No really. Yes, if they all are connected in serial or parallel you get a
total of 31,200 pF. If you, on the other hand make two seril chains and
parallel then you get the 1950 pF mentioned. They probably used enough in
serial to get the needed voltage rating and/or two in parallel to get the
needed current rating. Not uncommon to do. I would believe one cap of 2000 pf
would be much more expensive than the 8 used.
I don't know what voltage or current rating is required but I have used the
parallel/serial trix in other applications. Worked great. In one of my
applications I had to use sixteen (16!) 0.1 uF caps to get the right current
rating. One 1.5 uF cap burnt up.
73 de,
Hans - N2JFS
-----Original Message-----
From: Wilson Lamb <infomet@embarqmail.com>
To: towertalk <towertalk@contesting.com>
Sent: Sun, 17 Dec 2017 12:24
Subject: Re: [TowerTalk] TowerTalk Digest, Vol 180, Issue 26
There's a math problem here too....
WL
>
> 1. MFJ-998 autotuner problem (Roger D Johnson)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 16 Dec 2017 15:10:03 -0500
> From: Roger D Johnson <n1rj@roadrunner.com>
> To: Towertalk Reflector <towertalk@contesting.com>
> Subject: [TowerTalk] MFJ-998 autotuner problem
> Message-ID: <4944bc09-0723-5f26-bbcc-e18002def723@roadrunner.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> I recently discovered a problem with my MFJ-998 tuner that might also be a
> problem with other tuners.
>
> There are two banks of series/parallel capacitors that are switched on the
> input
> side of the L network to
>
> match low impedance loads. One bank consists of (8) 3900pf capacitors that
> total
> 1950 pf. In my tuner
>
> these caps were only 390pf!!
>
> If these PC boards were populated using a machine getting parts from a reel,
> there are probably more
>
> tuners out there with the wrong caps.
>
> 73, Roger N1RJ
>
>
>
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> ------------------------------
>
> End of TowerTalk Digest, Vol 180, Issue 26
> ******************************************
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|