[time-nuts] General Technology Corp model 304b
Ed Palmer
ed_palmer at sasktel.net
Sun Apr 29 18:36:17 UTC 2012
Hi Don,
You know that we're going to be swapping many emails, don't you? :-)
On 4/29/2012 11:16 AM, Donald Henderickx wrote:
> After following Ed Palmer's thread on 304b restoration,I was inspired
> to get my GTC (tracor) 304b ser#279 going. It seems that the failure
> of this unit was the break down of the foam that was wrapped around
> the vcxo located inside the control box. The vapors or the moisture
> the foam collected corroded the steel fasteners and caused the
> switches to become intermittent.
The foam around my OCXO is still in great shape. Still spongy and
providing lots of holding force for the OCXO. My unit is serial #449.
> The replacement of the foam in the control box is not that much of a
> problem,what I need help with is what to use around the Rb lamp base.
> The foam has turned to powder.
Do you mean foam around the back end of the lamp where the wire lead
comes out or the foam that surrounds the reflector (#16 in the picture
in the patent that describes the lamp (3311775))? My #16 foam is really
solid.
> Should I try Home foam sealant? The cell's ,of this seem about the
> same as the old foam.Will it take the heat?Should I make a fiberglass
> cocoon to put around the lamp base.
Read the fine print on the can. It may list the maximum temperature
rating. I'd try a fiberglass cocoon first just because it's easily
reversible if it doesn't work. When your unit is running is the lamp
test point voltage correct?
Ed
> The unit now achieves lock in about an hour. The only other thing I
> did was to replace the caps in the main supply.
> Any thoughts on the insulation?
> Don H
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