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Re: Almost ready to give up but...

 

Most transistor sold on eBay are fakes. You should file a claim and get your money back.
Re: Almost ready to give up but...

 

Update:
New 3SK40 I bought off of Ebay is bad.? Same problem as the old one: G2 is kaput.? So I ordered a NTE222 from Amazon.? Awaiting delivery.
I also found the ATTN switch has seen an EMP.?? Many of the resistors are fried & one was blown in two.
So now I wait....
--
-Bob
Re: Almost ready to give up but...

 

No need to worry about IC Q106, all that section is working, else you would not have the megacycle lock light flashing, this is the mixer chip for the Wadley loop, it takes the VFO and the harmonic gen products and converts them to the 52 meg IF. The output of this IF strip is rectified and used to light the LED, so this signal is present and correct.
The problem seems to be upstream from the second mixer, between this and the first mixer. Place a short wire to TP103 and see if any signals appear, this will eliminate the RF amp and front end tuning.

On Sat, Apr 8, 2023, at 11:05 PM, Bob W8RMV wrote:
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

--?
? Dayle Edwards
??dayleedwards@...
Re: Almost ready to give up but...

 

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
Re: Almost ready to give up but...

 

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.
Re: Almost ready to give up but...

 

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.
Re: Almost ready to give up but...

 

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

-Bob
Re: Almost ready to give up but...

 

Is your "lock LED flashing when tuning through the megacycle tuning?

On Fri, Apr 7, 2023, at 9:50 AM, Bob W8RMV wrote:

..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?


--?
? Dayle Edwards
??dayleedwards@...
Very very useful thread

 

I think this thread would be useful to anyone working on an FRG7
Re: Almost ready to give up but...

 

Also this thread is very useful for you
Re: Almost ready to give up but...

 

Check this out in reference to the 3SK40
Almost ready to give up but...

 

..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?
Re: Sacrilege

 

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.........
Re: Original tuning knob?

 

OK TNX!
73 Wilbert PA3DAE
Re: Original tuning knob?

 

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?
Re: Original tuning knob?

 

开云体育

Do the knobs rotate at different speeds? If so there may be better fine tuning using the inner knob.

?

73 Roger VE7LB

?

From: [email protected] <[email protected]> On Behalf Of Wilbert PA3DAE
Sent: Tuesday, March 7, 2023 5:44 AM
To: [email protected]
Subject: [Yaesu-FRG-7] Original tuning 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

Re: Original tuning knob?

 

That is not the original knob
Original tuning 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
Re: What mod it this?

 

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

 

My upgraded FRG7,?

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