Just bought a Cornell Dubilier Capacitor Analyer Model BF-50

[vortalexfan]

Originally Posted by Tube TV

Lol yeah. I forgot how they used the 12A6 as a rectifier. Just wire the grids to the plate and you're good to go. Come to think of it I think my tubes have JAN numbers on them. Those war surplus part must have gave Heathkit quite a edge allowing them to sell kits for far less than assembled equipment.

I loved mine till the transformer got some shorted turns between the some of the secondary windings and fried the wire wound pot for the main control. I still need to get around to rewinding the transformer. When it was working it was very accurate for both caps and resistors.

They must have got one sweet deal on all those post war parts. Might explain all the chicken head knobs on the equipment too. I wonder if the early scopes were running war surplus CRT tubes.....

All the caps used in this cap checker are capacitors I have in my stash the only capacitor I'm worried about being able to get is a .00112 uF cap that's in the 12A7 circuit somewhere, is that one a critical value or can that one just be replaced with a regular .001 uF cap and just be done with it?

[Tube TV]

Yeah that's a tricky on to get. It'll be a mix and match of .01 and a .0015 to get it.
You've got the value incorrect. It's .0115 MFD 2% 200 VOLT

I was checking through my caps and it's going to be a crapshoot of selecting caps that are that close, and I have to question how accurate my capacity meter is on my DMM getting that close of detail.

It's inportant to get it as accurate as possible as it is used in the bridge and I believe this is used on the low side of the scale for measuring small caps.

[vortalexfan]

Originally Posted by Tube TV

Yeah that's a tricky on to get. It'll be a mix and match of .01 and a .0015 to get it.
You've got the value incorrect. It's .0115 MFD 2% 200 VOLT

I was checking through my caps and it's going to be a crapshoot of selecting caps that are that close, and I have to question how accurate my capacity meter is on my DMM getting that close of detail.

It's inportant to get it as accurate as possible as it is used in the bridge and I believe this is used on the low side of the scale for measuring small caps.

Ok, yeah sorry, I was trying to remember the value off the top of my head as I didn't have the schematic in front of me at the moment, but either way, that's still going to be a tricky capacitor to replicate.

I'm assuming that the voltage of the capacitors doesn't matter in this case and I could go with 630 V capacitors and it would be fine, just the capacitance is what matters?

[Tube TV]

I think you're good with anything above around 50 volt.

[vortalexfan]

Originally Posted by Tube TV

I think you're good with anything above around 50 volt.

that's what I figured but I wanted to be on the safe side and ask anyways because I didn't want to mess up the accuracy of the device.

[vortalexfan]

I got my capacitor checker in the mail today, and it was packed really well, they even wrapped the box in paper just like how they used to do it years ago!

This sucker is much bigger than it looks in the pictures (and its heavy!)

this thing from what I can see looks like its never been touched except for that old power resistor and an unmarked capacitor, all of the rest of the capacitors in this thing are the original Cornell-Dubilier capacitors.

The control panel on this unit has a couple of patent dates from 1931 on it.

the rivets that held the control panel plate to the rear cover plate were all sheared off, so I'm gonna have to re-pop rivet the control panel board to the back cover and grind the rivet heads flush like the originals were.

Some of these capacitors are going to be tricky to get to unfortunately and its kind of cramped inside this thing.

[jr_tech]

The mysterious 21377 part, which looks like a capacitor:

https://antiqueradios.com/forums/vie...p?f=8&t=357126

jr

[vortalexfan]

Originally Posted by jr_tech

The mysterious 21377 part, which looks like a capacitor:

https://antiqueradios.com/forums/vie...p?f=8&t=357126

jr

Ok, so it looks to be a flasher device of some sort...

I'll leave that part alone.

[vortalexfan]

Well I checked the original 6E5 Tube (it was a coke bottle style tube) and it was a dud.

I also found a little black sheet metal shield looking thing inside the cabinet and I was wondering if it was supposed to be some sort of adaptor for the eye tube to adapt the eye tube opening to one of those slender non-coke bottle looking eye tubes.

