I added some small calculators to the ‘Software’ link. While rebuilding a Heathkit V-7 VTVM, I just couldn’t find a good match for a couple of out-of-tolerance precision resistors in the divider network. So I built my own: a) Toroid Calculator and b)
Precision Resistor Calculator.
I was given a Drake R-4A Receiver! A local ex-ham was downsizing and wanted to make sure it went to someone (else he was going to throw it out). Went through the bandswitch which appeared to be the only thing to be cleaned. Superb receiver, so quiet. Now to see if I can acquire the accompanying Transmitter (T-4), Speaker (MS-4) and Power Supply (AC-3 or AC-4) can be found as cheaply.
TrueTone D3603A by Western Auto
This is a swell portable, sold around 1956. My mom had one of these, in Green (D3603A) — I’ve never seen an example of the Maroon model (D3604A). That old one had a melted speaker grill grid, probably where she’d set an iron too close to it. It found it’s way to a garage-sale table and was gone, sometime in the 1980s.
The Less Common Color
Updated: I finally found the Burgundy-colored model a few years later. The logo “Truetone” is very faint on the front cabinet, but otherwise it’s in grand shape.
Many thanks to Mike Stute for giving me this one a couple of years ago, when I casually mentioned that my mom had had one of these.
Another in the S-38 Series from 1957-1961 era
I purchased the old radio for $30 from Jim Heye (K5WLQ). I never plugged it in, respecting the fragility of possible old paper and electrolytic capacitors, but the first thing I noticed was that the main tuning dial was strung backwards! The cabinet was nice, with a few nicks and scratches from a normal life — not as nice as I would have liked, but cleanable. The S-38E is the grey hammertone finish; it was also available in S-38EB (beige) and S-38EM (mahogany). It’s a swell example of the era, with the short (pre-1970’s) AM dial and the CD — Civil Defense — marks at 640 khz and 1240 khz.
The S-38 Series was introduced in 1946 (S-38) and were produced through 1961 (S-38E). The S-38E
was produced from 1957 to 1961, making it the end of the line, priced at about $50. Internally,
the radio is a classic “All-American 5”, which makes it very easy to work on. The original S-38 has 6 tubes, but subsequent models have 5.
Tube Lineup for the S-38E, all 9-pin ‘miniature’ tubes — a departure from the older octals:
- V1 – 12BE6 Mixer / Oscillator
- V2 – 12BA6 IF / CW BFO
- V3 – 12AV6 Detector / Audio Amp
- V4 – 50C5 Audio Output
- V5 – 35W4 Rectifier
Left to right: Antenna lugs A1, A2, Ground lug (soldered directly to the chassis!), cw adjustment (Mark II model only), phone output.
Note the use of miniature tubes. Serial number looks to be: 252816, with an over stamped Q42301. Not shown, to the right, the power cord is permanently attached.
The S-38E is a transformer-less radio, and like the S-38B, presents quite dangerous shock hazards.
At some point, however, an attempt was made to isolate B- from the chassis a bit, and to provide for some safety by bridging the B- (ground) and the metal chassis with a 470k ohm resistor in parallel with a 0.06 micro-farad capacitor. However this doesn’t completely remove 120VAC from the chassis or the antenna ground-lug, which is soldered directly to the chassis.
For safety, the switch, which is designed to connect one wire of incoming power directly to the B-, is moved to the other leg, and the newly polarized plug’s ‘neutral’ is placed at the point where the last filament is joined to B-. This assures that (provided the electrical socket is wired properly) the chassis, antenna ground-lug and B- are close to ground.
The power cord is attached to the radio. After a safety rewire, polarizing the cord assures
that the hot leg always is sent to the switch and the chassis-ground is tied to neutral.
This little radio is now receiving on all bands. I’ve received 40m CW and
11m CB. AM Broadcast is strong and clear.
- Radio is tuneable from 540KHz to 32MHz across 4 switched bands:
- Band 1 (AM Broadcast) 0.540 – 1.65MHz
- Band 2 1.65 – 5.1 MHz
- Band 3 5.0 – 14.5 MHz
- Band 4 13 – 31.0 MHz
Completed Appearance Improvements
- Cleaned the cabinet, dials, and knobs.
- Replaced some missing cabinet (back and bottom) screws.
- Finally bought some Bristol Keys to properly remove the knobs.
Always use Bristol Keys (McMaster-Carr #7048A55) to take the knobs off. Hex keys will occasionally ‘work’ to get the knobs off, but they will always destroy the little slug that holds the knob.
Completed Repair Items
- Cleaned the Band Switch, the front-panel switches and Volume Control with De-oxit
- Replaced the multi-stage Electrolytic with a terminal strip and 4 separate electrolytics
- Replaced all the tubular capacitors.
- Rewired the power connection and polarized the power plug for Safety.
