Presentation on theme: "Bring to first night PHILCO decal and set for W3ENM Tube tester"— Presentation transcript:
1 Bring to first night PHILCO decal and set for W3ENM Tube tester Dim bulb testerIsolation XFMRLead TwisterHand tools.Handouts.AA5 chassis.
2 How to Restore Your Tube Radio “Project” A Paul Pinyot, Solder Smoke and Burnt Finger presentation,to NHARC March 7th, 2012
3 Objective and GoalsMake an old tube radio chassis work good again. There will be minimal cabinet restoration techniques covered or suggested.To get hands on practical experience with old radio technologyEnjoy listening to the product of your Hands-On efforts.Have fun!
5 ScheduleMarch 7, Open to all! Kick off. This presentation and preparation discussion.March 8 through 27. Acquire your radio and service documentation (see presentation).March 28 pick parts and test tubes. I will bring a tube tester, parts bins (capacitors, resistors, lamps) for you to purchase replacement parts at my cost to you.April 4 and 25, and May 2. Continue restoration at NHARC.May Dayton Hamvention.May 23 electronic alignment. (see presentation).End of project.
6 What you need to COMPLETE your project An understanding of electrical safety and hazards.A radio and new replacement componentsService documentation (schematic, alignment data).A moderate to high soldering skill levelHand tools including:Soldering iron >=25w, rosin core solder, small wire cutters, Needle nose pliers, screw driversExtension cord for activities at NHARC meetings.Optional “lead wire twister” (see presentation).An assortment of other non specified hand tools are helpful.
7 What you need cont’. Contact cleaner and light lube oil. A copy of the steps in this presentation.About 8 to 16 hours for a five tube radio.About 10 to 40 hours for > five tube multi-band consumer radio chassis.Work at home commitment. There will NOT be enough time at NHARC meetings to complete a restoration.
8 Beyond this project’s scope Cabinet RestorationCommunications gear including but not exclusive to:Receivers like Hammarlund, Collins, Hallicrafters (except the S-38 line and similar).Transceivers.Transmitters.Hybrid gear (transistors, IC).
10 Steps to restoration Locate your radio. Find documentation before purchasing.Inspect and photograph (before restoration).Test for operationDisassemble and save all partsCold test all Transformers and coils.Test all tubes.
11 Order replacement tubes and other long lead items. Shine up chassis if so desired.Inspect wire insulation. Replace power cord.Acquire capacitors, resistors and lamps.Lay out copy of schematic including red and green pencilsReplace capacitorsReplace resistorsOpen IF cans and replace resistors.
12 Replace power cordClean controls and switchesDim bulb test your work then direct to line.AlignmentBurn-in for => 8hoursCheck alignmentClean cabinetReturn to cabinet and enjoy.
13 Locate your radio. eBay is popular. Ham fests. Flea markets. Garage/Estate sales.Family.
14 Find documentation http://www.nostalgiaair.org/Resources/ Domestic US consumer radios.For European and some domesticBoat anchors/test gearFor more links and resources.
16 Inspect and documentOne picture is much better than your (my) memory. Take lots of pictures. This is how most of my web site pictures are captured. Simply as a record of what went where.The cheapest digital camera is better than no camera at all.Macro capability is great. Or hold a surplus macro lens in front of a digital camera with out macro capability. It works. Believe me.
17 Test for operationThis step saves a lot of time. If you can hear the faintest of transmitters then most if not all of your tubes, oscillator coils, chokes, IF transformers, Audio Output Transformer, speaker, band switch, volume pots and many more things are working.Use a Variac set-up or a Dim Bulb Tester (DBT) to protect the parts made from Unobtainium.
18 Dim Bulb Tester Current limiting device. A “Must Use” on all restored chassis.To make and use one see:Alternative:Variac plus an amp meter plus a volt meter.
22 DisassembleTake the chassis out. Pulling off the knobs can be a challenge. They are often held on with set screws and rust.Have Zip Lock bags available and a sturdy cardboard box.The box will help protect your glass tubes.Wrap and tape the speaker with cardboard. I have put too many screwdrivers through paper cones. It will make you sick.Take pictures too.
23 Cold test all Transformers and coils If you had a successful DBT test you can skip this step.Use an ohm meter to DC test the coils, transformers, speaker for continuity.Mark off (highlight) these items in green on your schematic.Schematics often have a DC resistance on the coil schematic.
24 Test all tubesIt helps to have all tubes tested. A weak tube can throw you for a loop.Most tubes will be fineGuitar amp tubes take a beating.AA5 audio (50C5) and rectifier tubes (35w4) take a beating too. Look for hot shorts in the rectifier tubes.Put the tubes back into the chassis or use duds in place. More on this later.
26 This is rather self explanatory. Order long lead items.This is rather self explanatory.Order needed tubes.Grill clothRebuild crystal cartridges/idler wheelsRe-cone speakersSpecial caps and high watt resistorsSend off cabinet to refinisher.etc
27 Shine up chassis if so desired. PROTECT or remove the variable air condenser (Tuning gang capacitor) !!!Lots of manual labor and elbow grease.See: for ideas.
29 Inspect wire insulation Many radios manufactured during WWII has rubber insulation that does not last. It is hard as sugar candy or soft and gooey as chewed bubble gum.It needs to be replaced or covered with “spaghetti” or heat shrink insulation.Replacement is the desirable solution.Heat shrink over transformer leads is second best.
