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41-280, need help with tube ID - Printable Version

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41-280, need help with tube ID - Elrick - 01-14-2010

Hello, I'm newly registered but have been through many posts and other sites but I need some help from the experts. I'm working on getting my Great grandmothers' Philco 41-280 back up and running. My question is regarding the tube identification. There are two Audio Out tubes marked 41. Anyone know a cross reference identification number for these tubes. The only tube tester I've located in my town doesn't even accept this socket and they couln't provide me with a alternate tube ID in theircode booklet. I do know that Philco 84 tube in this set is also known as 6Z4. Thanks in advance and I'm sure to be around asking for advice as things proceed.

Re: 41-280, need help with tube ID - Raleigh - 01-14-2010

Elrick, the tube cross reference at Nostalgia Air http://www.nostalgiaair.org/Tubes/ gives only the 42 as a substitute for the 41. I've ordered several 41 tubes in ST style from Antique Electronic Supply or other tube vendors. AES list some NOS and used 41 tubes at their site now.

Vacuum Tubes, Inc says "The 6K6 is the octal equivalent." Obviously the octal tube won't fit in your 6 pin socket.

Why are you looking for a cross-reference? Are your 41s bad?

How far along are you in the restoration? Until you have recapped and rewired the radio, and cleaned the band switch, I doubt if you could be sure the tubes are bad unless they're broken or something. The main thing is to replace all electrolytic and wax capacitors and replace all the rubber-insulated wire before turning the radio on to see if the tubes work. They probably do.

Re: 41-280, need help with tube ID - Elrick - 01-14-2010

Raleigh, thanks for the repy. Not sure if my 41 's are bad because I have not been able to find a place that can test them. So far I've only found 1 shop that has a tube tester and it's pretty small and it doesn't accept the 6 pin socket. They did test the Loctal tubes and they ranged from about 45% - 65% good. The 41's may be fine, just wanted to get some information in case I had to order them. I have looked in a few places and didn't see any 41's listed. I'll do a re-cap job, check the resistors and replace the power cord then install the tubes and power her up. On the good side I don't seem to have the crumbling wire insulation that many have written about. Radio is complete, inside loop antenna and speaker are in decent shape cabinet has some scratches and dings but not too bad. I remember as a kid playing with the push buttons and sticking pointy things in the plastic over the station call letter windows. Later.

Re: 41-280, need help with tube ID - Raleigh - 01-15-2010

Funny about those rubber-insulated wires. I've electronically restored 5 1/2 of these 1940-42 radios with chasses similar to the 41-280. Most of the rubber-insulated wires were crumbled, but about 10% to 20% of the rubber wires are just as soft and supple as the day they were made. One wire will be crumbled to pieces, and the one next to it will be fine. Generally, I replace 'em all, since I usually need to desolder them anyway to change a cap or resistor, but I have left in place a few supple wires if an end is too difficult to reach or something.

On the 42-355 I recently finished, most of the rubber wires were crumbling, but on the band switch all the rubber wires were good. I started to replace the band switch wires, but eventually decided to leave them alone. I'm working on another 42-355 now, and all of the band switch wires are crumbling. There isn't a rubber wire anywhere in that radio that hasn't crumbled.