Clean scans of schematics are not available via internet, as far as I can find. The usual sources list the user and service manuals, but in some cases only for the ‘non-Mark II’ version. The available Mark II version schematic is a poor scan, in some places illegible. I replaced a tiny mica cap, C16 and if it had been missing or in bad shape, I’d not been able to read its value: 82pf. I plan to take a trip to the Dallas Library Sams Photofacts section for this and a few other scans.
- S-38E Mk II Schematic
- Service and Owners Manual
- A must buy for this and other S-38 series radios is a 10-piece Bristol L-Key Set (McMaster-Carr #7048A55).
These can be found on eBay for around $21 (plus shipping), but McMaster-Carr has the same set for $15.50 (as of Jan 2009)
The S-38E was given to a local gentleman who had contacted the W5FC Club and wanted to try some Shortwave Listening (SWL). I donated the S-38E to the cause, although antenna issues in his location limits his reception. http://www.websdr.org/ fixed that and he is now happliy listening in on CW QSOs all over.
Fortunately an identical S-38E recently replaced it, an almost pristine MKII model, which only required fresh electrolytics and power cord rewiring.
Finished the <a href=”TO-Y-600_refurb.php”>TransOceanic Y-600</a>. This is a magnificent radio and turned out nicer than I could’ve expected. A fortunate turn on this model was that the 1L6 tube is in good shape. Although in fairly ready supply, the tube has reached ‘unobtainium’ prices, even though solid-state substitutes are available. In any case the 50A1 was replaced with a solid-state replacement, which provides very stable current and voltage regulation, which is a good thing given the expense of the 1L6 tube.
Over the Holidays, finished the recap the <a href=”http://mikeyancey.com/S-120_refurb.php”>Hallicrafters S-120</a> that had been in the office.
Finished the <a href=”http://mikeyancey.com/S-38B_refurb.php”>Hallicrafters S-38B</a>; it’s seen some daily use in my office at work. This is my first run-in with the AC-DC power issue and I found a way to route the power cord ‘HOT’ through the switch to eliminate (unless the house wiring at the socket is reversed) shocks from a faulty cabinet insulator.
I snagged three Astron power supplies recently from a listing on Craigslist. It was quite an inexpensive buy, but they were heavily abused and needed some repair, so overall, it won’t work out to a huge profit, but it gives me an opportunity to apply some skill and come out on top.
The previous user, I’m told, was a car-stereo seller and used the Astrons in a large display of car stereos.
From the group, there was a 35-amp RS-35A which, after testing, appeared to be in fine shape; only the fuse was out of order – the previous user had replaced the 8A ceramic fuse with a 10A glass, 3AG fuse – both incorrect and unsafe. The large value would allow more current to be drawn than what it was designed for; ceramic fuses are more resistant to breaking given the high current. Replaced the fuse, tested the supply for regulation under load and it’s now powering my FT-897D.
The two others, both RS-50A models were substantially abused and showed signs of having been run well over-current and for longer than the 50% duty-cycle.
But both still provided regulated voltage!
Both had incorrect fuses – replaced both with correct 10A, ceramic fuses. One had a 20A, 32V fuse (on the 120V primary!). Both had burned wires and the large filter caps (100,000uf in one and two 51,000uf in the other) were toasted.
Astron supplies replacement parts, so I’ve already repaired and tested the newer model with the single 100,000uf cap. Now waiting for two 64,000uf caps to repair the other. I had to make replacement 13.8-volt ‘common’ cables with black, 10ga wire. That ought-a hold ’em.
How a Club Loaner Rig Becomes New Again.
This seemed like an extensive redo, but was not, because many of the boards went mostly untouched. It began with a redo of the HP-23 power supply with an HP-23RL board from The Heathkit Shop. And it ended with replacement of two of the Carrier Oscillator crystals, which with age had changed too much to adjust with serial or parallel capacitance.
For kits anyway, this was the pinnacle – the tip-top. No one would ever make a 20-vacuum tube transceiver again.
I purchased the rig and power supply for $75 from a W5FC
club sale of some old gear. The radio worked, having been gone through by the venerable OM, Don (W9VE).
However, a few issues cropped up, including an un-nulled carrier and a significant difference in
USB and LSB – USB is very muddy sounding and power output was low; LSB was completely normal and contacts
on 40m were made every time the rig was powered up!
In addition, CW output was almost nil with the CW filter in. Both the USB and CW issues pointed to the
center frequency of those two modes being outside the filter passband. Still, it was quite a buy, since
the HP-23B power supply can be found for well over $75 all the time on eBay.
The rig has stickers from the Heathkit factory where apparently it had been shipped to correct some
problems. These stickers date the rig’s assembly at before 1972. The rig works well with a Turner mic
(also from the same W5FC sale) and a later, fortunate fined was a brand new Electro-Voice 719 microphone
with the box, instructions, and (blank) registration card for $9.99 on eBay.
