Hi:
I am having a problem with a "Simple Receiver for Beginners". It is from a
design that was featured in an old (1981) ARRL handbook. It is a DC
receiver, looks like alot of fun, but it isn't fun now.
Here is the problem.

1) No oscillation! I can't find it (the VFO) on my DX-398 receiver at all,
or on my Radio Shack freq counter.
2) The power (+ side) electrolytic is supposed to be a 500uF, 16 volt. I am
using a 470uF 35 volt. It gets really hot!! Short somewhere?!?!?!

The VFO is REALLY simple, it has one transistor and about 7 other parts. I
can't seem to see what is wrong, and I have tried.

I would sure appreciate some Elmer'ing here!
ANY help would be much appreciated. I have the above mentioned tools at my
command, a multimeter, and an old Heathkit "scope. (which I really don't
know how to use.

Any chance?
Thanks in advance,
Tom
KCØGXX

"TC Dufresne" wrote in
:

Hi:
I am having a problem with a "Simple Receiver for Beginners". It is
from a design that was featured in an old (1981) ARRL handbook. It is
a DC receiver, looks like alot of fun, but it isn't fun now.
Here is the problem.

1) No oscillation! I can't find it (the VFO) on my DX-398 receiver at
all, or on my Radio Shack freq counter.
2) The power (+ side) electrolytic is supposed to be a 500uF, 16 volt.
I am using a 470uF 35 volt. It gets really hot!! Short somewhere?!?!?!

The VFO is REALLY simple, it has one transistor and about 7 other
parts. I can't seem to see what is wrong, and I have tried.

I would sure appreciate some Elmer'ing here!
ANY help would be much appreciated. I have the above mentioned tools
at my command, a multimeter, and an old Heathkit "scope. (which I
really don't know how to use.

Any chance?
Thanks in advance,
Tom
KCØGXX






Gotta be a short somewhere. Filter caps ain't supposed to get hot, and
yours is over rated to begin with.

In article , says...
"TC Dufresne" wrote in
:

Hi:
I am having a problem with a "Simple Receiver for Beginners". It is
from a design that was featured in an old (1981) ARRL handbook. It is
a DC receiver, looks like alot of fun, but it isn't fun now.
Here is the problem.

1) No oscillation! I can't find it (the VFO) on my DX-398 receiver at
all, or on my Radio Shack freq counter.
2) The power (+ side) electrolytic is supposed to be a 500uF, 16 volt.
I am using a 470uF 35 volt. It gets really hot!! Short somewhere?!?!?!

The VFO is REALLY simple, it has one transistor and about 7 other
parts. I can't seem to see what is wrong, and I have tried.

I would sure appreciate some Elmer'ing here!
ANY help would be much appreciated. I have the above mentioned tools
at my command, a multimeter, and an old Heathkit "scope. (which I
really don't know how to use.

Any chance?
Thanks in advance,
Tom
KCØGXX






Gotta be a short somewhere. Filter caps ain't supposed to get hot, and
yours is over rated to begin with.

and when you run an electrolytic at a different WVDC than it's rated at,
you can't be sure the capacitance is the same as marked on the can. but
it should still filter and not get hot. you'd think something else would
heat up if there was a short. should draw excessive current. unless it
blew something and is now an open, then the cap shouldn't get hot any
more.

The only time I have seen caps get hot is when they are in backwards. If
there is too much ripple voltage, the cap can get warm. I would double
check the wiring. I am not sure what method you used to make the VFO, so
everything is up in the air.

Pete

Active8 wrote in message
...
In article , says...
"TC Dufresne" wrote in
:

Hi:
I am having a problem with a "Simple Receiver for Beginners". It is
from a design that was featured in an old (1981) ARRL handbook. It is
a DC receiver, looks like alot of fun, but it isn't fun now.
Here is the problem.

1) No oscillation! I can't find it (the VFO) on my DX-398 receiver at
all, or on my Radio Shack freq counter.
2) The power (+ side) electrolytic is supposed to be a 500uF, 16 volt.
I am using a 470uF 35 volt. It gets really hot!! Short somewhere?!?!?!

The VFO is REALLY simple, it has one transistor and about 7 other
parts. I can't seem to see what is wrong, and I have tried.

I would sure appreciate some Elmer'ing here!
ANY help would be much appreciated. I have the above mentioned tools
at my command, a multimeter, and an old Heathkit "scope. (which I
really don't know how to use.

Any chance?
Thanks in advance,
Tom
KCØGXX






Gotta be a short somewhere. Filter caps ain't supposed to get hot, and
yours is over rated to begin with.

and when you run an electrolytic at a different WVDC than it's rated at,
you can't be sure the capacitance is the same as marked on the can. but
it should still filter and not get hot. you'd think something else would
heat up if there was a short. should draw excessive current. unless it
blew something and is now an open, then the cap shouldn't get hot any
more.

