Maintaining The Collins R-390 Receiver
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- เผยแพร่เมื่อ 10 ต.ค. 2024
- A bit of regular maintenance on the Collins Radio R-390 receiver. I had an issue a couple of weeks back where I was noticing a decrease in sensitivity and found a weak IF tube. After replacing the weak tube, I ordered more spares (I probably have 20+ spares of 6BJ6) but wanted to share my philosophy on maintaining and keeping in tip-top shape the vintage boat-anchor radio equipment from the 1950's and 1960's.
I used this tube checker in the Army when I supported the AN/GRC-26D teletype rig. I found it useful too:) How fun. These were great rigs in the field.
Well.. at the end you say thanks for watching, and I’d like to tell you, thanks for posting Sir!
73s
David, every year that goes by there are fewer of us old guys to keep that great old gear alive. Even the S-line gear is pretty ancient now. The R390 is a mechanical work of art, and was the peak of technology in its day. The two things I felt I could never afford back in the 60's were Collins Radios and Tektronix scopes. I'm the proud owner of a bunch of Tek instruments along with some good HP stuff. But my Collins dream is still unsatisfied. eBay prices are so high even now on good Collins rigs. I'm going to the Dayton Hamfest this year, maybe something will turn up.
Keep the videos coming. 73, Bill
Hi Bill,
It has always been a dream of mine to go to the Dayton hamfest. I love hamfests. But, it is so far away from El Paso it is not practical as I would surely want to bring back a bunch of stuff...
I also know what you mean about the high end test equipment like HP and Tektronix. It is truly amazing that we can now own this magnificent equipment that cost $35,000 just 20 years ago and now we can get it for $500.
The Internet, Ebay and TH-cam are miracles, in my opinion, where everybody can have some unique part that has been laying around for 50-60 years and they know what it is and there is something inside them (the seller and the buyer) that appreciates these little repair parts. I just ordered a 262 Kc IF transformer for the BFO in an old Gonset G-66B receiver. The old receiver works amazingly well but in the process of tuning it up, I accidentally damaged the BFO transformer and now I can't tune in SSB or CW. I hope I can fix it with the new part. Just a small example of our unique world today.
I do see some nice Collins gear on Ebay. Some prices I find reasonable and others that advertise as "beautiful" doesn't look so good in the pictures... and think about McIntosh vacuum tube amplifiers. They are truly ten times the price that they were in the 1960's and they continue to sell. On the other hand, Collins Radio equipment is probably similar or a little less expensive than new equipment 60 years ago. Oh well... It's a good time to be alive.
Very interesting video. Love this old boat anchor gear. I have an old Eddystone EA12 that uses the old Amatuer bands so it is of little use. But I love it. More radio videos please.
David, excellent video as usual. Here is the thing about tube testers and I'm glad you mentioned that they aren't the tell all. They can tell you that a tube conducts from the cathode to plate or if there is a dead short and some even detect leakage. Just because a tube reads strong emission doesn't mean it will work in all applications. If there is excessive interelectrode capacitance,it can make a tube exhibit oscillations at certain frequencies and that can throw off an oscillator just enough to make it not work or decrease sensitivity. Now that you have good tubes,I would go thru the alignment procedure again and you will be amazed at what you will gain. Also, make sure all the source voltages are up to spec and you will be amazed at how much it improves.Anytime you replace tubes in the RF,IF, Oscillator,or AGC,I would always give the alignment a once over. That receiver should knock out 1mv with no sweat especially at higher frequencies.My 390A measures about 1.2mv on the 20m band and I know I can make it better yet.
Hi Mike,
It is interesting how the tube tester showed the tube so strong but it was terribly sensitive to shock, to the point of almost not working. It went to the trash can.
If the receiver wasn't so heavy, I would check alignment more often but it is a real commitment to take that beauty to the shop.
From my last video, you can see I am working on the UTC 300B amp. It is coming along but I have a lot of other chores at the moment taking up a lot of my time and then the sheer manual labor of what I am doing refurnishing a house after a tenant lived there for 10 years wears me out. I am not 30 years old anymore.
Tube testers have their place no different from any other set of tools and no single tool does it all but I have found over the years that IF and RF amplifier tubes in the front end of a receiver should be the best-of-the-best a fellow has as it makes a lot of difference in the performance.
Mike, I just run across you name and realized we haven't emailed in some time. I know you send me stuff on my email but I rarely check that email anymore. My wife uses my email address much more than I do. I do keep up with my TH-cam email address... TheAudioShop@SBCGlobal.Net I hope you and your Mom are doing well and staying safe. Just wanted to say hello...
