>
Quite so - when all the components are right, but there is still a
problem, go for the board.
d
--
Pearce Consulting
* w w w .pearce.uk . com
On Tue, 22 Apr 2008 12:38:19 -0700, "Richard Crowley"
<rcrowley@xp7rt . net > wrote:
>"EADGBE" wrote ...
>> That's when I found it -- a *microscopic* crack in the trace between
>> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
>> so incredibly tiny that I easily overlooked it--repeatedly.
>>
>> I took one of my jumper leads and clipped one end of it to Q208's
>> emitter and the other end of it to the 3.3 ohm resistor.
>>
>> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>
>Its hard to imagine how the output node (where the two
>3.3 ohm resistors join) could be correct (6.4V) without
>the path through the lower 3.3 ohm resistor and Q208?
>
Pure coincidence - it was the breakdown voltage of the reverse biased
base-emitter of Q207.
>But at least you got it working. Good for you. Trouble-
>shooting ("fault-finding" as they call it in the UK) discrete
>circuits is rapidly becoming a lost art.
>
Quite so - when all the components are right, but there is still a
problem, go for the board.
d
--
Pearce Consulting
* w w w .pearce.uk . com
Re: Amplifier Problem - ***SOLVED***
On 2008-04-22, Don Pearce <nospam@nospam . com > wrote:
> On Tue, 22 Apr 2008 12:38:19 -0700, "Richard Crowley"
><rcrowley@xp7rt . net > wrote:
>
>>"EADGBE" wrote ...
>>> That's when I found it -- a *microscopic* crack in the trace between
>>> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
>>> so incredibly tiny that I easily overlooked it--repeatedly.
>>>
>>> I took one of my jumper leads and clipped one end of it to Q208's
>>> emitter and the other end of it to the 3.3 ohm resistor.
>>>
>>> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>>
>>Its hard to imagine how the output node (where the two
>>3.3 ohm resistors join) could be correct (6.4V) without
>>the path through the lower 3.3 ohm resistor and Q208?
>
> Pure coincidence - it was the breakdown voltage of the reverse biased
> base-emitter of Q207.
Rubbish. ( Well, possibly :-) )
Q207 was indeed hard off with its base at 0V. Q208 was not connected
to the output because of the fault. The output junction was therefore
biassed only by the emitter voltage or Q204 (8V nominal) via the
15 k resistor.
If the measurement was made with a 20 kohm/V multimeter on the 10 V range
(200k) then I would expect the potential divider effect to pad that 8
V down to about 7.4 V. EADGBE actually posted that the node was 7.3V
(not the nominal 6.4 V of the schematic).
OK, I admit it could have been reverse bias breakdown but I prefer my
version as it doesn't require that coincidence. (Well OK I do make an
assumption about the measurement kit instead ...)
--
John Phillips
On 2008-04-22, Don Pearce <nospam@nospam . com > wrote:
> On Tue, 22 Apr 2008 12:38:19 -0700, "Richard Crowley"
><rcrowley@xp7rt . net > wrote:
>
>>"EADGBE" wrote ...
>>> That's when I found it -- a *microscopic* crack in the trace between
>>> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
>>> so incredibly tiny that I easily overlooked it--repeatedly.
>>>
>>> I took one of my jumper leads and clipped one end of it to Q208's
>>> emitter and the other end of it to the 3.3 ohm resistor.
>>>
>>> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>>
>>Its hard to imagine how the output node (where the two
>>3.3 ohm resistors join) could be correct (6.4V) without
>>the path through the lower 3.3 ohm resistor and Q208?
>
> Pure coincidence - it was the breakdown voltage of the reverse biased
> base-emitter of Q207.
Rubbish. ( Well, possibly :-) )
Q207 was indeed hard off with its base at 0V. Q208 was not connected
to the output because of the fault. The output junction was therefore
biassed only by the emitter voltage or Q204 (8V nominal) via the
15 k resistor.
