Finals for president Madison

[kritic]

Hi Guys
I have a president madison that just blew the finals and 1 of the finals blew right in half and I cant read the number on it. Would anybody have the numbers on these finals so I could order a new one. Thanks in advance

(Transmit and receive finals)

Kritic

[Sandbagger]

Aug 15, 2011 18:35:44 GMT -5 kritic said:

Hi Guys
I have a president madison that just blew the finals and 1 of the finals blew right in half and I cant read the number on it. Would anybody have the numbers on these finals so I could order a new one. Thanks in advance

(Transmit and receive finals)

Kritic

First off, there is no such thing as a "receive final". The "final" transistor is the power amplifier stage of the transmitter. Typically radios like that can use a 2SC1969, a 2SC2312, or a 2SC1307. The bad news is that they're no longer made (Thank those damn Europeans and their strict regulations), and supplies are getting thin. Searching on the Internet will likely find you the part you need. But brace yourself for the price. But before that, make sure it is really the "final" that blew. If it actually broke in half, that would mean a short, and a heavy current draw, which may have damaged other parts in the chain.

Make sure the transmit driver transistor is not also bad.

[cbrown]

I believe the final transistor is a 2SC1307, and the driver is a 2SC1306. As Sandbagger mentioned, they are a tough find.

You may be able to replace them with a 2SC2166 driver and a 2SC1969 final, but getting the bias right on the 2SC1969 may take a little work.

Your other option is to look for a donor Madison that someone hacked and didn't destroy the transistors.

[Sandbagger]

Aug 16, 2011 9:05:15 GMT -5 cbrown said:

I believe the final transistor is a 2SC1307, and the driver is a 2SC1306. As Sandbagger mentioned, they are a tough find.

You may be able to replace them with a 2SC2166 driver and a 2SC1969 final, but getting the bias right on the 2SC1969 may take a little work.

Your other option is to look for a donor Madison that someone hacked and didn't destroy the transistors.

Or a donor of any Uniden SSB chassis radio. Anything from President Washingtons, to Realistic TRC-490s and 450's, to Cobra 148's will do. Lots of potential parts donors out there.

[kritic]

Thanks all for the replys... Ill be taking it to the repair man

[cbrown]

Aug 16, 2011 9:43:34 GMT -5 Sandbagger said:

Or a donor of any Uniden SSB chassis radio. Anything from President Washingtons, to Realistic TRC-490s and 450's, to Cobra 148's will do. Lots of potential parts donors out there.

Right, should have mentioned the other similar chassis radios. Thanks Sandbagger!