[Milsurplus] Alignment of tube tester I-177

[Bob Camp]

Hi,

The simple answer is yes.

All of the tube testers of that era had roughly similar internals. If 
you can find a schematic for the TV-7 on the net then you should be 
able to work from it.

The first thing to check is the rectifier tubes. If they have blown or 
are simply to far gone the meter will not properly zero. The next layer 
to the calibration is done with the sliding tap wire wound resistors. 
They are pretty obvious when you pull the unit out of the box. Past 
that some of the calibration was actually done by substituting in new 
parts.

My recommendation - simply swap out the tubes. If that doesn't fix it 
then go for the obvious burnt or broken parts you may find. Cleaning 
the switches can't hurt either.

Past that I suspect you will need to find a depot lever service manual. 
I have not seen one for the I-177 but one must exist.

The biggest thing you will find in the depot manual is a full schematic 
with all the part values. The alignment procedure many be a bit much 
with current equipment. (obviously it pre-dates modern test gear like 
DVM's ...)

	Enjoy!

		Bob Camp
		KB8TQ



On Apr 4, 2004, at 2:14 PM, Wim Lakeman wrote:

> Dear Listers,
>
> Recently I obtained a I-177 tube tester.
> I think there is a problem with the alignment of the tester.
> At the line test it is not possible to get the meter pointer exactly 
> at the
> line test postion of 1500 microhmos, even with the line test 
> adjustment knob
> rotated full clockwise. Maximum postion is about 1200 micromhos. In the
> power-off stand the meter points zero.
> Is there any hidden alignment knob in this tester?
> Any suggestions to solve this problem?
>
> Best regards,
> Wim Lakeman
>
>
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