Stuck tubes

[mike hadley]

Most of the tubes are loose in their bases which appear to be stuck in their respective sockets, as these are in shielded covers I could try and push the tubes out from underneath the chassis, is there an easier way of doing it this and are there any ways to re attach the tubes in the tube bases once removed,
I have read about acetone to activate the old glue, or high temperature epoxy, even a shellac mix, any ideas

[Joseph W Strickland]

Mike;

What type of tubes are these? Are they Octal types or some of the earlier tubes with a combination of large and small pins arranged in a circular pattern?

I have used some of the two-part epoxy to glue replacement octal tube keying pieces to the bottom of octal tubes which sustained a broken-off keying piece. I have removed bases from Loctal tubes too which had come unglued, and reglued using two-part epoxy.

The octal tubes, if they have their glass envelope completely separated from the plastic bases, might be able to be separated from their base by sucking out the solder in the pins. Either by solder wick or a solder sucker. Once apart you can judge the condition of the glue remaining. I have had some whose glass I broke away to use for octal plugs on equipment. Often the brown glue that was used is also loose against the plastic base and parts of it will fall out. That pretty well says that the old glue used does not provide good adherence over time.

The inside of the base and the outside of the glass would need to be squeaky clean - no chemical residues or fingerprints etc. I would think that a high temperature epoxy would work OK. There are some epoxy glues available at hobby shops made specifically for gluing glass to glass or other hard materials. Some of these are clear just like glass. I do not have any personal experience with this type but it sounds like a possibility.

Let's see if anyone else has done this type of repair and how they did it.

Good luck.

Joe

[mike hadley]

Hi Joseph,

The tubes are in my allwave fifteen, they are of the latter variety, large and small pins,

from previous restorations I have removed tube from base and soaked the it in methylated sprits overnight, this dissolves the shellac in the cement and can be removed really easily leaving a clean base.

I have used epoxy in the past but I want to give the scott the best I can, I do have some high temperature stuff left over from making the voice coil former for the speaker (300f), maybe this will do.

[Joseph W Strickland]

Mike;

Have you had any success in dislodging the tubes? There is one tool that I thought of which might be useful. It is a tool somewhat like a flat-blade screwdriver but the end is at about a 45 degree angle which is made for working around the pressed-in-place lids of metal paint cans. It gradually allows the lid to be pried loose without bending it if done carefully. That same tool might be slid under the edge of a tube base and carefully worked around the tube circumference to get it loose from a socket. Your idea of pushing up on the pins from underneath might work too, but be a bit difficult depending on the position of parts underneath.

Let us know how this turns out.

Joe

[mike hadley]

Hi Joe

over the last few days I have managed to get all of the tubes out of their sockets,

as I also mess around with clocks and watches, I tried my homemade ammoniated clock cleaning solution, works like a charm,

the solution consists of, household ammonia, metheylated sprits in equal parts and a good glug of strong detergent, the cheaper the brand the better, this can be used neat or diluted, only problem is that it stinks!

turned the chassis over and applied a drop or two to the pin sockets, waited about half an hour and with a slight pressure the tubes just pushed out, only one was difficult, the bfo 56 tube.

Then a simple clean up, amazing really as these were really stuck and I thought that I may be looking at several new tubes, I already tried contact cleaner and they just laughed at this stuff,

oh by the way, don't get this mixture anywhere near old varnish, as it leaves a streaky matt finish, (dont ask me how I know)

[Joseph W Strickland]

Mike;

By metheylated spirits do you mean methyl-ethyl-keytone? It is sometimes referred to as MEK. I have used it in the past to clean phonograph motors with varnish and congealed lubrication inside. I would prepare a bath of MEK and drop the motor down in the MEK and apply power. Then let it sit in the bath for an hour or so. When it comes out disassemble the motor and do any additional cleaning or polishing of the rotor shaft with jeweler's rouge or crocus cloth. Add new light machine oil of your choice and reassemble. If the rotor does not rotate freely, a couple of raps on the side with a tack-hammer or something not too large usually will relieve the tightness and straighten any tilted bearing surfaces. Tighten hardware and reinstall in record changer.

I also saw your thread about the Wunderlich tube and a 3A5 substitute. That looks like a good choice. Hope it works out as you expect.

Joe

[mike hadley]

Hi Joe

Sorry I forgot about things having different names your side of the pond, methylated sprits is methanol, it's sold over here in the uk for decorating, I know that ethanol will work but for some reason it's not so effective, acetone will also work well in this mixture,

I now have further problems with the set, I think that there is a dead 56 in the audio section, will have to try swapping tubes out,

I have purchased a tube tester to check all of the tubes, this is the first scott I have owned, normally the old style four tube set types can be fixed with relative ease, but this is fighting me to the bitter end, already had the power transformer rewound, recapped the power supply, made a voice coil and reconed the speaker, as the radio has been stored somewhere damp both the chrome and cabinet have suffered, started to recap the set as a previous owner has left things hanging in mid air, what a mess, kent has kindly provided me with some bathtubs to restuff as the old ones have had the lugs cut off,

still I have been fixing stuff for too long to be put off

 Mike

[Joseph W Strickland]

Mike;

It sounds as though this unit is somewhat in the condition of a Hallicrafters SX-25 I restored a couple of years ago. It also had resistors and capacitors that were hanging in mid-air. It took some queries to owners of the same model here to identify where some of these were originally connected. To add to the confusion, some of the values had been changed.

You are a determined restorer. I am sure you will have success with this receiver just like others you have undertaken to restore.

Best wishes!

Joe