Rcr1961
08-24-2013, 10:59 AM
I need a brightner for a 14BP4, I've never had to use one before but,
this crt is really on its last legs, and I need to do something till I can
get a replacement crt. The problem is which model of brightner do I use ?.
I see several on the bay that have the correct base, but how do I know
it will work on my crt ???.
Any info would be appreciated and, if anyone has a 14BP4 to sell, then I
wouldn't need the brightner !.
Thanks
Bob R.
kvflyer
08-24-2013, 11:07 AM
Bob,
You may want to start with the question of whether it is a parallel string or series string for the filaments. That should get you started. I think that there were even isolation transformer types for those situations where there was an H-K short...
Rcr1961
08-24-2013, 11:17 AM
It is for a parallel filament tv, Thanks
bob
dieseljeep
08-24-2013, 12:06 PM
It is for a parallel filament tv, Thanks
bob
Workman made one they sold as a Super Brightener. It boosted the heater voltage to 9 volts. It's surprising how much abuse those heaters could take.
I used them on the real "sickies". :sigh:
old_coot88
08-24-2013, 01:20 PM
:screwy:I've seen brighteners "bootstrapped", ie., a brightener plugged into a brightener, then into the CRT.
Rcr1961
08-24-2013, 07:41 PM
Ok, so most brightners just increase filament voltage, with
that in mind I made a voltage doubler, then ajusted a series resistance
till I ended up with 8 vdc across the filiment of the crt.
Now I can see the screen with the room lights on !, a vast improvment,:banana:
for as long as the decrepit 14bp4 lasts.
Anyone got a crt for sale ????, please let me know.
Bob R.
Tubejunke
08-25-2013, 12:14 AM
I have one that has a switch for series and parallel. That is my keeper, but I am fairly certain that I have some others. Sounds like your home made job did the trick for now. Great thinking!
kramden66
08-25-2013, 01:47 AM
i took a brightener that a set needed and put a resistor on it , the thing sent 10 volts to the crt , after the resistor 7 volts and that little extra is just enough to make a bright picture and better contrast , so thats an idea for others , this way you aren't constantly overdriving it and get a usefull picture out of it , if its too far gone then yes it will need more voltage.
i have seen rare cases where using a brightner for a hour or so after it is removed the picture is better then it was before and stays that way except for a slow time when the set is turned on but rarely does it stay that way.
mike
wa2ise
08-25-2013, 02:11 PM
maybe someone in your town has a Beltron, a machine that can fix up CRT cathodes. I used one on a weak CRT in a B&W RCA TV I have, and it made the CRT work without a brightener.