[R-390] re; R211
22hornet at gmail.com
22hornet at gmail.com
Sat Nov 7 19:28:50 EST 2009
I always though in order to prevent frying the crystal you have to turn the
heater off. That was one of the first things I learned when I got my R390A
On Nov 7, 2009 5:21pm, Bill Hawkins <bill at iaxs.net> wrote:
> Well, you could simulate the circuit with SPICE if you had all of the
> hardware and software and knowledge required, or you could bridge the
> 82K resistor with a 10K resistor and see what happened.
> Wait - a 1952 A model? Must have been early in the A generation, no?
> Maybe things changed.
> I'd give a better answer if I had the manuals at hand, but I've been
> thinning the collection to avoid the dumpster.
> Bill Hawkins
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of wli
> Sent: Saturday, November 07, 2009 5:51 PM
> To: R-390 at mailman.qth.net
> Subject: [R-390] re; R211
> I am in the process of going through the RF deck on my 1952 Collins R390A.
> The first thing that struck me was the chassis darkening in the
> subcompartment under HR202. As we know the heater is *on* all the time,
> cooking the Xtals. All the small components there showed the effects of
> lots
> heat with runny wax on the micas and darkened ceramic disc bypasses.
> One strange finding was R211. There was a 82K resistor, but all the
> manuals
> called for a 8.2K resistor. My question is: is this just an innocent
> error?
> Thanks
> W. Li
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