The PHILCO Phorum

Hello Gang:
Here's my story. I bought a Philco model 38-12 Code 121. It didnt work, replaced some caps and got it working. While cleaning the tubes, I noticed that the schematic said the DET-OSC tube was a 6A7.
Mine had a 6A8. The tube had a sticker that said it was replaced in 1947! Those 2 tubes are not interchanagable, are they? Could this have been modified so a 6A8 would work? The under chassis looked untouched. I had a similar problem on my Zenith that I posted a few days ago. What can I look for under the chassis? Need some Philco Gurus help on this .
Thanks, Buzz

If it has a 6A8, then somebody replaced the original 7-pin socket with an octal socket.

The 6A7 and 6A8 are electrically identical, but as mentioned above, the 6A7 requires a 7-pin standard socket, while the 6A8 requires an octal socket.

Indeed, a 6A7 is a 6 pin tube, while the 6A8 is an octal. Either the set has been modified or there was a production run change. This set was in the era where octal tubes were in pretty wide use.

BrendaAnnD Wrote:Indeed, a 6A7 is a 6 pin tube

Seven, Brenda:

http://www.nj7p.info/Common/Tube/SQL/Tub...p?Type=6A7

Hi guys.
You are right, this socket is an octal. Didnt notice it was diff from the others. Looks like a good job, not a hack job. So, i guess ill leave it as is, since it works ok..
thanks, Buzz

And the reverse might just happen today depending on what we have in the shop. Guilty as charged for some swaps. Try to leave a note somewhere in the set so the next person doesn't have to take a wild guess.