Rejuvenating CRTs - UK Vintage Radio Repair and Restoration Discussion Forum

6.3volts · 28th May 2010, 8:30 am

Can anone advise me about using a crt rejuvenator? I recently bought a BK Precision 467 and had hoped to test some 'sad' tubes. Nowhere is there any info on what to do with a Triode tube as all the tests and rejuvenations are to A1 which doesn't exist. Has anyone had experience of working with triode tubes and could advise me.

Kilham1 · 28th May 2010, 12:10 pm

The 'reactivation' is done by passing current between the grid and cathode just the emission test measures cathode to A1 current.
TBH it's usually not that effective anywy and you might be better just running the CRT with a slightly higher heater voltage for a while to see if it 'picks up'.
If it is almost dead you could try building a reactivator that measures grid current.

murphyv310 · 28th May 2010, 12:52 pm

Hi.
I don't think its possible with the B&K as you say A1 is tied into the test, but I do believe its possible to "Boost" a triode with the B&K, one think use the Clean & Balance setting, some of the old tubes are a little fragile and you can (i've done it) blow the cathode O/C.
Good Luck

Danny · 30th May 2010, 10:15 pm

hi i use a 467 for this its astrange machine though i had my 467 since new and its always read low when used to test tubes but im used to it. as for boosting tubes it is a hit and miss some come up ok and some just dont whan to know. do remember to set your heater control down when you have finished . As if you forget and connect up to a mazda with the voltage set to high "its by by heater" The clear shorts works well so does the leakage neons . you will of course need to make up a universal base for it so you can test the golden oldies. Danny

28th May 2010, 8:30 am	#1
6.3volts Pentode Join Date: Nov 2009 Location: Welshpool, Powys, UK. Posts: 121	Rejuvenating CRTs Can anone advise me about using a crt rejuvenator? I recently bought a BK Precision 467 and had hoped to test some 'sad' tubes. Nowhere is there any info on what to do with a Triode tube as all the tests and rejuvenations are to A1 which doesn't exist. Has anyone had experience of working with triode tubes and could advise me.

28th May 2010, 12:10 pm	#2
Kilham1 Retired Dormant Member Join Date: Apr 2010 Location: Kelso Posts: 6	Re: Rejuvenating CRTs The 'reactivation' is done by passing current between the grid and cathode just the emission test measures cathode to A1 current. TBH it's usually not that effective anywy and you might be better just running the CRT with a slightly higher heater voltage for a while to see if it 'picks up'. If it is almost dead you could try building a reactivator that measures grid current.

28th May 2010, 12:52 pm	#3
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,422	Re: Rejuvenating CRTs Hi. I don't think its possible with the B&K as you say A1 is tied into the test, but I do believe its possible to "Boost" a triode with the B&K, one think use the Clean & Balance setting, some of the old tubes are a little fragile and you can (i've done it) blow the cathode O/C. Good Luck __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

30th May 2010, 10:15 pm	#4
Danny Heptode Join Date: Jul 2003 Location: North Walsham, Norfolk, UK. Posts: 516	Re: Rejuvenating CRTs hi i use a 467 for this its astrange machine though i had my 467 since new and its always read low when used to test tubes but im used to it. as for boosting tubes it is a hit and miss some come up ok and some just dont whan to know. do remember to set your heater control down when you have finished . As if you forget and connect up to a mazda with the voltage set to high "its by by heater" The clear shorts works well so does the leakage neons . you will of course need to make up a universal base for it so you can test the golden oldies. Danny