Mr. Carlson Makes a Thermatron Power Supply for a BC-348

When I was 14, I had to make a power supply for a Heath HW-32A.   Mine ended up working, but it was nowhere near as nice as Mr. Carlson's BC-348 supply (shown in the video above).  I didn't have a sand blaster, nor a drill press, nor much of anything else, really.  

But hey, don't real boatanchor hams use Greenlee chassis punches?  What's with the drill press and the hole saws? 

Note that Mr. C takes care to make sure that the rectifier tube is in the proper angle FOR OPTIMAL VIEWING.  That's some serious attention to detail OM.  And whoa, DELICATE SURFACE MASKING TAPE from 3M?  Respect!  Also, era-specific looming material. 

His point about the importance of the cardboard washers in the power transformer was really useful.  I hadn't thought about that. 

Here are the two previous BC-348 videos: 

https://www.youtube.com/watch?v=nX87kwSshZ8

https://www.youtube.com/watch?v=Zqe6CBe0iGs

Thanks Paul! 

Some Really Amazing Test Gear

Wow. Really great test gear, and an amazing parts collection.   This guy even gets a "nice workshop" comment from Mr. Carlson.   Pac1085 seems to be in Rochester N.Y. and he says he specializes in the repair of vintage audio gear.  He should have more subscribers.  Does anyone have more info on him?  

Here is his channel:  https://www.youtube.com/@pac1085/featured

Mr. Carlson's ART-13 Transmitter (with Dynamotor)

Here we have a really cool video from Mr. Carlson.  In it he reveals (admits!) to what we already know:  HE IS A HAM RADIO OPERATOR.  FB Mr. C!

You can see that he is a true ham, with a true case of THE KNACK, when you see his reaction to the inside view of the ART-13.  He seems to gasp as he notes that there is a lot of "RF goodness" in that box.   There is a vacuum relay, a bread-slicer capacitor, there is even a variometer. And lots of good, big THERMATRONS.  Only a true ham, a true Knack victim can recognize this RF goodness. 

The Dynamotor that goes with this transmitter is really interesting to me.  I have been hearing these things whining in the background (audible noise, not a signal defect) on many early morning (Saturday 3885 kHz) of the Old Military Radio Net.  I can often hear the dynamotor of Buzz W3EMD as he transmits from Rhinebeck, New York.   It was great to see the inside of this device.  

Back in 2017, Hack-A-Day took a look at Dynamotors: 

https://hackaday.com/2017/07/04/retrotechtacular-dc-to-dc-conversion-rotary-style/

There are several good ART-13/BC-348 pictures on W3EMD's QRZ page:

 https://www.qrz.com/db/W3EMD   

I was especially taken by the handwritten frequency chart on the front panel of the ART-13.  This reminded me a lot of the handwritten readout that I have been using on various rigs, including (most recently) the 15-10 SSB transceiver. I hope Paul focuses on this paper-and-pencil frequency chart;  it is nice to step away a bit from the glowing numerals of San Jian. 

Mr. C points out that the ART-13 was the transmitter that was paired up with the BC-348 receiver.  He will be working on both in the weeks ahead. 

Thanks Mr. Carlson. 73 OM. 

Troubleshooting an Intermittent with Mr. Carlson. And Troublesome Tube Re-Branding.

This is a really great video on how Mr. Carlson (VE7ZWZ) did troubleshooting on a tube-type receiver. The problem was an intermittent.  They can drive you nuts, but Mr. Carlson show us how to stay sane. 

-- His use of ordinary observation at the start of the process is very important.  He notices a flickering glow in the voltage regulator tube.  The flickering coincides with the intermittent noise that he is trying to fix.  That is an important clue. 

-- He also can see that the grid of one of the AF amplifier tubes is getting way too hot: grid emission.  That is another important clue.  

-- He checks the grid voltage on the AF amplifier and finds that it is way too low.  It is fine on the other side of the resistor that carries the voltage to the tube.  But it is close to zero at the grid.   This means that the mica capacitors on the grid are suspect. 

-- He uses some fairly esoteric test gear -- a homemade device and an an old Heathkit signal tester -- to check his diagnosis.  They confirm that the mica caps are the problem.  He replaces the caps and the problem is gone.  A very satisfying troubleshoot. 

Mr. Carlson presents us with a lot of good info: 

-- 6K6 tubes were often in fact 6V6 tubes.  And 12AX7s were often 6VJ8s!  Manufacturers were deliberately re-branding tubes. So we shouldn't be surprised if some of our solid state devices turn out to be a bit different from what was promised.  This practice goes way back. 

