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Wards Airline Model 14WG-1108A series 1A48WG & C series 1A48This is a new restoration project on the bench at this time. Information will be periodically added as the project progresses. Before any work is done general assessment and preliminary cold checks are performed including but not exclusive of: Test audio OPT
Component replacements.I have begun going through and replacing bad components. This included all wax/paper capacitors, electrolytic capacitors, decayed brittle wires and out of tolerance resistors. The IF can wires get treated to shrink tubing to avoid disturbing delicate windings. Since this radio will be used perhaps daily, with a 5 CD changer in the phono input, I will be replacing any questionable wire or component for "Daily Driver" reliable operation. It is surprising how many resistors are out of tolerance. Most resistors in this radio have a silver tolerance mark. That is 10%. Some one commented that my meter may be bad. I then got that sinking feeling and went t the shop to verify its accuracy and precision. Both were easily checked by measuring the replacement resistors and trying a different meter. I am surprised at the quantity of bad resistors that I find in all restorations to date. See below:
Out of 26 fixed resistors all but five were significantly out of tolerance. And R28, series plate resistor, is just over the limit was also not replaced. That yields 76.9 percent of the resistors are bad. This is not uncommon. I find out of tolerance resistors in many restoration. It is an exception when a chassis has in tolerance resistors. At 4 cents each for the 1/2 watt, in quantities, it makes little sense not to replace the resistors. For me there would be exceptions to this rule of mine. One is if the restoration is a "Museum Show Piece" that is not to be powered up. Leaving original components is only for "looking at", to appreciate the "State of the Art" at the time of manufacture. Secondly if the technician wanted to rush the device off of the bench and await its quick failure they may choose to leave original caps and resistors. Not to mention the possible loss of irreplaceable components. Every resistor (and capacitor) has been verified against the schematic before retention or replacement. Technicians have been known to "tweak" values to compensate for other weaknesses or failures. And simply connect stuff up wrong.
Problem Found:The Output transformer (lower right) has an open primary on one side of the center tap. It is a Stancor universal replacement. Obviously it has failed once already. The two 41 output tubes check good on a Heathkit emissions tester. One strong and the other one just in the green above marginal. So this radio had played for its current owner. But, I doubt it sounded clean. I pulled the back the first few layers of insulation to see if the winding came loose from the lead wire. But no such luck. The primary is open some where inside the windings. The Challenge:Specify a replacement Output transformer to handle the power output, bias current and yield the correct plate impedance. The Data:
Conclusions:
The Solution:
AlignmentAlignment was successful today. After chasing a run-a-way oscillator (above 15 MHz) the problem turned out to be skewed alignment trimmer capacitors. The interstage and Oscillator trimmer caps interact to some unpublished degree. Opening the caps up wide and finding a known good primary frequency allowed the tracking of the signal up the band. Establishing a good primary signal entails a week signal properly centered about the intended oscillator frequency. I found it useful to follow the signal generator up the dial to the specified alignment point when the tuning gang is wide open. This unit was operating (Police and SW bands) on a higher image of the oscillator and input signal.
Once aligned WWV showed up exactly on both bands at 5, 10, and 15. The SW band is huge 5.350 - 18.300 MHz (see schematics).
Finished and playing loud and clear.
Second Chassis in the shop.This unit has the appropriate documented tube line up unlike the one above. Companies will make substitutions near the end of a model line with the spare but equally functional inventory in house.Preliminary test on the bench reveal all transformers and coils test good with an ohm meter. All but three tubes are good and strong. Two 6D6 tubes tested bad. One is week and one has a heater short. The eye tube is dark. No illumination. That is expected. These eye tubes only have a 1500 to 200 hour life expectancy. If you have a "Daily Driver" a switch can be inserted in the B+ line to extinguish the illumination on most eye tubes.Most if not all the under chassis wiring is brittle as sugar. It will need replacing. The top side eye tube insulation is also cracked. With the given room under the chassis this task should take about an hour and a half. The IF transformers will be addressed with heat shrink as well as the power transformer as necessary. Slipping a piece of heat shrink over the existing insulation, will restore the insulating characteristics of the wire. Hopefully the Power transformer will not have to be disassembled. It is not tough to do but adds time to the repair.Here are some before pictures:
A Restored Unit.
I forgot to mention. This chassis sounds great with a CD player plugged in the Phono jack. I tested it with a DVD player's audio output, a Stereo to Mono patch cable and a music CD. Just move the slide switch on the left rear chassis from Radio to Phono.
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