View Full Version : Brown drop caps


madlabs
07-25-2016, 10:38 AM
Hi All,

Working on a parts order for my Predicta Holiday. I have quite a few older CD "brown drop" caps. As I understand it, those are film caps but they are older. Not sure of the date but I got them from one of my Elmers so I know they have been kicking around for a while.

Considering the PITA to pull the PCB's on the Predicta, is it foolish to use these? The parts bill is adding up and I would like to use 'em but don't want to be penny wise and pound foolish.

Thanks!

JOnathan

Electronic M
07-25-2016, 11:17 AM
Originals in sets are hit or miss and the same probably goes for NOS. If you use them don't use any on the board unless you want a small risk of having to pull it again.

If it was not a predicta I'd probably tell you to try them if you want.

madlabs
07-25-2016, 11:32 AM
Tom, thanks. I use them freely in radios but and have never had a problem so far. But it is generally very easy to get to them in a radio so I haven't been to worried. For the Predicta, I think I will just order new caps.

Jonathan

andy
07-26-2016, 02:12 AM
...

madlabs
07-26-2016, 08:55 AM
Andy, I do have the stuff to test them. But I guess I am too lazy! Not really, I should put together a little setup to easily test caps. Do you think if they test good they are likely to remain good for years? I have some of these caps in a radio I repaired a few years ago and it is a daily driver for the owner and is doing fine.

For the Predicta I already went ahead and ordered new caps. I was having a cheapskate moment, I had to buy tires for the car this week. Ouch! But considering the difficulty in removing the PCB in the Predicta it seemed wise to go new.

Thanks!

Jonathan

DaveWM
07-26-2016, 09:27 AM
test after removing, test before replacing, make sure you have the same value going back in to avoid 10/.1x errors. Test for leakage on new caps before install. rare but does happen.

madlabs
07-26-2016, 10:06 AM
I have to admit I have never tested new caps but I can see where it is a good idea, not just for weeding out defectives but to verify you have the right value. I have a number of 50uA meter movements, so I'll start gathering up the stuff to make a dedicated tester.

Jonathan

Electronic M
07-26-2016, 10:39 AM
Or you could buy a Heathkit C3 or similar...

DavGoodlin
07-26-2016, 03:25 PM
EICO model 950 is another tester that runs to 500 vdc (eye-tube 1629)