[Premium-Rx] HF-2050 Power supply - fault light

[Rodney Bunt]

The power supply is low output. This could be that the power mains voltage is low, or prbably the
filter capacitors in the power supply have drifted lower in value, and therefore more intollerent
to voltage fluctuation. Check the 5 pin Molex connector for correct contact, they tend to discolor
when hot, so just nip the pins to provide a better contact in the plug.

Very easy to test, open up the case, look into the power supply section and measure the voltage
across the big blue capacitors. There are three of them the HF-2050 requires +15VDC at 1.5A,
-15VDC at 1A and +5.2VDC at 3.3A. You should see 27VDC for the + or - 15 volt supply, and 13 volts
for the +5 volt supply. The two 15 volt PS capacitors are the smallish ones the 5v PS capacitor is
the BIG one. Check the voltages on the caps. OR use a variac and up the supply voltage a little,
this is ok for a short time, BUT long time use will heat up the power supply too much, so OK for a
test etc. If the rig is a reliable starter, then the problem is in the low tech power supply and
easy and cheap to fix.

The supply was designed to work on quite a wide range of input AC voltage, maybe 85 - 130. On some
models there are primary taps for adjusting the imput voltage. If these are set too high then the
output voltage is too low nad the "power supply fault comparitors" make the "fault" light come on.

Hope this helps, been ther and seen that.

Rodney VK2KTZ



--- Jerry Strawman <jlstrawman at mchsi.com> wrote:
> Hello to all!
> 
> I have a HF-2050 that I would like to sell. It had performed flawlessly
> until recently.
> 
> The symptoms are that the display flahes at turn on.
> The normal message, "Power On Bit" does not appear
> as does not, "Bit Passed." The fault light goes on and off and on. The
> display alternates between 10000.00 and another frequency.
> 
> After turning on and off  2-5 times, the set operates
> normally. When warmed up, none of the symptoms appear.
> 
> I do not have the capability to troubleshoot the HF-2050.
> If you have any ideas as to the problem, or are interested
> in acquiring this radio, please contact me off the list.
> 
> Best regards to all,
> 
> Jerry Strawman,
> Des Moines, IA
> 
> 
> 
> 
> 
> 
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