If the measurement was made with a 20 kohm/V multimeter on the 10 V range
(200k) then I would expect the potential divider effect to pad that 8
V down to about 7.4 V. EADGBE actually posted that the node was 7.3V
(not the nominal 6.4 V of the schematic).
OK, I admit it could have been reverse bias breakdown but I prefer my
version as it doesn't require that coincidence. (Well OK I do make an
assumption about the measurement kit instead ...)
--
John Phillips
Re: Amplifier Problem - ***SOLVED***
On 22 Apr 2008 20:09:23 GMT, John Phillips
<news0804@DontUseThis.mainly.me.uk> wrote:
>On 2008-04-22, Don Pearce <nospam@nospam . com > wrote:
>> On Tue, 22 Apr 2008 12:38:19 -0700, "Richard Crowley"
>><rcrowley@xp7rt . net > wrote:
>>
>>>"EADGBE" wrote ...
>>>> That's when I found it -- a *microscopic* crack in the trace between
>>>> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
>>>> so incredibly tiny that I easily overlooked it--repeatedly.
>>>>
>>>> I took one of my jumper leads and clipped one end of it to Q208's
>>>> emitter and the other end of it to the 3.3 ohm resistor.
>>>>
>>>> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>>>
>>>Its hard to imagine how the output node (where the two
>>>3.3 ohm resistors join) could be correct (6.4V) without
>>>the path through the lower 3.3 ohm resistor and Q208?
>>
>> Pure coincidence - it was the breakdown voltage of the reverse biased
>> base-emitter of Q207.
>
>Rubbish. ( Well, possibly :-) )
>
>Q207 was indeed hard off with its base at 0V. Q208 was not connected
>to the output because of the fault. The output junction was therefore
>biassed only by the emitter voltage or Q204 (8V nominal) via the
>15 k resistor.
>
>If the measurement was made with a 20 kohm/V multimeter on the 10 V range
>(200k) then I would expect the potential divider effect to pad that 8
>V down to about 7.4 V. EADGBE actually posted that the node was 7.3V
>(not the nominal 6.4 V of the schematic).
>
>OK, I admit it could have been reverse bias breakdown but I prefer my
>version as it doesn't require that coincidence. (Well OK I do make an
>assumption about the measurement kit instead ...)
Mmmmm...... 20k/V multimeters are pretty rare beasts these days. I
have an old AVO 8 but I don't think I'd have the confidence to
estimate two decimal places in its voltage readings ;-)
My money is still on reverse breakdown. Trannies are almost as good as
zeners in this configuration.
d
--
Pearce Consulting
* w w w .pearce.uk . com
On 22 Apr 2008 20:09:23 GMT, John Phillips
<news0804@DontUseThis.mainly.me.uk> wrote:
>On 2008-04-22, Don Pearce <nospam@nospam . com > wrote:
>> On Tue, 22 Apr 2008 12:38:19 -0700, "Richard Crowley"
>><rcrowley@xp7rt . net > wrote:
>>
>>>"EADGBE" wrote ...
>>>> That's when I found it -- a *microscopic* crack in the trace between
>>>> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
>>>> so incredibly tiny that I easily overlooked it--repeatedly.
>>>>
>>>> I took one of my jumper leads and clipped one end of it to Q208's
>>>> emitter and the other end of it to the 3.3 ohm resistor.
>>>>
>>>> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>>>
>>>Its hard to imagine how the output node (where the two
>>>3.3 ohm resistors join) could be correct (6.4V) without
>>>the path through the lower 3.3 ohm resistor and Q208?
>>
>> Pure coincidence - it was the breakdown voltage of the reverse biased
>> base-emitter of Q207.
>
>Rubbish. ( Well, possibly :-) )
>
>Q207 was indeed hard off with its base at 0V. Q208 was not connected
>to the output because of the fault. The output junction was therefore
>biassed only by the emitter voltage or Q204 (8V nominal) via the
>15 k resistor.
