Trimmer tool for adjusting skeleton pre-set potentiometers

[I try hard]

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...

[floobydust]

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.

[I try hard]

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

[Ian.M]

Press a piece of plasticine into one to take an impression, or use a dental mirror.

[I try hard]

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...

[Ian.M]

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.

[I try hard]

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.

[Cyberdragon]

I just use my fingers for these.

(waiting for rants)

[sidspop]

Tey can usually be done by carefully using an ordinary straight trimmer at the side of the centre bit, and parallel to it.