Later B&K 1077B

[Geist]

Hi All;
I have a B&K 1077B, which is different than the other two that I have.. One is that its uses a different CRT, the base where the socket plugs in is smaller in Diameter than the others and it has foil wrapped around its neck.. The others are the 5BP4 variety, can't say for sure, as the number is no longer on the tube.. Also on the Board below the neck of the tube, on the right side, while looking at the front of the B&K unit.. That Board has two IC's, they both are cmos 4013's.. Anybody else have these later units and can anyone tell me what the IC's do ?? My schematic doesn't have any Ic's..
THANK YOU Marty

[Kevin Kuehn]

The two 4013's are used in a divide-by circuit off of the color crystal oscillator, to generate the horizontal scan frequency. I can email you a scan of the schematic.

[Geist]

Hi All;
Kevin, Yes, Please.. Do you need my email address ??
THANK YOU Marty

[Kevin Kuehn]

Yep, I'll send you a pm.

[Kevin Kuehn]

On second thought those two 4013's are not used as divide-by from the color crystal oscillator to create the horizontal frequency. I'm not sure, but I think they are using them to sync the color bars to the horizontal oscillator frequency.

[Kevin Kuehn]

Here's the early version of this circuit, as posted on Phil Nelsons 1077B page.



And the later version utilizing the two 4013's.