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Re: FRG-7 Mechanical adjustment
If there was anything of interest to take in?I’d agree, alas there is just propaganda and fake American accents …
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This is doubtful to enrich your grey matter.. Best 73 Radio (a sad demise but it had to come) On Sunday, February 23, 2025, 6:45 pm, John Walker via groups.io <reeferjon@...> wrote:
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Re: FRG-7 Mechanical adjustment
开云体育You will soon get fed up with it… I’m licenced and I’m Afraid you are now better off going to a gym or exercising of some type to keep healthy.. Sitting around a radio in 2025 is the most unhealthy pastime there is gents.. Most of the broadcast stations are gone on the tropical bands too. All I hear now is old hams talking to old hams about their prostate operations on 75 metres.. The Golden age is now over.. Spend your time getting fit, it’s wiser.. 73 M On 23 Feb 2025, at 16:39, John Walker via groups.io <reeferjon@...> wrote:
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Re: FRG-7 Mechanical adjustment
But John?
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There is nothing left to listen to anymore On Sunday, February 23, 2025, 4:01 pm, John Walker via groups.io <reeferjon@...> wrote:
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Re: FRG-7 Mechanical adjustment
Got it, there is a flat tension plate behind the front panel, remove the panel, clamp the shaft and you can increase the drag on the clutch.
Cleaned all the muck out and ts much better now.
Looks like its been dropped on its face at some time as shafts are a little bend.
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Anyone any thoughts on how to get rid of decade of nicotine smell?
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Br John.? |
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FRG-7 Mechanical adjustment
Good day all.
Question, how does the preselect drive clutch work please, has anyone had to adjust it.
I have some backlash that seems to be within the clutch mechanism, the output shaft to the toothed drive for drum and on to the VC couplers is good.
Interested if anyone has stripped the clutch before.
Br.
John. |
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Re: Ebay Lucky-Dip FRG7
Started again from the beginning.
1. stripped out the 2m converter, completely rewired the antenna connections and removed a pair of 1meg resisters from So239.
2. stripped the Band switch and cleaned the wipers, this made a big difference
3. cleaned the Dx/LOCAL switch again
4. mechanically aligned the preselect/Mhz and Khz dials
5. cleaned up potential dry joints
6. washed off the PCBs with IPA and inspected tracks
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Results, much better but still issues.
Worked part way through the alignment, stopped due to scope not being up to parr.
Worked through Q101 to Q111 voltage chart, found Q110 and Q111 C&B voltages out to list, adjusted VR102 nearly 1/4 turn and they are now somewhere near, LED goes out on most of range now, but its clear there is still a problem in the selective filter area. |
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FRG7 alignement
Good day All.
I have a TinySA that have been using as an RF sig gen and a Zeewiie DSO1151g scope that 'should' run past 100Mhz, well lets just say 30Mhz is about its limit, this means I'm unable to look at signals in RF range.
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My question, attached are sample alignment procedures.
Given that I dont have a fit-for-purpose scope (have three scope probes) but do have a TinySA and a NanoVNA (on the way) how should I then perform the alignements that require use of a scope, so what modifications do I make to testing and how should I review the results.
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Scopes, Im happy with using. SA and VNA interpretation, I'm not familiar with and no option to buy a higher bandwidth scope.
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Thank you.
Br John.
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Re: Ebay Lucky-Dip FRG7
开云体育Hey Mike.
Changed it today, nothing wrong with it, took the opportunity to resolder the joints around the area, no difference.
Will retake measurements of all TP again tomorrow and may crank up the signal gen a few db
Br
John
On 9 Feb 2025, at 21:35, Mike Anthony via groups.io <g4thn@...> wrote:
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Re: Ebay Lucky-Dip FRG7
开云体育Indeed, I get 112mV as well at the junction of R117 & R118. ?So something is shorted to ground here. R118 perhaps?Sent from Mike's iPad
On 9 Feb 2025, at 15:10, reeferjon via groups.io <reeferjon@...> wrote:
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Re: Ebay Lucky-Dip FRG7
Thank you Mike.
I do have the afore mentioned pages and they are great IF the set is working :-)
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I did some more investigation around Q106, all of the supplies measure correct.
No o/p on pin3 which is TP107
No i/p on Pin11
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TP101 confirms as 58Mhz
Then we come to a PD made up of R117 and R118, I'm not getting anything 'measurable' after R117, what level would that lightly be.
I calc that if i/p is 350mV then o/p should be around 112mV.
