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anyone out there with some orphaned pieces? Joe WA2L

Hello All, This isn't exactly Drake stuff, but similar. My Signal/One has developed an AC buzz on transmit. Probably a dead electrolytic. And probably HV, because there is no buzz on receive. The receive is all solid state, no HV involved. There are three HV supplies: 1500V for the PA plate, 250V for the screen, and -60V bias. I really don't want to troubleshoot this under power if I can help it; I have the greatest respect for that 1500V! In fact, the only instrument I have that's rated for such is an ancient Triplett VOM. I got out the Sprague TO-6 and started testing caps in circuit. Mostly they seem good. But there's one that definitely shows "no cap there, son!". It's one of the four series caps that filter the 1500V. These are chassis-mount units with a phenolic flange rivetted to the chassis, and a cardboard insulation shell. 150uF, 450V. So - take it apart and replace the guts with a modern cap? This is 2025, and equivalent caps are MUCH smaller than they could do in 1970. There probably isn't enough space underneath to just solder in an axial lead unit; the poewr supply board is on standoffs right above that area of chassis. Hayseed Hamfest has good looking caps, but they're a bit pricy. - Jerry, KF6VB

I have a DL-300 I've been using for testing my TR-4 and MN-2000. I decided to measure it's DC resistance and found it is 56 ohms. I expected either 50 or 52 ohms so was a bit surprised. I tried checking it directly on the ends of the resistive element and that also measured 56 ohms. I presume this isn't exactly normal and perhaps someone ran it with too much power for too long but I don't know that. From what I can tell about it's construction, I presume these resistors wouldn't normally drift like some other resistors but I don't know that for sure. 56 ohms isn't exactly terrible but I am wondering if that's true. Anyone know about these? Thanks, Barry - N4BUQ

Not really a big deal but thought I would check in to see if this is common. R-4C tied into T-4XC in normal transceive config. I'll listen around on the R-4C for a while, and I'll turn on the T-4 if I think I'll be transmitting in the next few minutes. Immediate drop in RX signal by a few S-units. Rx signal also shifts in frequency by maybe 100Hz. I can even duplicate this with the 25KHz calibrator. Turning off T-4XC "lights up" the receiver again. Common? -- Craig/W8CS Greenville, SC

I couldn't find the relay in Garey's BOM for the T-4XC. I have found the listing of the original relay in the TR-4C -- it is a P&B R10-E1-Y4-V2.5K I can't see why they shouldn't be the same. The keying circuits in the two sets are identical and switched to the 6FQ7 on both rigs. Anyone with a T-4XC open could do us a favout by reporting back to the group as to the relay part number is. 73, Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent with Proton Mail secure email.

Has anyone tried using a DDS VFO connected to a receiver such as the R-4B, and also connected via a "T" to the VFO input of a boatanchor transmitter such as the 2-NT? I'm thinking that might work to give me transceive capability while I'm tuning with the DDS VFO, but I just haven't tried it yet. --Ed, N3CW--

How do you determine that your final tubes are near EOL? Currently when I tune up my T-4XC, particularly when I peak the "Load" control I have to perform this really quickly to get a peak, because iP and output power will slowly fall if I hold this for more than a couple of seconds. I have to "chase" the load peak with a falling ammeter. I don't know if what I'm seeing is related more to a secondary effect, such as the cathode resistors heating up and increasing their resistance, or whether the finals themselves are getting "soft." I can still achieve >100W output on all bands. The AC-4 has been recently rebuilt. I'm sure that I can determine the root cause with time, but I'm curious how y'all determine the health of your final tubes. -- Craig/W8CS Greenville, SC

Sold: After I purchased my R7 receiver I began the search for the connecting cable from the TR-7 to the R7 which would allow transceiver operations. I had no success and had just about given up when two came on the market. I acquired both and would like to pass along the unused one to another ham who is searching for the elusive cable. Full disclosure: this is not an original Drake cable but instead came from the aftermarket. That said, it’s new and works with my rig. The price is $100 shipped and PayPal is fine. I know $100 for a four foot cable is high but it seems the Cinch Jones connectors used are very hard to source nowadays making it difficult to homebrew the cable. Any questions please contact me off list. Thanks, Tom KF5WBS

Playing with my A Line today, after fixing a damaged T-4 and then cleaning out the relay of my minty T-4X. I’m not a fan of the flat disc “skirt” for the main tuning but by golly, I love the feel of that fluted knob! Granted, these rigs look like it’s still 1967 but I don’t feel the need for a thumb or finger indent! Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from Proton Mail for iOS

I have a TR-4 (early model with no noise blanker) that I’ve recapped and aligned to the best of my abilities. It receives great and I get good TX output but every report I get back says they can understand me but my TX audio is crap. I’ve listened to my signal on another radio and it sounds muffled/garbled. No hum in the signal just a very not natural sounding voice. Mic is an Astatic 200 (going off memory). I plan to trace the audio from my mic down the Tx path to try and find the issue. Has anyone experienced this?

