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Tube Radio Restoration

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Presentation on theme: "Tube Radio Restoration"— Presentation transcript:

1 Tube Radio Restoration
Paul from Penn Hills KB3LZP Oct 23, 2007 KB3LZP

2 Introduction. This lecture is to cover the basic techniques of Tube Radio chassis electronics restoration. Cabinet is not covered. Resources No knowledge of electronics is required but it does help a lot. A properly restored tube radio can give many year of service, pleasure and a sense of accomplishment. Oct 23, 2007 KB3LZP

3 What is covered. What level of technology are we dealing with.
Identify your tube radio candidate. To plug it in or not. Safety. Steps to restoration. Parts identification. Why replace good looking parts. Oct 23, 2007 KB3LZP

4 What is covered Cont’d. Tubes go bad often, NOT. Replacing Capacitors
Replacing Resistors Power Cords and polarized cords. Cleaning, Dial cords, Miscellaneous. Power up. Initial tests and checks Alignment equipment Oct 23, 2007 KB3LZP

5 What is covered Cont’d. Alignment Burn-in Alignment again. Enjoy
1940 Motorola Catlin US $2,550.00  Sep-05-07  22:39:25 PDT (6 days 1 hour) Oct 23, 2007 KB3LZP

6 1. Level of technology Pre war 1930’s up through 1960s Hollow state.
AM Old FM megahertz pre-war band The Zenith Bakelite set pictured had the old 45MHz FM band. Domestic or European These restoration techniques apply to any vintage technology, Hollow or solid state. Oct 23, 2007 KB3LZP

7 Radio Tubes 80 12SA7
12SQ7 Oct 23, 2007 KB3LZP

8 Tube Data Beam Power Pentode
High Voltages Oct 23, 2007 KB3LZP

9 2. Identify your tube radio candidate.
Is it a family radio of sentimental value? Do you like the way it looks? Will you like tube sound. Do you just like it? Is the price right? $101 and 25hrs left Oct 23, 2007 KB3LZP

10 Black Dial Tube Count Popularity Exposure Oct 23, 2007 KB3LZP

11 Wires Alignment Availability Cost Sockets 37-611 Oct 23, 2007 KB3LZP

12 Hallicrafters. HAM GEAR
Oct 23, 2007 KB3LZP

13 Volksempfänger (Germany)
Sonorette France Saba 310w 1930 Volksempfänger (Germany) Like Brands Cost, availability, Personal choice Restorable Oct 23, 2007 KB3LZP Grundig

14 Cost High End Chassis Case/cabinet Oct 23, 2007 KB3LZP

15 Zenith Stratosphere console radio 16-A-63
eBay item Closed at: US $21,000.00 Estimate: US $12, US $15,000.00 History: 23 bids Auction Date:Sep-15-07 07:00:00 PDT   High Bid: Internet Bidder Item location: Nashville, Tennessee USA Oct 23, 2007 KB3LZP

16 3. To plug it in or not. Do not plug in your newly acquired UNRESTORED radio. Parts can be made of “Unobtainium”. Shorted rectifier tubes can let the magic smoke out of the power transformer. Varriac Dim Bulb tester Emerson Catlin $610 4days left. Hairline crack. Oct 23, 2007 KB3LZP

17 1929 Radiola 60 after power up The Unobtainium leaked out.
Oct 23, 2007 KB3LZP

18 4. Safety Power Cord AA5’s are Transformer less Isolation Transformers
Store bought Home made VA verses Watts Transformer internal shorts use a meter. Dim bulb Work Surface, Shoes, humidity. Oct 23, 2007 KB3LZP

19 Isolation Transformer
Key Features: Primary 115VAC, 50/60 Hz., Secondary 115VAC Provides circuit isolation. Electrostatic shield between primary & secondary. Hi-pot tested to 2 KV RMS. Circuit breaker in primary. Standard 3-wire, grounded plug & receptacle. Input (primary) connected to 5 foot long cord & standard North American plug (NEMA 5-15P). Output (secondary) connected to 1 foot long 3-wire, standard North American grounded receptacle (NEMA 5-15R). North American Mark of Safety - C UL & UL listed (File #E211544) Remember - These units do NOT convert line frequency Oct 23, 2007 KB3LZP