@@ElPasoTubeAmps Thanks David.
Great video, thanks. I will try your system on my 390a that is in need of some tlc.
Thanks for sharing. Even though I have only been a ham for a couple of years I still love the old boat anchor stuff. I am working my way backwards in time. IC-7300, TS-820S, DrakeTR-4... Not sure what is next!
You probably can't go wrong with the vintage Collins equipment unless someone has already gotten to it and messed it up. Got to love it and take your time. Don't ever wholesale "re-tube" it with supposed "new NOS" tubes from Ebay. It is a mechanical/electrical love affair with this old equipment to make it work properly again. Kind of like a carburetor type 1960 automobile engine. Switch contacts issues are almost always an issue. Be very careful with the wafer switches because if you mechanically mess one up, it is probably the end of the equipment. Use good contact cleaners sparingly.
I never had the Drake equipment but I know it was, in its day, quality equipment. My guess is it is not as mechanically sound as the Collins so it probably has more switch/contact issues.
There is definitely a difference even in the Collins equipment between the military grade equipment like the R-390 and the amateur equipment like the 75S-3. They are both highest-quality instruments but the R-390 is a higher grade piece of equipment because of the mechanical/electrical quality and construction. Keep the boat anchor equipment on the air. People will compliment you on the good quality of the audio. 73 WA4QGA
Thanks for the reply. I constantly get great reports on the old Drake, and especially on the Kenwood.
Collins gear is definitely in my future. Just wanted to get through any repair failures on the less desirable gear first. I appreciate your videos. Thank you for sharing your knowledge and experience.
Thanks for this. I have several “BAs” that I maintain, the R390A among them. I’ll have to try that SSB Adapter you mentioned.
Here is a link to the SSB adapter for the R-390
www.treetopcircuits.com/docs/SB390Manual.pdf
I don't sell or have anything to do with this company but I have found the adapter to be excellent. Makes tuning SSB fantastic. You do have to be a little prepared that everything in the instructions may not be exactly as you experience in your particular radio. Mine being a R-390 and not the "A" model may have had something to do with that. Per the instructions included with the adapter, my radio did not have a hole in the chassis that they described so I had to carefully make one and put a rubber grommet in place to protect the wire going thru the hole. The adapter also disables the Carrier Level meter when the BFO is off but I don't find that an issue. Thanks for your comments.
ElPaso TubeAmps: Very good, thanks David.
That’s a bit interesting about the radium. I never noticed. As a USAF AFSC 207X2 we sat at racks in front of four R-390 Receivers pretty much all shift. I wonder how much I sucked in over eight years? I wonder if I can get military insurance and VA now? 😀 This was very very interesting! I really loved that old radio! Thank you for the information. Maybe some day I’ll find one to buy.
Do your fingers glow in the dark...when you were spinning and grinning during that bleeding mid shift
I have three of the R390A's with the original meters and yes they are radium painted and slightly hot.
I find that my R-390 has a very pleasant quality to the SSB audio. Much less high pitched like most all other receivers that I have and it seems highly compressed SSB audio is easier to understand on the R-390 than my other receivers.
On the other hand, very weak signals, right at the noise level, are a bit harder to copy than, for example, on the 75S-3 receiver. My 75S-3 receiver has the slight edge on copying SSB right at the noise level. Do you experience something like this with your R-390A's?
I understand the loss of interest. I have been on since 1963 and my interest over the years has been intense and passive. I get on and have an average of 3-4 QSO's per week so, I am somewhat back into it.I am also still very much into building and measuring and now posting on TH-cam and am a die-hard boat-anchor guy. Now I can have all the toys I wanted as a kid...
I added a device to my R-390 made by a company called Treetop www.treetopcircuits.com/pmwiki/pmwiki.php/Main/Products
While the receiver worked very well, the device made and sold by Treetop out of Canada make it much nicer to use. I use my R-390 almost exclusively over the 75S-3 or the iCom because, as you mentioned, it is indeed practically HiFi even on SSB with the added adapter.
Many signals today are way too processed and are tedious to tune in but the R-390 does a marvelous job and any decent sounding signal sounds like they are in the room with you.
Thanks for your comments and best of luck with your equipment and sells, I assume on Ebay.
73 WA4QGA
Dave,
The printed labels on tubes mean little, as a tube branded GE could have been built by (for instance) RCA. What does matter is the plant of manufacture and the specific production run.
Eli D.
