As the saying goes, I am self taught & I had a bad teacher.
I got the scope out (means I am desperate) I can see the 1st & 2nd ocs.
I can see the lock unlock working & the comb freq on the scope.
I pulled Q105 2nd Mixer & Q104 and both tested fine.
But I see very little at TP107 coming out of the premixer IC Q106.
And I do not see the 3MHz coming out of the good Q105 over to the IF/AF board.
So I am thinking it maybe that IC Q106 or maybe someone messed with the alignment.

Thanx for the comments.? The slog continues...
--
-Bob

And, if the previous guy has twiddled the 1st IF? coil tuning slugs, it will need a realignment in that section. Correct alignment here is crucial.

Well, it seems the tuneable IF section, 2 to 3 megs is working, the loop section, ie, megacycle selector is working, so the money goes on the second mixer back. This is a juncton FET, it may be open. There is little to go wrong with the 55 meg first IF section, there is a dual gate FET in there, that never gives problems, neither does the front end balanced mixer. So, i would check the second mixer, just replacing it is easy and cheap? and will eliminate that one.

Mike - I've seen many of those posts.? Looks like the SMD part is most promising.
Dayle - Yes.? All 1MHz segments lock fine.

-Bob

I think this thread would be useful to anyone working on an FRG7

Also this thread is very useful for you

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@...>

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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/FRENDX-1982-11-OCR-Page-0013.pdf

By: MikeM <mmaghakian@...>

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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