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Finally repaired my original TR-7 PBT board that I roasted the U1001 analog switch on. (Dieter was right!) Took about a month to get the IC via eBay/Asia. Unsoldering that dude took about two hours to get all the little pins out after I surrendered and used the "Wedge" method of chopping it out and unsoldering the pins afterward. Still pretty rough on the circuit traces. Because of this I dug through the junk box and put in a 14 pin DIP socket instead of directly soldering the IC in. I was very surprised that it came right up after I set the 13.695 VXCO. Boom. Not sure if there is a sweeter-sounding receiver when everything's dialed in. Next up: 1) The "better all-band transmit mod", 2) grounding mod to eliminate 40m parasitic, and 3) Cinch-Jones plug and fan mod to remove 120V from unit. Tip of the cap to you guys for helping me keep this relic on the air. -- Craig/W8CS Greenville, SC
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I was about to make the "Better All Band Transmit Modification" to my TR-7A when I noticed that the digital control board is different: Is my best option now to use the traditional "cut the parent board trace" for pin 11 on the DCB? Thanks -- Craig/W8CS Greenville, SC
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I am reminded that my stock of FT-243 and HC-6/U crystals on oddball frequencies is dwindling again. Here at AF4K Crystals, I use them for rebuilding onto useful frequencies. Does anyone have a stockpile of such vintage crystals? They look like this: FT-243 - May have a bakelite or metal front cover. HC-6/U Can only use the ones with a soldered seam. Both have pins spaced about 1/2 inch (0.486") Let me know what you have and we can discuss how I can get them here for reuse by current operators. Reuse is the best form of recycling, right? Thank you. Steve WD8DAS sbjohnston@... http://www.wd8das.net/ http://af4k-crystals.com/ -------------------------------------------------------------------- Radio is your best entertainment value. --------------------------------------------------------------------
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TR-4 Resistance Chart
15
I started checking the resistance values in my TR-4 and found that Pin 7 of V2 is around 355K. The value in the chart is 246K and I'm wondering how that's possible. Pin 7 has a 330K and a .005uF connected to it so I can't see how that can be 246K. Is that a typo and should've been 346K? I know the values aren't meant to be taken as exact but, unless R125 is under it's designated value, I can't see how it could be less than 330K but perhaps I'm missing something about this circuit. Thanks, Barry - N4BUQ
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These 1/2W resistors look original. I have yet to measure them but they don¡¯t look cooked. There are a couple of other places where the repair soldering isn¡¯t stellar but this rig right now is working on 80-15 with full (well, 100-150W) power and receive. I suspect that 10 needs an oscillator coil tweak. My question is re the resistors. Was this the original configuration? I¡¯ve worked on very early T-4 and T-4X¡¯s that have 1W cathode resistors. Also note the monolithic filter that was the originally used in the early sets ¡ª note there¡¯s no cutout in the chassis so this is the first soupcan replacement. It¡¯s a late summer 1966 build (23xxx). Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from Proton Mail for iOS
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Radio Monaco Coastal Station
2
For those of you interested in one of Drake's major forays into maritime service/supply, you can read more about the Radio Monaco Coastal stations at both of these websites; https://www.facebook.com/groups/148087645522509/posts/-monaco-radio-vhf-coastal-marine-radio-station-cs-3af-and-hf-cs-3ac-in-addition-/1370195633311698/ https://3a2lf.blogspot.com/ If it comes up in French, right click your mouse and scroll down to "Translate to English" and Mr. Google will do a pretty good job of that. Many of the pics (if not all) can be clicked and made large. Enjoy! 73 Peter VE7PS
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Mic for Drake TR7
26
Hi all, I have a TR7 i just received, but no microphone to go with it. My question is: what mic would be good to purchase for use with the TR7? A Shure 444d desk mic has been suggested, and there are plenty available, but what hand mic would be equivalent ? Is there a Shure hand mic model that I should look for? If you have one for sale, please contact me, my info on QRZ is good. Thanks for your response and suggestions in advance. 73, Robert WD8PAQ
