1959-1962 Zenith
"Super De Luxe Trans-Oceanic Portable"
Model B600 / Chassis 6A40
Short-Wave Radio Restoration

Zenith "Super De Luxe Trans-Oceanic Portable"
Model B600 - / Chassis 6A40



Years Produced: 1959-1962

Found in a Barn:

I found the Zenith Trans-Oceanic model B600 on Thursday September 13, 2007 in a junk barn near Bar Harbor, Maine. The condition was undamaged and 98% complete, but very dusty with some serious surface grime. Nothing a little soap and water could not remedy. The cabinet's brass trim was in nice condition too. There were only two apparent physical problems with the radio and those were: 01) a broken tuning dial cord, and 02) the red "ladder line" to the Wave Magnet antenna (for broadcast bands) had been nibbled by mice. Fortunately, there were no leaking batteries inside, but there were remnants of a mouse nest (copious sunflower seeds and floor carpeting) in the battery compartment. I discovered more wire damage and a missing tube (50A1) when I got it home. The barn mice are going to miss this radio.

The final incarnation of a distinguished line of Zenith short-wave tube radios, the Trans-Oceanic model B600 includes a neat little fold-down log book and a telescoping, seven section, 52 inch (132 cm) Waverod antenna (for short-wave) with a fluted cap and retaining clip. The historical significance of the model B600 is that it was the last portable vacuum tube radio made in the U.S.A. The model B600 was produced from 1959-1962 and was highly prized in its day.

The history of the evolution of the Trans-Oceanic is an interesting one. There is a book called, "The Zenith Trans-Oceanic - The Royalty of Radios" which is an excellent chronicle. Authors are: John H. Bryant, AIA and Harold N. Cones, Ph.D. See Literature page for details.

Found at Super's Junkin' Co. Route 102 in Town Hill, Bar Harbor, Maine (207-288-5740 / super ]at[ acadia.net). The negotiated price was about $45, but the radio was included with a number of other items, so the exact price is not possible to determine.

Details:

Tuning Range:

Seven switchable bands provide the following coverage:

Standard Broadcast: 540 - 1600 kHz
Weather Band: 4.0 - 9.0 MHz
Weather Band: 2.0 - 4.0 MHZ
16 meter Band: 17.40 - 18.20 MHz
19 meter Band: 14.80 - 15.60 MHz
25 meter Band: 11.40 - 12.20 MHz
31 meter Band: 9.30 - 9.90 MHz

Valve (tube) Lineup:

1U4 (RF amplifier)
1U4 (IF amplifier)
1L6 (Converter) (rare tube)
1U5 (Detector / AVC / First audio)
3V4 (Audio output)
50A1 (Current regulator / Ballast) (rare tube)
Table 1:
Tube Testing Results and Replacement Prices
Original Tube Tube Type Tested (AWA Museum) 30-sep-2007 Replacement
1U4 RF amplifier bad (Zenith tube) 1U4 - $4.60 (tubesandmore.com)
1U4 IF amplifier good (RCA tube) N/A
1L6 converter good (Sylvania tube) N/A
1U5 detector  / AVC / first audio weak (Zenith tube) 1U5 - $6.15 (tubesandmore.com)
3V4 audio output bad (Sylvania tube) 3V4 - $5.95 (tubesandmore.com)
50A1 current regulator / ballast discovered missing
23-sep-2007		 replacement tube: "D5TF30"
Radio Daze $27.00
24-sep-2007

Mains:

Battery Power:

Wanted / Needed:

References: Important Schematic Information:

The website, "Nostalgia Air" (www.transoceanic.nostalgiaair.org) has an on-line .pdf schematic for the Trans-Oceanic model B600 with chassis 6A40, but it did not match what was in my Trans-Oceanic model B600 with chassis 6A40. Fortunately, the only thing I lost was the time spent making a capacitor shopping list. Even though the .pdf file annotations clearly indicate it was made for the model B600 with chassis 6A40, the component values on the .pdf file were not even close to the component values I found in my radio. My particular radio has "MODEL B600" printed on the inside of the rear cabinet door, and has "CHASSIS 6A40" printed on the rear of the chassis. So, I do not think the chassis has been swapped. I conclude that the on-line .pdf files are for another model, not the B600 with the 6A40 chassis.

