Taylor Model 60 signal generator

[Sinewave]

Actually there are 6 connections. 5 and 6 coming from the insulation layers.

Just about to measure them and then try to find out where they should be going.

[Sinewave]

Actually ignore the above about this having 6 and not 5. You'll see why below.

I de-soldered everything to make some measurements.

Results are

Between 1 and 2 = 47ohms
Between 1 and 4 = 450ohms
Between 2 and 4 = 404 ohms
Between 5 and 6 = 170 ohms

I couldn't get a thing from terminal 3 to anything, so I suspect that it's only used to terminate the end of what I've labelled 6.

[Mike Watterson]

So maybe 5 & 6 is the isolated feed back to ground/0V and grid circuit, 2 is HT, 1 is RF triode anode and 4 is audio Triode anode?
Though I'm probably wrong

1 --(47)-- 2 --(404)-- 4
==================
. 5 -- (170)-- 6

I have a doubt as I'd have expected the separate winding to be the lowest resistance and 1--2 to be much higher. Unless Pin 1 is capacitor isolated from grid and then 5--6 is in the HT feed to RF triode.

See which wires go to HT and which to which anodes and if any to 0V?

[Sinewave]

Thank you

Yes I was confused by the higher resistance winding too. Yes the audio valve in the modulation stage is a triode.

As it came to me,

1 goes to a Modulation switch contact where it's switches in via two caps in series which goes to pin 4 of the Mod tx, which is connected to the tiode anode.
2 goes to rectifier capacitor +110v
3 -
4 to triode anode
5 to capacitor +70v
6 out to the RF stage

There is a connection on the triode grid, via a capacitor which goes to another set of contacts on the switch, where the common has a missing wire. This is what led me to believe that some things may not be in the right place as I'd have thought the grid would go to the common, but then where on from that I can't be certain.

[Sinewave]

I must add that the triode pin 1 goes to is the audio triode.

I've just taken the RF stage apart to see - Mod Tx 6 is going to the RF tridoe anode.

Whilst trying to fathom this out, I wonder if this is a rare item as there's nothing on the internet about the model 60.

Following the drawings for the 65 isn't much help as it appears to have a different modulation transformer.

[Mike Watterson]

OK , so 1 is capacitor isolated audio feedback (only connected when Modulation is on), 2 is HT and 4 is Audio triode anode. The CW position will allow external modulation.

5 & 6 then modulate the HT / RF on the RF osc. (70V HT and anode).

That makes sense of the transformer winding resistances and the only difference from 65 is the HT common on winding feeding grid (using capacitor isolation) vs ground referenced. AC wise it's the same arrangement as the 65.

So the Mod/CW switch somehow connects the feedback to the grid. The external audio in socket (if fitted, I forget), may go to the common of switch via a pot and thence to grid via a capacitor, mine has the socket always connected and that can give a low level audio out on the Mod position.

Perhaps the model 60 was short lived or for a particular military customer. I think the 65 came out in 1943?

[Sinewave]

Thanks Mike.

I made a drawing showing the grid connections to the audio out section.

As I say above, there is another connection from the grid via a capacitor to the mod switch, but the common of that particular contact set isn't connected to anything, until I can find out why and where it should go.

[Sinewave]

Hopefully I get some time to work on this over the weekend. Would like to get it working.

If not, at least I know the mains transformer and and rectifier tube is good and I can use it on a homebrew project.

[Mike Watterson]

The common of the switch must connect the capacitor setting frequency and DC isolating the feedback winding.

[Sinewave]

A point to note, which confuses me a little is that on the common of that switch, there was a small wire soldered to it with the other end having snapped off something. That wire from what I can see is long enough to reach terminal 1, 2, 3 or 4 of the modulation tx, yet not long enough to reach anywhere else. The tx had come lose from it's mountings, which suggests enough movement to have perhaps snapped the wire off a terminal. There was evidence of a snapped wire on terminal, which was removed when I de-soldered to make tests.

Possibly terminal 1 then in that case if it should go to the feedback winding?