Tektronix 160 Series

[AlanBeckett]

Anyway, back on the job.
Mundane stuff first - Cables. These connect the PSU to the other Modules.

   

There appears to be two types - Long ones to connect the PSU to a Module and short ones to loop between the Modules. They look to be in reasonable nick and they buzz out OK so onward and upward, except that I'll have to make some more.

Now the 162 Waveform Generator.

               

It's a neat little unit with no Covers. I don't think they're missing because none of the others have any. There are only 6 Valves although most are Doubles. There's one double Electrolytic which will bear keeping an eye on. By the way, the bend in the Front  Panel isn't the Camera, it really is there. Everything seemed clean and unstressed and all the Controls moved. A judicious application of Switch Cleaner seemed in order and a check of the Valve Pins.
So, fire it up with the Controls set to what I hoped was something sensible and see what's coming out.
The best I can say is a complete shambles. The Waveforms are awful and the Controls seem to have very little effect.
So, I've left it on soak while I RTFM.

Alan

[AlanBeckett]

I've been diverted by Domestic Demands. I hope for not too long
In the meantime herewith the Block Diagram, Schematic and Description.
Back soon.

Alan

       
  162Description.pdf (Size: 4.36 MB / Downloads: 22)

[Ed_Dinning]

Hi Alan, just come on this thread and your lucky purchase.
It could make a nice valve tester with facilities for frequency and linearity tests as well.

Ed

[AlanBeckett]

Steady on Ed I've got to get it going first, but it's an interesting idea.

Alan

[AlanBeckett]

Having completed the Means to the Means to the End - http://golbornevintageradio.co.uk/forum/...p?tid=4754 - and the Means to the End - http://golbornevintageradio.co.uk/forum/...p?tid=4758 - I can get back to the End 

When I plugged in the 163 the Waveforms could be best described as a shambles. This is after all Tektronix so the least you should expect is a good clean Sawtooth.
First step was to check the Voltages, and it turned out that when Loaded the -170v, which is the source of all Wisdom, would only go to -165. I can't really believe that it being 5 Volts low poses a problem. Nevertheless, it seems a good idea to start with the right Voltages, hence the Load etc.

So, back to the PSU.

Alan

[AlanBeckett]

Back to the Real World.
I got the PSU back on the Bench and, after a bit of Head scratching, jumpered up the Load to give suitable values for the -170V and +70V. The Results were, to say the least, unimpressive.
The -170 would still only go to -165 which is odd because I'm sure it did when I first tried it.
Again, I can't think that 5Volts would make a difference to the other Units. Nevertheless, the -170 is the source of all Wisdom for the PSU so it seems a bad idea not to start with it correct.
Here with the Manual's view of the possible problems:-

   

And the Schematic:-

   

Certainly everything looks clean, tidy and unstressed.I measured all the Resistors in-situ and they all seemed reasonable - I'm reluctant to disconnect the ones on the Tag Strips unless I have to because of the Silver-loaded Solder, although I have some.  However I did disconnect R9 1nd R11 at the Pot end and they measure spot on - they're precision ones. I also tried adding some Resistance to them which made not one iota of difference.

So, there'll be a short intermission while I do some Valve Testing. I haven't got any spares of course

Alan

[AlanBeckett]

So, some Valve Tests. A quick lash-up with a couple of PSUs and Meters suffices. Further to another Thread it's quite easy to do provided you have the bits.

   

14B4-A, the Series Regulators, first.
Herewith the Data:-

  12B4A.pdf (Size: 231.06 KB / Downloads: 13)
With Va = 150 Volts, Vg = 17.5 Volts Ia measured 30mA against 34 mA - 88%. That should be OK.

6U8 next.
Data:-

  6U8A.pdf (Size: 616.54 KB / Downloads: 15)

Pentode Section first:-
With Va = 125 Volts and Vg = -1 Volt Ia was 9.8 mA against 9.5 mA, so that's 'New'.
Triode Section:-
With Va = 125 Volts and Vg = -1 Volt Ia was 9.8 mA against 13.5 mA, which is approximately 72%

So, the Triode Section is a good bit low which might be significant.
I'll order one while I investigate other Components. There are several ancient Capacitors in there which will bear investigation.

Alan

[Alan Douglas]

The company I worked for bought a 160 setup like that (four panels) around 1964. It was in a sonar-transducer test fixture, which I eventually obtained at an employee auction, and I must have found a home for it as I don't see it around now. They're not all that common.

[pwdrive]

I like the valve tester  

Lawrence.

[AlanBeckett]

Splendid. It's good to know at least one thing that it was used for in anger.

Alan