Mac's Service Shop: Not Always Right
By John T. Frye
"That portable record-player looks pretty new to be in the shop for repair already,"
Barney remarked as he watched Mac carefully place a blanket underneath the fine
leather case of the instrument to prevent its being scratched by stray bits of solder
on the service bench before he started . removing the motorboard carrying the three-speed
"It's a brand new birthday gift that's not even been presented yet," Mac said.
"Just proves they don't build 'em like they used to, huh?"
"Not necessarily. Nothing's the matter with this player. I'm simply going to
do a little conversion job on it to add to its usefulness."
"What kind of a conversion job?" demanded Barney, who had all the curiosity of
an old maid bluejay.
"I'm going to install a midget closed-type 2-circuit phono jack in a corner of
this motorboard. The leads from the pickup go to this jack so that when the jack
is empty they connect to the input of the player amplifier in the normal manner.
However, when a phono plug is inserted into the jack, the 'hot' lead from the crystal
cartridge is disconnected from the input of the amplifier and goes instead to the
tip of the phono plug, and the 'ground' lead of the cartridge connects to the sleeve
of that plug."
"I don't get it."
"It's quite simple. Next I make up a patch cord from about five feet of microphone
cable with a phono plug on one end and a phono tip plug on the other. When the phono
plug of this cord is inserted into the jack of the record player and the phono tip
plug is inserted into the 'phone' jack of a radio or TV set, the portable player
can be heard through the amplifier and speaker of the set. At the same time, the
amplifier and speaker of the record player itself is silenced."
"So advantage can be taken of the larger speaker and more powerful amplifier
normally found in radios or TV sets in listening to records played on the portable
record player. Many radios and TV sets are equipped with phono jacks, and the records
sound far better when played through them. What's more, there are a lot of older
radio-phonograph combinations sitting around practically unused because the TV set
has usurped their place in the living room and their single-speed turntables will
not play the popular 45 and 33 rpm records. Quite often, though, these sets have
audio systems capable of quite good reproduction when a modern pickup is fed into
them. With most of these combinations, you have only to pull out the plug on the
end of the shielded lead corning from the 78 rpm turntable and insert the patch
cord from the portable player. This gives these fine old sets an entirely new lease
"At the same time, whenever you wish to use the player for purely personal listening
wherein neither audio power nor high fidelity is essential, all you have to do is
remove the patch cord and the player is ready to go. There are no awkward dangling
cords, and nothing has been done to detract from the appearance of the record player.
I've performed this operation on several portables lately, and the owners are very
happy with the result. In fact, the owner of this player heard about the conversion
from another customer and wanted it performed on this fine little phonograph before
he presented it to his daughter."
"Sounds like a real cool idea, man," Barney approved. "You can have your music
for dancing through the rumpus room radio and still take it with you!"
"There's only one thing to watch. A few of the portable players may use a 'hot'
chassis with one lead from the cartridge connected to it. In that case, the lead
should be transferred from the chassis to the frame of the phono jack, and a 0.05 μfd.,
600 volt capacitor should be connected between the jack frame and the chassis. This
prevents danger of serious shock or of shorting out the line voltage when connecting
the record player to a grounded radio chassis."
"Oh, oh!" Barney exclaimed in a low voice. "Don't look now, but here comes that
old grouch, Elmer Hinkle. Let's take to the hills!"
Barney's attitude was not without reason. Elmer Hinkle was a typical grouch,
tight as a roll of Scotch tape and suspicious of everyone. He marched straight on
back to the service department, carrying a small radio in the crook of his skinny
arm. On his face was an agonized distortion of normal features that he fondly believed
was an ingratiating smile.
"Mac, my friend," he began briskly, "I had a little argument with some of the
boys over at the garage, and I'd like to know if I was right."
"What about, Elmer?" Mac asked warily.
"I was saying you told me very little of your charges was for what you actually
did. You said the work involved was simply snipping wires and doing a little soldering.
What you charged for was the use of your instruments, your experience, and your
know-how in locating the trouble with a set. Was I right?"
"Why yes, Elmer; I guess you were. I did say something like that."
"Good!" Elmer exclaimed as he permitted his facial muscles to relax into their
normal sour expression. "That's what I wanted to hear, and you're not going to wiggle
out of it. You there, boy; you're a witness."
"'Witness to what?" Barney demanded belligerently.
"Witness to the fact he can't charge me more than fifty cents for fixing this
radio," Elmer said triumphantly. "He don't need to use his instruments or his experience
or his boasted knowhow because I've already found out what is wrong with my set.
All I want him to do is solder in this new distributor that my nephew got for me,"
he said as he pulled a cartridge-type filter capacitor from his coat pocket and
brandished it under Mac's nose.
"How do you know it needs a new 'distributor,' as you call it?" Mac asked as
he placed the little receiver on the service bench and plugged it in.
