I had one blow years ago, It blew the white debri all over the inside of the
amp and
scared the &*%$#%$ out of me. I was lucky and only the cap went. My wife
came running in and wondered what the hell happened, she was not impressed :-)
I decided to change all of them with new ones, hihi.
Anyone else have them blow and can share with us ?
Bob
K6UJ
On Mar 28, 2012, at 2:31 PM, Carl wrote:
> A lot depends upon the quality of the cap to start with, its enviroment which
> also includes RF since electrolytics react poorly to it as seen in Dentron
> amps with only 500pf plate choke bypasses that are run hard on 160/80M.
>
> Many of the amps I get in for service have 80's date codes on the caps and
> those I always strongly recommend get changed. Subsequent testing confirms
> leakage is already in the twilight zone but not yet dangerous.....on most but
> there are exceptions.
>
> Since Computer Grade caps arent that expensive its good insurance. I buy all
> mine, no matter the amp, from Ameritron at $13.50 each for 270uF or $108 for
> 8 of them. These fit the Alphas, Amp Supply, Ameritron and a few others.
>
> Other amps such as Heath, Command, QRO, etc get the CDE 381LX series 330uF
> 450V 105*C caps from Mouser at $14.75 a pop but I buy the 25 qty at $9.95
> since I use so many. They are also retrofitted into amps using the twist lock
> cans and the 30mm dia 220uf fits the NCL-2000 clips perfectly.
>
> Since the tolerance is far better than originals I cut down on extra heat and
> current by replacing 30-50K equalizers with 100K 3W MOX.
>
> Carl
> KM1H
>
>
>
>
> ----- Original Message ----- From: "Bob K6UJ" <k6uj@pacbell.net>
> To: "amps@contesting.com" <Amps@contesting.com>
> Sent: Wednesday, March 28, 2012 4:33 PM
> Subject: Re: [Amps] How Do You Know When Filter Caps Begin to Fail?
>
>
>> Pete,
>>
>> My understanding from input received on this reflector is that the
>> electrolytic filter caps have reached the end of their lifespan and
>> are prone to go out after about 15 years. This varies of course but it is
>> good idea to change them out if they are as old as yours.
>> The problem with these guys is that when they go you don't normally have any
>> pre indication and they usually go kaboom and take out
>> other stuff along with it. Cheap insurance to replace them.
>>
>> Bob
>> K6UJ
>>
>>
>>
>> On Mar 28, 2012, at 9:16 AM, Pete Smith N4ZR wrote:
>>
>>> I have an SB-220 that dates at least to 1978. There is no external sign
>>> of any problems, and the amp has been heavily used in contests for at
>>> least 20 years. It still delivers over 1300 watts on 80-20. Is there
>>> going to be any warning of a capacitor failure? Will there likely be
>>> any cascading damage to other components? Is it conventional wisdom that
>>> I should replace them as a precaution?
>>>
>>> --
>>> 73, Pete N4ZR
>>> The World Contest Station Database, updated daily at www.conteststations.com
>>> The Reverse Beacon Network at http://reversebeacon.net, blog at
>>> reversebeacon.blogspot.com,
>>> spots at telnet.reversebeacon.net, port 7000 and
>>> arcluster.reversebeacon.net, port 7000
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
>> _______________________________________________
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