20 BAMA 5. Steps Documentation Pull Schematic and Alignment procedure
BAMA Oct 23, 2007 KB3LZP

21 More Resources Click on “Links”
                                                PHILCO   REPAIR   BENCH • USENET GROUP Oct 23, 2007 KB3LZP

22 5. Steps to restoration - Gear
ISOLATION TRANSFORMER 100w gun, Flux, Solder, sponge Solder sucker Pliers, screw drivers, sockets VOM DVM impedance Alignment tools RF Oscillator with modulation tone Freq meter or Digital SW receiver. Screw drivers, nut drivers etc. Work surfaces Oct 23, 2007 KB3LZP

23 Oct 23, 2007 KB3LZP

24 5. Steps to restoration – Chassis prep
Separate chassis and cabinet Protect dial glass! Cover speaker Close tuning gang Blow off dust outside. Clean chassis Fabricate chassis stand. Oct 23, 2007 KB3LZP

25 5. Steps to restoration cont’. Initial checks
Check for bad parts made of Unobtainium Varmints Band switch! Power transformer (Pwr Xfmr) Audio Output transformer (OPT) IF transformers Oscillator coils Pots. Bias resistors CANDOHMs Variable air cap Antenna coils Low volts Power Transformer check Full voltage no Pwr Xfmr load check. Tube Testing Use the Red and Green pencil on the schematic. Oct 23, 2007 KB3LZP

26 Nice Radio? Oct 23, 2007 KB3LZP

27 Mr. Jingles slept here Oct 23, 2007 KB3LZP

28 5. Steps to restoration cont’ Selecting and acquiring parts
Capacitors Electrolytic Silver Mica Poly…… Resistors Inductive resistors Power Tubes, Test with Emissions or mutual conductance tester. See for some tube theory. Metal Tubes Pin 1. Tube base size in Philco shields. Oct 23, 2007 KB3LZP

29 Using GT tubes as substitutes for non-GT tubes
From "Radio News" Warrn J. Dougherty11/44      Warren J. Dougherty, a serviceman of Kinkaid, Kansas, has called to our attention one of the factors most overlooked when replacing G-type tubes with the more newly-designed GT tubes. Invariably these GT tubes, with metal base, have their No. 1 pin grounded. Inasmuch as many manufacturers use all available socket pins for common tie-points, considerable damage may be caused when grounding the No. 1 pin. A particular case is the RCA Model BT-42 which was originally equipped with G-type tubes. When changing to GT tubes with metal base, the condenser, C16, 400-µfd. condenser and 1-megohm resister, R7, in the plate circuit of the 1H5 should be disconnected from the No. 1 pin of the 1N5 tube socket, as in this particular case, it was used as a common terminal connector. The metal base occasionally will short out the plate voltage from the 1H5 tube, resulting in a nonoperating receiver.   © , Nostalgia Air Oct 23, 2007 KB3LZP

30 Gas Bad Tube Oct 23, 2007 KB3LZP

31 5. Steps to restoration cont’
Wire, hookup, power cord. Dial glass/plastic, Dial scales. Hardware Cabinet parts for another day. Oct 23, 2007 KB3LZP

32 Electrolytic Capacitors
Tubular Axial Capacitors                                      Orange Dips                               Metalized Polypropylene Film Good replacement for Wax/paper caps. Metalized Polyester Film Self-healing property Metal-Foil Polypropylene Film Orange epoxy coated for superior heat, solvent and moisture resistance. Excellent stability for High Current / High Frequency / Temp. Compensation Applications. 500 Volt Dipped Silver Mica Capacitors                  Metalized Polyester Film Highly reliable with "self-healing" performance 1 pF to 5000 pF, Electrolytic Capacitors Y2 Safety and Interference Suppression Capacitors Oct 23, 2007 KB3LZP