Working on a T-4 that I sold and has come back for repairs after UPS played Mad Max with it. I can't remember if the functionality of TUNE and SSB are dependent on there NOT being an open key in the KEY jack. This makes sense merely because the TR-3 and TR-4 function that way but I can't check against my T-4X because the T-4X is a very late one that is more similar to a T-4XB (4-wafer FUNCTION switch), Anyone out there with an early T-4X or a T-4 that can verify this for me? If I close the key (when it's inserted into the KEY connector), I can use TUNE, SSB and AM. If the key is open, TUNE, SSB and AM don't work. If I'm correct, I can send this back to its new owner. Hopefully, UPS won't abuse it again! 73, Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent with Proton Mail secure email.

I never liked the fact that there was the AC for the PS7 routed through the TR7. I have used a good power strip for years and tried to not switch the volume control to OFF since I read about them being unobtainable, and failing both electrically and mechanically. Working on a project TR7 and PS7 with a younger ham, I decided that I should finally figure out how to keep the AC out of his and my TR7s. As we were checking out the PS7 I looked at the circuit board that has the voltage switching and all that (mounted by the switches being pop-riveted in place, seriously???) and decided there had to be a better way that to mess with that wiring. And then an idea came to me that should have 40+ yrs ago when I got the rig. Surplus Sales has the Jones connectors (for a cable, but we did not connect any cable) that are the same configuration as on the back of the rig. Part Number: (CNE) P310CCT https://www.surplussales.com/items/107904/vintage-cinch-jones-metal-backshell-clamp/ With it we just jumpered pins 1-2 and 3-4 inside the connector (check your PS7 and TR7 manuals to see) and then plugged it on to the cable from the PS7 and it works just like the PS7 was plugged into a turned-on radio. If you need ALC or VOX, you'll need to get another connector to plug-in to the back of the TR7, but we have not needed either yet. Then we leave the PS7 cable that has the AC and wires for the ALC and VOX coiled up behind the PS7 and turn things on with the power strip. Now only the 12V cable is plugged into the TR7. Of course the fan will need to be changed to 12 VDC on the radio. That will be our next upgrade. Before recommending the Jones connector from Surplus Sales to the group, I called them to make sure there were more available. They checked stock and said that they should have at least several hundred. Thought I'd share this idea with the group. I am sure others may have done something similar, but it is nice to know where we can still get Jones connectors at a reasonable price. 73, -Glenn/ WB0DKT

Have you guys/gals seen this ? https://forums.qrz.com/index.php?threads/drake-r8.950149/ Thought someone here might have an interest. de Jim W4QE

I'm trying to get my head wrapped around the sideband schemes for the TR-4 and have a question. Below is a table of how the sideband lamps react with the various BAND and SIDEBAND switch positions in my TR-4. Is this normal? I suspect it is and it is a matter of getting used to setting the SIDEBAND switch appropriately to get the "proper" sideband and, from what I can see, it's primarily an issue with 40M. Is that correct (and, hopefully nothing is wrong with those switches, etc., in my TR-4)? BAND SIDEBAND LOWER UPPER 80 X 40 X 20 X 15 X 10 X 10 X 10 X 80 X X 40 X X 20 X X 15 X X 10 X X 10 X X 10 X X Thanks, Barry - N4BUQ

As I recall, there’s no TR-4Cw/RIT manual as such. I’ve been relying on the non-RIT manual with a two-page RIT addendum. But if I’m wrong…I would sure like a copy. I do have K4OAH’s TR-4C service manual but the included schematic does show D6. Did he produce a service manual specific to the Cw/RIT model? Any informed guesses as to why there’s no PTO Zener regulation in the RIT model? Paul, W9AC

Anyone know what the inductance values are supposed to be for the two coils in these instruments? It's a bit odd to me the manuals I've seen don't include that so was curious. I suppose I could calculate it easily enough. Thanks, Barry - N4BUQ

Check the 50 kHz LO injection into the product detector and the second mixer. This is not a typical failure. Rob, NC0B