[Heathkit] HEATHKIT IT-28 vs C-3

[Kenneth G. Gordon]

On 11 Feb 2008 at 17:57, Bob Macklin wrote:

> You can see pictures of them here:
> 
> http://www.nostalgickitscentral.com/heath/products/heathkit_test.html
> 
> The IT-28 is an improved C-3. The claim is that the eye tube operates
> with more sensitivity on the IT-28.

Yes. It has an amplfier to drive the eye-tube. There is a 
fellow-ham who sells a kit on Ebay that modifies the C-3 into 
an IT-28 work-alike.

> I have a C-3 and it does every
> thing I need to do.

I have two of them, which I restored not too long ago. I use 
one at work, and one at home, and find them very useful 
and fairly accurate. The C-3 also measures resistance.

I also wrote a fairly long article for Electric Radio Magazine 
on that restoration some time ago. Anyone contemplating 
using a C-3 might find it useful. The article is owned by ER 
Mag, and Ray will be happy to send you a copy of that 
magazine for a very reasonable fee.

One thing I forgot to include in that article was the fact that if 
you swing the main control knob all the way to the right, and 
then test a very-high value electrolytic for leakage, when 
you release the leakage control, the discharge of the 
capacitor under test can blow the "right end" of the main 
control variable resistor to an open circuit, necessitating its 
replacement.

It is a 10K linear taper wire wound pot.

Ken Gordon W7EKB