You may check out the EnerSys Cyclon 2 volt E & J series of cells. Or perhaps the Powersonic PS-260 might work. Maybe with a little bit of modification.
Clifton
:When I went to electronics school, we always called G.E. "generous electric". Working on old G.E. things we found out that G.E. had their OWN way of making things, regardless of what someone else thought or did. After looking at my 3 G.E. 250 RECHARGABLE VIBRATOR sets built back in 1946 and reading both Sam's and Rider's, a bias cell was used in both circuits. At first I thought it was a mistake but now I found out it is real!! Here's the question: Wnen a bias resistor is used in 250 G.E.'s and NOT in all the other circuits of G.E. sets and other makes and models, WHY,WHY would G.E. CHOOSE TO use a bias cell instead of a resistor???? Does it have something to do with the fact that a 2 Volt battery is used in the set??. Could a bias resistor be used and what would be the result if a bias resistor was used??. If a person was to use a resistor, how would the correct value be determined? By trial and error or by using the tube manual and guessing?. A resistor would give a negative grid load to the 2nd detector-1st audio stage and be a LOT,LOT more stable. I haven't had much of a chance to really get involved with research on it yet, but hopefully later on I can get to it. The 250's are almost impossible to find and the battreies are DEFINATELY impossible to find. I have 3 of these sets at home and the tubes and looks of these sets are fantastic!!!! The vibrators are in good shape also.Probably not worth a lot but I've had them for a LONG, LONG time. .Since high school and a younger age. The battery was a WILLARD 25-2 out of CLEVELAND. Maybe another can be substituted, either a NI-CAD or some other brand of LEAD-ACID.There's not a lot of room in the battery compartment--2.5sq. in. around the bottom and about 6in. high.There are two plug-in holes in the battery for two prongs in the chassis. Can anyone help out???? All replys will be greatly, greatly appreciated!!!!
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Raymond:
The reason that GE used a bias cell was, in order to save battery power, the tubes are directly heated, they have no cathodes. It is very difficult to put a cathode resistor in a circuit without a cathode.
Lewis
:
A lot of designs are done in certain ways for no other reason than the engineer prefers it. He may give all sorts of reasons of why this is the "best way" but usually it's just that he's done it this way before, it worked, and sees no reason to change. Then the next guy will come along and do it the way he thinks is "best".
I also have a GE 250 radio. I am using a sonnenschein a502/10s 2V Gel Cell. It is smaller than the original battery so it fits in the compartment no problem. It charges and runs the radio just fine. I can't remember where I bought mine (in 2009), I think it was an aircraft supply place I found on line. Google "sonnenschein a502/10s" and there are plenty of places that sell them.
Good luck,
Mark
P.S. make sure you make the leads from the batery to the chassis as short as possible. When I first installed mine I was temporarily using clip leads coiled up and was ghetting TONS of "hash" from the vibrator. Thought there was still something wrong, turned out that when I perminantly installed short (about 3 inch) leads for the battery, all the hash went away.
:When I went to electronics school, we always called G.E. "generous electric". Working on old G.E. things we found out that G.E. had their OWN way of making things, regardless of what someone else thought or did. After looking at my 3 G.E. 250 RECHARGABLE VIBRATOR sets built back in 1946 and reading both Sam's and Rider's, a bias cell was used in both circuits. At first I thought it was a mistake but now I found out it is real!! Here's the question: Wnen a bias resistor is used in 250 G.E.'s and NOT in all the other circuits of G.E. sets and other makes and models, WHY,WHY would G.E. CHOOSE TO use a bias cell instead of a resistor???? Does it have something to do with the fact that a 2 Volt battery is used in the set??. Could a bias resistor be used and what would be the result if a bias resistor was used??. If a person was to use a resistor, how would the correct value be determined? By trial and error or by using the tube manual and guessing?. A resistor would give a negative grid load to the 2nd detector-1st audio stage and be a LOT,LOT more stable. I haven't had much of a chance to really get involved with research on it yet, but hopefully later on I can get to it. The 250's are almost impossible to find and the battreies are DEFINATELY impossible to find. I have 3 of these sets at home and the tubes and looks of these sets are fantastic!!!! The vibrators are in good shape also.Probably not worth a lot but I've had them for a LONG, LONG time. .Since high school and a younger age. The battery was a WILLARD 25-2 out of CLEVELAND. Maybe another can be substituted, either a NI-CAD or some other brand of LEAD-ACID.There's not a lot of room in the battery compartment--2.5sq. in. around the bottom and about 6in. high.There are two plug-in holes in the battery for two prongs in the chassis. Can anyone help out???? All replys will be greatly, greatly appreciated!!!!
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