Wireing of a 10BP4
 

I was given a 10BP4 today that appeared to be dead. No heater no emissions.

I resoldered the pins and got the heater to show some life but still no emissions.

I removed the cap to do a little further cleaning but as I looked at the CRT I could see that the CRT is not numbered is the same way as the cap. What would seem to be wire 10 on the CRT is cut off and wire 9 (grid #2) is soldered into pin 10 on the cap.

Is this the correct wireing, wire 9 into pin 10?

If the heater is working shouldn't I expect to see a least a small amount of emissions or is it possible to have a working heater and no emissions? My tester doesn't indicate any shorts.

Thanks

Here is the 10BP4 data sheet, if that's any help.

http://tubedata.tigahost.com/tubedat...49/1/10BP4.pdf

Phil Nelson

Thanks Phil,

Just to make it a little more interesting while cleaning the CRT leads for resoldering I managed to brake one off. I remember from an earlier thread that Eric managed to resolder a broke lead back on. I had no luck for some reason my solder doesn't want to stick. may be that I need some soldering flux..

With the short lead, the glass will act as a heat sink, so you may need a bigger iron. Also make sure whatever is left of the lead is clean. Rosin core solder should work fine if the wire is clean.

Kevin

I had to scrape around the wire with a sharp pick to remove some of the glass, then I cleaned the wire and tinned it with some plumbers acid flux.

My connection was tenuous but sufficient to get the job done.

As for the other question, the heater wires go to pins 1 & 12, the others go in order to the pins on either side of those two, i.e. all five are consecutive, no skipped spaces.

I think I have a Drummel around somewhere.. I noticed that the glass around the wires run relatively deep into the tube and rises a little higher on the outside of the tube. I'll try to remove as little as possible but right now the wire only extends about a 32nd to a 16 inch above the glass.

I am keeping in mind that I don't know if this CRT is good or not afterall it didn't show any emissions even when I got the heater to come one for over a minute..

Good news and bad news.. I managed to get the broken wire soldered back on and the cap as well but during the whole process the heater got burned out.

When I tested the tube after making the repair I couldn't get the heater to light up. I tested for continuity but found the heater open. I removed the cap again but couldn't get a short on the heater no matter what I did..

I guess I burned it out during the resoldering work.

One less 10BP4 in the world and it's all my fault.


:tears:

Your CRT was likely very gassy to start with, and the heater was bound to burn out eventually due to the presence of gas (oxygen and nitrogen) in the tube. This would also explain your lack of emission. So you probably did not cause the demise of he CRT, it was doomed.