I have a General Electric mode 250 portable radio that I'm going to re-cap. In the power supply there are three .5 UF caps that have 2 leads on each end. They are C29, C30 and C34. The schematic is here:

http://www.nostalgiaair.org/PagesByModel/630/M0007630.pdf

Has anybody seen these before? Can I substitute regular caps with one lead at each end and tie the 2 wires that went into the originals together?

This is an interesting radio, it is powered by a (long gone) 2 volt lead acid battery connected to a vibrator and transformer to get the 90 volt B+. I bought a 2V Gel-cell battery from a Glider supply company (!) and the radio works but I'm only getting about 65v B+. AC goes into a step down xformer & rectifiers to charge the batt. So when running on AC, it gets stepped down, then stepped up again. Doesn't seem too efficient to me!

Thanks and happy new year,

Mark

Perhaps it's just two .5uf caps in each package with a common negative lead.
That's my guess... lol

:I have a General Electric mode 250 portable radio that I'm going to re-cap. In the power supply there are three .5 UF caps that have 2 leads on each end. They are C29, C30 and C34. The schematic is here:
:
:http://www.nostalgiaair.org/PagesByModel/630/M0007630.pdf
:
:Has anybody seen these before? Can I substitute regular caps with one lead at each end and tie the 2 wires that went into the originals together?
:
:This is an interesting radio, it is powered by a (long gone) 2 volt lead acid battery connected to a vibrator and transformer to get the 90 volt B+. I bought a 2V Gel-cell battery from a Glider supply company (!) and the radio works but I'm only getting about 65v B+. AC goes into a step down xformer & rectifiers to charge the batt. So when running on AC, it gets stepped down, then stepped up again. Doesn't seem too efficient to me!
:
:Thanks and happy new year,
:
:
: Mark
:
:
:
I'm looking at the print on your GE 250. That is an interesting set up. Looks to me you need six .5 capacitors and wire them as shown in the schematic. Seems all those vibrator power supply radios have some odd looking circuits. But it is some kind of tuned thing, and it's done that way for a reason.

Mark,

I took a look at the schematic.

I would suggest that you could replace these caps with a normal 0.5 120V cap as you suggested.

In the mean time, I will look through some of my old GE literature for a description of those caps.

Gary

:I have a General Electric mode 250 portable radio that I'm going to re-cap. In the power supply there are three .5 UF caps that have 2 leads on each end. They are C29, C30 and C34. The schematic is here:
:
:http://www.nostalgiaair.org/PagesByModel/630/M0007630.pdf
:
:Has anybody seen these before? Can I substitute regular caps with one lead at each end and tie the 2 wires that went into the originals together?
:
:This is an interesting radio, it is powered by a (long gone) 2 volt lead acid battery connected to a vibrator and transformer to get the 90 volt B+. I bought a 2V Gel-cell battery from a Glider supply company (!) and the radio works but I'm only getting about 65v B+. AC goes into a step down xformer & rectifiers to charge the batt. So when running on AC, it gets stepped down, then stepped up again. Doesn't seem too efficient to me!
:
:Thanks and happy new year,
:
:
: Mark
:
:
:

Looks like some type of feed thru cap. If you replace them with regular caps you may get more vibrator hash.
Are the existing one's defective ?
Bob

:Mark,
:
:I took a look at the schematic.
:
:I would suggest that you could replace these caps with a normal 0.5 120V cap as you suggested.
:
:In the mean time, I will look through some of my old GE literature for a description of those caps.
:
:Gary
:
::I have a General Electric mode 250 portable radio that I'm going to re-cap. In the power supply there are three .5 UF caps that have 2 leads on each end. They are C29, C30 and C34. The schematic is here:
::
::http://www.nostalgiaair.org/PagesByModel/630/M0007630.pdf
::
::Has anybody seen these before? Can I substitute regular caps with one lead at each end and tie the 2 wires that went into the originals together?
::
::This is an interesting radio, it is powered by a (long gone) 2 volt lead acid battery connected to a vibrator and transformer to get the 90 volt B+. I bought a 2V Gel-cell battery from a Glider supply company (!) and the radio works but I'm only getting about 65v B+. AC goes into a step down xformer & rectifiers to charge the batt. So when running on AC, it gets stepped down, then stepped up again. Doesn't seem too efficient to me!
::
::Thanks and happy new year,
::
::
:: Mark
::
::
::

removed 2 of the .5 UF double-lead caps from the power supply and here's a pic:

I checked them first on my digital cap meter and they read .65 UF, then on the Heathkit IT-11 cap checker and could not even get a capacitance reading. On leakage test, they show shorted at 10 volts and up! (Thus showing the importance of testing these old things at their rated voltage) Also the .003 UF/1500 volt cap on the secondary of the step up transformer is shorted.

Next, ohmed out the leads and the pair of terminals at each end are connected together so I guess I can replace them with regular .5s

So, as soon as my order from AES arrives, I'll replace them & see what happens.

Just to be sure, got out the heat gun, melted the wax & got them out of their tubes.. .The 2 leads on each end are one piece. Unrolled one & looks just like a normal cap, 2 layers of foil with wax paper between, all rolled up.

Mark,
So these are single caps? And the double lugs on each
side are just for convenience of having an extra place to connect to?
Bob

:Mark,
:So these are single caps? And the double lugs on each
:side are just for convenience of having an extra place to connect to?
:Bob

Exactly, the lug at each end is just a U-shaped piece of metal where the bottom part of each U is connected to one side of the cap.

Mark,

Thanks for disecting that cap and solving the mystery.

I must say, GE had a very "interesting" way of showing them on the schematic, sure made me think.

Gary

::Mark,
::So these are single caps? And the double lugs on each
::side are just for convenience of having an extra place to connect to?
::Bob
:
:Exactly, the lug at each end is just a U-shaped piece of metal where the bottom part of each U is connected to one side of the cap.

