I've just received an RCA 8TS30 and was checking the crt with my Sencore CR70. It shows no G1 or H-K shorts and high tracking, but no response to cutoff test or emission. Does the position of the ion trap influence these readings or do the results indicate a total dud? I've let the filament run all night just to wake it up prior to these tests. Any ideas?

no ion has nothing to do with that. Make sure you have the correct gun (red) and bias setting. Do not rejuvenate, its best to try it in the set and see what you get.

if you want to see if its working at all use a lower neg bias, that should get it going.

Indeed, sometimes you need to switch to a lower negative bias switch range. I find that quite a few tubes won't work at the specified bias range, but if they test good for emission with a reduced negative bias, they still seem to work quite nicely in a real set.

Tubes that are really dead won't give much emission at any bias setting.

If varying the bias has no effect, something else to consider is that the cathode might be open. Either from a bad connection in the base or inside the neck. try touching up the solder on the base pins. If it is ope inside the neck, it is possible to re-weld it using your Sencore.

would you be nice enough to give me the pin outs on the 10bp4 i have some i want to check with my cr70 using the universal adapter. thanks steve

Here is the 10BP4 data sheet with pinouts:

http://tubedata.tigahost.com/tubedata/sheets/049/1/10BP4.pdf

The tubedata website is a good one to bookmark. Data sheets for zillions of tubes.

Phil Nelson

phil thanks so much i did bookmark that site. it will be very usefull. steve

I see on the various threads showing the use of a Sencore CR70, that it doesn't have a socket for the old type B&W CRT's. Wasn't one available? Seems like one could make one easy enough. Just wondering!

The Sencore CR-70 seems to be the most taunted CRT tester. But, I have a CR133 that does have sockets for the 10BP4. But, the CR133 won't test 7BP4 electrostatic CRTs.

Carl


I see on the various threads showing the use of a Sencore CR70, that it doesn't have a socket for the old type B&W CRT's. Wasn't one available? Seems like one could make one easy enough. Just wondering!

The CR70 has a universal adapter with little clip leads for the older CRTs. A 10BP4 style adapter sure would be handy though. That's about 90% of what I use mine for :yes:

The old B&K 466 tester's built-in cable fits right onto early black-and-white CRTs. The adapters for other CRTs have plugs that are fully-pinned equivalents of the connector on a 10BP4 or similar.

Well I've finally finished the rebuild on the 8TS30 chassis and everything is working right. Picture and sound are excellent, tested with 8XP4 test crt and external speaker. The only remaining problem is that the 10BP4 picture tube that came with the set is completely shot and does not respond to any of the restoration procedures previously suggested in this thread. So... I'm looking for a 10BP4 A, B or C as available. Anybody got one they'd like to sell or swap something for? Please send me a PM.