Another Nombrex 27 question?

[robreddog]

Hi, I decided I wanted to improve my testing knowledge, looked through the forum and it seemed to me a good start would be this model, found the right one (non runner) and it arrived earlier this week.

While waiting for it to arrive I bought one of those little Chinese frequency meters and leads and plugs/sockets. Opened it up and fired it up getting some output on a couple of ranges on AM and RF. Decided then to start changing those Hunts starting at the RF output, Hence I come to the first query, C22 should be .01uF according to my schematic but is actually a 0.04uF it is the original, did Nombrex stray from the schematic with something slightly different and I assume its position in the circuit is not critical?

Anyone know what the thread is in the knobs, one screw is missing I am thinking BA, but what size?

Rob.

[Keith956]

It's just an AF coupling capacitor, not critical.

For the knobs, 4BA was a common grub screw size in the day - I recently needed a grub screw for an old 'chicken head' knob, and found cutting a 4BA screw's head off to give a thread length of 1/4 inch, then cutting a slot in one end with a fine hacksaw gave a perfect replacement.

[barrymagrec]

I just looked at the Knobs on my Nombrex 31 and was surprised to find the grubscrew was 6BA.

[robreddog]

have to replace rf transistor and a afz12 arrived today.
my question is about the s (screen ?) connection as the old one 2n588 did not have one although there is a spare place available for it (ground).
should i connect it ?.
also is there a schematic for my model 27 that has 6 coils.
thanks

[frsimen]

Hello Rob,

I think you'll find that you have got 8 inductors, as in the circuit diagram. The missing "coils" will be lengths of stiff wire, or maybe a printed trace. They will be used on ranges 7 and 8. Careful examination of the band switch should allow you to find them.

Paula