Good point, Eli
I do know all of the manufacturers built and sold to each other with the buyers label on the tubes. Makes sense for only one manufacturer to tool up to make a certain tube and make lots of them. That really stands out in the European made Mullards/Telefunken, etc 12AX7 and like tubes. I see it also in the vintage 6L6 and 6550 and surely others. I mentioned it because I know people can become very brand oriented, especially in modern day audio tubes and maybe the tubes made today in China and Russia and elsewhere, brand name might be more important than long ago. I also wanted my message to be, you don't know what you got or how the tube is going to perform until you have done all you can to evaluate it and then actually put it in the equipment and see how it performs - one tube at a time.
I didn't show something that happened afterwards because I had already created the video but one of the original tubes that was in the R-390 and was measuring very well on the tube tester, became noisy in the third slot of the IF amplifier stage. I started to add it in to the video but time got the best of me. I noticed it because the receiver is so quite but the noise level started going up and down intermittently. Very obvious and since I had been fooling with the IF amplifier tubes ... well... After removing the cover again, I gently tapped on the tubes I had just installed and, there it was, noise as could be with gentle tapping. I checked it again, cleaned the pins gently with a wire brush, swabbed on a bit of contact cleaner but it was noisy and was not a poor socket connection. I replaced it. Why it showed up now and not before, I can not say. Maybe I moved it from a lower/higher gain position in the IF chain where previously it was working fine. Oh well - such is the unpredictable life with vacuum tubes -. :-)
Thanks for the clear and helpful video. I had one of these after college but with many moves, well , it's heavy and I sold it. Anyway I just picked up another one. Could you tell me if yours is silkscreened or engraved? Looks to be silkscreened as is mine. Engraved would be easier to restore... anyway thanks for the practical tips and your alignment video will be SO helpful.
Mine is engraved and I have found that with lots of patients and careful work, the white can be restored with something as simple as White-Out. Same with the lines on the knobs except for some of the years of wear and tear. Good luck with your restore. I added an inexpensive tunable outboard RF preamp to the front end and it really made it come alive. As sensitive (and still very quite) as any of my other receivers. 73 WA4QGA
@@ElPasoTubeAmps thanks for the tips, yes a preamp would help out and certainly not hurt as I remember there is no way you can overload the front end on these things.
You have the IF gain in the R390 set to high. That 1uv signal should not have been as noisy as it was.
Hi Elpaso. My R390 and all 5 390a register loud at .1 micro volts. Specs a little less sensitivity
I appreciate you telling me that. I can detect 1 uV with no issue but I don't know if I could hear 0.1 uV at all. It is a marvelous old receiver but I have it in "storage" right now - over to the side on a cabinet, not in a hot/cold shed or garage. Sadly, I don't have much use for it right now. For a general coverage receiver I have the 51S-1 and even a iCom 736 with a good general coverage receiver in it. Thanks for the information.
Yes understand. Mine are all in storage including a 51-S 1 and a 75-S3 but I’ve never had them powered up at the same time
Try putting a bright light near your meters for a few seconds, my line level meters glows in the dark for maybe 30 seconds to a minute after I take the light away, the carrier level meter is dead though doesn't absorb light anymore, but it's pretty cool.
Thanks, I will try that. My meters are reasonably "hot" from being radioactive but so far I have seen no glowing. in the dark 73
Thanks for your videos, could you let me know where you found the meter for your tube tester, I have the same tester and my meter also sticks. I found a replacement for it, but it also sticks.... guy said it worked fine??? thanks again for all of the information you give in your videos. CarlAlso, I have an old Big Ben alarm clock with bright green numbers that wakes up my radiation meter... de N6NZX
Hi Carl,
I got the meter from Ebay. They are made in Taiwan and look kind of cheap from the back side but they work.
I think any "NOS" so-to-speak meter that is also 60 years old is likely to stick. Here it the link for one advertised right now.
www.ebay.com/itm/TV-7-TV-7A-U-TV-7B-U-TV-7C-U-TV-7D-U-tube-tester-meter-replica-NEW/112907833995?hash=item1a49d4d28b:g:YlgAAOSwVtZaDnHv
What about a small RF preamp based on 4x Nuvistor vacuum tubes, one driving a 4:1 balun to drive two in balanced mode which will drive the last 4:1 balun which should give a useful gain boost.
Don't give me any ideas... :-) Like I need another project.
I do have some of the Nuvistor tubes and sockets. I like the idea. If i build such a circuit I will post it and we can all see how it turned out. Thanks.
i just bought one of these things. ive been shortwavin for 50 some odd years and this is mt 1st and i dont know much about them. have you ever had one where the rf gain has no effect? its running wide open and the control measures good . any ideas?
wow, i can see why Collins was the best
Saves on Condoms though!