The correct schematic for the Zenith Trans-Oceanic B600 with chassis 6A40 can be found at many local public libraries under the name Sam's Photofact (Set 381 - Folder 16).

Sam's Photofact (Set 381 - Folder 16): Before you pay top price (eBay, on-line vendors, etc.) for photocopies of Sam's Photofact Sets, check the public library first. Many of them still have the old Sam's Photofact Sets readily available and will let you make copies for a nominal fee. A photocopy of a typical twelve-page Sam's Photofact Set will cost about $1.50 at the public library. Learn more.

Restoration History:

17-sep-2007 (Monday - vacation): Removed the plastic faceplate and cleaned all the plastic knobs, push-buttons and the tuning dial with a toothbrush and Murphys Oil Soap ®. Vacuumed the sunflower seeds and scattered debris out of the cabinet. Used Kiwi ® black shoe polish paste on the "Black Stag" exterior of the Trans-Oceanic B600. Used Novus ® Plastic Polish #2, and Meguiar's ® Cleaner Liquid Wax on the Wave Magnet antenna housing. This initial cleaning took several hours but was well worth it.

19-sep-2007: Bought a photocopy of the Owner's Manual and Sam's Photofact set for the radio from eBay. The Photofact Set was not advertised as such, but that is what it was. Price was: $9.75 plus $3.00 shipping. The quality was not very good. The schematic part of the Sam's package was illegible on the smaller print. The larger photos were dark and not very good quality. I got rooked on this one.

19-sep-2007: Bought a "made-to-scale, high resolution replica" of the radio User's Guide. Price: $13.95 plus $4.95 shipping. Seller emailed and said they would not be able to ship until 24-sep-2007.

23-sep-2007 (Sunday): Removed the radio chassis from the cabinet. Used a 5/16" socket to remove the two screws from the underside of the radio cabinet. There are two access holes in the base of the Trans-Oceanic cabinet to get to the 5/16" screws. I discovered that the Type 50A1 (current limiting) tube was missing. Also discovered further minor wire damage by the mice. Will need to order some #20 AWG, cloth covered, stranded wire (black, red, white) to replace the frayed wires.

24-sep-2007 (Monday): Printed and studied the on-line .pdf schematics and made an inventory of the capacitors to prepare a shopping list. Discovered that the on-line .pdf file for the model B600 on the www.transoceanic.nostalgiaair.org site was not even close to what I found in the radio. The correct schematic for the Zenith Trans-Oceanic B600 with chassis 6A40 can be found at many local public libraries under the name Sam's Photofact (Set 381 - Folder 16).

24-sep-2007 (Monday): Purchased the missing 50A1 tube from Radio Daze. Price was $27.00. The replacement tube was actually a Type "D5TF30", which is supposed to be the same as the 50A1. Since NOS (New Old Stock) 50A1 tubes were ranging from $59.00 to $89.00 I was happy to get this D5TF30 for $27.00.

25-sep-2007 (Tuesday): Copied the Sam's Photofact (Set 381 - Folder 16) at the Rochester Public Library. Cost: $1.65.

30-sep-2007 (Sunday): Test tubes at the AWA Museum. Three bad tubes: 1U4, 1U5 (Zenith tube), 3V4.

30-sep-2007 (Sunday): Create table of replacement parts to be ordered.

02-oct-2007 (Tuesday): Placed order for tubes, capacitors, cloth covered wire, dial cord, tension springs, etc. See table below. Ordered from AES (Antique Electronic Supply).

02-oct-2007 (Tuesday): Received dial cord in mail from Dave Thorn.