In article ,
says...
The only time I have seen caps get hot is when they are in backwards. If
there is too much ripple voltage, the cap can get warm. I would double
check the wiring. I am not sure what method you used to make the VFO, so
everything is up in the air.

please reply to the person you are answering. it makes the discussion
easier to follow.

mike

In article ,
says...
The only time I have seen caps get hot is when they are in backwards. If
there is too much ripple voltage, the cap can get warm. I would double
check the wiring. I am not sure what method you used to make the VFO, so
everything is up in the air.

please reply to the person you are answering. it makes the discussion
easier to follow.

mike

The only time I have seen caps get hot is when they are in backwards. If
there is too much ripple voltage, the cap can get warm. I would double
check the wiring. I am not sure what method you used to make the VFO, so
everything is up in the air.

Pete

Active8 wrote in message
...
In article , says...
"TC Dufresne" wrote in
:

Hi:
I am having a problem with a "Simple Receiver for Beginners". It is
from a design that was featured in an old (1981) ARRL handbook. It is
a DC receiver, looks like alot of fun, but it isn't fun now.
Here is the problem.

1) No oscillation! I can't find it (the VFO) on my DX-398 receiver at
all, or on my Radio Shack freq counter.
2) The power (+ side) electrolytic is supposed to be a 500uF, 16 volt.
I am using a 470uF 35 volt. It gets really hot!! Short somewhere?!?!?!

The VFO is REALLY simple, it has one transistor and about 7 other
parts. I can't seem to see what is wrong, and I have tried.

I would sure appreciate some Elmer'ing here!
ANY help would be much appreciated. I have the above mentioned tools
at my command, a multimeter, and an old Heathkit "scope. (which I
really don't know how to use.

Any chance?
Thanks in advance,
Tom
KCØGXX






Gotta be a short somewhere. Filter caps ain't supposed to get hot, and
yours is over rated to begin with.

and when you run an electrolytic at a different WVDC than it's rated at,
you can't be sure the capacitance is the same as marked on the can. but
it should still filter and not get hot. you'd think something else would
heat up if there was a short. should draw excessive current. unless it
blew something and is now an open, then the cap shouldn't get hot any
more.

In article , says...
"TC Dufresne" wrote in
:

Hi:
I am having a problem with a "Simple Receiver for Beginners". It is
from a design that was featured in an old (1981) ARRL handbook. It is
a DC receiver, looks like alot of fun, but it isn't fun now.
Here is the problem.

1) No oscillation! I can't find it (the VFO) on my DX-398 receiver at
all, or on my Radio Shack freq counter.
2) The power (+ side) electrolytic is supposed to be a 500uF, 16 volt.
I am using a 470uF 35 volt. It gets really hot!! Short somewhere?!?!?!

The VFO is REALLY simple, it has one transistor and about 7 other
parts. I can't seem to see what is wrong, and I have tried.

I would sure appreciate some Elmer'ing here!
ANY help would be much appreciated. I have the above mentioned tools
at my command, a multimeter, and an old Heathkit "scope. (which I
really don't know how to use.

Any chance?
Thanks in advance,
Tom
KCØGXX






Gotta be a short somewhere. Filter caps ain't supposed to get hot, and
yours is over rated to begin with.

and when you run an electrolytic at a different WVDC than it's rated at,
you can't be sure the capacitance is the same as marked on the can. but
it should still filter and not get hot. you'd think something else would
heat up if there was a short. should draw excessive current. unless it
blew something and is now an open, then the cap shouldn't get hot any
more.

"TC Dufresne" wrote in
:

Hi:
I am having a problem with a "Simple Receiver for Beginners". It is
from a design that was featured in an old (1981) ARRL handbook. It is
a DC receiver, looks like alot of fun, but it isn't fun now.
Here is the problem.

1) No oscillation! I can't find it (the VFO) on my DX-398 receiver at
all, or on my Radio Shack freq counter.
2) The power (+ side) electrolytic is supposed to be a 500uF, 16 volt.
I am using a 470uF 35 volt. It gets really hot!! Short somewhere?!?!?!

The VFO is REALLY simple, it has one transistor and about 7 other
parts. I can't seem to see what is wrong, and I have tried.

I would sure appreciate some Elmer'ing here!
ANY help would be much appreciated. I have the above mentioned tools
at my command, a multimeter, and an old Heathkit "scope. (which I
really don't know how to use.

Any chance?
Thanks in advance,
Tom
KCØGXX






Gotta be a short somewhere. Filter caps ain't supposed to get hot, and
yours is over rated to begin with.

Tom:

The hot cap has two likely possibilities: either the cap is shorted
internally (an ohmeter check will show leakage) or you have bad diode(s) so
AC is being applied to the cap. An ohmeter will show the diodes as bad.

Of course a wiring error could also be involved, but I am assuming you have
double checked that.

If the cap is running hot you probably don't have the correct voltage for
the VFO, and correcting it may solve the other VFO problem.

Roger K6XQ