WAS: TV Missing color diagnosis, CRT need rejunivation

Try unsoldering all 3 cathode pins then solder a fly lead to the dud cathode and give it brief dabs on the chassis - if the CRT is scrap anyway you've nothing to lose and I've found this sometimes wakes up a sleepy cathode!

Another thing that may work is to boost the heater voltage a little. Disconnecting the heater winding from both pins of the CRT and then powering it with a few turns of wire around the flyback core will work. It usually takes 3-5 turns of wire for the normal 6.3V. Note the brightness of the heaters before you start and then aim for something a little brighter with the new winding. If you have a true RMS volt meter, you can measure the voltage and go for something around 8 volts. A regular DMM won't give you an accurate reading for this application. Andy Cuffe

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And don't go overboard, I tried 5 turns on an old monitor once and the heater lit up light a lightbulb.

I use this setup to redo Sony CRT's. I don't know what type of T.V. you have, but it's the same basic setup. Be very carefull doing this!!!!

I would like to share this great tip with all you great helpfull Tech's

out there! This is only for Technicians who really know there way around the inside of a T.V.! Please don't just anyone try this!! If you

don't have a proper CRT rejuvinating set, this will be a great fix, for

an otherwise lost cause.

Sony 1 K problems, that is T.V.'s with the red, or green, or blue having too low, or high of an emission to get a raster due to the "blanking circuit", can be solved with an odd, & somewhat dangerous technique! With the set off, unsolder each cathode on the CRT board, then momentarily bridge the gap of each gun, one at a time, to see how much emission there is. You will have to raise the G 2 pot to get a bit

of raster in a darkened room! Next solder the two good cathodes (usually only one is out of gain specs), back, leaving the bad one. Now

this is where it gets dangerous!!! While the set is off remove the focus line from the CRT socket ( 5000 volts), & while the set is running, momentarily make contact with the unsoldered leg of the bad gun. Do this with caution, & at least five times. It will try to arc, but just keep a steady hand, & keep the wire with a good insulated tool

at the unsoldered leg only. Now, while the set is off, unhook the G 2 wire, & set it to about 200 volts DC unloaded, & charge a 100 uf capacitor @ 250 volts. Do this two, or three times, then discharge it to the unsoldered gun, while the set is runing. Do this charging, & discharging to the gun at least five times! At this point, you should see the bad gun get brighter, & brighter. I have done quite a lot of experimenting, & this will save a lot of those Sony CRT's, that would otherwise be toast. Grey scale comes back to within a close enough spec, to make the customer happy. Just don't give a long warranty. Hope

this helps you all out. Take care, Dani.

Monitors are a completely different can of worms! The heater supply is taken from the PSU instead of the flyback for a reason, the different line periods for different scan modes makes it next to impossible to accurately regulate heater power!