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Mark; You wrote...... "In the TR4310 I have here, and in the manual that came with it, there is definitely no PTO! The analogous function is provided by the VRTO synthesister, which has essentially the same circuitry as the somewhat rare Drake RV75 synthesised VFO, but a different mechanical layout to make it fit inside the '4310's case. Were there two versions (generations) of '4310 - one (early) with a PTO and the later (produced at the time of the TR7A) with VRTO? I do have a dim recollection of reading about a commercial / rack-mounting version of a TR7. The model 'TR43' rang a bell, but could not find any reference to it on www. (We found out a few months back that the TR4305 looked to be a fixed channel {crystal controlled} version of a TR5.)" Possibly..... though I have not been able to find out if the TR-77 and R-77 models produced for Radio Monaco had a true PTO (though with only a digital display) or if it had the VRTO tuning. There weren't very many made. I have seen pics of Radio Monaco with as many as six Drake rack-mounted stations, though one online reference to the TR-77 and R-77 says they only had four racks. Search YouTube to see Fernando's TR-77/R-77 station. I have never seen/heard of a "TR-43". Sindre could possibly shed some light on this topic. Sindre? 73 Peter VE7PS
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T-4xc blows AC4 fuses
3
I recently acquired a T-4XC that had been sitting around at least a dozen years. It seemed to work as it should, however, when I develop more than 40 watts out, the fuse in the AC4 blows. I have two AC4's, one with upgraded caps. The result was the same with both power supplies. I went ahead and ordered the Hayseed cap assembly, but wondering where else to look. The AC4's have no problem with my main T-4XC. thanks, Burt W3IO
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TR5 reed relay
Hello Drake community, I have a tricky one. There is a reed relay in the TR5, just after the low pass filters, which will short circuit the receiver during TX and connects it during RX. So there are two contacts, one NO and one NC. I think they chose reed relays because of the full bk capability. Now in my TR5, while the short circuit part seems to work, the switching part remains open. RX is heavily attenuated. It seems the relay is damaged. It is labeled wabash 1952-1-1 H1 An internet research didn't reveal much except some wabash relays on ebay with different part numbers. I hadn't heard of that company before. They seem to be Coto these days. www.cototechnology.com Any ideas? TNX and 73 Dieter DL5RDO
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Drake Items For Sale
I have a couple of Drake items and an excellent to mint condition Gonset G66B receiver with Gonset 120VAC 6/12VDC power supply for sale on my For Sale webpage. Items For Sale If interested in purchasing any of the items listed on the above webpage, contact me off group at my email address mikew5rkl at gmail dot com 73 Mike W5RKL https://www.w5rkl.com
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T-4XC to Heathkit SB-200 operation
3
I assume this question has been answered a hundred times, but can't seem to track it down. How are T-4XC users triggering the "Antenna Relay" on the SB-200? I was using a Kenwood TS-590 previously, and the amp has the 'soft switch' mod. thanks, Burt W3IO
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I'm not the first to have done this, just reporting this to help if anyone is on the fence. I noticed some poor performance on my T-4XC that I pulled out of mothballs this year after a long siesta. Did the heathkit shop AC-4 upgrade, no difference in output, more of a preventative thing with 48 year old caps. Started poking around the finals section and noticed that the cathode resistors were 17.2 and 19.3 ohms, pretty out of spec for 15 ohm resistors. This week I got around to looking at the rest of the circuit including screen, screen supply, and meter shunt resistors. R49 2W 1.5Kohm was heat-swollen and running 1600 ohms R50/R51 screen resistors (68 ohm) were measuring 73/76 ohms R59 meter shunt resistor (3.3 ohm) was measuring 4.5 ohms Replaced all of these with upgraded/over-spec components and WOW what a difference. Easily hits 100W output on 10M, 150W+ on lower bands. No, I'm not going to run this unit at those numbers but nice to see the potential. And this is with what I consider to be "soft" final tubes. Also installed a couple of binding posts on the rear panel which pigtail across the meter shunt resistor for easier bias set/checks. I could post pictures of the mods if anyone is curious. -- Craig/W8CS Greenville, SC
