How to clean loctal tube sockets?

[cbenham]

The Philco set in my avatar has several loctal tubes that cause interruptions in the picture and crashing noises in the sound.

I've cleaned the tube pins, cleaned the socket contacts, tried NOS replacement tubes, checked for cold solder joints and wires that were never soldered in 1950 on the sockets.

The top of the sockets have a light colored cover that I've never tried to remove for fear of doing irreparable damage to them.

Anyone know some good tricks to making these 60+ year old sockets reliable again?

Thanks for any help.

Cliff

[Eric H]

Are you sure it's the sockets causing the problems?
What you are describing sounds a lot like bad Mica Caps.

[Reece]

Loctal tube contacts are problematic. The pins corrode and have to be scraped clean. Some clean out sockets using welding torch cleaning tools. I would try scraping the tube pins and spraying them with contact cleaner, then plugging and unplugging several times when wet. The sockets may have been loosened up by people pulling the tubes without knowing how. To pull a loctal, it has to be tilted in the direction of the bump on the metal base. Otherwise the socket can be damaged.

[earlyfilm]

Originally Posted by cbenham

The Philco set in my avatar has several loctal tubes that cause interruptions in the picture and crashing noises in the sound.

Anyone know some good tricks to making these 60+ year old sockets reliable again?

Cliff,

I've not talked to one of those little buggers in 50 years, but the way we handled them in the late 1950's was to see if the set trouble was possibly in the circuit where the loctal was, and if not, leave the thing alone! It was SOP to never pull them for routine testing.

However, if the set issue indicated a possibly the loctals were at fault, we would attempt to pull the tube, which could be extremely difficult if a mouse had visited the set.

After testing the tube, we polished the locking clamps on the socket and tube base, with a rag wet with GC tuner cleaner. We then soused both the socket and the tube base with cleaner and inserted and removed the tube half a dozen times. Since GC tuner cleaner was a conductor when wet, we let the set dry at least 12 hours, then reinserted the tube, and started normal service procedures.

At that time, one could still buy replacement sockets, but the only ones I remember replacing happened after mice visits.

James

[Reece]

They are still available for sale: I Googled "loctal socket" and found a number of sites selling them. Hope you don't have to replace any!

[snelson903]

harbor freight tools, if you have a store near you is were i got a pretty good tourch tip cleaner for a buck or two its not industrial but good enough for cleaning sockets also, they have a large selection of small wire brush cleaners any sizes works good for cleaning contacts switches ex . and vary small file assort. they also a wire brush that looks like a tooth brush good for cleaning tubes themselfs at the base [ be gentel when cleaning with wire brush tube pins ] and contact cleaner its automotive try there stuff.

[cbenham]

Originally Posted by Eric H

Are you sure it's the sockets causing the problems?
What you are describing sounds a lot like bad Mica Caps.

I thought about that, but when I reseat the tubes, the problems stop and
the set runs well.
If I tap on the chassis near the tubes, the problems return.

I'll rule out the micas for the moment unless physically cleaning the sockets via the suggestions offered here don't work.
Thanks,
Cliff

[compucat]

It is interesting that this thread came up about loctal sockets because I have a favorite Philco five tube radio (model 47-250 I think) that I have not used in a couple of months. I plugged it in to listen to Coast To Coast AM and I get background static like thunder crashes all over the dial. The set uses loctal tubes and I suspect those very narrow pins are not making good contact. I restored it about three years ago and it has been very reliable. I guess it is time for a little routine maintenance. Philco loved using those tubes but I think the regular eight pin octals are a better choice.

[Phil Nelson]

CAIG sells a little stainless steel brush that I have used for cleaning sockets.

http://store.caig.com/s.nl/it.A/id.2...2&category=202

Phil Nelson

[noisebox]

If you need to replace a loctal I've found these are the best. Very sturdy and great pin contact system.

http://tubedepot.com/sk-8pinl.html

[miniman82]

I've replaced loctal with octal before, on a split chassis Philco. The 7N7 tube used as an oscilator was bad, but I didn't have any spares. Fix was to put a 6SN7 in it's place.

[compucat]

Originally Posted by noisebox

If you need to replace a loctal I've found these are the best. Very sturdy and great pin contact system.

http://tubedepot.com/sk-8pinl.html

I have bought those sockets before. They are very sturdy. Far better, I think, than the originals. Changing tube sockets is a big repair with a high margin for error.

[compucat]

I opened up the Philco and did a good cleaning of all the tube sockets. The loctal socket for the converter tube was dirty causing weak reception. Also there was a lot of fine dust inside the radio. After a good cleaning, dusting and a little Deoxit, the set works like new again. It is a 46-250 and those loctal sockets can be problematic.

[Mal Fuller]

I don't have a loctal socket nearby to refresh my memory, but it seems to me that the loctal socket's contacts could be bent closed from underneath using a small pick or screwdriver to restore contact tension. I don't remember having to replace any loctal sockets, but that's not a sure sign that I never had to change one.

[snelson903]

your right ,after cleaning just alittle bend or slight moving it over to center.