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Trimmer tool for adjusting skeleton pre-set potentiometers
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Topic: Trimmer tool for adjusting skeleton pre-set potentiometers (Read 1685 times)
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I try hard
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Trimmer tool for adjusting skeleton pre-set potentiometers
«
on:
February 10, 2018, 08:57:14 pm »
I'm currently converting a 30 year old 2 meter transciever (Yaesu FT480) to allow it to operate with UK repeaters. One necessary step is to reduce the FM deviation from the original plus/minus 5kHz to plus/minus 2.5 KHz. I'm quite comfortable with the procedure and have the necessary mod/dev meter and know clearly the trimpots and location for the adjustment. However, with this radio the trimpots have a peculiar central circular hole about 1.2mm diameter with no hex flats or screwdriver slot to allow adjustment. Has anyone come across this type before or could suggest a method of gripping the skelton wiper to enable it to be turned? Many thanks in advance...
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floobydust
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Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #1 on:
February 10, 2018, 10:04:08 pm »
A picture would really help.
It is probably a Japanese manufacturer (Murata, TDK etc.) so sometimes you can back-track the alignment tool, if it is a specialty one.
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I try hard
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Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #2 on:
February 11, 2018, 11:10:46 am »
Thanks very much for that floobydust. It's a bit tricky for me to get a picture as there is limited scope for raising the radio casing panel due to a closely tethered wiring harness linked to the speaker and other circuitry on the inside of the panel. Obviously I will have to remove this to carry out the adjustment though so I will try. Its almost as if the accessible side of the pot is the rear face and there might be a screwdriver slot on the reverse side - but this is impossible to access without serious dismantling. Point noted about the probable source of the pot. I'll take a look on google.
Kind regards
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Ian.M
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Posts: 13033
Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #3 on:
February 11, 2018, 12:34:00 pm »
Press a piece of plasticine into one to take an impression, or use a dental mirror.
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I try hard
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Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #4 on:
February 11, 2018, 03:45:42 pm »
Thanks Ian.M. I took a photo of a similar pot - easier to get at. I think there may be some sort of screwdriver slot after all...
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Ian.M
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Posts: 13033
Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #5 on:
February 11, 2018, 05:34:56 pm »
If that's got a protruding lug bent up on either side of the rotor center, then you need a piece of dowel with the end slotted to fit over the lugs, and a pin in the end of it to fit in the center hole so it doesn't slip sideways.
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I try hard
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Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #6 on:
February 12, 2018, 10:57:59 am »
OK Ian.M. Well it looks as though I could get a well fitting screwdriver blade in. It has to be a snug fit into the lugs so I may have to get the grindstone out. Point noted about the centre pin - I'll try to contrive something.
Thanks again.
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Cyberdragon
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Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #7 on:
February 23, 2018, 07:37:39 pm »
I just use my fingers for these.
(waiting for rants)
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*BZZZZZZAAAAAP*
Voltamort strikes again!
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sidspop
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Re: Trimmer tool for adjusting skeleton pre-set potentiometers
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Reply #8 on:
March 03, 2018, 01:09:57 pm »
Tey can usually be done by carefully using an ordinary straight trimmer at the side of the centre bit, and parallel to it.
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Trimmer tool for adjusting skeleton pre-set potentiometers
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