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T-4XC no output on 40M. SOLVED
2
Had to step away for a bit to go see my daughter. Finally got back on this project and found a ¡°sketchy¡± solder joint on C165, a ceramic capacitor on the injection trimmer for 40 meters. Resoldered and touched up a few others while I was there. Back to full output on all bands. Larry
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I've been using one of the PLJ 6LED counter modules in an external housing for digital frequency readout for my R4C. I'd like to mount the display inside the existing dial window on the R4C, but the window isn't really wide enough to view all the digits. So, would like to modify the width of the window but would need a bezel to give it the desired finished look. I've searched the usual sources for an appropriate bezel, but haven't come up with anything that will fit properly. I wonder if anyone else has located one? 73, Floyd - K8AC
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Ordering K4OAH Manuals
7
I've been to the K4OAH site but it's slightly unclear how to order. Is it sufficient to send the funds (PayPal, etc.) with a note stating which manual one is ordering? I bought one before Garey's passing but not since so I want to make sure how to do that now. I presume I could send an email to the mindspring address on the K4OAH site as well? Thanks, Barry - N4BUQ
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SP75 with Heil mic
15
My question is, is there a mod to the SP75 if you are using a Heil Mic on the TR7? I am getting some problems with Audio and TX on my station that I installed an SP75 with a Heil Goldline mic. The amp is an L7 that is very stable with the SP75 out of the circuit. Any comments are most welcome. Bob
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OFF-TOPIC: Finding nearby US hams
9
On a recent walk, I noticed a new vertical antenna a few blocks from me. It had traps, so most likely a ham. Back home, I was surprised to find city-data.com has FCC license data organized by community. To take a look, enter this in your favorite search engine and append a US city and state. site:city-data.com amateur radio licenses Example: site:city-data.com amateur radio licenses Montpelier, Vermont 73, Tom, AG9X
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Neutralizing a TR-4
I've posted recently about some problems I've had neutralizing the finals in my TR-4. I think in the last post I made about it, I stated that the original 12pF (C77) that's across the variable capacitor, C76, tested completely bad ("No, unknown, or damaged part"); however, it occurred to me that this tester (a "T7") isn't spec'd to test below 20pF so the original may still be good. In any case, I ordered some replacements (a 10pF, a 12pF, and a 15pF) and they arrived today. I tried the 12pF and got basically the same results as the original (a semi-null with C76 fully open). I then decided to try a 2pF SM I happened to have and that gave me a semi-null with the plates fully closed so I figured the sweet-spot must be somewhere between those two values. Since I didn't have anything on hand at around 7pF, I connected the 15pF and the 10pF in series to obtain 6pF across C76 and that gives me a null with the plates virtually at the half-way point so now I'm searching for a suitable capacitor in the 6pF range but I'm not finding anything. Anyone know where I might find a suitable capacitor? If I can't find something, I may just stick with the two capacitors in series but I'm not very fond of a "flying splice" like that. What I'm really wondering about is why this rig needs only half of the original value capacitor in that place. I know that Steve has mentioned a brand of tubes that apparently needs a little more capacitance but haven't heard anything about needing less and so I'm wondering what could be causing that. As far as I can tell, there are no other capacitors in parallel with those two but several other capacitors connected to that part of the circuit in one way or the other. Any suggestions as to anything I might look for or maybe I should just chalk it up to the rig being 60 years old and several factors could be at play because of aging parts. Thanks, Barry - N4BUQ
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On the TR-4CW the S meter swung to the right and stays there also there is just a very faint sound of audio. Then about two minutes later the fuse in the power supply blew! Mark
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Sat 8:39am
Sat 8:39am