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Following up on a prior thread, I checked my 42-380 chassis and instead of a 80 tube as a rectifier, it has a 6X5. Checked the tube layout sticker on the cabinet and sure enough, it has the 6X5 listed. I know this tube all too well as my Zenith 12-S-475 had two of these and they blew the power transformer. As I read up on these, the less I liked them, so I will take everybody's advice and replace it with silicon diodes. In the meantime I did want to confirm they were used on the 42-380. They probably used it after Pearl Harbor as production wound down.
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Use a 6X5GT and you will be fine. The 6X5G tubes were the ones that had the reputation for shorting.
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I just happen to have the Philco 1942 RMS Year Book on my desk here, so I looked...it shows a 6X5G, no mention of an 80. So it originally came out with a 6X5G. No mention of an 80 ever having been used in the service notes or in the production changes listed in the back of the book.
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Ron Ramirez
Ferdinand IN
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I would have guessed that it would have an 84 tube rather than the 6X5.
Terry
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The neurosis over 6X5 tubes seems to have originated from Brand Z sets with crappy power supply designs. The set you mentioned used a pair of them in the power supply rather then using a 5Y4/5Y3/80 to do the same job even though that transformer had a 5 volt winding for that purpose. It was really stupid in that a 6X5 has a maximum current rating of 70 ma, to get around this they connected both diodes in each 6X5 together in parallel to make a single diode. I guess they thought this would give them the equivalent of a 140 ma rectifier, well no it didn't. To make matters worse brand Z was notorious, especially in the 1939-42 sets, for using power transformers that were barely adequate to do the job.
The Philco 42-380 used a 6X5 rectifier, the 41-280 and 40-180 often used a type 84, which is a six pin equivalent of a 6X5. Here's the difference between these and the Brand Z model, these sets used 7 tubes not 12, they also used type 41s which are a six pin equivalent of a 6K6, not 6V6s, they also only ran them at 190-195 volts on the plate and screens rather then 220 volts.
Regards
Arran
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Well, spare the transformer if it's still good, and use a couple of ten cent diodes and a hefty dropping resistor bolted to the chassis to tame the B+ and add a fuse.
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Or..... just use a 6X5GT and you wil be OK.
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Speaking of the type 41s, the plate current is 18.5 ma, verses 47 ma for the 6V6s used in the brand Z set, so all of the tubes added together don't even come close to breaking that 70 ma maximum current limit for the 6X5. As I said the previous renditions of these sets, the 40-180 and 41-280 used type 84s which are exactly the same as a 6X5 but with six pins, why no hysteria about type 84 rectifiers?
Regards
Arran
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Five pins, so it is, I don't think I have anything that uses a type 84, I do have lots of sets that use a 6X5, mostly 5 and 6 tube jobs. In any event the only real difference is in the heater current and the base, the 6X5 has a 600 ma heater. Another similar tube to an 84 is a 7Y4 loctal, I'm not sure if these were ever used in a 42-380 but they were used in some Philco sets. One thing is puzzling however, in one book I found that the maximum output current of either the 6X5 or the 84 was 75 ma, in another 70 ma, in yet another reference they say the the max on an 84 is 60 ma.
Regards
Arran
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This is what I use as a replacement for a 6X5. No muss, no fuss, just plug it in and you're off and running. They work like a champ.
http://www.webervst.com/ccap.html
Larry
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Interesting.......
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