[Milsurplus] Bathtubs redux

[Moe Fretz]

Rub a dub dub       two caps in a tube:))         Help me

On Mon, Jan 5, 2009 at 3:34 PM, <wf2u at ws19ops.com> wrote:

> Hello all and happy 2009,
>
> About 2 weeks ago I asked for opinions regarding bathtub capacitor
> recapping.
>
> Just relating my experience with recapping the bathtubs in the E.H.
> Scott RCH receiver I was working on.
>
> The bathtubs didn't contain oil, just plain beeswax. Used a 100 W
> soldering iron to unsolder the lid, which popped off in seconds.
> Poured the melting besswax out, kept the wax impregnated paper spacers
> between the caps. Unsoldered the caps from the tabs (there are small
> through holes where the leads come out and soldered to the bottoms of
> the tabs). Opened the holes with solder sucker, put in the new 630V
> mylar film caps, soldered everything back together, sealed the lid
> again and the whole bathtub looks intact.
> Reconnected the leads which connect the tubs to their appropriate tie
> points.
> Each tub took approximately 15 minutes to do.
> The receiver is now very much alive, and working  normally. I tweaked
> it according to the manual, but it wasn't very far off the optimum.
> It's a hot receiver, very stable, good BFO injection (although I'm not
> using it for SSB, but sideband reception is excellent even with RF
> gain control alsmost to the max. Stability is above expectations.
> Audio quality is superb.
> Since it has no filters or adjustable bandwidth in the IF chain - the
> receiver is a bit broad this way but usable - for crowded band
> conditions I'll use an external audio filter on CW. The receiver is
> going to be used with my Mackay Marine 167BY transmitter in the FT-102
> Liberty/Victory Ship radio console. According to the FT-102 manual and
> some radio room photos, the receivers used in these consoles are
> either the RMCA AR-8506B (mine needs recapping but works OK so far) or
> the E.H Scott SLR-F which is the same as the Navy RCH. So far looks
> like the Scott is the better performer.
>
> Again, thanks for all the input on "retubbing"...
>
> 73, Meir WF2U
> Landrum, SC
>
>
>
> What's nice is that in the Scott RCH all the tubs are very accessible
> and the screw heads are on the outside surface of the chassis.
> Drilling small holes prior to heating up the caps of course makes
> sense for draining the oil.
> This will be a good rehearsal for doing the restoration of the
> bathtubs in my ex-RCAF AR88LF which is another project waiting its
> turn...
>
> 73, Meir WF2U
> Landrum, SC
>
>
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-- 
Moe Fretz
Collection and Preservation
Of Canadian Tube Radios,
Communication Equipment,
Vintage Ham gear and Military Radios.

Don't crush them ---- Restore them.


Ontario Canada
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