My TV-2 experiences;
1) Broken Quality Meter Miraculously Turned
Normal Accidentally:
1 When I purchased two TV-2A/U7's from
a Virginia police officer,
I had them sent to me by surface mail
package.
One was not pretty but its function
was very good, the other was cosmetically
excellent but somehow its function
was not as I expected.
I tested one tube by my TV-7 tube tester
and the tube tester showed that
the tube I tested was a good one, but
whne I tried to test this same tube with
my TV-2A/U tube tester it did
not show a good reading, so I
was greatly disappointed,
and tried every means possible, and
thinking it a good idea I over-turned the
Signal V.R
and tried to make the indicator
go beyond the RED LINE, but this was a great
mistake, I should
have read the instruction manual beforehand.
As a result, Quality Meter indicator
went far to right hand side, and when
I handed off the push button, the meter
indicator did not go back to the 0
point. There is no adjustment screw on the
Quality Meter,
besides this tube tester is a military
model, and all the meters are completely
sealed and
if I should open it, I will most probably
break the meter. So I had almost given up,
but
one day I carried it in my car, and
to my surprise when I re-checked the tube
tester was
normal, and obviously the shock and
vibration during my transportation caused
the tube tester's
quality meter to be vibrated and
came back to its normal status, without any
repair at all.
This is a miracle? perhaps
so, but it is very likely that the quality
meter's indicator
was stacked somewhere inside the meter
and accidentally it was released from its
stack,
and came back to its normal condition
without any repair at all.
2)Replacement of Quality Meter;
If the Quality Meter is broken,
there's no other way than to replace it with
a brand-new or
a normal meter. Jack, engineer, at
Scherrer Instruments, Inc, St. Louis, Missouri,
however
suggests that he can repair the meter
if you know the FS of the meter, you simply
replace a
moving section of a replacement meter
and embed it to the former TV-2 meter.
But this takes an expert skill, and
if you can find just a similar broken TV-2
with a good
quality meter then this is a better
and cheaper way to repair your bad TV-2.
I asked Mr. Simon Lee, Audiotronics
in Hong Kong if he had any broken TV-2 tube
tester.
and Yes, sir he had one, for a reasonable
price of 300.00 dollars, all the meters okay,
as well as its transformers. The only
defect was some of the switches are rusty
and the
tester was not working properly because
of bad potentiometers.
Why Amercian tube testers from Hong
Kong? You may wonder, yes I was curious,
too.
Simon says that he gets those tube
testers from Taiwan, where US armies were
stationed.
My friend's TV-2 was saved in
this way, by replacing the Quality Meter
from a broken TV-2
tube tester from Hong Kong, China. And
the rest of the parts he sold at Yahoo Auction
site
for a high price!!
3)Burned High Voltage Transformer T2:
There was somebody selling a broken TV-2
tube tester at Yahoo Japan Auction site.
The seller said that this tester is
broken and it seems that one of the
transformers seems
to have been burned, and the signal
meter is stuck and does not function.
This TV-2 tube tester seems to have
been sent by Surface Mail package from the
United
States and was broken while it was
on a boat across the ocean. Even though the
burn of
T2 transformer cannot be explained,
it must have been wrong before it was bought.
A friend of mine purchased this tube
tester thinking he could repair it.
But just a bit of electric knowledge
is not enough to repair this giant tube tester!
This gentleman asked me for a copy
of maintenace manual, and tried to check
the
tube tester. As soon as he turned
on the switch the wire-wound resistor R2
1 k ohm
turned extremely hot and started to
burn, and he had to turn the switch off immediately.
He and I studied the maintenance manual,
and learned that this resistor is usually
not
necessary for home use, whereas it
is necessary when used at the battlefield
where they
had to depend on their generator for
AC power. However, even if this resistor
was removed
nothing was improved, fuses blew
off if the plate potentiometer was turned.
We took it to an electric specialist,
and we learned that somehow T2 high voltage
transformer
measures only a couple of ohms, and
which is obviously strange because a transformer's
primary normally shows 10-15 ohm
resistance, and he concluded that without
replacing that
transformer this tube tester has no
value at all, and cannot be repaired
at all.
I sent emails to Jack, Scherrer
instruments, Inc. and he promised me to look
for proper
replacement transformer for us, but
he could not do so.
And after all even if we could find
one, the price might turn out to be outrageous,
and will never suit our purpose, and
we gave up repairing this tube tester.
The signal meter was easily repaired
by this specialist, it is firmly sealed all
right,
but you can open it from the front
side, you carefully removed the front glass,
and then
you remove the scale and repair the
stuck portion of the meter!
I succeeded in finding a store in the
United States, where they say they have hundreds
of
TV-2 tube testers for sale, and they
also sell TV-2's that require some repair
and
calibration as well. So I recommended
my friend who had purchased a broken TV-2
to purchase
a perfectly working model and to sell
his broken TV-2 at Auction site as TV-2 for
Parts, and
he was able to sell it for a real high
price!!
The above are some of my experiences
as regards broken TV-2 tube testers.
I have dozens of repair experiences
on TV-7 tube testers, because most TV-7's
have some
bad circuits or parts.
September 16th,2002