04-oct-2007 (Thursday): Purchased ($10) original red Wave Magnet antenna wire from a member of the Trans-Oceanic Yahoo! group. This is a 300 ohm balanced line.

06-oct-2007 (Saturday): Received new Wave Magnet wire (red, 300 ohm, balanced line).

09-oct-2007 (Tuesday): I compared the new Wave Magnet wire (red, 300 ohm, balanced line) which came from another Trans-Oceanic B600, to the one in my project radio, and it did not have the same green wire going to the "G" terminal (see photo). Is the green ground wire correct and original? It is very conveniently located next to the "G" (ground) terminal of the chassis, but the solder on the green wire does not look factory original, and the schematic does not indicate a ground connection at "L1" (loopstick, a.k.a. Wave Magnet). I will assume it was added later, and not add a similar ground connection to the new balanced line.

10-oct-2007 (Wednesday): Stopped at Radio Daze on my way home from work to buy the capacitor value I forgot to order from AES. Radio Daze part number "C-MF.01-630". Value is: 0.01 µF, 630V, "orange drop" (needed 1, bought 2). Also got a 5 inch section of ground wire (braided, small gauge) for the telescoping short-wave Waverod antenna shaft. The ground wire was a little bit large, but it soldered into the pin just fine. Still need to solder the other end to the Waverod shaft. Screwed the Waverod telescoping antenna back into the Black Stag cabinet to keep it out of the way. Also soldered the new red, 300 ohm, balanced line into the Wave Magnet loop antenna assembly.

Replacement Parts:

Table 2:
Replacement Parts for Zenith Trans-Oceanic B600
Compiled: 30-sep-2007 through 02-oct-2007. Placed order: 02-oct-2007
Vendor: "AES" (Antique Electronic Supply - www.tubesandmore.com)
Schematic part number Original component and composition Value (original) Value (replacement)
 Composition of new part Vendor (Part number) Price ($) Quantity (actual) Ordered Total ($)
V1 RF amplifier and/or IF amplifier (valve) 1U4 1U4 miniature glass vacuum tube AES (1U4) 4.60 2 1 (only one 1U4 valve tested bad) 4.60
V4 detector / AVC / first audio (valve) 1U5 1U5 miniature glass vacuum tube AES (1U5) 6.15 1 1 6.15
V5 audio output (valve) 3V4 3V4 miniature glass vacuum tube AES (3V4) 5.95 1 1 5.95
C1 four-section electrolytic capacitor A: 60 µF 150v, B: 20 µF 150v, C: 40 µF 150v, D:200 µF 150v N/A N/A N/A N/A 1 0 0
C2 electrolytic capacitor 12 µF 150v 10 µF 160v (12 µF is not readily available) axial lead electrolytic AES (C-ET10-160) 0.91 1 2 1.82
C34 paper capacitor 0.047 µF 200v 0.047 µF 600v SBE 715P orange drop AES (C-RD047-600) 0.97 1 2 1.94
C9, C38 paper capacitor 0.047 µF 400v 0.047 µF 600v SBE 715P orange drop AES (C-RD047-600) 0.97 2 4 3.88
C37 paper capacitor 0.047 µF 600v 0.047 µF 600v SBE 715P orange drop AES (C-RD047-600) 0.97 1 2 1.94
C26, C32 paper capacitor 0.022 µF 200v 0.022 µF 600v SBE 715P orange drop AES (C-RD022-600) 0.87 2 4 3.48
C29, C33 paper capacitor 0.022 µF 400v 0.022 µF 600v SBE 715P orange drop AES (C-RD022-600) 0.87 2 4 3.48
C39 paper capacitor 0.1 µF 200v 0.1 µF 600v SBE 715P orange drop AES (C-RD1-600) 1.16 1 2 2.32
C36 paper capacitor 0.01 µF 600v 0.01 µF 630v SBE 715P orange drop Radio Daze (C-MF.01-630) 0.31 1 2 0.62
M1 selenium rectifier current (measured) 0.63 1N4005 (1A, 600v) diode silicon AES (P-Q1N4005) 0.25 1 2 0.50
M2 selenium rectifier used with 220v adapter (if applicable) 1N4005 (1A, 600v) diode silicon AES (P-Q1N4005) 0.25 1 2 0.50
R36 dropping resistor for "M1" rectifier 130 ohm, 3w 150 ohm, 5w power resistor to compensate for efficiency of new "M1" silicon diode rectifier wire wound AES (R-Q150) 0.70 1 2 1.40
N/A dial cord diameter unknown 0.028" dia. cloth AES (S-M75) 1.00 per foot length unknown 6 feet 6.00
N/A tension springs for dial cord original size unknown new size unknown metal AES (S-H400) 1.00 per 10-pack 3 1 (package of 10) 1.00
N/A wire (red) red #20 AWG stranded, cloth covered #20 AWG stranded, cloth covered #20 AWG stranded, cloth covered AES (S-W705L-25) 6.75 per 25' spool 1 foot (approx.) 1 (25' spool) 6.75
N/A wire (white) red #20 AWG stranded, cloth covered #20 AWG stranded, cloth covered #20 AWG stranded, cloth covered AES (S-W709L-25) 6.75 per 25' spool 1 foot (approx.) 1 (25' spool) 6.75
N/A wire (black) red #20 AWG stranded, cloth covered #20 AWG stranded, cloth covered #20 AWG stranded, cloth covered AES (S-W704L-25) 6.75 per 25' spool 1 foot (approx.) 1 (25' spool) 6.75
Final Order
Vendor (Part Number) (Quantity) (Date Received):