>
>If the measurement was made with a 20 kohm/V multimeter on the 10 V range
>(200k) then I would expect the potential divider effect to pad that 8
>V down to about 7.4 V. EADGBE actually posted that the node was 7.3V
>(not the nominal 6.4 V of the schematic).
>
>OK, I admit it could have been reverse bias breakdown but I prefer my
>version as it doesn't require that coincidence. (Well OK I do make an
>assumption about the measurement kit instead ...)
Mmmmm...... 20k/V multimeters are pretty rare beasts these days. I
have an old AVO 8 but I don't think I'd have the confidence to
estimate two decimal places in its voltage readings ;-)
My money is still on reverse breakdown. Trannies are almost as good as
zeners in this configuration.
d
--
Pearce Consulting
* w w w .pearce.uk . com
Re: Amplifier Problem - ***SOLVED***
EADGBE wrote:
>
> That's when I found it -- a *microscopic* crack in the trace between
> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
> so incredibly tiny that I easily overlooked it--repeatedly.
Jeepers. You would normally find that around any PCB-mount jack or DC
socket. Unless the whole thing has had a severe jarring. May have been a
heat/cool fatigue thang.
geoff
EADGBE wrote:
>
> That's when I found it -- a *microscopic* crack in the trace between
> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
> so incredibly tiny that I easily overlooked it--repeatedly.
Jeepers. You would normally find that around any PCB-mount jack or DC
socket. Unless the whole thing has had a severe jarring. May have been a
heat/cool fatigue thang.
geoff
Re: Amplifier Problem - ***SOLVED***
In article
<8355664a-be99-4169-940f-4314e360b300@s50g2000hsb.googlegroups . com >,
EADGBE <hwbosshoss@comcast . net > wrote:
> Good News!
>
> This headphone amplifier has been REPAIRED and is now working
> perfectly.
>
> Here's what happened:
>
> I have been taking parallel measurements between the "good" and "bad"
> channels since the beginning.
>
> I took voltage measurements, resistance measurements, tested ALL
> capacitors, and tested ALL transistors.
>
> But someone in my original thread (I can't remember who offhand --
> sorry) did mention checking the circuit board traces.
>
> "No need," I thought. "The circuit board and all solder joints look
> fine to me."
>
> But in a fit of desperation, I nonetheless decided to whip out a
> tester I hadn't used yet: my magnifying glass.
>
> That's when I found it -- a *microscopic* crack in the trace between
> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
> so incredibly tiny that I easily overlooked it--repeatedly.
>
> I took one of my jumper leads and clipped one end of it to Q208's
> emitter and the other end of it to the 3.3 ohm resistor.
>
> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>
> Q205's collector now measures +7.09V, and Q206 now has the following
> measurements:
> B: +6.51V
> C: +7.08V
> E: +5.84V
>
> I was able to bridge the crack with a well-placed solder trail, and
> the headphone amp now sounds great.
You should *always* bridge the crack with a strand or two of fine wire;
that'll keep it from cracking again, Real Soon Now.
Isaac
In article
<8355664a-be99-4169-940f-4314e360b300@s50g2000hsb.googlegroups . com >,
EADGBE <hwbosshoss@comcast . net > wrote:
> Good News!
>
> This headphone amplifier has been REPAIRED and is now working
> perfectly.
>
> Here's what happened:
>
> I have been taking parallel measurements between the "good" and "bad"
> channels since the beginning.
>
> I took voltage measurements, resistance measurements, tested ALL
> capacitors, and tested ALL transistors.
>
> But someone in my original thread (I can't remember who offhand --
> sorry) did mention checking the circuit board traces.
>
> "No need," I thought. "The circuit board and all solder joints look
> fine to me."
>
> But in a fit of desperation, I nonetheless decided to whip out a
> tester I hadn't used yet: my magnifying glass.
>
> That's when I found it -- a *microscopic* crack in the trace between
> the emitter of Q208 and its adjoining 3.3 ohm resistor. The crack was
> so incredibly tiny that I easily overlooked it--repeatedly.
