[Pepperoni]

The 7A6 tube on this 40-190 won't go all the way into its Loctal socket without extreme force. So much that I don't want to force it in. I've inspected the socket for solder globs, distorted locking ring etc. but I don't see anything out of the ordinary when I compare it to the other Loctal sockets.

What could cause this one to not want to lock in? Or even get past the locking ring. Tried a couple different tubes, same thing.

Pepper

[Dave]

Use a pick tool, needle file or something the same size of the tube pins & gently push it straight down into each opening of the socket. That should help loosen it up some. DO NOT USE ANYTHING LARGER THAN THE TUBE PIN!!! It will make things too loose which will cause arcing & carbon deposits and cause a whole new set of problems. You can also try using a fine grit sandpaper on the tube pins if they look dull.
Dave

[Pepperoni]

Thanks Dave! I played with the center post of the socket and for what ever reason the tube went in easier. Metal o-ring or something was hung up. I scrape all my Loctal tube pins to get them real shiny. I've seen a ton of problems due to dirty pins and even sockets with those things. Personally I'll take an octal over a loctal anyday.

The set is working but it just doesn't seem right. I hook up the original antenna to it (oval long box) and it receives stations but it's just week. Volume all the way up and it's just not as loud as it should be. So I'm working that problem now. I hook my 75' attic antenna up to it and it gets a lot better but still not what it should be.

Pepper

[codefox1]

I'd give it a good blast of deoxit. Then look through with a strong light on the other side and see if there are any obstructions. The center recepticle has no other function than locking the tube in. Should it be encrusted to the point of not being able to stretch enough to receive the tube, clean it out if you can. Else put in a new socket. Better that than ruining otherwise good tubes.

[Pepperoni]

You know I took a small screwdriver and flexed the center parts of the socket. Everything is flexible enough for the tube to just snap right in. Little baffling. The tube's in now so I'm just gonna leave it alone. Gotta figure out tis reception problem. It's just weak using the original antenna box but my big antenna in the attic improves reception considerably. Go back at it in the morning. Resistance readings are quite a bit off from what's called out on the schematic. Resistances inside the antenna box. May have to open that up.

Pepper

[Texasrocker]

Loctal tubes pins corrode easily. After scraping them shiney clean, ( I use a exacto knife),.. I then spray a small amount of WD-40 into a small container, dip in a Q-Tip, and then apply it generously to all the scraped tube pins. I also apply a small amount to the tube sockets top side on the chassis. Installing and then removing the loctal type tubes a few times helps assure the sockets connections make good contacts if they are dirty. Adding the WD-40 helps prevent oxidation from happening again in the near future also. Works for me. A oldtimer WW2 Radio tech taught me that trick many years ago.

[codefox1]

Agree. You can ask your dentist or hygieniest for a worn out scaler, which will still be plenty sharp for removing "Loctitus" from the tube pins. Deoxit with the cleaned tube as an agitator rocked around a bit finishes the task. Always bend the tube in the direction of the guide pin or "nipple" when removing , and you will be fine.

[exray]

As I understand it, Caig's Deoxit isn't much good on loktal pins because they are of some aluminum alloy that deoxit isn't suited for. WD40 has always worked better for me

[Texasrocker]

Agreed Exray! And never forget that WD-40 works better than deoxit for loosening up rusted control shafts on all old electronics!!, and seems the carbon traces inside jumps back to life also! If any old potentiometers can be saved, WD-40 can do it!! I keep a small can of deoxit on my bench just to be cool when the younger generation visits my shop, but I always use WD-40 instead loosening up and re-lubing old controls! Why?... it just works better!! That old WW2 tube tech taught me that also!! The Deoxit is a waste of unnecessary money, but it looks nice in the Can on my workbench to the youngsters!! I now invest in "Blue Shower" Electronics Cleaner when I can afford it, to clean out old dirty tuning condensers that my compressed air misses. A much "better" investment indeed! WD-40 ROCKS!! Use it and never look back my friend!!