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From: Phil Allison on 11 May 2010 21:56

"David Brodbeck"

"Phil Allison"
> ** Is C54 actually a * tantalum* bead cap ????
>
> If so, no special explanation is needed for its fiery demise.

Could be. It's 10 uF, polarized, which could be either. It was too
badly charred to tell what it used to be, but I didn't find the
remains of an electrolytic can rattling around in the case, so a
tantalum does seem likely.


** FYI - tantalum bead caps look like this:

http://www.allproducts.com/manufacture97/suntanbe/product1.jpg

They are known to catch fire and emit smoke and bits of the tantalum oxide
"slug" for no good reason.

If you found a "can" then the cap is an ordinary electro that overheated,
the electrolyte boiled and burst the seal.



.... Phil


From: Meat Plow on 13 May 2010 08:51
On Tue, 11 May 2010 12:05:53 -0700, David Brodbeck wrote:

> On May 10, 7:33 pm, Meat Plow <mhyw...(a)yahoo.com> wrote:
>> If you have some way to limit current, use it. I have a supply that I
>> can dial in from 0 to 35 amps and it comes in real handy
>
> Will do. I don't have a variable-limit supply, but I do have one with a
> fixed 1.5A limit that I plan to use for initial low power transmit
> testing.

That will help you not fry some of the bigger stuff but there is nothing
like a 0 to 15 volt, 0 to 35 amp supply with volt/ammeter.
From: JW on 13 May 2010 09:08
On Thu, 13 May 2010 12:51:27 +0000 (UTC) Meat Plow <mhywatt(a)yahoo.com>
wrote in Message id: <pan.2010.05.13.12.51.27(a)gmail.com>:

>On Tue, 11 May 2010 12:05:53 -0700, David Brodbeck wrote:
>
>> On May 10, 7:33�pm, Meat Plow <mhyw...(a)yahoo.com> wrote:
>>> If you have some way to limit current, use it. I have a supply that I
>>> can dial in from 0 to 35 amps and it comes in real handy
>>
>> Will do. I don't have a variable-limit supply, but I do have one with a
>> fixed 1.5A limit that I plan to use for initial low power transmit
>> testing.
>
>That will help you not fry some of the bigger stuff but there is nothing
>like a 0 to 15 volt, 0 to 35 amp supply with volt/ammeter.

Even better if it has OCP. If the current drain reaches a user programmed
setting (IE those BJTs are about to blow!), the power supply will shutdown
its output completely, instead of just dumping continuous current to
whatever the current is set to.
I have an Agilent 6643A which does this. While they cost $3K new
you can pick 'em up for a 10% of that on Ebay. I paid just a bit over $300
for mine.

http://www.home.agilent.com/agilent/product.jspx?id=839301&pageMode=OV&pid=839301&lc=eng&ct=PRODUCT&cc=US&pselect=SR.PM-Search%20Results.Overview
From: Meat Plow on 13 May 2010 09:42
On Thu, 13 May 2010 09:08:10 -0400, JW wrote:

> On Thu, 13 May 2010 12:51:27 +0000 (UTC) Meat Plow <mhywatt(a)yahoo.com>
> wrote in Message id: <pan.2010.05.13.12.51.27(a)gmail.com>:
>
>>On Tue, 11 May 2010 12:05:53 -0700, David Brodbeck wrote:
>>
>>> On May 10, 7:33 pm, Meat Plow <mhyw...(a)yahoo.com> wrote:
>>>> If you have some way to limit current, use it. I have a supply that I
>>>> can dial in from 0 to 35 amps and it comes in real handy
>>>
>>> Will do. I don't have a variable-limit supply, but I do have one with
>>> a fixed 1.5A limit that I plan to use for initial low power transmit
>>> testing.
>>
>>That will help you not fry some of the bigger stuff but there is nothing
>>like a 0 to 15 volt, 0 to 35 amp supply with volt/ammeter.
>
> Even better if it has OCP. If the current drain reaches a user
> programmed setting (IE those BJTs are about to blow!), the power supply
> will shutdown its output completely, instead of just dumping continuous
> current to whatever the current is set to.
> I have an Agilent 6643A which does this. While they cost $3K new you can
> pick 'em up for a 10% of that on Ebay. I paid just a bit over $300 for
> mine.
>
> http://www.home.agilent.com/agilent/product.jspx?
id=839301&pageMode=OV&pid=839301&lc=eng&ct=PRODUCT&cc=US&pselect=SR.PM-
Search%20Results.Overview

That's great if you know within a decent tolerance how much current what
you are working on draws at inrush or at an idle.
From: JW on 14 May 2010 05:11
On Thu, 13 May 2010 13:42:04 +0000 (UTC) Meat Plow <mhywatt(a)yahoo.com>
wrote in Message id: <pan.2010.05.13.13.41.59(a)gmail.com>:

>On Thu, 13 May 2010 09:08:10 -0400, JW wrote:
>
>> On Thu, 13 May 2010 12:51:27 +0000 (UTC) Meat Plow <mhywatt(a)yahoo.com>
>> wrote in Message id: <pan.2010.05.13.12.51.27(a)gmail.com>:
>>
>>>On Tue, 11 May 2010 12:05:53 -0700, David Brodbeck wrote:
>>>
>>>> On May 10, 7:33�pm, Meat Plow <mhyw...(a)yahoo.com> wrote:
>>>>> If you have some way to limit current, use it. I have a supply that I
>>>>> can dial in from 0 to 35 amps and it comes in real handy
>>>>
>>>> Will do. I don't have a variable-limit supply, but I do have one with
>>>> a fixed 1.5A limit that I plan to use for initial low power transmit
>>>> testing.
>>>
>>>That will help you not fry some of the bigger stuff but there is nothing
>>>like a 0 to 15 volt, 0 to 35 amp supply with volt/ammeter.
>>
>> Even better if it has OCP. If the current drain reaches a user
>> programmed setting (IE those BJTs are about to blow!), the power supply
>> will shutdown its output completely, instead of just dumping continuous
>> current to whatever the current is set to.
>> I have an Agilent 6643A which does this. While they cost $3K new you can
>> pick 'em up for a 10% of that on Ebay. I paid just a bit over $300 for
>> mine.
>>
>> http://www.home.agilent.com/agilent/product.jspx?
>id=839301&pageMode=OV&pid=839301&lc=eng&ct=PRODUCT&cc=US&pselect=SR.PM-
>Search%20Results.Overview
>
>That's great if you know within a decent tolerance how much current what
>you are working on draws at inrush or at an idle.

True. Start low and work your way up. :)
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