Intermittent PYE Valve Radio.

[LanceReed]

Hi all.
I am looking for some help please.

I have a 1950's Pye radio, Its power supply works all the time, but sometimes I get radio broadcast then other times nothing at all? Any help with what's wrong would be greatly appreciated?.

Thanks, Lance.

[Station X]

Hello and welcome to the forums.

What model number or name is the set? Knowing this will enable us to give you better advice.

[LanceReed]

Hi Thankyou for the welcome.
It's a P76. As of now there is no sound coming from any of the bands?
And I think there's a valve not lighting up?
Thanks Lance

[stevehertz]

Sounds like - for starters at least - you need to attack all switches, pots and valve bases with Servisol switch cleaner.

[LanceReed]

Hi, where's the best place to buy the Servisol switch cleaner and new valve please?

[mickm3for]

Hi CPC for servisol and what number is the valve Mick

[stevehertz]

You can buy servisol switch cleaner on eBay. Click and buy, probably easier that signing up with a components supplier, all the form filling etc. That's assuming you're already on the bay.

[Nuvistor]

If the valve doesn’t appear to be lit when the radio is working then the valve is probably ok. See how the radio works after the switch cleaning.

[LanceReed]

Hi all, thanks for your replies, when I get the servisol back, have I got to be careful where I spray it?? Or can I just spray over the parts with it... Taking out the valves and spraying the sockets etc? Sorry for my luck of knowledge?

[newlite4]

Just use it sparingly, it is expensive stuff. Just gently spray onto switch contacts, into valve base sockets and onto the valve base pins, mopping up any excess spray. Work the switches and re-insert the valves whilst the Servisol is still liquid to increase its effectiveness. This set has the B8G series of valves. These are held in place by a spring clip that surrounds the base. Before removal or re-insertion of the valves, pull the clip away from the valve base to avoid breaking the glass pip that projects from the bottom side of the valve, this will avoid breakage of the valve.
Neil

[LanceReed]

Thank you for explaining Neil.
Yea, there is some dust build up inside too. I will order some servisol now.
Thanks again.

[Nuvistor]

Clean the switches etc with the power switched off and unplugged.After cleaning the switches etc leave the radio unplugged from the power for 15 mins or so to let any volatile products evaporate.

[stevehertz]

Originally Posted by Nuvistor

Clean the switches etc with the power switched off and unplugged.After cleaning the switches etc leave the radio unplugged from the power for 15 mins or so to let any volatile products evaporate.

I see no reason for that to be honest. It's a safe switch cleaner designed for purpose. I spray it, operate the switch or pot rapidly but carefully many times and then if appropriate or desired, apply power etc. I even use it with power applied at times. I'm not trying to be controversial, please enlighten me if I'm wrong.

[Nuvistor]

Hi Steve,
I just found it could practice, spraying onto a paxolin switch wafer that has HT on it could cause tracking, I found it safer to let any alcohol type solvents evaporate.

Perhaps I am being over cautious, but that’s me.

[stevehertz]

Frank, ok, really not wanting to labour a point or get into a petty disagreement, but I doubt very much if a tried and tested, industry standard product development for cleaning switches would create a tracking problem. It would be wholly unfit for purpose if that was the case.

[Radio Wrangler]

Before we all go down the bottomless pit labelled "Safety", Frank's logic looks sound to me. If you don't know for sure that a switch cleaner fluid is a good insulator while drying and acting, if there are no reassuring statements on the tin, then it makes sense to not trust it with mains or any other high voltage until it's dried and had a run-up with a megger.

Even if the switch cleaner is impeccable itself, non conducting and non flammable, there are no guarantees on anything it washes out.

David

[Nuvistor]

It’s probably a hangover from when I used Radio Spares switch cleaner in the 50’s/ early 60’s and I just kept to those ways.
In case anyone hasn’t seen it, it was very volatile enough to give you a headache in confined spaces and could melt various plastics, it could certainly move dirt and old grease.

[ms660]

From the Super Servisol 10 tech. data sheet.

"After spraying, always leave for at least 4/5 minutes to allow dispersal of solvent vapours, before operating the equipment."

Lawrence.

[Radio Wrangler]

There's a can on the top shelf...

Servisol "Switch cleaning lubricant"

"Spray onto switch contacts, relays, commutators, condensers etc," "Allow three or four minutes before operating" It must be older than Lawrence's can and they've been toughening up or else minutes ain't what they used to be. More likely they've changed the alcohol component to something more acceptable.

And then in large, unfriendly letters FLAMMABLE with the correct black on orange symbol.

"Keep away from sources of ignition do not spray on incandescent objects"

Clear enough I would have thought. Only someone especially daft would ignore all that.

David

[ms660]

Originally Posted by Radio Wrangler

It must be older than Lawrence's can

I don't have a can.

Lawrence.