Hello,
The panel meter (plate voltage 0-3Kv) of my Linear amplifier fl-2100Z is
broken.
Do you know or can find spare parts.
Or you know the characteristic electric of the panel meter ?
Thanks
Max

"Max" wrote in message
...
Hello,
The panel meter (plate voltage 0-3Kv) of my Linear amplifier fl-2100Z is
broken.

We often see requests for analog meters, which are fragile and hard to come
by, to say nothing of expensive. If the objective is to refurbish a vintage
amplifier, then probably the best bet is to find a junk amp to cannabalize
for parts.

But if the objective is to actually -use- the amp, then a micro and an LCD,
along with a little design work, can lead to a meter that is more accurate,
more robust, and cheaper than the original.

...

"xpyttl" a écrit dans le message de news:
...

"Max" wrote in message
...
Hello,
The panel meter (plate voltage 0-3Kv) of my Linear amplifier fl-2100Z is
broken.

We often see requests for analog meters, which are fragile and hard to
come by, to say nothing of expensive. If the objective is to refurbish a
vintage amplifier, then probably the best bet is to find a junk amp to
cannabalize for parts.

But if the objective is to actually -use- the amp, then a micro and an
LCD, along with a little design work, can lead to a meter that is more
accurate, more robust, and cheaper than the original.

..



Hi,
Thank you for your answer.
The digital LCD is another solution, but I wanted to keep the spirit of the
old amplifier.
However, I don't know the value of galvanometer, it is not indicated in the
diagram of the manual, It is written only M1.
Regards
Max

"Max" ) writes:
"xpyttl" a écrit dans le message de news:
...

"Max" wrote in message
...
Hello,
The panel meter (plate voltage 0-3Kv) of my Linear amplifier fl-2100Z is
broken.

We often see requests for analog meters, which are fragile and hard to
come by, to say nothing of expensive. If the objective is to refurbish a
vintage amplifier, then probably the best bet is to find a junk amp to
cannabalize for parts.

But if the objective is to actually -use- the amp, then a micro and an
LCD, along with a little design work, can lead to a meter that is more
accurate, more robust, and cheaper than the original.

..



Hi,
Thank you for your answer.
The digital LCD is another solution, but I wanted to keep the spirit of the
old amplifier.
However, I don't know the value of galvanometer, it is not indicated in the
diagram of the manual, It is written only M1.
Regards
Max

There was a time when the value of the meter was printed on the paper
that holds the scale, like down in the corner. It may nor may not be
visible without front cover on.

I don't know how consistent that was, but of the good meters I have
around (as opposed to really cheap ones seen as tuning meters in various
bits of consumer equipment) I think they all have the value printed on
the paper.

Michael VE2BVW

xpyttl wrote:


"Max" wrote in message
...
Hello,
The panel meter (plate voltage 0-3Kv) of my Linear amplifier fl-2100Z is
broken.

We often see requests for analog meters, which are fragile and hard to
come
by, to say nothing of expensive. If the objective is to refurbish a
vintage amplifier, then probably the best bet is to find a junk amp to
cannabalize for parts.

But if the objective is to actually -use- the amp, then a micro and an
LCD, along with a little design work, can lead to a meter that is more
accurate, more robust, and cheaper than the original.

==============================
However in the RF environment of an power amplifier it might be very
difficult to suppress RF in a micro/LCD equipped device.

I would go for a replacement moving coil meter by checking the voltage
metering circuit resistors and after finding a suitable low mA meter (size
wise) ,determine its resistance and initially replacing the defective meter
with a resistor of that value. You then can measure the mA current through
that resistance . If that current is higher than the replacement meter
can handle ,replace a series resistor in the voltage metering circuit by a
(preferably ten-turn) trim potmeter and adjust the current through the
resistor to the corresponding current through the future replacement
meter.

You then either change the replacement meter's scale or accept the existing
one . Then install the replacement meter ,removing its temporary
replacement resistor in the circuit and finally with a suitable HV meter
adjust the reading of the new meter with the trimpot .

If the above HV meter can't handle 3000 V but say only 1000 Volts ,use a
variac at the AC supply input to the amp and temporarily reduce the HV-DC
voltage to the amp to 1000 V Then adjust the meter reading (with the
trimpot ) to 1/3 of the meter scale.

After all ,this is a homebrew NG.


Frank KN6WH/ GM0CSZ

Hi,
Thanks all for your help, I had several
responses to this post.
My best wishes for 2008
Cordially
Max

*Sorry for my bad English.

On Dec 20, 8:05*am, "xpyttl" wrote:
But if the objective is to actually -use- the amp, then a micro and an LCD,
along with a little design work, can lead to a meter that is more accurate,
more robust, and cheaper than the original.

I have to disagree here. For time-varying parameters of great interest
- certainly plate current is the most interesting, but only a little
behind is plate voltage - analog meters, and them bouncing up and down
in response to modulation, are essential to correct operation and
maintenance.

Bargraph-type LED or LCD meters are popular on recent equipment, and
while they have the visual trend to the eye and also lack moving
parts, they still aren't up to the same snuff that good old fashioned
analog meters have.

The thought of watching modulation peaks using a digital panel meter
is laughable. Maybe if you're sending an unmodulated carrier it would
be of value!

Tim.