Just bought a Cornell Dubilier Capacitor Analyer Model BF-50

[dieseljeep]

Originally Posted by Tube TV

I don't know how a NP electolytic would work and you'd likely only be able to get 2.2 mfd and have to mix and match to make up the difference. You could try it. Myself I would stick to a film caps. Heathkit used big war surplus oil filled caps for this capacitor on the old model C1 condenser checkers.

I looked up the schematic for the Heath-kit C-1.
It's dated 1948! I think Heath-kit would've never survived without those war-surplus parts and tubes. A 12A6 for a rectifier? They used them in a few kits as both a rectifier and an output tube.

[Tube TV]

Originally Posted by dieseljeep

I looked up the schematic for the Heath-kit C-1.
It's dated 1948! I think Heath-kit would've never survived without those war-surplus parts and tubes. A 12A6 for a rectifier? They used them in a few kits as both a rectifier and an output tube.

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.....

[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?

[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.