[vortalexfan]

OK, so the 2.4 uF cap (C1) in this unit is listed as an AC voltage capacitor, is that correct or is that a typo in the manual?
I'm asking because there are no capacitors listed in mouser or digikey that's an AC rated cap at that value (no 2.4 uF 60 VAC caps.)

OK so an update, I removed the original 2.4 uF Cap from the unit and it looks like what they did at the factory was used a 2 uF 60 VAC capacitor in parallel with a .4 uF 600 VDC capacitor to come up with the 2.4 uF 60 VAC capacitor, which I ended up having to do something similar which was order a 2.2 uF 63 VAC (100 VDC) capacitor and then a .22 MFD 630 VDC capacitor which will be paralleled to come up with the 2.4 uF cap I will need.

unfortunately the .12 uF cap is turning out to be a tricky capacitor to locate (they list it as a capacitor that is available at Mouser but its not one that they keep in stock and the factory lead time is 22 weeks.)

[vortalexfan]

OK, so that green resistor you guys thought looked out of place and looked like it might of been replaced, its original to the unit, its R12 on the schematic for this unit, its the 15K ohm 5W WW resistor that bridges between switch 6 and 7 on the leakage test button panel, and it does actually have spaghetti sleeving on it, its really dark brown colored which is why it doesn't look like its got any on the leads in the picture.

[vortalexfan]

OK, so I was checking out the capacitors a little more closely in this unit and there are 4 mica capacitors that are not marked and I'm not sure what those are supposed to be, I was wondering if the 4 mica capacitors isn't the .0115 MFD capacitor, because otherwise I don't see any caps marked with the value .0115 MFD in this unit.

Also there seems to be some capacitors in this unit that aren't listed in the parts list/schematic for this unit, such as a second .12 MFD 400 VDC capacitor and a second .4 MFD 600 VDC capacitor (the first one was part of the 2.4 MFD 60 VAC capacitor.)

Any ideas as to what those caps might be all about?

[vortalexfan]

UPDATE: I figured out what the second .4 uF 600V capacitor was from, it was replacement for the second .5 uF 600V Capacitor that was in the unit, (which I was wondering why there didn't seem to be a second .5 uF 600V cap in the unit.)

Also I noticed that there was quite a bit of shoddy repair work done on this unit in the past (this was apparently owned by the US Government at one point in time as the case was etched twice with marks stating US-H920M and then OE-1968, and whoever was doing the maintenance on this device for whatever Government agency that owned this did quick and sloppy work, basically just did whatever they had to to keep it going), so I corrected a lot of shoddy repair work including relocating that green power resistor (which was original to the unit as it had the same part number listed as the manual listed for that particular part) so that it was going down along the bottom side of the switch array rather than the back of the switch array like it was previously.

[vortalexfan]

OK so I have a question about this unit, since the original 6E5 tube was DOA (open filiment) I'm going to have to replace the original 6E5 tube with another eye tube and the only semi functional eye tubes I've got (that produces a bright green glow) is a 6N5 and a couple of 6U5/6G5 tubes and the 6N5 eye tube I have is the brightest of all of the eye tubes I have.

My question is, could I use a 6N5 eye tube in this unit and this unit still work?

Any help with this matter would be appreciated.

[vortalexfan]

OK So I got the capacitor checker up and running finally, unfortunately my eye tubes I have are not very bright so I have to have the lights off overhead in order to see anything.

Any ideas as to what that black sheet metal shroud thing is that I was referring to in an earlier posting?
See attached picture below.

Also it seems like the flasher module (the C-D Part No. 21377) isn't working because when I was going through the various capacitor tests that are supposed to utilize that section (leakage tests) the eye tube didn't flash, and I was using really old paper caps that I would of thought would of triggered that function.

Also was this thing supposed to have test probe leads? I'm asking because there are standard sized banana plug inputs on the control panel that accept standard size banana plugs, and this thing didn't have any test leads with it when I got it.

Any help with this would be appreciated.