AES (1U4) (1) (rec'd. 09-oct-2007)
AES (1U5) (1) (rec'd. 09-oct-2007)
AES (3V4) (1) (rec'd. 09-oct-2007)
AES (C-ET10-160) (2) (rec'd. 09-oct-2007)
AES (C-RD047-600) (8) (rec'd. 09-oct-2007)
AES (C-RD022-600) (8) (rec'd. 09-oct-2007)
AES (C-RD1-600) (2) (rec'd. 09-oct-2007)
Radio Daze (C-MF.01-630) (2) (rec'd. 10-oct-2007)
AES (P-Q1N4005) (4) (rec'd. 09-oct-2007)
AES (R-Q150) (2) (rec'd. 09-oct-2007)
AES (S-M75) (6 feet) (rec'd. 09-oct-2007)
AES (S-H400) (1) (rec'd. 09-oct-2007)
AES (S-W705L-25) (1) (rec'd. 09-oct-2007)
AES (S-W709L-25) (1) (rec'd. 09-oct-2007)
AES (S-W704L-25) (1) (rec'd. 09-oct-2007)		     Grand Total: 65.83 (shipping not included)

Replacement Parts (Questions / Answers):

Since I am a relative newcomer to the realm of vintage radio restoration, I have not yet amassed a large inventory of spare parts. When I take on a new project, I like to start by making a shopping list so everything will be available when I commence work. You would not start making a cake with only some of the ingredients in the kitchen, and the same holds true for your vintage radio work. Most of the information gathering is strait forward. I scrutinize the schematic, and cross reference it to the parts list (when available) and note any components which may be subject to failure due to the advanced age of the set. These include the paper capacitors, electrolytic capacitors, and the selenium rectifier. A few resistors may be needed, and I also test the vacuum tubes so that I know what I need. So far, this basically boils down to using good organizational skills. However, there are usually a few things that need clarification before I place that order. Most of the questions involve "best practices" in the field of vintage radio restoration, or perhaps a bit of radio theory. Each project is different and provides an opportunity to learn more. This section includes some of those questions and answers as they apply to the Zenith "Trans-Oceanic" Model B600.

Question 01 (01-oct-2007):
Selenium Rectifier "M1" and "M2":
Can I substitute a Type 583-BR34 (3A 400v) silicon bridge rectifier for the selenium rectifier ("M1" and "M2" in the schematic)? According to the schematic, M2 is only used when the 220v adapter is fitted. I am not sure if M1 and M2 are part of a single selenium rectifier or not. Maybe all selenium rectifiers had four leads, and to replicate one, I would need four diodes, but I just do not know that for certain.

