Re: Type 111 Pretrigger Pulse Generator


Tim Phillips
 

From Tim P (UK)
Hi; This is the mod to supply double pulse output. See Hakan's page

http://hakanh.com/dl/kits.htm

I think it was used to set up the loop gain on samplers.

Tim

On Thu, 18 Mar 2021 at 03:16, Sean Turner <sdturne@q.com> wrote:

Hey all,

I was wondering if anyone knows of any factory mods that were done on the
Type 111? I have an example that has a significant divergence from the
schematic in the manual, namely around the fixed increment control. It's a
little circuit mounted on an aluminum tab with a small ceramic strip on the
inside and three socketed transistors on the outside, and there is a pot
installed instead of the switch. I can't discern that this control has any
effect on anything, and it is definitely not present in any scan of the
manual or any pictures of the internals of other Type 111s.

Furthermore, it is factory quality assembly work, so I'm assuming it's
either factory or someone who was really careful.

I put three photos of the circuit here (
https://groups.io/g/TekScopes/album?id=261991). I annoted one of them to
show the four places where the mystery circuit is wired into the main PCB.

Thanks!

Sean

Sean





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