Pete - I'm pretty sure you have an FRG-7. If so what circuit mod have
you done to fix the horrible S-meter circuit action?

Thanks,

Frank
K3YAZ
Tucson (where it has been raining for 5 days!)

I didn't change the function of mine. Is your responding too slowly or too
quickly? On another note, that MW attenuator can be bypassed by rerouting
the RF path of the MW input filter to the 50 Ohm input. This eliminates the
1k resistor and the other components that are in the series string. There is
a Yaesu users group on Yahoo. They do mention that S-Meter mod, and they do
have documentation for this mod. You can also find the schematic and the
owner's manual on this site. The nice thing about this schematic is that it
is a complete scan, instead of the partial multiple scans.

Pete

" wrote in message
...
Pete - I'm pretty sure you have an FRG-7. If so what circuit mod have
you done to fix the horrible S-meter circuit action?

Thanks,

Frank
K3YAZ
Tucson (where it has been raining for 5 days!)

On Dec 12, 2:46 am, "Pete KE9OA" wrote:
I didn't change the function of mine. Is your responding too slowly or too
quickly? On another note, that MW attenuator can be bypassed by rerouting
the RF path of the MW input filter to the 50 Ohm input. This eliminates the
1k resistor and the other components that are in the series string. There is
a Yaesu users group on Yahoo. They do mention that S-Meter mod, and they do
have documentation for this mod. You can also find the schematic and the
owner's manual on this site. The nice thing about this schematic is that it
is a complete scan, instead of the partial multiple scans.

Pete

" wrote in message

...

Pete - I'm pretty sure you have an FRG-7. If so what circuit mod have
you done to fix the horrible S-meter circuit action?

Thanks,

Frank
K3YAZ
Tucson (where it has been raining for 5 days!)

Thanks Pete. Mine just has a very compressed range. If you adjust it
so the background level with no signal is about S-1, few signals are
above S-9. Conversely, if you calibrate it on a known S-9 signal, the
"noise floor" is typically S-4 to S-5, very inaccurate. From the
existing circuit design it appears that some type of adjustable gain
meter amp is needed with the set-point pots.

Best FRG-7 I've had otherwise. Looks and performs like it came right
off the assembly line. Even the 6 kHz ceramic IF filter is good with
very steep skirts and good audio. Quite unlike the previous 2 FRG-7s
I had. This is one Marty was not watching!!

Frank
K3YAZ

That is good. I like that receiver quite a bit. I also did a full bypass on
the emitters of the 455kHz I.F. amplifiers. Yaesu uses a partially bypassed
emitter to give some negative feedback, probably for stability. I haven't
had any negative effects from doing the full bypass, except for the increase
in I.F. gain that I was looking for.
When I mentioned the MW attenuator mod, I forgot to mention that you reroute
the MW input signal to the unused MW input termimal on the preselector range
switch.
That has to be one of my alltime favorite receivers. Right now, I am working
on a redesign of my R-388. I am going to convert it to a solid state unit. I
have enought dual-gate MOSFETs laying around, at least to complete the
modifications. There is just something about analog receivers, when you
think about all of the mechanical design that was done in order to make it
happen. Synthesized units are much cheaper to manufacture.

Pete

" wrote in message
...
On Dec 12, 2:46 am, "Pete KE9OA" wrote:
I didn't change the function of mine. Is your responding too slowly or
too
quickly? On another note, that MW attenuator can be bypassed by
rerouting
the RF path of the MW input filter to the 50 Ohm input. This eliminates
the
1k resistor and the other components that are in the series string. There
is
a Yaesu users group on Yahoo. They do mention that S-Meter mod, and they
do
have documentation for this mod. You can also find the schematic and the
owner's manual on this site. The nice thing about this schematic is that
it
is a complete scan, instead of the partial multiple scans.

Pete

" wrote in message

...

Pete - I'm pretty sure you have an FRG-7. If so what circuit mod have
you done to fix the horrible S-meter circuit action?

Thanks,

Frank
K3YAZ
Tucson (where it has been raining for 5 days!)

Thanks Pete. Mine just has a very compressed range. If you adjust it
so the background level with no signal is about S-1, few signals are
above S-9. Conversely, if you calibrate it on a known S-9 signal, the
"noise floor" is typically S-4 to S-5, very inaccurate. From the
existing circuit design it appears that some type of adjustable gain
meter amp is needed with the set-point pots.

