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Author Topic: R390 Help needed.  (Read 28118 times)
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ke7trp
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« on: February 26, 2010, 12:45:46 AM »

I am resurecting an old R390 NON A model.  It was a mess.  Owned by a CH6 guy.  I know this because when I got it, It was tuned right into CH 6 CB.

I found some bad tubes. Checked them all tonight with the TV7.  I need one IF tube.  6bj6.  Its reading 20 on the scale. The others are reading 80.  $3 at tubesandmore down the street.

I popped the covers off the pots and sprayed Deoxit. That fixed the pots. Nice and smooth no crackle anymore.

Someone took the 3TF7 ballast out and stuck in two resistors. Seems to work.. Should Try to find one? Anyone have one?

The set is now working FB. I had to calibrate the BFO. It was way out.  Its sounding good.  

I noticed that the wire in the picture is not hooked up.. I have no idea where it goes. Can someone help and identify its location?

I am going to have to align the thing. On some bads the readout is up to 6 KC off. Seems simple enough.  I will do this once I get the new IF tube.

BIG problem that I need help with. BOTH this R390 and my R390A do NOT turn off.  Even in the off postion, The Receivers lights stay on. I studied the switch. I dont see anyway to adjust it. Can someone help me with this?


Parts needed: 

Top and bottom covers.
3tf7 ballast tube.
5! large size tube shields
6! small size tube shields
Correct power cord with plug for back of set!

THanks!

Clark



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w3jn
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« Reply #1 on: February 26, 2010, 04:59:04 AM »

Don't bother with a new 3TF7.  There are several ways around this.  Look in the receivers forum here for some of them.  One is to plug in a 12BY7 or similar (requires socket rewiring) another is to replace the BFO and PTO toobs with 12BA6s then short two of the 3TF7 terminals.

The microswitch on the power switch assembly is bad.  Needs to be cleaned/replaced.
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Todd, KA1KAQ
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« Reply #2 on: February 26, 2010, 11:05:18 AM »

So first off Clark, is this a R390 as the subject line says, or a R 390 NON A? The latter is much harder to find parts for!  Grin

All joking aside, a similar approach is to use a.... (searching memory banks).....47 ohm 5 watt resistor between pins.....2 and 7 of the ballast socket, no other changes needed. Been a while since I did this workaround, but the 3TF7 is basically a resistor used to absorb voltage changes in situations of poor line regulation, not something we often encounter in civilian life these days.

Essentially the same thing as John's 12BY7 recommendation which actually looks better since there's a real toob in the socket. Just another option depending what you have in the junk box for parts.

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ke7trp
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« Reply #3 on: February 26, 2010, 12:19:46 PM »

Ok. I will leave the resistors in place then. 

Anyone have any idea about this wire???

C
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« Reply #4 on: February 26, 2010, 12:40:00 PM »

Hard for me to make out in the photo, but the location tells me it might have gone to the the diode load located on the back panel. Navy versions of this receiver brought the diode load connection out to the front panel for easier access (instead of having to remove the receiver from the rack onboard ship) during regular use and maintenance. If there's a small plastic socket near the headphone jack, that would be the clue, though some owners swapped panels to get rid of the 'unoriginal' hole.

Missed it in your original post, but the power switches on these things are notorious for welding themselves shut over time. Very common failure point, unless you've owned one for years and never had a problem, in which case I'm making it all up.  Grin I'd try googling R390 switch or something similar to see what comes up for possible sources of replacements Someone had a stock of NOS a year or so back, Fair might have some as well.

The more you play with these great sets, the more intuitive it all becomes. The R-390 is especially fun, and most rewarding. I especially like the cast aluminum criss-cross support in front.
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ke7trp
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« Reply #5 on: February 26, 2010, 12:46:25 PM »

That jack on mine is the headphone jack.  It could go to one of those contacts. I cant tell. It just looks like it was broken off over time. Someone please flip there R390 over and see.. Its a solid White wire. 