Great radio
I am surprised that they didn't use TELEFUNKEN Space Charge Vacuum tubes which would have made the unit very portable because you could run it of 2x 12V batteries.
see R392 ! Uses regular 6AK5 and 6BA6 like 26a6 tube etc at 24 volts. Portable works very well. Used with T195 TX for RTTY station.
Yep... glow-in-the-dark dials in the original meters have radium-printed scales. I remember years ago about how many surplus outlets would have to pull out those meters before selling the receiver... folks often bought R-390's with two holes where the meters used to be... I guess some folks got paranoid about that tiny amount of radiation that was being emitted from the meters.
Indeed, our society has become afraid of just about anything and everything the media can terrify us with. In California, they would surely require a sign on the meter telling everyone not to eat it (or smoke it) and that the State of California has determined that this product contains chemicals that cause cancer. I can only assume legal marijuana has no adverse affects in California. The Internet tells us that California is about to determine roasted Starbucks coffee causes cancer. Got to die of something. I guess my R-390 will kill me. :-)
Understood... many have definitely been fake-newsed and false-flagged and fake-educated to blind compliance.
But, despite that, I don't think anybody ever got sick and died from nuclear-S-meter-poisoning while listening to the radio :-D .... not unless they scraped off and ground up the dial's paint and snorted it or something like that, and I don't think anyone's done that with their R-390 meters........ hopefully.
That 3-1000 looks so awesome there... you do some fine work...continued success to you.
Thank you. I can't quit laughing. I didn't mean to pick on CA so heavily. It is indeed a beautiful state and I have been there many times. It must be the radium...
You're welcome. ....and yup.... better put some 3 inch thick lead shielding around those terrible meters.. lol :-D :-D :-D !!
Can you give me a recommendation on a nos tube dealer? i bought a few and I spent a lot on a mullard thats went microphonic shortly after using i think the guy's selling old used tubes, I dont want to put his business out there for selling bad stuff just don't think I want to go through the same stuff again.
I have bought tubes from a lot of different sellers and when it comes to 50-60 old tubes, you really never know what you are going to get. On the other hand, I have found that most of the sellers are truly honest and want to sell top quality vacuum tubes. Many of the sellers have a return policy. That is the only people I deal with anymore. I have been burned by dishonest sellers but I have to admit I wasn't as careful as I should have been and I did not stick to the strictest degree and follow Ebay policy in returning the tubes. Bottom line is, be very careful when replacing the tubes in an old radio like this. The tubes you have in it may be perfectly good. There may be a weak one - or two - but TLC is the only way to deal with these old pieces of equipment. I would never completely and blindly "retube" a device like this although there are sets of tubes sold just for this purpose for several of the more popular pieces of equipment. Buying a replacement-set might be a good idea to have spares but I recommend going thru all the steps with each tube individually and keep up with where any tube was removed from so you can always get back to step-one before you started. Being able to back-out of a situation has saved me many times as I did repair on equipment for NASA and WSMR for 26 years and some problems just don't seem to want to be resolved but compounding the problem was not acceptable. Fortunately our career is not on the line in our ham shack but it is easy to make a mistake and damage something that may not be able to be found for repair. This happened to me with a Gonset G-66B receiver when I was aligning it and did the BFO adjustment. Everything went perfect up to that point where in the turning of the powdered iron slug, the whole insides came loose from its mount and twisted and broke the wires off. I didn't know this at the time but afterwards in continuing to try and adjust it, the diddly-stick was going down the side of the IF coil and breaking off the tiny wires and damaging the coils directly. I have ordered another 262 Kc IF transformer and already removed the old one (that is how I know what happened to the old one) but repair is going to be difficult and may not turn out good. The old Gonset receives AM very well but with no BFO I can not receive SSB or CW. Best of luck with purchasing tubes. I have found that having lots and lots of spares that I can carefully comb thru is the only way I can maintain my boat anchor equipment in top working order. Hope this helps.
My go to guy is Jim McShane. ( mcshanedesign.net/ )
Do you have a Collins 618m-2
No, don't have that one - just the HF stuff. I had to look up the 618m-2 and see it is a VHF unit.
That radioactive dial would bother me.
Hi John,I am sure it is completely harmless unless the radioactive material was scraped off and ingested into the body. At that point it might be harmful even deadly but if I understand it correctly, a button-cell battery can also be deadly if swallowed. It is radio active so that it will glow in the dark. I suppose the military personnel using these receivers might have to operate in darkness ?? but still need to see all the dials on the front of the receiver. These receivers were top-secret devices when they came out and the manuals that come with them tell you when and how you are to destroy the receiver if overrun by the enemy. Interesting stuff.
Ok so u r a tube jockey, prob an accountant too!