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From: Meat Plow on 14 May 2010 12:02
On Fri, 14 May 2010 05:11:56 -0400, JW wrote:

> 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. :)

And put your nose close to it and inhale. I do a lot of troubleshoot with
my senses. After 30 some years I can distinguish just what's hot or
burning, smell ozone from HV, hear things snap crackle pop etc...

From: JW on 17 May 2010 05:30
On Fri, 14 May 2010 16:02:23 +0000 (UTC) Meat Plow <mhywatt(a)yahoo.com>
wrote in Message id: <pan.2010.05.14.16.02.21(a)gmail.com>:

>On Fri, 14 May 2010 05:11:56 -0400, JW wrote:
>
>> 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. :)
>
>And put your nose close to it and inhale. I do a lot of troubleshoot with
>my senses. After 30 some years I can distinguish just what's hot or
>burning, smell ozone from HV, hear things snap crackle pop etc...

Also a good tip, but when doing so I wear safety glasses. I've had a few
things go critical mass just as I lowered my nose for a sniff! Gotta love
those - practically fell out of my seat.
From: Meat Plow on 17 May 2010 08:05
On Mon, 17 May 2010 05:30:57 -0400, JW wrote:

> On Fri, 14 May 2010 16:02:23 +0000 (UTC) Meat Plow <mhywatt(a)yahoo.com>
> wrote in Message id: <pan.2010.05.14.16.02.21(a)gmail.com>:
>
>>On Fri, 14 May 2010 05:11:56 -0400, JW wrote:
>>
>>> 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. :)
>>
>>And put your nose close to it and inhale. I do a lot of troubleshoot
>>with my senses. After 30 some years I can distinguish just what's hot or
>>burning, smell ozone from HV, hear things snap crackle pop etc...
>
> Also a good tip, but when doing so I wear safety glasses. I've had a few
> things go critical mass just as I lowered my nose for a sniff! Gotta
> love those - practically fell out of my seat.

How true :) I've had my fair share of electrolytic out-gassing up the
nose. Never had anything with the potential to injure blow up in my face.
From: David Brodbeck on 18 May 2010 02:45
On May 11, 6:56 pm, "Phil Allison" <phi...(a)tpg.com.au> wrote:
> **  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

Didn't find a can, so almost certainly it's a tantalum. Good catch, i
probably would have replaced it with an electrolytic if you hadn't
said anything.

Hoping to get this thing put back together later this week. Been way
too busy to get to it 'till now. I'll let you know what happens.
From: Phil Allison on 18 May 2010 06:36

"David Brodbeck"
"Phil Allison"
>
> ** 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.
>

Didn't find a can,


** Funny how you used that word earlier.

so almost certainly it's a tantalum. Good catch, i
probably would have replaced it with an electrolytic if you hadn't
said anything.

** Did you read the warning above about tants I just gave you ???

There is no reason to use them if space permits a normal electro.



..... Phil


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