[R-390] re; R211

[Craig C. Heaton]

W. Li,

Don't think the signs of overheating are cause by high VAC to the heating
element, other circuits would also be screaming. Have you put a thermocouple
between the hold down strap and HR202. Could be a stuck thermostat, I
believe looking at the drawing there is one built into HR202.

R211, innocent error. Does anyone have one belly up at this time to check
the value on another RF deck? In my Amelco R235 was incorrect, must of
worked at one time, the QA/QC stickers are still on the top/bottom cover &
frame. The crystal calibration was not working when I got the Amelco and a
correct R235 didn't help, had to replace all the silver mica's. Great
practice getting the RF deck belly side up.

Craig, 



-----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 3:51 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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