Or perhaps I should use two separate 1N4005 (1A, 600v) silicon diodes. One for M1 and one for M2 (if applicable). The reason I ask is because it looks like the selenium rectifier (M1 and M2) are two separate diodes in the schematic. They appear to be half wave rectifiers. They are not drawn as a four diode "bridge" (full wave rectifier) as found in the Grundig "2066 PX" radio schematic.

Answer:
Use separate diodes. These diodes are individual units in the set. You may not even have the 220 volt adaptor. It plugs into to the top of the chassis and looks like a caged square box.


Question 02 (01-oct-2007):
Does a replacement diode need a dropping resistor?
To compensate for the efficiency of a new silicon bridge (or diodes), a "dropping" resistor of about 100 ohm / 5W would be required. Would new silicon diodes need a dropping resistor too?

Answer:
The new diodes (individual or bridge) have a silicon junction that will drop 0.7 volts. The selenium rectifiers dropped from 10 to 40 volts depending on the diode and current flowing through. You should use a series resistor to drop the extra volts. Set the series resistor R36 (originally 130 ohms 3w) (after "M1" on schematic) up to about 150 ohms and re-check your B+ (plate voltage relative to the cathode). Adjust the resistance to get B+ correct. Check your line voltage first. Somewhere in the Sam's Photofact Set it will specify the line voltage. If your line is not on the specified test voltage, then mentally compensate the B+ in your head. The schematic shows R36 as a 3w resistor. So, a 3 watt minimum for the replacement is fine. To be sure, measure the voltage drop across your final value resistor and use Ohm's law to figure the actual power (in watts) (P = EČ / R) and double it for safety. The notes on the schematic say +/- 15% on the voltages.

If you have the 220 volt adaptor, set the unlabeled resistor (620 ohm 15 w) (shown after "M2" in the schematic) after setting the new R36 value. Otherwise, leave the unlabeled resistor alone.


Question 03 (01-oct-2007):
Replacing capacitor "C2" (12µF, 150v, electrolytic):
I was trying to find a suitable replacement for "C2" (12µF, 150v, electrolytic). Radio Daze and AES (Antique Electronic Supply) did not carry the exact value, and the Mouser web page returned a lot of hits, but when I drilled down into the .pdf files, the only 12 µF 150 v electrolytic capacitor was about $26.00. Mouser e-mailed me and verified this was true.

Replacement capacitors should be the exact same capacitance value (12µF in this case) and the same or higher WVDC (working voltage). So, I think I could use two 6 µF electrolytic capacitors in parallel to add up to 12 µF. Or I could also use two 24 µF electrolytic capacitors in series to get the 12 µF value. Unfortunately, 6 µF and 24 µF are not standard values either.

Answer:
C2 - Just go UP to the next commercially available/convenient µF value (15uf). No problem. Just do not go LOWER on the VOLTAGE rating (WVDC) or POOF! Capacitor C2 is for the the AVC (automatic volume control). If it is significantly larger (say, 24uf) it will slow down the AVC response. You would only notice this when tuning across loud strong stations. You would hear a slow return to loudness of the static between stations. A little smaller (10uf) should not be noticeable.

Acknowledgements:

The restoration of this radio could not have been accomplished without the support of various people and resources. Their contributions included advice, parts, and encouragement, and they made it much easier to be successful. Thank you.

Thanks to: Paul Pinyot (Pennsylvania), Dave Thorn (Penn Yan, NY - dial cord), AES (Antique Electronic Supply), Dennis D'Amico (original, red, Wave Magnet antenna wire).

c o n t a c t / h o m e
© Black Sparrow Photography / Jeff Miller
Zenith "Trans-Oceanic" B600 Short-Wave Radio Restoration
Established: September 23, 2007