I chose to only do invisible or ‘functional’ mods which didn’t significantly alter the radio. But here are a list of Service Bulletins and the most popular (and necessary) Mods.
Subsequently found an SB-600 speaker, with an additional HP-23A inside for cheap. This had been
originally built by WB8LOL – now K5LOL, Thomas, who’d built it originally built the unit in Detroit. He,
and the rig, found their way to Texas and via K5BJI (Mike Goidl), I obtained the supply.
As a result of all the research, I’ve found some superb resources for part. Here are a few.
- McMaster-Carr – superb online catalog and search tool
- 9540K33 7/8″ x 5/8″ w/washers – feet for HD-10
- 9540K56 25/32″ x 9/16″ w/washers – feet for HW-101 – fits #6 machine screw
- Elliots Hardware – great stock of fasters (McMaster-Carr Numbers)
- 90054A148 – #6 1/2″ Hex Washer sheet metal screw
- 90054A146 – #6 3/8″ Hex Washer sheet metal screw
- 90053A144 – #6 1/4″ Sheet Metal – for RF Cage
- Ralphs Electronics
- Amphenol 2-pin, Mic Plug – http://www.ralphselectronics.com/ProductDetails.aspx?itemnumber=AMPH-80MC2M
- Amphenol 2-pin, Panel Jack – http://www.ralphselectronics.com/ProductDetails.aspx?itemnumber=AMPH-80PC2F
- Type 86-3-24 – strain relief cover –
- Type 86-CP11- 11-pin Plug –
- Type 78-S11 – 11-pin Socket –
- Panel Mount of 78-S11 requires –
- Plain Cover –
- Type 86-3-24 – strain relief cover –
- Leeds Radio in New York.
- http://www.leedsradio.com/parts-sockets.html (78-S11)
- http://www.leedsradio.com/parts-connectors.html (86-CP11)
There appear to always be a few items remaining to do, but the HW-101 operates properly now and
I’ve had two contacts so far: first on 20m (WA7ND) and the USB appears to work, but the Electro-Voice
mic connector shorted out temporarily ending that QSO. Secondly, on 80m with KC9MOS and the
ElectroVoice mic cord appeared to be working again for the duration. I’ll continue to be looking
for bad out-of-spec parts that might show up in performance, but the rig is working nicely!
Completed Appearance Improvements
- Replaced the front panel with a fresh, clean one.
- Replaced the rubber feet – McMaster-Carr 9540K56 is a perfect fit for the HW-101
- Replaced some missing cabinet screws.
Completed Functional Mods and Improvements
- Improved the power supply with a re-cap via the HP-23RL board, cleaning up some poor assembly and soldering.
- Converted to handle Low-Z headphones – external speaker now mutes properly with “modern” 32-ohm headphones.
- Improved the CW operation by increasing drive to the VOX relay
- Killed most of the CW side-tone audio on key-up by dumping sidetone to ground.
- Some mods had already been done, including the meter zeroing issue and some TX/RX improvements.
- Replaced the poorly soldered Amphenol MIC jack.
- Rebuilt the old power cord to supply 120V AC to the Power Switch on the HW-101
Final Completed Items – December 2008
- Replace the USB and CW carrier oscillator crystals – bringing the CW and USB right back into IF passband, probably within 100hz or so.
- Replace the old RCA RF Out jack with a BNC connector. The BNC is better than either the old RCA or a ‘UHF’ connector, plus the single-hole, bulkhead mount BNC didn’t require enlarging the hole.
- Actually found a nearly broken output connection while replacing the RCA antenna connector – fixed.
- Decided to not add a volume control to the side-tone. Maybe at a later date.
- Replaced the grotty old 1/4 inch headphone jack.
- Replace the Carrier Null pot with a new 200 ohm trimpot
Continuing Updates – May 2009
- Swapped the 6EA8 Speech Amplifier (V1) with the 6GH8A which is a higher output version.
My 25-year-old Weller WTCP gave out.
I was repairing one of the two Astron RS-50A power supplies I picked up recently and when I swapped the tips to get more heat out to the massive transformer center-tap… nothing. No clicking. The neon light was on, but no heat was home. It was a terrible discovery.
I’d had that old iron since Mostek. I think I bought it at some employee discount. Lots of projects from the old days and from recently were completed with that good ol’ tool.
So, my choices were to buy a replacement soldering pencil from Fry’s for $69.99, or just get a new one; the WES51 is not much more and is ESD and has a variable heat control. So I sprung for the new iron. But now: what to do – part out my old friend? Can’t let that 2A transformer go to waste. But I can’t hack apart an old friend. Aw, heck, went right back to Fry’s and snagged a TC-201A pencil to go with it. Now it’s the garage soldering iron. I think we have soldering covered here at the house.