"My nephew, who learned all about radio in the Navy, told me it did," Elmer boasted;
"and he's forgot more about radio than you'll ever know."
"I hear nothing wrong with it," Mac said, trying hard to keep his temper, although
Barney could see that the back of his neck was turning red.
"Wait a few minutes and you'll hear it hum like a bumblebee," Elmer said; "but
I'm warning you I'm not going to pay for any of your phony diagnosing. I already
know what's wrong. Just go ahead and do like I told you."
Sure enough, as the set continued to operate a noticeable hum appeared and quickly
"I don't think -" Mac began.
"You're darned tootin you don't!" Elmer interrupted. "That's what you want to
charge me for. Quit stalling put in that new distributor."
Mac's lips drew into a thin line, and quickly removed the set from its cabinet.
In a couple of minutes he snipped off the leads of the old capacitor and had soldered
the new one in place. He slid the set back into its cabinet and turned it on. In
a few minutes it was humming just as loudly as before.
"You tricked me! You put that thing in wrong on purpose!" Elmer shrieked.
"Now, Elmer, stop that screeching and listen to me," Mac said sternly. "I never
cheated a customer in my life, and I'm not starting with you, although you surely
have got it coming. I tried to tell you I didn't think the original capacitor was
bad, but you wouldn't listen. Now you stand there without opening your yap while
I find out what is wrong with this set. So help me, if I hear another word out of
you, I'll double your bill."
Under this dire threat, Elmer kept silent; but it was only by means of a very
visible effort. Mac slid the chassis out of the cabinet again and used the rubber
tube puller to remove the hot 50C5 tube. From the tube stock a new tube was obtained
and placed in the socket. The set was turned on and once more slid into the cabinet
so that the baffle would accentuate any low-frequency hum that might be present.
After several minutes, it remained hum-free, even when Elmer placed a suspicious
ear right against the speaker opening.
"You satisfied that's the trouble?" Mac demanded of Elmer, who still was keeping
his lips tightly sealed.
"I reckon I am," Elmer said grudgingly; "but just wait 'til I get hold of that
know-it-all nephew of mine. He charged me a whole two dollars for that distributor
I didn't need. A fine radio man he is!"
"Don't be too hard on him," Mac said. "He's probably plenty smart about radio
equipment used in the Navy. I know the training those boys get is first class. This
case, though, could trip up almost anyone not experienced in radio receiver servicing.
The clue was the fact the hum was not there at first but came on fairly gradually.
Open filter capacitors seldom act like that. This case was caused by a cathode-to-heater
leakage that increased as the output tube warmed up. Only experience, of which you
think so little, let me suspect this."
"Well," Elmer snarled, "what do I owe you?"
Mac thought a little and then said, "Elmer, I'm just going to charge you for
the tube and my regular minimum charge for a service job that would not normally
require removing the chassis. You do not deserve this break, but I hope the experience
has taught you a lesson. The next time, have faith in me or take your work to someone
you do trust. Here's your bill. Pay Miss Perkins out front."
Elmer snatched the bill from Mac's hand, looked at it, and then started for the
door. As he reached it, though, he stopped and turned around. He swallowed hard
a couple of times and then blurted out, "I've been an old fool!" Without another
word he bolted through the door.
"Say, that was better than a soap opera," Barney exclaimed. "I guess Elmer proves
that in radio servicing the customer is not always right."
"That saying came from the retail selling business," Mac agreed; "and it most
certainly does not apply to any kind of servicing. After all, there is no reason
to suppose that the customer knows anything about the equipment he brings you to
repair. If he did, he would probably repair it himself. A funny thing is, though,
that few of the men customers like to admit this ignorance. They like to have you
believe that if they just had the tools and the time, they could repair their radio
and TV sets themselves.
"The good technician does not destroy this fiction, but neither does he buy it.
He listens politely to the customer's opinions, but then he relies on his own knowledge
and experience to determine what is wrong and to correct it. He does not take refuge
behind that business of the customer always being right to justify putting in parts
not needed or performing unnecessary services, any more than a doctor would take
out a sound appendix simply because the patient is convinced his gall bladder pains
are from appendicitis."
"Yep," Barney agreed, "I guess it is part of our job to protect customers from
their own ignorance!"
Mac's Radio Service Shop Episodes on RF Cafe
This series of instructive stories was the brainchild of none other than John T.
Frye, creator of the Carl and Jerry series that ran in
Popular Electronics for many years. Mac's Radio Service Shop began life
in Radio & Television News
magazine (which itself started as simply Radio News), and then changed
its name to Mac's Service Shop after the magazine became
World. 'Mac' is electronics repair shop owner Mac McGregor, and Barney
is his eager, if not somewhat naive, technician assistant. 'Lessons' are taught
in story format with dialogs between Mac and Barney.