Old Roberts radio repair?

[tonytech]

Carbon tet is now regarded as extremely toxic and harmful to the environment.
We used to use it in school because it has a refractive index close to glass......
Now its a big BIG No NO.

T

[bigherb]

Yeah I had to go back to sniffing benzine

[Bowton Lad]

Carbon tet is now regarded as extremely toxic and harmful to the environment.
We used to use it in school because it has a refractive index close to glass......
Now its a big BIG No NO.

T

CTC was used in fire extinguishers from 1912 until the 1950s when it was banned because it is toxic.

[tobydog]

Carbon tetrachloride was a good cutting fluid for machining hard metals from my toolmaking days.

Dichloromethane and pure acetone also had a verrrryyyy nice aroma.

[Oldiebut goodie]

Mmmmmmmmmmmmmmm.............Acetone now that is nice Just used loads cleaning the bilges prior to fibreglassing a fuel tank in position.

[tonytech]

Carbon tet is now regarded as extremely toxic and harmful to the environment.
We used to use it in school because it has a refractive index close to glass......
Now its a big BIG No NO.

T

CTC was used in fire extinguishers from 1912 until the 1950s when it was banned because it is toxic.

My Dad served servicing flying boats in Northern Island during the 2nd WW, I've got his notebooks detailing fire fighting with C tet.

[ghost123uk]

Most of the suggestions so far are just plain wrong and some will damage the "pot" (potentiometer) beyond repair, though as has been said, a new one will be less than £5 and easy to fit if you are ok with soldering.

Tobydog had it right, here are some more info on the stuff you need = HERE. My source = 30+ years as an electronics engineer

[dave friday]

Ok ghost ,when I started work as a tv service engineer in 1958 carbon tet based switch cleaners were the only type of switch cleaner available...later Servisol was a bit better but Electrolube was the best.for cleaning video tape recorder heads denatured alcohol was the best as it didn't leave any residue.
The problem with cleaning silver switch contacts is that to stop the contacts tarnishing there has to be something to stop the air getting to the contacts,so...oil!?.
No sign of the "op"have we frightened him/her off?

[ghost123uk]

Agreed with that Dave, though personally I would not put oil on a carbon tracked pot. Proper switch cleaner every time for me (though I remember when they changed the formulation of Servisol when it went "CFC Free" and it was nowhere near as good after that, but still good. I have used Vaseline to good effect on normal switches, after cleaning them, for the reasons you state.

I bet like me you used Acetone to carefully clean heads with a cotton bud (carefully because as you will know, but others may not, it dissolves many plastics ) It is also brilliant for cleaning pinch rollers. It seems to "leach out" all the crud and leaves the pinch roller soft and rubbery again, like the texture of a school eraser. That in turn makes the tapes (remember those) track across the head much better, with no vertical "creeping".

Now, discharging CRT's =

[New Kentish Campers]

Now, discharging CRT's =

Our bench technician used to discharge them [when replacing tubes] using one screwdriver in the little hole where the 'tripler' lead went, and another touching across it, to discharge into quite an impressive large spark across onto the metal shield around the crt [with the set off, obviously] I presume he's still alive

[dave friday]

Yes one screwdriver in the eht hole and another screwdriver from the aqudag sp? To the first screwdriver!
We/I use to change valves without switching the set off,I have a burn mark on the end of my left index finger (eht )!!,live chassis etc (no health and safety !!)

[voodoopenguin]

Many thanks for all the responses to my query, gives me something to try.

Paul

[ghost123uk]

I have a burn mark on the end of my left index finger (eht )!!,live chassis etc

I have a burn mark on my left wrist that was from a CRT that had not been powered up for years. I couldn't / didn't believe it would still have a charge in it !

[voodoopenguin]

Took a while to get round to buying some contact cleaner but did today. Took a couple of swigs and the radio sounds fine now, no crackling.

Thanks to all,

Paul

[Oldiebut goodie]

I think we had forgotten what the original query was!
Were we helpful enough amongst the 2 pages? (you were supposed to use it on the pot not take a couple of swigs - urrrrghh......)