Re: 12BY7 substitute
BTW a 12GN7 while not a direct substitute has the same pinout and is about twice the plate dissipation and higher transconductance than the 12BY7. I could not find one to try but it would be an
By
Doug Crompton WA3DSP
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#70020
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Re: 12BY7 substitute
I think I have answered my own question. These tubes are basically one and the same. I found quite a few in my stash, and this RCA is numbered with all three types. I ended up using a JAN GE 12BY7A
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Doug Crompton WA3DSP
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#70019
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Re: TR7 Service Kit - Extender Boards Needed
I'll let Ron know to remove Bob's ad for those boards. He might have forgotten to advise him that they were all sold. Mike, should I remove your boards from the parts & service doc on his site? 73's,
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Mark - WB0IQK
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#70018
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WTB TR-7/R7 Cabinet
Looking for a Excellent top cabinet if anyone knows where I might find one. An excellent original R7A manual would be nice too. Marty KL7AM
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KL7AM
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#70017
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Re: TR7 Service Kit - Extender Boards Needed
Mike, FYI in Drake parlance this is known as the "Jumper Board" and is described as such in the TR7 service manual. 73 -Jim NU0C "Mike Bryce" <prosolar@...> wrote:
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Jim Shorney
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#70016
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Re: Sourcing T4Xany cathode and screen grid resistors
I don¡¯t have the answer to that. I did, however, throw out some carbon resistors recently (and I¡¯m in an ongoing process with my stock, which dates back decades) that were grossly out of spec,
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Steve Wedge, W1ES/4
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#70015
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Re: Sourcing T4Xany cathode and screen grid resistors
Steve, I agree. This is more of a temporary fix for me. Once I get everything working I will go back and replace them with new parts. What I don't remember is what is the drift profile of carbon comp
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Bill Leonard N0CU
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#70014
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Re: DRAKE MN-2000 Ceramic wafer replacement/repair for Antenna Selector Switch help?
This is a standard sized wafer that has a quirky difference from a standard 2 pole 5 position wafer. The Common for one side is in the middle instead of at one end. You get around this by drilling out
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Gary Follett
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#70013
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Re: TR7 Service Kit - Extender Boards Needed
Those are the boards that I have and they work very well. 73, Steve Wedge, W1ES/4 Time flies like an arrow. Fruit flies like a banana. Sent from Proton Mail for iOS
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Steve Wedge, W1ES/4
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#70012
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Re: Need help with the planetary drive on T-4XC
That is also an advantage. Slightly OT, general purpose grease on the PTO bearings is what Drake used and its use also helped keep those 10 balls in place during reassembly. 73, Steve Wedge, W1ES/4
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Steve Wedge, W1ES/4
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#70011
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Re: Sourcing T4Xany cathode and screen grid resistors
The problem with that with respect to the cathode and screen resistors is that the out of tolerance parts will continue to drift out of tolerance. It¡¯s best to use new replacements of the original
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Steve Wedge, W1ES/4
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#70010
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Re: TR7 Service Kit - Extender Boards Needed
dave and the group, finding .156 connectors are easy¡ªdigikey and mouser have them by the millions! However, you need to know the series like KK or KW, KS, the pitch. Do you want locking tabs? What
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Mike Bryce
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#70009
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Re: TR7 Service Kit - Extender Boards Needed
Can anybody tell me where to get the .156 connectors from please? Thanks Dave G4FAW
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Dave Cutts <g4faw@...>
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#70008
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Re: Need help with the planetary drive on T-4XC
Steve & Joe, I was suspecting that oiling the bearings could cause slipping. However, both of the veriers I have were packed with a thick grease. So, I will follow Steve's recommendation and try some
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Bill Leonard N0CU
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#70007
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Re: Need help with the planetary drive on T-4XC
Gary, That is my plan. I am going to stop at Harbor Freight today and pick up an 8 in C clamp. I have been thinking about how the assembly should go. My theory of the moment is that the preload
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Bill Leonard N0CU
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#70006
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Re: Sourcing T4Xany cathode and screen grid resistors
Since I have several boxes full of resistors, I have simply been measuring the starting resistance and calculating what parallel resistance is needed. I trimmed the meter shunt to 1% and matched the
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Bill Leonard N0CU
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#70005
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Re: TR7 Service Kit - Extender Boards Needed
Hi, gang! Several years ago, I came out with a set of extender boards for the TR7. They consisted of a board set for each specific card. One for the Audio/IF, another for the power supply/osc board,
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Mike Bryce
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#70004
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Re: Sourcing T4Xany cathode and screen grid resistors
Why not just buy from Mouser or Digikey? Both located in the USA. Better pricing and more variety available and an excellent on line catalog, no minimum order. 73, Jim W7RY -- Thanks and 73, Jim W7RY
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Jim W7RY <jimw7ry@...>
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#70003
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Re: Sourcing T4Xany cathode and screen grid resistors
Yes, these guys are great. I¡¯ve bought lots of caps from them. Steve Wedge, W1ES/4 Time flies like an arrow. Fruit flies like a banana. Sent from Proton Mail for iOS
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Steve Wedge, W1ES/4
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#70002
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Re: Need help with the planetary drive on T-4XC
I use heavy wheel bearing grease. It provides plenty of friction. I won¡¯t look up the brand, as the jar of this stuff is from the 1950¡¯s and has been a lifetime supply for both my dad and me.
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Steve Wedge, W1ES/4
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#70001
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