The AM Forum

Cleaning the original tubes for the BC-610H...

This morning I began unwrapping each of the original tubes for the BC-610H I am currently restoring.
Each tube was carefully wrapped in newspaper over 30+ years ago...

Each tube was filthy, basically caked on dust...
I gently dry wiped wiped down each tube, watching not to remove the glass labeling. Then a damp terry cloth, then a dry buff....

Some tubes already had the paint labeling worn off...

I did notice one of the 807's and both 32B8's base's were slightly loose.

Also one of the 807's top cap came off and was found at the bottom of the box.
The anode of the top was not harmed or the area were the anode enters the tube at the very top appears sealed.

I know that I can re solder the top cap, but what can be used as a adhesive for the cap and also the same for the bottom base?

I've come across this product while doing a search...

http://www.emissionlabs.com/datasheets/glue.htm

Any inexpensive suggestions to repair then into a tube tester?

Thanks...
Len

Furnace cement can be used after the glass is cleaned and anything loose in the cap is removed.

Moisten both, apply cement, hold down cap and solder the lead. Just filament voltage is required to cure overnight and wipe off excess with a damp sponge.

Some have used superglue but Ive also seen photos of fractured glass as the stuff expands when cured.

Carl

Much appreciated...

Tks Carl....

I've used JB Weld with good results for plate caps.

YMMV

Craig,

I've never had a problem with superglue for loose bases on smaller tubes including 3B28's.  I use the thin consistency, not the gel.  If the original cement is still intact, but no longer attached to the envelope, you only need the littlest bit of glue to rebond it to the glass.  I've also used superglue on anode caps of 866's and 811's but it doesn't hold too well.

I don't know what it is about 3B28's but I believe every one of mine have has had the base re-glued.

Thanks for the info it is very much appreciated...

Also looking at the tubes carefully....I noticed that 2 tubes are listed as 6L6W and 6L6WGB

The transmitter calls for 1 6L6 and a 6V6WGT.

It appears as though one of these tubes were subbed for the 6V6WGT.

If I remember correctly, the 6L6 has a a higher plate voltage than the 6V6 so you can sub a 6L6 in the 6V6 spot...

I need to check my substitution manual to confirm...

Any 6V6 will be fine, its not running in a comm trailer towed thru the battlefield and doesnt need a mil spec ruggedized version. Same with the 6L6, any flavor will do.
Depending where its used a 6L6 in place of a 6V6 might give excessive output.

Carl