I will just put it on a power strip like the others. Its a 2 to 3 hour job to get to that switch and they are $75.  LOL

C
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WV Hoopie
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« Reply #6 on: February 26, 2010, 01:05:09 PM »

If it is the same switch as the R-390/A, Fair Radio use to sell them for ten bucks,

Craig,
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ke7trp
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« Reply #7 on: February 26, 2010, 01:10:14 PM »

I need to call them anyways.. Thanks for the tip

C
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ke7trp
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« Reply #8 on: February 26, 2010, 02:21:54 PM »

I got almost all of these parts from Ron and Gary at Fair radio.  Spent more then I wanted but I got this radio cheap and its going to be damn nice when its done.

I do need:  7 medium sized knobs and both large size knobs. This radio has an odd ball knob set on it. 


Clark
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WZ1M
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« Reply #9 on: February 26, 2010, 04:18:56 PM »

Clark: I have R-390A knobs. Email me of list.
Regards,
Gary...WZ1M
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ke7trp
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« Reply #10 on: February 26, 2010, 08:36:59 PM »

Thought you guys might want to see what I have been doing all day.. Smiley

This R390 came cheap but it also came with about an inch of Grease and Grime all over the damn thing. The worst I have seen in a long time. 

I started by checking tubes and taking inventory of the parts I was missing.  All those parts where picked up from either people on this forum, guys on the radio or Gary and Ron at Fair radio.  All parts are inbound except the knobs. 

I scrubbed this radio down by hand over the sink. I chose not to put it in the dishwasher or hose it out. Just good old fashioned work with hot soapy water got it clean. Now, the only thing that is left is the Mildew coating the military but on the radio.  The dirt and Grime is gone.

The knobs where Hand scrubbed and soaked in the sink.  The front panel was scrubbed by hand. It needs a repaint. Its now at least clean though.  Who repaints these panels?  I dont feel up to the task..

It turned out really nice.  The goal here is a nice, complete and functional R390 that I can use with my new Transmitter.  304Tls modulating 4-400s.  I think this one will be perfect.  Total investment is going to be in the $350 to $400 range. Not bad for a completed r390.

Here are before pics


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ke7trp
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« Reply #11 on: February 26, 2010, 08:38:38 PM »

And After..  I put the incorrect knobs back on because I dont have the correct knobs yet.. Once they come in, I will install them and it will look complete.

C


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ke7trp
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« Reply #12 on: February 27, 2010, 02:17:20 PM »

ANYONE have the manual for the R390?  I cant seem to find it. 

C
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w3jn
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« Reply #13 on: February 27, 2010, 02:47:42 PM »

http://bama.edebris.com/manuals/military/r390/
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ke7trp
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« Reply #14 on: February 27, 2010, 02:51:35 PM »

Thanks.. I did not notice the millitary section. I looked under Collins and saw the R390a but no R390.. 

Thanks again

Clark
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ke7trp
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« Reply #15 on: February 27, 2010, 11:24:36 PM »

Ok.. Lots of time spent today cleaning this thing.  I repainted the Meter covers and the Freq display cover. Sanded them down by hand and repainted. They look FB!

With the correct knobs, and covers, This will turn out real nice.  I mounted a hammond 600ohm to 4 ohm Transformer on the back with existing screws.  Fit nicely. 

Now I wait for the rest of the parts to arrive....

C
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flintstone mop
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« Reply #16 on: March 01, 2010, 11:15:57 AM »

CLARK
You have your hands full reviving that poor soldier!!!!
Many years of abuse and bad ju-ju.
Looks like it was left out in the weather or a really crumby loaction the last 10 yrs.

Fred
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ke7trp
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« Reply #17 on: March 01, 2010, 12:13:04 PM »

You should see it now!   Its as clean as clean can be.. Just going to do the gear train today.  Then its done inside.  I ordered the knobs.. I repainted the meter covers and freq covers.  Its really comming to life!

C
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ke7trp
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« Reply #18 on: March 01, 2010, 11:12:21 PM »

She is comming right along!

I got some basic black knobs for the radio.  They actualy look and fit great.  I am still looking for the large tuning knobs. I really hate how these look. 

I also painted the meter cover and Freq cover. I put LEDs in the FREQ cover.

The Gear train got cleaned and degreased today. I lubed the sliders, cams and gears. WOW what a difference! It turns sooooooo smooth now. 

