[R-390] More PTO pics

[KC8OPP Roger S.]

Barry,

When I look at the pictures, especially PTO4 I wonder
if tube pin #7 is a little shy on solder.

Good Pics, hope you get this PTO working.

73's
Roger
KC8OPP

--- Barry <n4buq at knology.net> wrote:

> I put some more hi-res pictures on the website
> 
> www.knology.net/~thelanding
> 
> They are large (~1.5MB) files, though.
> 
> I'm curious about the "feedthrough" clamping device
> in PTO5.JPG.  Does
> anyone know if unscrewing this will release the
> coaxial cable?  I want to
> replace the cable, but I'm not sure how this "clamp"
> is disassembled.
> 
> I did a little testing on that capacitor lead
> tonight.  A very slight
> pressure on it would cause it to fully touch the
> frame.  I could slide some
> dental floss under it, but I could feel a slight
> pressure as it slid under
> the wire so that gives you some indication of just
> how close it was to the
> frame.
> 
> I moved the capacitor lead well away from the frame
> and tested the PTO.
> After calibrating my 'scope (it was reading just a
> bit low), and measuring
> the output with a scope probe (instead of with a
> direct connection with
> RG-58 coax), I'm seeing 4.8V peak-to-peak now.  This
> is an improvement over
> what I was seeing.  Part of this was due to my
> incorrect measurement
> methods, part of it was calibration issues, and part
> of it may have been
> that lead so close to the frame.  I'm thinking it
> wouldn't be worth it to
> rebuild the thing at this point.  I might see 5 or 6
> volts if I did, but I
> might not and it's not worth risking those little
> irreplacable solder posts
> to find out.  I *might* replace the 2.2k simply
> because they have a bad
> reputation for going high (this one is a little high
> already) and I have a
> 2W replacement that would ensure good operation for
> a long time to come.
> 
> Anyways, thanks to all for "listening" to me.  It's
> been "fun", but I think
> I'm going to move on to other parts of this
> restoration project.
> 
> Barry - N4BUQ
> 
>
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