>
> I took one of my jumper leads and clipped one end of it to Q208's
> emitter and the other end of it to the 3.3 ohm resistor.
>
> I then took voltage measurements. EVERYTHING WAS NOW ON SPEC:
>
> Q205's collector now measures +7.09V, and Q206 now has the following
> measurements:
> B: +6.51V
> C: +7.08V
> E: +5.84V
>
> I was able to bridge the crack with a well-placed solder trail, and
> the headphone amp now sounds great.
You should *always* bridge the crack with a strand or two of fine wire;
that'll keep it from cracking again, Real Soon Now.
Isaac
Re: Amplifier Problem - ***SOLVED***
"isw" <isw@witzend . com > wrote in message
news:isw-E21138.21043922042008@newsgroups . com cast . net ...
> > I was able to bridge the crack with a well-placed solder trail, and
> > the headphone amp now sounds great.
>
> You should *always* bridge the crack with a strand or two of fine wire;
> that'll keep it from cracking again, Real Soon Now.
Why use fine wire? I just use an off-cut from a resistor leg for normal size
traces. Much easier to place and they're pre-tinned as well.
MrT.
"isw" <isw@witzend . com > wrote in message
news:isw-E21138.21043922042008@newsgroups . com cast . net ...
> > I was able to bridge the crack with a well-placed solder trail, and
> > the headphone amp now sounds great.
>
> You should *always* bridge the crack with a strand or two of fine wire;
> that'll keep it from cracking again, Real Soon Now.
Why use fine wire? I just use an off-cut from a resistor leg for normal size
traces. Much easier to place and they're pre-tinned as well.
MrT.
Re: Amplifier Problem - ***SOLVED***
"Mr.T" wrote ...
> "isw"wrote ...
>> > I was able to bridge the crack with a well-placed solder trail, and
>> > the headphone amp now sounds great.
>>
>> You should *always* bridge the crack with a strand or two of fine wire;
>> that'll keep it from cracking again, Real Soon Now.
>
> Why use fine wire? I just use an off-cut from a resistor leg for normal
> size
> traces. Much easier to place and they're pre-tinned as well.
"Fine" is a relative term. And some PC boards are too dense
and use traces that are too narrow to use resistor lead wire.
I typically use 30Ga wire-wrap wire for that purpose. But I
agree that just bridging the gap with a blob of solder is not
an optimal solution.
"Mr.T" wrote ...
> "isw"wrote ...
>> > I was able to bridge the crack with a well-placed solder trail, and
>> > the headphone amp now sounds great.
>>
>> You should *always* bridge the crack with a strand or two of fine wire;
>> that'll keep it from cracking again, Real Soon Now.
>
> Why use fine wire? I just use an off-cut from a resistor leg for normal
> size
> traces. Much easier to place and they're pre-tinned as well.
"Fine" is a relative term. And some PC boards are too dense
and use traces that are too narrow to use resistor lead wire.
I typically use 30Ga wire-wrap wire for that purpose. But I
agree that just bridging the gap with a blob of solder is not
an optimal solution.
Re: Amplifier Problem - ***SOLVED***
"Richard Crowley" <rcrowley@xp7rt . net > wrote in message
news:6798sjF2nic0cU1@mid.individual . net ...
> >> You should *always* bridge the crack with a strand or two of fine wire;
> >> that'll keep it from cracking again, Real Soon Now.
> >
> > Why use fine wire? I just use an off-cut from a resistor leg for normal
> > size traces. Much easier to place and they're pre-tinned as well.
>
> "Fine" is a relative term.
But not so much when you say "a strand or two".
> And some PC boards are too dense
> and use traces that are too narrow to use resistor lead wire.
Which is why I already said "for normal size traces". That covers a lot of
audio gear.
MrT.
"Richard Crowley" <rcrowley@xp7rt . net > wrote in message
news:6798sjF2nic0cU1@mid.individual . net ...