Best FRG-7 I've had otherwise. Looks and performs like it came right
off the assembly line. Even the 6 kHz ceramic IF filter is good with
very steep skirts and good audio. Quite unlike the previous 2 FRG-7s
I had. This is one Marty was not watching!!

Frank
K3YAZ

Pete KE9OA wrote:
Right now, I am working
on a redesign of my R-388. I am going to convert it to a solid state unit. I
have enought dual-gate MOSFETs laying around, at least to complete the
modifications.
snip

Do you have any FETRONS on hand? There was a rather broad line of tube
types available in this form for quite a few years. I tried to
duplicate that line using discrete parts mounted on old tube bases and
had some success.

Regards,

Michael

Hi Michael,

I haven't seen those things for years. I will end up taking your approach
when I finally do the redesign. I remember the old
Pepperdyne modification to the 75A-4 receiver that was featured in Ham Radio
years ago. I still might have that magazine laying around.
I finally got through with my old S&S Engineering digital display tonight.
Some of the LED segments were flickering, so I removed all of the IC sockets
and soldered all of the ICs in directly. Same thing with the DIP switches
for the programmable offset. They became intermittent, so I removed them and
used jumpers to hardwire the desired offset.

Pete

"msg" wrote in message
...
Pete KE9OA wrote:
Right now, I am working
on a redesign of my R-388. I am going to convert it to a solid state
unit. I have enought dual-gate MOSFETs laying around, at least to
complete the modifications.
snip

Do you have any FETRONS on hand? There was a rather broad line of tube
types available in this form for quite a few years. I tried to
duplicate that line using discrete parts mounted on old tube bases and
had some success.

Regards,

Michael

msg wrote:


Do you have any FETRONS on hand?

WOW! Talk about a blast from the past! I hadn't thought about them
in years!

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

Pete - found the problem with the weird S-meter movement on the
FRG-7. It was due to excessive voltage on the 9.5V rail (11.2V). The
zener for the pass transistor regulator was way out of tolerance. I
replaced it with a 10V zener, re-calibrated the S-meter and it reads
like a normal meter now.

Frank
K3YAZ


On Dec 12, 2:46 am, "Pete KE9OA" wrote:
I didn't change the function of mine. Is your responding too slowly or too
quickly? On another note, that MW attenuator can be bypassed by rerouting
the RF path of the MW input filter to the 50 Ohm input. This eliminates the
1k resistor and the other components that are in the series string. There is
a Yaesu users group on Yahoo. They do mention that S-Meter mod, and they do
have documentation for this mod. You can also find the schematic and the
owner's manual on this site. The nice thing about this schematic is that it
is a complete scan, instead of the partial multiple scans.

Pete

" wrote in message

...

Pete - I'm pretty sure you have an FRG-7. If so what circuit mod have
you done to fix the horrible S-meter circuit action?

Thanks,

Frank
K3YAZ
Tucson (where it has been raining for 5 days!)

I am glad that you found the problem. That FRG-7 is a nice receiver. Nothing
like home radio repairs. I repaired a Grundig Satellit 3400 for a friend of
mine, so he gave me a Yaesu FT-211. The memory battery was bad, so it
"dumbed down" the microprocessor. I removed the battery and reset the uP,
and everything is working ok.
He has another Satellit 3400 for me to repair. The BFO injection frequency
has drifted out of the I.F. passband, so it will be a simple adjustment to
recalibrate that. The big thing is the turret bandswitch......the designer
uses a square shaped nylon bushing that has a round hole in its center. This
bushing keeps the turret in position, so that it makes good mechanical
contact with the finger stock contacts, similar to the bandswitch in a
Hammarlund SP-600. My unit had the same problem. Since only 1mm or so is
required to shim the bandswitch, copper tape works fine. This eliminates the
front to back play that can develop over the years.
His other 3400 had the typical problem of the blown RF amplifier for the
single conversion ranges. Since the original transistor doesn't seem to be
available, an MPS-H81 (also a PNP device) is a great substitute. This device
has a higher Ft than the original, so the sensitivity is actually improved
over a stock 3400. Of course, you see the usual problems, such as an
oxidized I.F. bandwidth switch, etc. I thing that the Satellit 3400 was
probably the best design they ever made, even better than the Satellit 6001.
I also have one of those units. Too bad Grundig got away from that turret
bandswitch, with its gold plated contacts.............that design was a
classic.

Pete