Mark,

Thanks for disecting that cap and solving the mystery.

I must say, GE had a very "interesting" way of showing them on the schematic, sure made me think.

Gary

::Mark,
::So these are single caps? And the double lugs on each
::side are just for convenience of having an extra place to connect to?
::Bob
:
:Exactly, the lug at each end is just a U-shaped piece of metal where the bottom part of each U is connected to one side of the cap.

Gary,

No problem, it was fun melting them! I've now replaced all the paper & electrolytic caps in the radio, also opened up the vibrator & cleaned the contacts. and... it actually works! Sounds pretty good too, though there's a fair amount of hum from the vibrator. Still not getting the full 85-90 volts B+, more like 75. Haven't aligned it yet, either.

What I like about this radio is it's built like a tank! case and chassis are made from cast metal, VERY heavy! With its transformer for stepping the AC down and vibrator/transformer to step it back up, this has got to be the most over-engineered radio I've ever seen!

Here's a pic of the inside, behind front panel, with new caps:

From front, with lid open. Loop antenna is in lid:

Back open, showing battery & vibrator:

:Mark,
:
:Thanks for disecting that cap and solving the mystery.
:
:I must say, GE had a very "interesting" way of showing them on the schematic, sure made me think.
:
:Gary
:
:
:
:::Mark,
:::So these are single caps? And the double lugs on each
:::side are just for convenience of having an extra place to connect to?
:::Bob
::
::Exactly, the lug at each end is just a U-shaped piece of metal where the bottom part of each U is connected to one side of the cap.

I have the same radio, and used to have a problem with low B+. Look at the brown cylinder in the upper left corner of the photo. It connects to R14 and ground. On the schematic you may miss it but that is (was) a 6 volt dry cell. It biases the 3Q5GT output tube and reduces it's load on the power supply. You will even get more volume and probably clearer sound. The only other thing to do is open the vibrator (mine is missing the cover) and clean and align the contacts. Good Luck!
:
:
:

OOPS! I also wanted to say I got a battery from Radio Shack that fit well enough that I didn't need to modify the radio to use it. http://www.radioshack.com/product/index.jsp?productId=2062138

::
::
::
:Anthony

Thanks Anthony! That's one thing I haven't gotten to yet. Will pick up a batt on the way home tonight & give it a try. I did open up the vibrator & cleaned/aligned as best I could.

Mark

:OOPS! I also wanted to say I got a battery from Radio Shack that fit well enough that I didn't need to modify the radio to use it. http://www.radioshack.com/product/index.jsp?productId=2062138
:
:
:::
:::
:::
::Anthony

Yup, that did it, picked up the battery at radio shack, popped it in there and now I have 85v B+. Less vibrator hum, too! I opened up the bias cell and it had 4 of the 1.5v acorn-shaped cells in series. Hope to get time to align it this weekend.

Thanks again, Mark

:Thanks Anthony! That's one thing I haven't gotten to yet. Will pick up a batt on the way home tonight & give it a try. I did open up the vibrator & cleaned/aligned as best I could.
:
:Mark
:
:
::OOPS! I also wanted to say I got a battery from Radio Shack that fit well enough that I didn't need to modify the radio to use it. http://www.radioshack.com/product/index.jsp?productId=2062138
::
::
::::
::::
::::
:::Anthony

Hi Mark,

There is a way to rejuvenate the 1.5V bias cells.

Carefully drill a small hole in the carbon disc. Be careful not to drill too close to the edge of the zinc button or you risk shorting the carbon disc to the zinc button.

Using a syringe, insert a few drops of water. Then u
Using a toothpick apply a small amount of silicone to seal the hole.

There are several posts on this site with more detailed info. It doesn't always work but it is worth a try.

I have done this with great success.

Gary

:Yup, that did it, picked up the battery at radio shack, popped it in there and now I have 85v B+. Less vibrator hum, too! I opened up the bias cell and it had 4 of the 1.5v acorn-shaped cells in series. Hope to get time to align it this weekend.
:
:Thanks again, Mark
:
:
::Thanks Anthony! That's one thing I haven't gotten to yet. Will pick up a batt on the way home tonight & give it a try. I did open up the vibrator & cleaned/aligned as best I could.
::
::Mark
::
::
:::OOPS! I also wanted to say I got a battery from Radio Shack that fit well enough that I didn't need to modify the radio to use it. http://www.radioshack.com/product/index.jsp?productId=2062138
:::
:::
:::::
:::::
:::::
::::Anthony

Hi Mark,

There is a way to rejuvenate the 1.5V bias cells.

Carefully drill a small hole in the carbon disc. Be careful not to drill too close to the edge of the zinc button or you risk shorting the carbon disc to the zinc button.

Using a syringe, insert a few drops of water. Then, using a toothpick apply a small amount of silicone to seal the hole.

There are several posts on this site with more detailed info. It doesn't always work but it is worth a try.

I have done this with great success.

Gary

:Yup, that did it, picked up the battery at radio shack, popped it in there and now I have 85v B+. Less vibrator hum, too! I opened up the bias cell and it had 4 of the 1.5v acorn-shaped cells in series. Hope to get time to align it this weekend.
:
:Thanks again, Mark
:
:
::Thanks Anthony! That's one thing I haven't gotten to yet. Will pick up a batt on the way home tonight & give it a try. I did open up the vibrator & cleaned/aligned as best I could.
::
::Mark
::
::
:::OOPS! I also wanted to say I got a battery from Radio Shack that fit well enough that I didn't need to modify the radio to use it. http://www.radioshack.com/product/index.jsp?productId=2062138
:::
:::
:::::
:::::
:::::
::::Anthony