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I know the tracks are a bit fragile on these so will await a response before unsoldering on end and checking the values of R117 and R118. |
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Re: Ebay Lucky-Dip FRG7
开云体育See comments below line by line. I have to ask first though, do you have circuit diagram? Better still the September and October 1981 articles in Short Wave magazine by JL Linsley Hood? With these to hand and read and understood you will be in a much better place to get the Frog working again. ? From: [email protected] <[email protected]>
On Behalf Of reeferjon via groups.io
Sent: 08 February 2025 18:52 To: [email protected] Subject: Re: [Yaesu-FRG-7] Ebay Lucky-Dip FRG7 ? Today spent a few hours to see why its deaf and the lock led stays on below approx 15Mhz. These are the measurements I got so far. Anyone any thoughts? ? Inject 3Mhz into antenna ? Lock LED is lit, will not go out (goes out above 15Mhz). The LED is driven by the Darlington pair Q110 and Q111. When there is enough voltage (>0.5rms) present at TP110 then this is enough to extinguish the LED. Therefore, you are not getting enough signal down the Q107 to Q109 amplifier chain. Q111 will be on and the LED lit with its base drive supplied by R131. But when Q110 gets enough base drive to turn on, it will remove the base voltage from Q111 and the LED will go out. ? ? TP101 = 58Mhz approx 350mV pk-pk This shows that the Q201 oscillator stage is functioning correctly. ? TP103 = 0hz ?approx 0mV pkpk Here is certainly one problem. If you are injecting a 3MHz signal into the antenna socket then you should be able to see this at TP103. So the signal is getting lost somewhere between the antenna socket and
TP103. Check at the input to T102 and then at C101 which is the input to RF amp Q101. After this there is the LPF which is that rod with several coils. ? TP104 = 2.5Mhz approx 100mV pkpk This is at the output of the second mixer Q105. For a signal to appear here this is likely coming from the signal you see at TP101 which gets fed two ways, one of which ends at the first mixer which is Q102 and Q103. Try looking for this at VR101. After this the signal will progress through T105 T106, Q104, T107 and T108 then Q105 before appearing at TP105.
? TP107 = 0Mhz approx 0mV This suggests that Q106 which is the IC on the board, has died. This chip mixes the 58MHz and 2-3MHz signals and so if this is dead, there will be no signal at TP107 ( and neither will there be enough signal at TP110 to turn off the LED) ? TP109 = 0Mhz approx 0mV This reinforces my guess that Q106 is dead since this test point is on the end of the chain starting at Q106. You should be seeing the output of the Q106, Q107, Q108 and Q109 chain here.
I am puzzled about this result. If there is no signal at TP109 then there will be none at TP110 either. ? As to there being no sound output try touching or injecting say 3KHz at the centre connection of the AF gain control. That at least will prove the AF PA stage and associated components. |
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Re: Ebay Lucky-Dip FRG7
Today spent a few hours to see why its deaf and the lock led stays on below approx 15Mhz.
These are the measurements I got so far.
Anyone any thoughts?
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Inject 3Mhz into antenna
Mhz set to 3Mhz, preselect set to 3Mhz Band set to B Am set to AM ATT and tine set to normal Dial set to 0Khz S meter reads 9-11 Lock LED is lit, will not go out (goes out above 15Mhz) TP101 = 58Mhz approx 350mV pk-pk
TP103 = 0hz ?approx 0mV pkpk TP104 = 2.5Mhz approx 100mV pkpk TP106 = 1Mhz approx 800mV pkpk TP107 = 0Mhz approx 0mV TP109 = 0Mhz approx 0mV TP110 = 52Mhz (TP104 with Mhz and band set to 28Mhz = 52Mhz 200mV pkpk) |
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Re: Ebay Lucky-Dip FRG7
开云体育I saw another box which is not standard under the chassis alongside the Crystal oscillator. Perhaps another converter?Sent from Mike's iPhone
On 8 Feb 2025, at 08:38, reeferjon via groups.io <reeferjon@...> wrote:
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Re: Ebay Lucky-Dip FRG7
The unit with the 38.667 MHz x-tal is a FET 2 meter converter. Br Marcel Op vr 7 feb. 2025 21:42 schreef Mike Anthony via <g4thn=[email protected]>:
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Re: Ebay Lucky-Dip FRG7
开云体育The extra unit sounds like a converter to allow reception of another band of frequencies. As in converting say the 2m band down to 28MHz or similar. And the replacement 455KHz filter-nice!Sent from Mike's iPhone
On 7 Feb 2025, at 19:32, reeferjon via groups.io <reeferjon@...> wrote:
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