Its going to look FB ontop of the T368!

Clark


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Ed/KB1HYS
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« Reply #19 on: March 02, 2010, 06:23:38 AM »

That rig looks sweet now!  Amazing what elbow grease and determination will do.  I have no idea about that wire, but on my  A ihave a similar wire in a similar place. It appears to have been cut off. The rig always work FB so I never bothered tearing apart the laced bundles to trace it and see what it was.  I figured I'd do more damage trying to fix a non-problem then just letting it be.
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73 de Ed/KB1HYS
Happiness is Hot Tubes, Cold 807's, and warm room filling AM Sound.
 "I've spent three quarters of my life trying to figure out how to do a $50 job for $.50, the rest I spent trying to come up with the $0.50" - D. Gingery
ke7trp
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« Reply #20 on: March 02, 2010, 11:10:06 AM »

Thanks Ed!  Its been alot of work.  But fun and it kept me busy! I just cant wait to fire it up! 


C
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ke7trp
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« Reply #21 on: March 09, 2010, 01:06:59 AM »

All the parts came in today.   The Replacement covers DO NOT fit the R390.  I compared the A to the regular and found that the regular 390 has a double thickness side bracket.  Oh well.  Guess I will send them back. I will mount this radio in a cabinet so it will be covered.

The tubes and tube shields where installed.

I made a new power cord.  3 wire with ground to the ground pin.  Looks really nice and fit right in.

The new ballast tube was installed with a shield.

I mounted the Hammond 600 ohm to 8 ohm transformer on the back using existing screws.

The reciever fired right up.  A wisp of smoke out of the on and off switch indicated this probably should be replaced. 

I had a horrible static sound with lots of microphonics. I traced this down by tapping around with a pen to the Relay on the bottom. I smacked it and it fell deaper into the socket. The noise stopped and the sound cleared up.

I tested all bands with the Sig gen. Its pretty close. 75 is dead on.  10.000 WWV is dead on.  40 meters is 4 KC off. Not sure what to set to bring this back in line.

I used it for an hour or two and listened to the AMI net. Its clear and strong on the RX.  At one point, YEC took the needed to 60 DB and I calibrated that meter Smiley The audio is about the same as my SP600.  Not nearly as nice as the 28 but I did not expect it to be. Its decent audio though. NO hum and the best noise limiter I have used. It took ALL the buzz right out.

The ONLY two problems left are:

1. The reciever wont turn off and a wisp of smoke came out the switch.. TIme for a new one.

2. The break in function DOES NOT work.  I put clip leads on the Breaking screw to ground and operated the switch.  NADA. Nothing. 

The coil on the relay is good.

There is no voltage to the coil ever, no matter the postion of the front switch or the grounded Screw terminal.

The Front switch works, I tested it with the meter.  What ever supplys this system with power is not doing its job.. Any advice on this would be helpfull!

Clark
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« Reply #22 on: March 09, 2010, 11:33:51 AM »

Those receivers had a selenium rectumfryer that supplied the power for the break-in relay from the filament circuit. The rectumfryer is probably toast (or missing). I have replaced a few of them over the years.


                                                          The Slab Bacon
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ke7trp
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« Reply #23 on: March 09, 2010, 11:38:46 AM »

ahh...   Man, I wish I had the manual printed out. Its killing my eyes to try to look at this Schematic.

C
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ke7trp
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« Reply #24 on: March 09, 2010, 05:14:45 PM »

Not many R390 people on this forum. I would think lots of you have used them or own them.  Getting no help here at all with this one Sad

I spent a few hours tracing down the break in problem. The wires are all good. There is no volts comming out of the PS for this rail. What a mystery this one is. 

I ended up clipping on to the relay contacts and then powering off my Mute buss in the shack. It works like it should. One day I will have to get a second PS or rip this one out and figure out why the hell it has no output for that tap.

I also pulled the panel today, Pretty easy really.. About 10 minutes. I took the PS switch apart. Its toast. The contacts are welded. I ordered a new one. When it gets here, I will install it. For now, Its up and running on a Power strip. I just turn the strip off when I walk out the room.

The 390 really matches the T3 nicely.. Going to use it tonight if all goes well!

Clark
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