332F Dial Overhaul

[GEC 1972]

Hi Everyone, got a query regarding the dial on my 332F. It's recently started returning very slowly which I assume is down to dried up lubrication. Will it need expert attention as there's two areas I'm concerned about. The first is that appears there's a spring under a fair amount of tension in the centre hub. The second is that am I right in thinking the return speed is critical as this generates the pulses and that this will need setting up again after being cleaned and relubricated?
Thanks in advance.

[Nickthedentist]

They're not actually that difficult to do, but you're right to be wary of the spring - it needs to be let-down gradually.

I have some pics of a stripdown which I did which I will post if I can find them.

Nick.

[GEC 1972]

Thanks for your reply Nick, the photos would be great if you can find them.

[oldmoley1]

Originally Posted by GEC 1972

Thanks for your reply Nick, the photos would be great if you can find them.

Watching this with interest, since I have a number of phones in this situation and currently view dials in very much the same light as an unexploded bomb (i.e. I'm terrified I'm going to muck them up!). Any information will be of great interest.

[Nickthedentist]

I'll have a look on my work PC tomorrow if I get a chance.

[Nickthedentist]

Here's what I found. Apologies if they're not much use, but I took them merely to help me reassemble it properly, not intending them to be posted here.

Hope they help.

Nick.

[Nickthedentist]

And the rest.

The only tools I used are what's shown, i.e. a socket from my socket set, and a well-fitting flat-bladed screwdriver or two.

Note the multi-compartment storage box - very useful for keeping things safe and in the correct order.

The pics are posted in the order I took them, so should represent the order in which things come apart.

The spring is safe in its own little barrel. I can't recall whether or not I took it out of this to clean it. I suspect not (though good clockmakers would!).

Nick.

[GEC 1972]

That's brilliant Nick, thank you. Will have a go at mine soon. Got a few others that probably need doing as well.

[russell_w_b]

When I did my first telephone dial years ago, I removed the contact block and boiled it for ten minutes in clean water, like my granda used to do with clocks, then immediately lubricated it. It worked fine (still does!), although I wouldn't recommend it now.

[oldmoley1]

Interesting - I've been thinking about getting an ultrasonic cleaner to clean bits and pieces like this, but always feel a bit uneasy about plunging these parts in water. Anyone got any experience of ultrasonic cleaning?

[russell_w_b]

Originally Posted by oldmoley1

Anyone got any experience of ultrasonic cleaning?

Years ago I cleaned up several circuit boards from an Eddystone B6038E 1kW MF transmitter using an ultrasonic tank. I filled the tank with de-ionised water and chucked in a dash of methylated spirits as a non-ionic surfactant. It was all very unscientific, but it worked a treat and the transmitter went back into service at a different site.

You can get ultrasonic cleaning fluid - no idea what it consists of - so you can put your dial or whatever in a sealed plastic bag, and place it in the tank with water as a transmitting medium.

Small ultrasonic tanks come up in Aldi occasionally. Not sure if they're big enough to accommodate a telephone dial though. They're usually advertised for cleaning jewellry.

[Nickthedentist]

Whatever you do, you MUST take the dial apart. Attempts at cleaning by immersion with it all assembled will not do any good at all.

[russell_w_b]

Originally Posted by Nickthedentist

Whatever you do, you MUST take the dial apart.

Quite so, Nick. All subsequent dials I have done were stripped right back (and in some instances, the springs replaced with those from modern dials) and lubricated in accordance with the instruction laid down here.