[Collins] Collins 32S3

Tue, 21 Oct 2003 13:21:18 -0400

Check the DC cable's shield where it connects inside the 516F-2. Known and well documented regarding missing filament voltage.

Stu, k2qde

----- Original Message -----
From: "Dr. Gerald N. Johnson, electrical engineer" <[email protected]>
Date: Tuesday, October 21, 2003 11:27 am
Subject: Re: [Collins] Collins 32S3

> A time delay fuse makes better power supply protection than a fast 
> blowbecause the time delay fuse can have a lower current rating 
> and still
> handle the turn on surge. If the power supply has been made solid 
> statethe turn on surge will be much larger charging the filter 
> capacitorsrapidly. Tubes prevent that part of the turn on surge. 
> New and larger
> filter capacitors make the problem worse.
> 
> The line voltage the transformer was designed for was most likely 115
> volts, and your line voltage is more likely above 120 volts. That
> increases the saturation of the core and some transformer core 
> materialswill have a high retention (stays magnetized at the last 
> peak when
> turned off) causing the core magnetization to draw a larger surge 
> on the
> first half cycle, if the applied voltage is opposite the polarity 
> of the
> last half cycle the core saw. Higher voltage at some times of the week
> will make this surge magnitude greater at those times. There may 
> be a
> "thung" sound from the transformer core the instant its turned on. A
> sign of this phenomena.
> 
> I'd go to a MDL 3 fuse, maybe a MDL 3.2. Its decently slow blow to
> handle turn on surges, yet more sensitive to continued overloads. I'd
> wish for an MDL 3.5 but they aren't made.
> 
> According to my 32S1 diagram, the 6.3 for the 312B-4 console lamp 
> comesfrom the same circuit that supplies the 32S1 meter lamp, PTO 
> filament,and the PTO dial lamp. I have no idea where that wire 
> enters the harness
> or where the actual connection was made. Only tracing by tugging will
> have any chance at all of finding the lost voltage. Though 
> checking that
> part of the heater circuit may show up something. 
> 
> 73, Jerry, K0CQ, Technical Advisor to the CRA
> -- 
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
> Sponsored by the Collins Radio Association
> http://www.collinsra.com
> 