In article CNEzf.140599$WH.64582@dukeread01, says...

I've got a problem with my Astron RS-20 power supply. With no load,
it's fine, but anything above 4amps or so makes it drop way down and my
rig drops out of lock. I haven't measured it under load but the rig
works ok to 10 or 11 volts so it must be dropping below that.

I found a schematic and downloaded it, all the voltages are fairly close
to what it says on the schematic with no load, I haven't made any
measurements with a load on it. I'll pick up a headlight tomorrow to
put a load on it and make more measurements.

Does anybody have any ideas?

Thanks,
Kerry, WD5ABC

Is it just simply RF getting back into your supply and causing
havoc? Perhaps the supply is O.K.? You need at least 3 headlights
to get the supply under a load that compares to your rig. Try
more lights and see if it craps out.

Gudmundur wrote:
In article CNEzf.140599$WH.64582@dukeread01, says...

I've got a problem with my Astron RS-20 power supply. With no load,
it's fine, but anything above 4amps or so makes it drop way down and my
rig drops out of lock. I haven't measured it under load but the rig
works ok to 10 or 11 volts so it must be dropping below that.

I found a schematic and downloaded it, all the voltages are fairly close
to what it says on the schematic with no load, I haven't made any
measurements with a load on it. I'll pick up a headlight tomorrow to
put a load on it and make more measurements.

Does anybody have any ideas?

Thanks,
Kerry, WD5ABC


Is it just simply RF getting back into your supply and causing
havoc? Perhaps the supply is O.K.? You need at least 3 headlights
to get the supply under a load that compares to your rig. Try
more lights and see if it craps out.


Nothing normal ever seems to happen to me... I did go out to get a 2nd
headlight so I could get about 7.75 amps on it. I found a 1000uf
capacitor that had a leg corroded so badly that apparently during the
move it wiggled around enough to break loose. I went to the local Radio
Shack (which, by the way, has apparently turned into a cell phone store)
and they didn't have any 1000uf but they did have some 470uf caps so I
put two of them in parallel to get close to see if it mattered. Pins 11
and 12 showed about 8 or 9 volts too low before but now they are right
on according to the chart on the Astron schematic. I connected one
headlight (3.75 amps) and turned on the supply. It showed 13.59 volts.
Then I connected the 2nd headlight (4 amps) and it stayed dead on
13.59 volts. Looks like I'm in business!

Somebody has been into this supply before and butchered it, so I may
clean up a few things while I'm in it. I guess I should fix that
capacitor, the next guy in there will say the same about me if he sees 2
paralleled 470ufs instead of a 1000 uf!

THanks for your help guys!

73,
Kerry
WD5ABC
PS This post may look different, I'm on my Linux box out in the shack
tonight.

....[snip]....
and they didn't have any 1000uf but they did have some 470uf caps so I
put two of them in parallel to get close to see if it mattered....
^^^^^^^^

I sure hope you meant "series"!-)
---
--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

On 25 Jan 2006 21:43:04 -0600, wrote:

....[snip]....
and they didn't have any 1000uf but they did have some 470uf caps so I
put two of them in parallel to get close to see if it mattered....
^^^^^^^^

I sure hope you meant "series"!-)

Why?

Mcalhoun must have been thinking about resistors!

"budgie" wrote in message
...
On 25 Jan 2006 21:43:04 -0600, wrote:

....[snip]....
and they didn't have any 1000uf but they did have some 470uf caps so I
put two of them in parallel to get close to see if it mattered....
^^^^^^^^

I sure hope you meant "series"!-)

Why?

In article , wrote:

....[snip]....
and they didn't have any 1000uf but they did have some 470uf caps so I
put two of them in parallel to get close to see if it mattered....
^^^^^^^^

I sure hope you meant "series"!-)
---

I hope you are an underclassman, who hasn't actually taken any college
level classes in Electronics Design or Circuit Evaluation. If not,
you definitly ask for your money back, because you didn't learn anything.

Me

Me wrote:
In article , wrote:

....[snip]....
and they didn't have any 1000uf but they did have some 470uf caps so I
put two of them in parallel to get close to see if it mattered....
^^^^^^^^

I sure hope you meant "series"!-)
---

I hope you are an underclassman, who hasn't actually taken any college
level classes in Electronics Design or Circuit Evaluation. If not,
you definitly ask for your money back, because you didn't learn anything.

Me
2 470uf in parallel is close to 1000uf. This was on the Extra class
Ham exam. I got my ticket 40 years ago. Why do you think an Amateur
Radio Operator should necessarily have college level Electronics Design
Experience? This is an Amateur newsgroup, unless cross-posting.
Gary N4AST