33 Max capacitor voltage Replacing Wet Electrolytics and High Surge Dry Eelectrolytics From "radio service dealer" Solar Capacitor Sales Corp.9/44      Properly installed miniature size capacitors can replace wet and high surge voltage dry electrolytics in practically all receivers. To insure satisfactory operation, the circuit surge voltage must not exceed the surge peak voltage of the replacement capacitor (525 volts for 450 volts working). In many cases this means series connection of replacement capacitors.      To determine the circuit surge voltage, temporarily replace the faulty unit by a 1 or 2 mfd., 600 or 1000-volt paper capacitor. Then connect a 1000 ohms/volt or higher reistance voltmenter across the capacitor. Watch the meter pointer as you snap the set switch. The surge voltage is the voltage at which the pointer hesitates after its first swing before begining a relatively slow decrease to operating voltage as the set warms up. This test should be made with the highest line voltage which may occur in the location where the set will be used.      If the surge voltage is too high for a single miniature unit, connect units of the proper capacitance and voltage rating in series to serve as the replacement.      Dry electrolytics with a capacitance as low as two-thirds of the original capacitance will usually be found satisfactory when replacing wet electrolytics.   © , Nostalgia Air Oct 23, 2007 KB3LZP

34 Carbon composition ½ w about $0.20
Carbon Film 1/2 w 5% about $0.07 Carbon composition ½ w about $0.20 Use above 18 MHz 5 % tolerance Low inductance Low capacitance Watch for inductance. High quality performance at economical prices 1/2 & 1 Watt General shotgun replacement. Metal Oxide 1 and 2 watt 12/17 cents 5 % tolerance Power Supply section. Cathode Bypass Candohm replacements Metal Film ½ w about 11 cents 1 % tolerance Epoxy coated precision resistors POWER Resistors Wire Wound very inductive. 5 watt $0.37 Power Supplies Candohm replacements 10 watt $0.50 AKA Sand, cement, Ceramic, wire wounds Oct 23, 2007 KB3LZP

35 Hardware Oct 23, 2007 KB3LZP

36 Dial Scales and Covers Ben Dijkman & Co
eBay My World: jmpalm ( 190     )   Ben Dijkman & Co Oct 23, 2007 KB3LZP

37 Oct 23, 2007 KB3LZP

38 Decals Oct 23, 2007 KB3LZP

39 6. Parts Identification Waxed paper capacitors Electrolytic
Mica capacitor Ceramic Caps Polystyrene capacitors MicaMold capacitor Carbon Comp resistors, American, European Power Resistors Candohm Selenium Diode Oct 23, 2007 KB3LZP

40 7. Why Replace good looking parts
Capacitors Resistors Pilot lamps Wire Line Cord Fuse Dial String Known problem parts (i.e. Philco 370pf, 6X5 rectifier tube shorts) Oct 23, 2007 KB3LZP

41 Oct 23, 2007 KB3LZP

42 Candohm Grounded tab Oct 23, 2007 KB3LZP

43 Oct 23, 2007 KB3LZP

44 8. Tubes go bad often, NOT. Tubes last a long time unless abused
Test all tubes - Does it work in the radio? Mutual Conductance Emissions Eye Tubes EM34, 6E5, 6E5C, 1629 Sources of tubes, NOS or Used Oct 23, 2007 KB3LZP

45 Oct 23, 2007 KB3LZP

46 Filament voltage booster
Oct 23, 2007 KB3LZP Add a B+ switch to extend tube life

47 9. Replacing Capacitors Test all new caps Leave tubes in sockets!
Waxed paper caps clip and solder Electrolytic Restuff Add a terminal strip Solder onto convenient points RF Bypass/UL rated safety caps. Transoceanic comments Silver Mica Disease Oct 23, 2007 KB3LZP

