March 18, 2020 at 6:11 pm #13426
Has anyone used one of these?
I’m having no luck finding a 5Y4G close to home. This will work if you move the pin locations to suit a 5Y3GMarch 19, 2020 at 5:26 am #13429Alistair ThomsonForum Participant
When I was a kid I had an RME69 communications receiver. The rectifier tube had died on me and, knowing something about electronics back then (but not a lot), I removed the glass envelope and wired a pair of 1N4007 diodes in to the exposed base pins.
It worked beautifully for about five minutes, then all the electrolytics blew up. That was the bit I hadn’t known! It was good to see in your advert that the suppliers warn users about that!March 19, 2020 at 7:28 am #13431Jean MarcotteForum Participant
I replaced a 6X4 that had a cathode to filament short in my german radio by 1N4007 diodes. I also had to replace the power transformer and some components around it because it caught fire… I used two 1N4007 in series for each side with a resistor in series with the output to lower the output voltage and limit the initial current. If you don’t have that resistor, the voltage on your caps rises instantly to a much higher value when you put the power on.The two diodes in series is just an insurance policy in case one breaks down. If I remeber well the resistance was around 100 ohms 5w.March 19, 2020 at 8:56 am #13434Les DicksonCVRS Member
I replaced an 80 in much the same way as Jean Marcotte, with two diodes in series and some hefty resistors. I had to experiment to get the correct resistance. I also added a thermistor to the power supply to bring up the voltages slowly.March 19, 2020 at 10:13 am #13435
Can a thermistor be wired in with the original rectifier 5Y4G in place? Can they be used in AA5 radios? I hate the way the little Emerson I have spikes on start up. I imagine it’s pretty hard on everything.March 20, 2020 at 8:26 pm #13491
Many thanks Jean Marcotte!!!
Jean was kind enough to find me a 5Y4G in order to advance the repair/troubleshooting on the Philco 38-04 radio AND dropped it off at my place!!! Radio now plays quite well, but needs a volume pot and also an on/off 4 tone switch. perhaps it’s sacrilege to move stuff around, but I thought to yank the 4 tone on off switch (far left) and replace it with a conventional on/off volume switch, then install the 4 tone switch where the volume switch (far right) was. Only the on off is buggered, the 4 position tone part works great. This is a more conventional set up and solves the problem of finding a on/off 4 position tone switch. I have not looked for a on/off vol switch with the long shaft required for these radios. Is one place cheaper/better than another for that type of part?
Gary in Montreal
Attachments:May 2, 2020 at 7:15 pm #14129John MattatallForum Participant
I also replaced an “80” with diodes and resistors, in my case, 680 ohms. good tip on the themistor.June 6, 2020 at 9:15 pm #14788Don HenschelForum Participant
There are some tube sellers in the United States with very reasonable prices including NOS. if all else fails try them and I will sift through my emails for them and post when I find. Many hard to find NOS tubes from 30’s and 40’s for $10 give or take as well. My tubes are very difficult to find and a 5Y4 is a walk in the park! Try finding European CT8 based from 1930’s or a PenDD61 that my 1936 Philco 444 uses! They were discontinued a year or two after this radio was no longer produced and are very hard to find. The dreaded Zenith eye tube is easier to find!
Attachments:June 7, 2020 at 6:53 am #14794
Since posting, made a pretty good list of tube guys in my area and for the most part, they have come through. I rarely need anything exotic as the radios I have been repairing so far, are pretty run of the mill. I’m just trying to avoid buying anything from the States whenever possible because of the exchange rate ,sometimes duty and the shipping. Often doubles the price of the part !
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