I was just wondering if a socket adapter was used on the B&K 400 to test a 10BP4 ?

I cannot get any emmision reading off this tube , and it says that G2 is open , but pin # 6 on the B&K has no connection on a 10BP4 .
The 10BP4 should be OK , I had some dull raster , and that was with original caps in the set .

Any ideas ? :scratch2:

I was just wondering if a socket adapter was used on the B&K 400 to test a 10BP4 ?

I cannot get any emmision reading off this tube , and it says that G2 is open , but pin # 6 on the B&K has no connection on a 10BP4 .
The 10BP4 should be OK , I had some dull raster , and that was with original caps in the set .

Any ideas ? :scratch2:

I don't know about the B&K 400, but my 465 doesn't use an adapter for the 10BP4. I would expect pin 6 of a 12 pin base to be used for G4 if a CRT has one. G2 on the 10BP4 is pin 10.

I'm not sure what it means by open. G2 should have infinite impedance so open would be good.

I have trouble with the socket on my 465. On some tubes it doesn't make contact very well.

John

My B&K 440 doesn't use an adapter either. I have trouble with making good contact on some tubes too. Perhaps the socket can be opened up and the contacts squeezed a little with needle-nose pliers ?

The socket will be somthing I look at .
Would I be correct that if G2 was open there would be no brightness ?

I think you're correct that if G2 were actually open, you would have no brightness. But I don't have first hand experience.

John

If G2 were open, you'd have little, to no brightness.
Open cathode might make a dim raster that is un controllable.
Pin 6 is a focus grid used on later tubes.
Bill Cahill

While it must be in the socket connection , I get almost no emission at all , it will move the needle less than 1/8"
Im going to retry this tonight and see what happens .....
I can see G2 , and the connection , and it appears to be well attached , it could also be a bad solder joint at the CRT socket .

So I checked and cleaned all the connections .
Still the same reading , with the lights off I can faintly see the G2 neon bulb lit on one side which is good .
But still no emission to speak of , maybe just a really tired 10BP4 .
I guess I'll know more once I get the recap done .
I pluged the set in when I got it , and there was dim raster , so hopefully this will improve with new caps .

What's my chances on picking up a used 10BP4 , and what is the price .

Sounds like your tube is very tired. Tried rejuvenating it?
That tube used to be very commonly used, so, you should be able to find a good used one without too much trouble.
New old stock ones are pricey, but, also a good option.
Bill Cahill

I gave it a few zaps about 3 seconds each with the B&K 400 on the low setting , no better reponse with the emission .
Should I try the medium or high settings ?
How long should I zap it for ?

I guess the emission is so low there are few electrons reaching G2 , actually it takes about a full minute before I get the G1 neon bulb to light up .
Must be pretty weak .

Should I try the medium or high settings ? - only as a last resort.

How long should I zap it for ? - no more than 1 second.

I prefer letting the tube cook at a slightly higher filament voltage for a few minutes rather than use the Intensifier. Especially if it's been sitting for years.

Do you have the manual for the 400? Here's an excerpt:

You should set the Selector switch to the Dynamic Intensifier-Lo position. Wait 15 seconds. Press the Dynamic Intensifier button momentarily. (Caution: Do not hold down the button over 1 second.) After the tube has been rejuvenated in this position, turn to Emission position on the Selector switch and check the emission again....

If the emission is over 300 you have completed the rejuvenation. One the tube has been rejuvenated, do not try to get more out of the tube by rejuvenating it again as you may destroy the cathode surface...

If the emission does not read 300 or better, try the Med position....

If the emission does not read 300 or better, try the Hi position....

If you cannot bring the emission current up by using the Hi position, the tube cannot be repaired and no attempt should be made to do any more to that tube :(

Done that , I had to push it to the high setting , and Im now getting 520 ua emission , and the G2 is lit up , not as good as G1 , but it is lit .:banana:
The emission was with the cut off control all the way , or with the emission button pressed .


Many thanks bandersen for the info . :thmbsp:

By the way what is the cut off control used for ?

Congrats. I'm happy to share what knowledge I can. My manual is a copy from another TV collector :)

...Cut-Off. This control is used to determine if the tube under test will cut off with the proper grid voltage.

To check the cutoff, turn the Selector Switch to the CUTOFF position. Rotate the cutoff control until the meter reads at the "Cutoff" line on the meter. If the Cutoff control pointer reads within the "good" range, the tube cut-off is good.

If not, the tube may still be usable but you may have trouble with the contrast, brightness, etc.

- Bob

Here's a link to a scan of the B&K 445 manual (http://www.bobandersen.com/manuals/B&K445_manual.pdf). It's pretty much the same as the 400 & 440 manuals.

You might also want to recap the B&K 400. Of course I'm assuming it has electrolytics like the B&K 465.

John

I don't have a manual for mine , thanks for the link .
After running for a while it has stayed at 400 ua .
The heater voltage on my B&K is about 5.8 V
I connected a 6.3V supply to it anf that raised it into 500 ua range .
at 7.5V it was 600 ua
The life test shows that its tired out .
However this is much better than the 0 emission reading I started out with .
My G2 problem was actually a bad neon bulb in the B&K , so G2 is OK .
Cutoff appears to be within limits .

My G2 problem was actually a bad neon bulb in the B&K

Don't you just love using vintage test equipment :D

Don't you just love using vintage test equipment :DThat's the best part !:yes:

John , there's one elctrolytic 50 mfd 150 V , or somthing like that , and a .1 1000 V wax paper cap in the 400 , Most likely both are shot .
Also a small selenium rectifier .
One of these days pretty soon it's going to get those changed .