48 Transoceanic B600 C46 Oct 23, 2007 KB3LZP

49 ~90v ~90v C40 C45 Silver Mica Disease Oct 23, 2007 KB3LZP

50 C2 Oct 23, 2007 KB3LZP

51 10. Resistors Test all new resistors Clip and solder
Combinations parallel and series. Add a terminal strip. Heat dissipation power resistors Inductance above 18MHZ Pilot lamps on a rectifier tube filament. Oct 23, 2007 KB3LZP

52 Volume Controls High Resistance Tapped Switched Cleaning/replacement.
Linear, logarithmic, audio taper. Oct 23, 2007 KB3LZP

53 11. Power Cord Replace it with Zip Cord and a new plug.
AA5 Hot chassis Audio Output tube is to be near neutral potential. HUM Ref. Radiotron Designer's Handbook, Fourth Edition, P. Langford Smith, 1952? GFI on an AA5 Adding a fuse. Power Transformer chassis leakage. Oct 23, 2007 KB3LZP

54 12. Cleaning, Dial cords, Miscellaneous.
CRC Contact Cleaner Chassis cleaning (Tape tube sockets) Replace Dial cord. Grommets for tuning cap and line cord Dial scale replacement. Speaker cone repairs Oct 23, 2007 KB3LZP

55 13. Power up Clean the bench first.
Look at each tube pin, terminal lug and trace parts for cold solder joints. Use an Isolation Transformer even on transformered units! Use a Variac with volt amp meters Amp Clamp Multiplier trick Dim Bulb Tester. Oct 23, 2007 KB3LZP

56 Inrush Current limiters
Oct 23, 2007 KB3LZP

57 Initial tests and checks
Tube filament glow Snapping sound Magic smoke. Static Thunder Storm static crashing silenced with volume control. Hum Tuned to a station swap plug. No station Not affected by volume control. Check transformer phasing for minimal leakage. Check all B+ and bias voltages. Oct 23, 2007 KB3LZP

58 Alignment - Gear RF Generator
Isolation Transformer time! Coverage of radios capabilities 400khz to 20 MHz Harmonics 110 MHZ for FM radios IF frequency khz 225 khz autos 12.7 mhz FM radios AF modulated tone Oct 23, 2007 KB3LZP

59 Alignment - Gear VTVM or High Impedance DVM Frequency Counter
B+, Line voltage, AGC and Audio Output Frequency Counter Digital SW receiver Alignment tools IF core When to use - Wood, plastic, fiberglass, metal, Allen wrench. Trimmer caps Seal from slipping. Birthday candle Fingernail Polish Oct 23, 2007 KB3LZP

60 Alignment - Procedure Burn in 30 minutes No fast moving breezes
Follow Instructions IF affects dial linearity Clean and bake band switch Denatured Alcohol Bake oscillator and IF coil(s) Don’t forget to Align dial indicator Use generator lead draped over chassis, loop or internal antenna Watch max output on HP-606 signal generator. Oct 23, 2007 KB3LZP

61 Hot Chassis AC-DC Radio.
AA5 Hot Chassis AC-DC Radio. Oct 23, 2007 KB3LZP

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67 Grundig 88U 3 tube 5 sections
Transformered AC radio Oct 23, 2007 KB3LZP

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70 Parts Sources "King Of Controls!" Mark Oppat's Rubber, knobs, buttons Mark Oppat's Oct 23, 2007 KB3LZP For more vendors see: and follow the “Links” button

71 Resources rec.antiques. radio+phono Converting to a 6E5C Octal tube
USENET Newsgroup rec.antiques. radio+phono Parallel Resistor calculator Converting to a 6E5C Octal tube www. DjVu Solo 3.1  Use for BAMA files. Oct 23, 2007 KB3LZP

72 Philco 38-9 Oct 23, 2007 KB3LZP

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85 Thank You You can find this presentation on:
Links Page. Oct 23, 2007 KB3LZP

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