> >> You should *always* bridge the crack with a strand or two of fine wire;
> >> that'll keep it from cracking again, Real Soon Now.
> >
> > Why use fine wire? I just use an off-cut from a resistor leg for normal
> > size traces. Much easier to place and they're pre-tinned as well.
>
> "Fine" is a relative term.
But not so much when you say "a strand or two".
> And some PC boards are too dense
> and use traces that are too narrow to use resistor lead wire.
Which is why I already said "for normal size traces". That covers a lot of
audio gear.
MrT.
Re: Amplifier Problem - ***SOLVED***
In article <480ef4cd$0$30463$afc38c87@news.optusnet . com .au>,
"Mr.T" <MrT@home> wrote:
> "isw" <isw@witzend . com > wrote in message
> news:isw-E21138.21043922042008@newsgroups . com cast . net ...
> > > I was able to bridge the crack with a well-placed solder trail, and
> > > the headphone amp now sounds great.
> >
> > You should *always* bridge the crack with a strand or two of fine wire;
> > that'll keep it from cracking again, Real Soon Now.
>
> Why use fine wire? I just use an off-cut from a resistor leg for normal size
> traces. Much easier to place and they're pre-tinned as well.
Depends on the width of the trace...
Isaac
In article <480ef4cd$0$30463$afc38c87@news.optusnet . com .au>,
"Mr.T" <MrT@home> wrote:
> "isw" <isw@witzend . com > wrote in message
> news:isw-E21138.21043922042008@newsgroups . com cast . net ...
> > > I was able to bridge the crack with a well-placed solder trail, and
> > > the headphone amp now sounds great.
> >
> > You should *always* bridge the crack with a strand or two of fine wire;
> > that'll keep it from cracking again, Real Soon Now.
>
> Why use fine wire? I just use an off-cut from a resistor leg for normal size
> traces. Much easier to place and they're pre-tinned as well.
Depends on the width of the trace...
Isaac
Re: Amplifier Problem - ***SOLVED***
"isw" <isw@witzend . com > wrote in message
news:isw-AA34EA.20404123042008@newsgroups . com cast . net ...
> > > You should *always* bridge the crack with a strand or two of fine
wire;
> > > that'll keep it from cracking again, Real Soon Now.
> >
> > Why use fine wire? I just use an off-cut from a resistor leg for normal
size
> > traces. Much easier to place and they're pre-tinned as well.
>
> Depends on the width of the trace...
Which is why I said "for normal size traces".
The post I replied to OTOH said "*always*". That is what I objected to.
(Doesn't anybody read before replying?)
MrT.
"isw" <isw@witzend . com > wrote in message
news:isw-AA34EA.20404123042008@newsgroups . com cast . net ...
> > > You should *always* bridge the crack with a strand or two of fine
wire;
> > > that'll keep it from cracking again, Real Soon Now.
> >
> > Why use fine wire? I just use an off-cut from a resistor leg for normal
size
> > traces. Much easier to place and they're pre-tinned as well.
>
> Depends on the width of the trace...
Which is why I said "for normal size traces".
The post I replied to OTOH said "*always*". That is what I objected to.
(Doesn't anybody read before replying?)
MrT.
Re: Amplifier Problem - ***SOLVED***
"Mr.T" wrote ...
> "isw" wrote ...
>> > > You should *always* bridge the crack with a strand or two of fine
> wire;
>> > > that'll keep it from cracking again, Real Soon Now.
>> >
>> > Why use fine wire? I just use an off-cut from a resistor leg for normal
> size
>> > traces. Much easier to place and they're pre-tinned as well.
>>
>> Depends on the width of the trace...
>
>
> Which is why I said "for normal size traces".
> The post I replied to OTOH said "*always*". That is what I objected to.
> (Doesn't anybody read before replying?)
I suspect that the standard "normal" trace width may have
shrunk while you weren't looking. Or maybe you have the
luxury of working on older, more human-scale equipment.
