B&K 1076 TV analyst

[DaveWM]

somebody pointed me to a crossover cap at parts express. Looks perfect.

[bandersen]

Cool! I thought they only had 100v caps ? Can you point me to the one you found ? I need to recap mine too

[DaveWM]

http://www.parts-express.com/pe/psho...=027-940&DID=7

if you want when I order I will get a couple extra, save you on the shipping as I will just put one in the reg mail.

I need to go over and see what else I need but will prob order in the next day or two.

[bandersen]

Originally Posted by DaveWM

http://www.parts-express.com/pe/psho...=027-940&DID=7

if you want when I order I will get a couple extra, save you on the shipping as I will just put one in the reg mail.

I need to go over and see what else I need but will prob order in the next day or two.

Sure, that's mighty nice of you

[bandersen]

How are you managing to recap the circuit boards ? Did you leave them in place or remove them ? Either way, it looks like a hassle!

[DaveWM]

I am going to leave them be, not sure about how those pins work that hold them in. I have a solder sucker iron that works great on PCB.

I hope to stuff the 3 section can tonight. I figure no hurry on replacing that NP cap since I just want to see if I can get it up and running thru the RF output anyway.

[DaveWM]

Banderson, can you confirm the value of C9a/b. Per the schematic it is a 50/50mfd both at 150v.

It should be a can on the bottom of the set on the left side looking at it from the bottom, closest to the power tranny. Mine was switched out.

[DaveWM]

oh and confirm the can is a common POSITIVE!

[bandersen]

Sorry, I have a couple 1077s which are a bit different. C9 is a 0.047 uF cap to the yoke test signal output. Mine do have a couple 10uF and a 20uF with positive to ground. They are for filtering the B- supply.

[DaveWM]

anybody else with a 1076 let me know. the bias cap (I think) in mine does not match up with my schematic. I just dont trust it since it does not look orig (the cap).


The 330 resistor comes off the bias supply diode to a 10uf section of the cap.

then a 3.3k resistor goes from that point to the second section a 50uf. This section is tied to the 3rd section a 20uf (so 70uf total).

from the 70uf total junction it goes to the V1 photo multilplier tube (blk stripe), and to 33k power resistor on a term strip (brw stripe). Che can is connected to a term strip that is rivuted to the chassis (not solderd just rivut). Per the can its a 50/20/10 350v on all POS can.

[DaveWM]

besides not being able to find this setup on the schematic i am concerned that it may not be orig to the unit based on bridging the two sections together. I figure if the factory wanted a two section cap it would have come that way.

[DaveWM]

of course the other problem is the schematic has a 9a/b pos can cap but I cant for the life of me find the b section on the schematic. I have already come across a miss marked cathode bypass cap (+ to ground) so my confidence in the schematic is not the highest.

[bandersen]

For what it's worth, here's the 1077 power supply schematic: http://www.bobandersen.com/images/B&...scan004001.jpg

It uses three separate caps for that bias supply.

[DaveWM]

I am just going to use a two section 10 and 70 uf and wire it the way it is. there are some other differences from the schematic, for one the schematic has two diodes in series, I assume for some kind of voltage drop across one of them. This one does not and it all looks original. May have something to do with the 3.3k resistor after the 330 ohm. Just going to assume it was working so will go with it.

[DaveWM]

whew done with the recap. only iffy thing is the dumb 10uf 450v caps are not clear on the negative.

they have cardboard on both ends (axial NSL brand), pinched on both ends.

Has a solid strip that has arrows in it pointing to one end. I am assuming this in negative since IIRC all modern caps ID the neg terminal.

I even scrapped one. Turned out the center of the cap was the negative. That threw me.