30 Inspect wire insulation continued. Spaghetti is third.Avoid paint on insulation. Thickness is not controllable.Keep a tube in all the sockets. This is where socket breakage is high!Use 600 volt UL rated insulation.Use stranded for any connection off of the chassis (i.e., speaker, dial lamps, antenna, etc).
32 A Tube Socket storyA broken tube socket degrades the performance of a radio. Dust and dirt accumulate and cause a short. Once an arc has occurred a carbon track is laid down. It is very hard to remove all the carbon and replace with a high insulation material.Put a tube into any socket before soldering or de-soldering any pin connector!Practice this preventative measure and all will live happily ever after.
33 Acquire capacitors, resistors and lamps Most schematics have a list of parts. Electrolytic and paper containing capacitors are a priority for replacement. Mica and ceramic caps are good to keep.Use 630 volt polypropylene (<1 uf) capacitors in all positions (unless a higher voltage is needed).Use 450 volt Electrolytic capacitor in the power supply (160 volts for AA5)I will bring my parts bins to pick your parts. (Your $ cost will be my $ cost. No mark-ups.)
34 Electrolytic Capacitors Tubular Axial CapacitorsOrange DipsMetalized Polypropylene FilmGood replacement for Wax/paper caps.Metalized Polyester FilmSelf-healing propertyMetal-Foil Polypropylene FilmOrange epoxy coated for superior heat, solvent and moisture resistance.Excellent stability for High Current / High Frequency / Temp. Compensation Applications.500 Volt Dipped Silver Mica Capacitors1 pF to 5000 pF,Metalized Polyester FilmHighly reliable with "self-healing" performanceElectrolytic CapacitorsY2 Safety and Interference Suppression CapacitorsLine to Line (X) andLine to Chassis.
35 Micamold & “Black Beauties” Mica Mold is a company that made nano and pico farad capacitors that look like mica or ceramic “domino” capacitors. But they used paper.These capacitors must be replaced!“Black Beauties” or “Bumble Bee” capacitors also have paper inside and MUST be replaced.
36 Acquire capacitors, resistors and lamps continued. Most carbon composition resistors are bad. If not now they will be later after getting hot. They have been sitting absorbing moisture and thermal cycling for decades of non use.Just replace them now and avoid the failures later.Use ½ watt 5% Carbon Film resistors.Use new Carbon Composition for circuits operating over say 18 MHz (HF).Do NOT use New Old Stock (NOS) carbon composition resistors. They go bad on the shelf.
37 Carbon composition ½ w about $0.20 Carbon Film 1/2 w 5% about $0.07Carbon composition ½ w about $0.20Use above 18 MHz5 % toleranceLow inductanceLow capacitanceWatch for inductance.High quality performance at economical prices1/2 & 1 WattGeneral shotgun replacement.Metal Oxide 1 and 2 watt 12/17 cents5 % tolerancePower Supply section.Cathode BypassCandohm replacementsMetal Film ½ w about 11 cents1 % toleranceEpoxy coated precision resistorsPOWER Resistors Wire Wound very inductive.5 watt $0.37Power SuppliesCandohm replacements10 watt $0.50AKA Sand, cement,Ceramic, wire wounds
38 Lay out copy of schematic with red and green pencils Mark off or Highlight components in Red when replaced.Trace the connections in green to verify the circuit is original factory design.Undocumented, unapproved, mods were made to gear when parts were not available (war time) or the shop was too cheap to properly repair the fault.
39 Replace capacitorsReplacing the capacitors first will give you more room to replace other parts.Use hook and crimp method. This makes for a fast and strong replacement. It also more importantly keep the part in the same relative place as the original.The performance of plenty of radios is affected by parts placement and wire dress.
40 Replace resistors Use the hook, crimp and solder method. A Lead Twister tool is really helpful with resistor replacement.
42 Lead TwisterA lead twister adds little coils to the lead wires of the new parts.Cut out the original part near the body.Slip the new part’s coils over the old lead wires and solder.This maintains the original component position and makes for a quick secure solder joint.See: to make one.
43 Open IF cans and replace resistors Sliver Mica disease (AA5)Replace ResistorsSee:
44 Hot test restored chassis Please use a dim bulb tester…….
45 Hot test restored chassis Use a Variac, volt and amp meter OR DBT. Once passed then plug directly into the line (mains).Tune in a strong station on Broadcast.More than likely you will hear a station or more.If you are lucky the dial frequency may be close.
46 Alignment Get alignment data. Warm up RF generator and frequency counter.Connect voltmeter to AGC or AC meter to speaker terminals.Perform Alignment
47 Trouble?If the DBT passes trouble shoot after your first alignment. The IF transformers could be so far off the radio will not receive.If still dead use appropriate trouble shooting techniques to repair.
48 Alignment I will bring alignment gear. Follow the alignment procedures.An RF generator with AM modulation is commonly required.A Frequency meter (or general coverage receiver) is needed to set the RF gen.Burn in the radio 4 to 8 hours.Perform the alignment again.
49 Put it all back together. Clean your cabinet.Make cosmetic improvements.Check for electrical safety again.String up an antenna and enjoy your new old radio.