crt & tube tester question

[timmy]

i have the bk 440 crt tester and was wondering if anyone had the book to take a look at the schematic to check 2 resistors i have changed. one is right of the meter and the colors were lousy but it looks like a 20k and the other appears to be coming off one of the 3 lights on the front and that was burned and the colors tells me its a 10 ohm and probably 2 watt, it looked like brown, blk, blk,silver,i was getting something like 750k, cant be right but it was burned. the dynascan 500 i have i tried to test a 6x4 tube but i guess this tester cant test it or i just dont understand what its saying. it says i have to use a 510 socket panal whatever that means im really not sure. maybe someone can help me with these questions.the brown, blk,blk resistor i used a white stone wire wound type in place of the carbon one that was green in color.the white wire wound resistor i put in was 10 ohm 2 watt and the other one appears tobe red, blk, orange, silver which is 20k so i put 2 10k in series for 20k but the old one checks at 23k.thanks.

[stusnyder]

you can get the schematic at etestmanuals.com or bkmanuals.com or vintagemanuals.com. Or just do a search on bk440 and maybe you can find a free copy.

[timmy]

well i didnt find a free copy but there is one on ebay and i have to laugh because they took a picture of the schematic and a pic of the parts list and everything is listed so i printed it out and solved the problem. both resistors it turns out are 10k ohms one is 1 watt the other is half watt, thanks to ebay and who ever posted such a nice pic that i was able to print and read,lol,lol.....

[stusnyder]

cool...saved yourself a few bucks...now you can put that towards caps and resistors

[timmy]

well there is only 2 caps in this bk 440 everything else looks ok but this big resistor i think burned up because i tracked that line all the way to a crt socket and could be that it may have been used on a badly shorted crt to begin with or maybe someone tried to remove a short and press the button to long and burned the weak link, the resistor.this resistor comes right off the high voltage transformer.

[timmy]

i want to change the 2 caps in this bk 440 crt tester and 1 is a 5uf 250v electrolytic and the other is what they are calling a 0.1uf 1000v tubular cap, any suggestions on what kind of cap this is and what to use in todays caps, would this one be a mylar type? thanks all

[bandersen]

Polyester or polypropylene would be fine. Allied, Mouser and I'm sure others have 0.1uF caps rated for 1,000 volts and higher.

[timmy]

so i guess any solid type cap with those same rating, would polyester film be just as good?

[bandersen]

Originally Posted by timmy

so i guess any solid type cap with those same rating, would polyester film be just as good?

Sure.

[timmy]

do you know the bk 500 dyna scan tube tester, well i tested a tube i know that is good and it shows good on the meter but the short light glows very little would this be bad caps as well, because it is old and it all looks original.

[bandersen]

I'm not familiar with the 500.
It could be leaky caps. It could also be the tester is a little overly sensitive for the leak test. I have a Hickok that has a little trimmer for short sensitivity. You can make a good tube look bad or vice-versa by adjusting that control. There's a simple calibration procedure outlined in the manual for it.

Perhaps you have the manual for yours ?

[timmy]

i have the manual i downloaded but says nothing about calibration. but it says dont continue with the tube test if the short light shows but i continued and shows good.

[bandersen]

It's possible for a tube that has a short to test good. Your tester is probably testing the tube's emission. You an still get good emission with certain elements shorted. You can also damage your tester so I'd heed the warning in your manual.

[timmy]

ok well maybe tomorrow ill test it again and it also says to lightly tap the tube and see if the light goes out

[timmy]

hey guys i have literally hundreds of new electrolytics all kinds of values so i was thinking is it possible to substitute these caps, for a 450v 50uf i have a 450v 47uf and for a 450v 5uf i have 5 450v 1uf in paralle and for a 250v 20uf i have 2 250v 10uf again in paralle would this be useful in my tubetester and for crt tester for replacements? i dont think this cap would be close enough but ill ask you guys,for a 0.1uf 1000v i have a 5.6nf 2000v metallized cap would this be close to use? i dont know just how critcle these caps have to be not tomake a big difference in performance. thanks