Check this out in reference to the 3SK40

..I thought I'd give the group a try.

Friend gave me an old FRG7 to fix for him.? No fine tune on the front & has some corrosion on the chassis.

Symptoms:

• Only a light hiss from the speaker with volume turned all the up

• No stations or s meter movement

• Can hear the 455 IF (I think on 1455) if I mess with LOCK

So I check for the obvious:

• PS voltages OK.? Electrolytics ESR are fine.

• All connections seem fine

I suspect Q101 & find only G2 is working & replace it.? No change.

When I was checking component voltages I notice Q102/103 Emitters somewhat high at 2.5 & 2VDC

Also find that Q401 has 5.2vdc on G2 (vs 2.7).? I pull 401 & it checks fine.? I start searching for cause & misread the schematic looking for R133 to find R135 on the RF board completely missing (missing from Yeasu's component view also??).? So I install it, no change.

I then check Q407 voltages (connects up to Q401) & they are fine.? Further inspection of the IF/AF board I find a big solder blob left behind from another incompetent tech.? Remove it & no change.

I do insert a 3MHz signal into the the IF/AF board & get a loud report.

So I find 3 issues & still have a non working radio.? I am very surprised how quiet the AF is even at full volume.? I know it can get pretty loud when I inserted the 3MHz.

Any suggestions before I return the unit with a sad face.

Thanx - Bob W8RMV

ps - is there a good (cheap) source for 3SK40's?

This radio started as a very neglected FRG7, too rough to repair, too good to throw out. With the help of an angle grinder, the top chassis section was removed, and new alloy chassis plates fitted. The new circuitry I designed around vacuum tubes, arranged to use the existing Yaesu front panel controls.
The radio? works as intended, an MDS of -108 dB, and a -91dB sensitivity for a 12dB SINAD, slightly better than the solidstate version.
The frequencies used are similar to the Racal RA17, with the first IF at 40 mHz, the loop at 37.5, as apposed to the? FRG freqs at 52 and 55 megs.
Tubes are 6AU6s for all loop amplifiers and mixer stages, 6BA6 remote cut off pentodes for AGC controlled stages, ECH81 triode/heptodes , 1 each for the 4th mixer and VFO, product detector and BFO, 6BL8 for the 2nd mixer and audio preamp, and an OB2 neon for voltage stabilisation.... 15 in all. I even managed to replicate the Yaesu lock LED, this time it glows green when locked.........

OK TNX!
73 Wilbert PA3DAE

Like said it isn't a original knob and but a after marked one installed by many owners to have a more fine /? course tuning posibility.

I have seen this on aprx 50% of the sold FRG-7's in the Netherlands (Marktplaats).

--

73 Lex PH2LB?

开云体育

That is not the original knob

Hi,

Can anybody tell if this Sommerkamp FRG-7 tuning knob is an original design for this receiver? I don't see any pictures on the internet with this kind of tuning knob.

Tnx!

73 Wilbert

That add on is an NFM demodulator, this radio has been used as a tuneable IF for VHF convertors..

My upgraded FRG7,?

Ed Shaw was a well known DXer in the 70s and 80s and had a column in NASWA
I found a column in which he described the mods he did on his FRG7
I put it in the mods folder, check it out

MikeM <mmaghakian@...> added folder /7 - FRG-7 Mods/Mods from Ed Shaw

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The following files and folders have been uploaded to the Files area of the [email protected] group.

• /7 - FRG-7 Mods/Mods from Ed Shaw/24FFFAC9-8663-45D7-B3B0-9900C62CA83A.png

By: MikeM <mmaghakian@...>

---

The following files and folders have been uploaded to the Files area of the [email protected] group.

• /7 - FRG-7 Mods/Mods from Ed Shaw/FRENDX-1982-11-OCR-Page-0013.pdf

By: MikeM <mmaghakian@...>

---

The following files and folders have been deleted from the Files area of the [email protected] group.

• /7 - FRG-7 Mods/Mods from Ed Shaw/Ed Shaw mods

By: MikeM <mmaghakian@...>

If memory serves me correctly it was to deal with microphonics

Fellow Frogers,

? Just picked up a new-to-me FRG-7 and noticed what seemed to be an unkown mod consisting of a DPDT slide switch (S-7) w/ two? resistors (R-18 & 19), connected to the internal speaker.

But surprise, some of the schematics show these components in the lower right near the speaker.? However, they are not on the parts list, nor are they mentioned in operating / calibration instructions or circuit description.? There are no related labels on chassis or cabinet.

The switch is physically attached to a frame brace in the upper right rear of the chassis, just below the white battery plug/socket.? Switch is poorly positioned and clearly not intended to be accesssed often or easily.?

The resistors are either switched out of circuit, or placed in series w/ speaker: one between audio & speaker, the other between speaker & chassis gnd.

The only in-circuit effect seems to be some lowering of the volume.

Serial # 300585 and apparently this radio lived in Canada at some point.

Any idea what this undocumented "feature"? is about?

Hi Andrew, The FL-101 transmitter looks very similar to the FRG-7. But when the FL-101 is used with the FR-101 the pair will work in transceive mode after the interconnecting cables are attached.
73 Roger VE7LB

I am looking for an aftermarket speaker replacement for the main speaker on the FRG-7. Has anyone had success with finding one?

Thanks, Lex, for that 3D-printed knob design. I was lucky enough to find an original knob on eBay. Also, thank Cesar for your reply. This is one neat radio. I am researching a suitable AM transmitter to get more out of the one AM channel. I might consider building one from scratch and looking into a loop antenna for the USB and LSB. Does anyone know if this receiver had a transmitter that went with it, like the FT-101 FR-101? Or was this just a stand-alone unit?

The knobs of the first model FT-101? look like the on a FRG-7.

But the knobs you are pointing to in the e-bay link are from the newer models of the FT-101 (E, ET, Z, MD etc) and look like the one's used on a FRG-7700.

Looking at the prices on e-bay for original knobs, scared the hell out of me.?
--

73 Lex PH2LB?

开云体育

Read that ft 101 is the same. Found this:

Hello Andrew,

These are very hard to come by. I had the same problem and often 3D print parts, I designed my own (as close as to the orginal as possible).?

?

So when you access to a 3D printer (of not ask, friends, family, you local community center) you can print your own.
--

73 Lex PH2LB?