"Mr.T" wrote ...
> "isw" wrote ...
>> > > You should *always* bridge the crack with a strand or two of fine
> wire;
>> > > that'll keep it from cracking again, Real Soon Now.
>> >
>> > Why use fine wire? I just use an off-cut from a resistor leg for normal
> size
>> > traces. Much easier to place and they're pre-tinned as well.
>>
>> Depends on the width of the trace...
>
>
> Which is why I said "for normal size traces".
> The post I replied to OTOH said "*always*". That is what I objected to.
> (Doesn't anybody read before replying?)
I suspect that the standard "normal" trace width may have
shrunk while you weren't looking. Or maybe you have the
luxury of working on older, more human-scale equipment.
Re: Amplifier Problem - ***SOLVED***
Richard Crowley wrote:
> "Mr.T" wrote ...
>> "isw" wrote ...
>>>>> You should *always* bridge the crack with a strand or two of fine
>> wire;
>>>>> that'll keep it from cracking again, Real Soon Now.
>>>> Why use fine wire? I just use an off-cut from a resistor leg for normal
>> size
>>>> traces. Much easier to place and they're pre-tinned as well.
>>> Depends on the width of the trace...
>>
>> Which is why I said "for normal size traces".
>> The post I replied to OTOH said "*always*". That is what I objected to.
>> (Doesn't anybody read before replying?)
>
> I suspect that the standard "normal" trace width may have
> shrunk while you weren't looking. Or maybe you have the
> luxury of working on older, more human-scale equipment.
>
>
In any case, a small wire (like one strand of some zip cord--30 gauge?)
is an improvement over nothing at all.
jak
Richard Crowley wrote:
> "Mr.T" wrote ...
>> "isw" wrote ...
>>>>> You should *always* bridge the crack with a strand or two of fine
>> wire;
>>>>> that'll keep it from cracking again, Real Soon Now.
>>>> Why use fine wire? I just use an off-cut from a resistor leg for normal
>> size
>>>> traces. Much easier to place and they're pre-tinned as well.
>>> Depends on the width of the trace...
>>
>> Which is why I said "for normal size traces".
>> The post I replied to OTOH said "*always*". That is what I objected to.
>> (Doesn't anybody read before replying?)
>
> I suspect that the standard "normal" trace width may have
> shrunk while you weren't looking. Or maybe you have the
> luxury of working on older, more human-scale equipment.
>
>
In any case, a small wire (like one strand of some zip cord--30 gauge?)
is an improvement over nothing at all.
jak
Re: Amplifier Problem - ***SOLVED***
"Richard Crowley" <rcrowley@xp7rt . net > wrote in message
news:67bq7pF2lk6jeU1@mid.individual . net ...
> I suspect that the standard "normal" trace width may have
> shrunk while you weren't looking.
Nope, but what's normal for an audio amp is not necessarily "normal" for a
computer motherboard. Since we weren't discussing computers, they are not
included in my comment.
>Or maybe you have the
> luxury of working on older, more human-scale equipment.
Yes, since most micro-miniature equipment is not really designed to be
worked on, and we were discussing an audio amp, not digital electronics.
As usual, people can argue endlessly about linguistics, frankly I'm not
interested.
MrT.
"Richard Crowley" <rcrowley@xp7rt . net > wrote in message
news:67bq7pF2lk6jeU1@mid.individual . net ...
> I suspect that the standard "normal" trace width may have
> shrunk while you weren't looking.
Nope, but what's normal for an audio amp is not necessarily "normal" for a
computer motherboard. Since we weren't discussing computers, they are not
included in my comment.
>Or maybe you have the
> luxury of working on older, more human-scale equipment.
Yes, since most micro-miniature equipment is not really designed to be
worked on, and we were discussing an audio amp, not digital electronics.
As usual, people can argue endlessly about linguistics, frankly I'm not
interested.
MrT.
