Re: BPF trimmer sensitive to screwdrivier touch?


David Wilcox K8WPE
 

No, just too much trial and error. With the ceramic ones you know where you are before you remove the tuning device. I also have damaged some cores on old if cans with metal but the ceramic seems to be a little softer, fits better. Anyway, I like the ceramic. I have a handful of the old plastic and fiber ones too from the old days but the ceramic ones seem to work better than those too.

I am just a fool for newer and more tools in my shop. Ha!

Dave K8WPE

On Mar 17, 2018, at 8:07 PM, Jess Gypin <ontarget1911@gmail.com> wrote:

I’ve used them all. Metal screw driver, just stick it in there, make a tweak and then pull it out to see what happens. What’s the big deal brain damage?

On Mar 17, 2018, at 5:07 PM, David Wilcox via Groups.Io <Djwilcox01=yahoo.com@groups.io> wrote:

I use ceramic screw drivers to adjust any tuned circuit part. The metal screw driver will change the frequency by detuning the coil or trimmer cap. There are some plastic tuning wands a available too but I like my ceramic set. Just look for ceramic screw drivers at Amazon. $10 to $14 a set.

Dave K8WPE

On Mar 17, 2018, at 4:39 PM, g3xaq <alan@g3xaq.net> wrote:

I did notice one thing during alignment: when peaking the receiver BPF trimmer the level changes (and I get noise on the audio) when I apply a metal screwdriver to the trimmer. Is this expected? I've checked and I do have the trimmer inserted the right way round: it is aligned with the silk screened component overlay.

Before I go in gung-ho with a soldering iron and risk damaging the trimmer and/or PCB, is this expected behaviour or not?

73, Alan G3XAQ

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