-- I liked Mr. Carlson's final sensitivity test on the receiver -- he just waved his hand near the antenna connection and we could hear the receiver respond.  Excellent. 

-- Mr. Carlson is very negative about the use of polystyrene caps in oscillator circuits.  But we these simple and cheap caps being used to good effect in oscillators in India.  

-- The leaky and bad micas were a bit surprising.  Carlson speculates that their proximity to heat-producing resistors might have caused the trouble. 

Finally, it is interesting to hear the Canadian pronunciation of radio words:  Solder with the L pronounced (as in the UK).  Farad with the second A long and the final D emphasized (I say it just as the first two syllables of Michael Faraday's last name). 

Thanks Mr. Carlson. 

Mr. Carlson Replaces Old Capacitors -- Bathtub Capacitors

I recently posted a video from CuriousMarc about whether or not to replace electrolytic capacitors in old pieces of gear.  This is a hot topic in restoration circles. 

This week Mr. Carlson put out a video (above) in which he got rid of a bunch of "bathtub" capacitors in an old receiver. 

One of the many interesting things in Mr. Carlson's video was how his test gear initially showed the old capacitors to be good, but on further examination with better test gear he found them to be BAD! 

Out with old, in with the new!  

Mr. Carlson's New Lab and Workbench

I am very glad to see that Mr. Carlson is NOT slowing down.  In fact he has built another lab and is ramping up.  FB!  

Mr. Carlson's Grand Receiver Restoration Project -- Your Input Sought (video)

Mr. Carlson (VE7ZWZ) is launching a series of videos on the restoration of some old boatanchor receivers.  I have been working on an old HQ-100, so this all resonates well with me. 

He asked for viewer input on which of these receivers he should work on first.  I voted for the SP-600 because I wanted to see how difficult it really is to change out the infamous Black Beauty capacitors.  My second choice was the R-390, but I warned Mr. Carlson that he might need a chassis crane for that one.  No kidding.  Really.   

I look forward to watching the series.  Thanks in advance Mr. Carlson. 

Mr. Carlson's New Lab. And his Amazing Tek Collection

Mr. Carlson Restores an All-American Five -- Tribal Knowledge! SITS! Flattening the Curve! (video)

It is always a pleasure to see a new video on Mr. Carlson's awesome YouTube channel, especially in these days of Staying-In-The-Shack (SITS).  Obviously Mr. Carlson is doing his bit in this area.  FLATTEN THE CURVE!   Thanks OM! 

My recent bout of S-38E madness has peaked my interest in the All American Five design, so this March 10, 2020 video was especially interesting to me.  Mr. Carlson puts out so much great tribal knowledge.  I didn't know about "rounder" resistors.  I didn't know that you have to be careful not to short out (to the IF can case!) the 455 kc transformers.  I really like his approach to dial cord restoration.  

Mr. Carlson's discussion of the adjustment of the front end tuner circuit on this broadcast band radio was very interesting.  Unlike the S-38 radios, there are no front end coils being switched in as you change bands. In fact, it appears that that big coil/antenna inside the back cardboard piece IS the front end coil.  This discussion has caused me to question my front end alignment technique for the S-38E.  Did I have an appropriate antenna or antenna substitute across the antenna terminal when I set the peak on the input LC circuit?   I will check on this.  Hooray!  One more thing to do during the COVID-19 SITS period.  

UPDATE:  I checked on this using the test set up described in an earlier post, but this time with my antennas connected.  First with a 40 meter dipole, then with my 130 foot doublet, then with a 50 ohm dummy load I was still able to see the resonance dips at exactly where I wanted them to be. 

My favorite bit of Carlsonian wisdom from this video?  Mr. C's confirmation that some hum in All American Five receivers IS NORMAL!  (This may be too much for the folks who find normal band noise to be offensive.)  

Mr. Carlson's Lab Attacked by Dangerous Canadian Snow Static! (Video)

Even when describing something as simple and basic as snow, Mr. Carlson is electronically awesome.   This video made me realize that in the event of an EMP, his will probably be the only lab to survive.

The SolderSmoke Daily News took up the topic of snow static back in 2011.  Be sure to read the comments, especially the one from KC7IT about the QUARTER INCH ARCS that woke him up in the dorm at MIT.  Check it out: 

https://soldersmoke.blogspot.com/2011/10/snow-static.html#comment-form

I've got to get one of Mr. Carlson's 2020 calendars!