[Hammarlund] HX-500 trials

[Jeff]

AC voltages out of the transformer are 900 VAC, 350 vac, 6.8 vac.

Filter chokes test OK -- although I don't have my LCR bridge. According 
to the schematics, the HV choke should have a resistance of 160 ohms, 
mine is 172.  LV choke should be 250 ohms, mine is 271.

LV circuit is a CLC filter.  At the output of the LV rectifier, voltage 
is 380 vdc, should be 270.

At the output of the CLC, voltage is around 280 vdc, should be 230.

Regulated voltage is 151 vdc.

Screen voltage is about 250, should be 200.

Capacitors are what is specified in the Hammarlund power supply update 
schematic.  My HV is running close to 1 KV.

Voltages are just way high across the board.  I've gone over and over 
the supply and verified nothing's shorted or connected incorrectly.

The factory specification for the transformer was 900-320-110-0-320-900, 
with filament lines of 12.6 and 6.3.  It was run very close to the max 
voltage of the 6146, and hammarlund even says to be careful switching 
the rig on and off.

As always, appreciate the advice.  Still getting a solid 100 watts out 
now of carrier, but can't test any further than that.

Jeff
WB3JIH




On 4/25/2016 10:18 PM, Kenneth G. Gordon wrote:
> On 25 Apr 2016 at 19:56, D C _Mac_ Macdonald wrote:
>
>> Maybe somebody converted a choke input power supply filter to capacitor input?
> That is a possibility:
>
> If the DC voltage out of the rectifier stack was around 640 VDC, going cap-input would give
> around 900 VDC out of the filter (640 X 1.414 = 905), but choke input would show around
> 575 VDC (640 X 0.9 = 576)
>
> Or, if the choke was shorted, the filter would then actually be a capacitor-only filter. With
> ~640 VDC out of the rectifier, the output voltage would be around 905 VDC as for a
> cap-input filter.
>
> Seems to me that we have two problems here. Too high voltages, and an "issue" at the
> final.
>
> Without killing himself, he could competely disconnect any and all filtering, then measure
> the voltage out of the rectifier. That would tell us something...
>
> What is the AC voltage out of the transformer? That would also tell us something...
>
> Ken W7EKB
>
>
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