[Collins] problem with 516-f2

[Glen Zook]

With no load at all on the power supply, 1080 VDC is not "way" too high although you will get 30 to 50 volts higher with the solid-state rectifiers.  The 516F-2 is rated at 940 VDC with 55 mA of load and 820 VDC at 210 mA.  Also, this rating is at 115 VAC input and you probably have more like 125 VAC line voltage these days.

The low voltage is rated at 300 VDC at 170 mA and 285 VDC att 210 mA.

Which filament voltage are you reading!  The filament voltage for both of the rectifier tubes should be 5.0 volts with the 5U4 and 5R4 rectifier tubes plugged in.  With no tubes and with the higher line voltage 5.5 volts is nothing to worry about.

Now, if you are talking about the 6.3 VAC "regular" filament voltage then there is definitely something wrong!  The 516F-2 is rated at 6.3 VAC at 10 amps and that will be higher without a load and with the higher line voltage.

Are you measuring across the white/green wires on the power transformer?  One of those should go to ground and the other to pins 8 and 9 on the power cord.  If you are measuring at the connector end of the power cord then I would look very carefully at the shield of the power cable.  The shield is the only ground connection between the power supply and the rig.  Unfortunately, Collins only put a single solid wire at the chassis end from the chassis to the shield.  Quite often this wire breaks and the ground gets really screwy.  I always replace this solid wire with a piece of braid (i.e. from RG58/U coax).  That way the cable can "flex" and the ground wire doesn't get broken.

The 5 VAC windings for the rectifier tubes should be yellow to the 5R4 and slate to the 5U4.

Now there are other colors used on some of the 516F-2 power supply transformers so the colors that I listed may not be what is in your particular power supply.

Although some people do use solid-state rectifiers with the 516F-2 I prefer to use the tube rectifiers.

There are some voltage readings on the schematic and also in the #6 "specifications" on page 4 of the manual.

Glen, K9STH

Website:  http://k9sth.com


--- On Fri, 5/27/11, yash at aol.com <yash at aol.com> wrote:

Bought a used supply and did a dumb thing,never powered it up and tested it. Instead I just went ahead and replaced all the caps, the 3-25k wire wounds,put a new line cord  and a new diode for the bias supply.The tubes were smashed and haden't got the two tubes I ordered ,so I put the 2 solid state  tubes I had ,in place. fired up the supply,...no smoke,  but have way too high voltages

1.  the bias seems ok,within range when you adjust the pot. 
    
2.  the Hi voltage is around 1080 vdc no load.

3. the low voltage is around 410 vdc  no load

4. the fil reads about 5.5 vac.... seem low?

there is a low level buzzing noise ,hard to tell, where from, when powered up.

I have traced the wiring as best as I can follow it,lots of fadeing on wire colors. Re checked all the new parts for proper direction + -, Iam beginning to get fuzzy eyes. Since there is no voltage or data chart in the manual ,Iam lost.
 
Any chance the SS tube replacements causing a problem,that might go away when the tubes are put back, they couldn't cause such a high voltages at no load? Plan to keep the supply on tubes when its finished. would be grateful for any help on this.