[UK-CONTEST] PST61

[peter Jackson]

Hi, I have a PST61 and yes it has had problems with the pot. Mine went faulty under warranty and Ron fitted a new one. He sent me the old one and as I had experiences with precision pots during my working life I took it apart.
Its a multi turn wirewound 10K but only uses about 100ohms for 360deg travel. I assume this is to obtain best linearity. The wiper is connected to two plated wipers than make contact with a plate in the end cover. It needs bending towards the end cover to make better contact. Best to smear some contact grease on it.
To remove it remove the 6 screws on the bottom cover removing the centre 2 first as these secure the bracket that holds the pot.
Unsolder the 3 connections you can now withdraw the pot as there is a pin though the shaft which slots into the drive.
Carefully prise off the clips that hold the back plate on and carry out the above.
Its difficult to fix the clips back securely so I put a small tyrap round the body of the pot to hold the clips tight. You could of use super glue but you might have to remove in the future.
This is important, when you solder the leads back on make sure the one connected to the wiper is soldered on the side of the tag nearest to the other two in other words away from the back plate. The clearance is very small and if you leave a large blob of solder on the tag it will intermittently earth to the back plate. I know it happened to me and it took a lot of head scratching trying to find why the rotator kept stopping.
Having said all that its a very powerful rotator and will turn anything the average ham needs.
Hope this info is of help. 73 Pete G3KNU