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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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.
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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.
Inject 3Mhz into antenna
Mhz set to 3Mhz, preselect set to 3Mhz
Band set to B
Am set to AM
ATT and tone set to normal
Dial set to 0Khz
S meter reads 9-11
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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.
?
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TP101 = 58Mhz approx 350mV pk-pk This shows that the Q201 oscillator stage is functioning correctly.
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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.
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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.
TP106 = 1Mhz approx 800mV pkpk This is the output signal from the sealed box under the chassis from the crystal oscillator Q301. So this is working
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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)
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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.
TP110 = 52Mhz
(TP104 with Mhz and band set to 28Mhz = 52Mhz 200mV pkpk)
I am puzzled about this result. If there is no signal at TP109 then there will be none at TP110 either.
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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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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
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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Marked Astec, not sure what that is yet.
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I saw another box which is not standard under the chassis alongside the Crystal oscillator. Perhaps another converter?
Sent from Mike's iPhone
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On 8 Feb 2025, at 08:38, reeferjon via groups.io <reeferjon@...> wrote:
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thank you Marcel, a great starting point, I will pull the images down today
br
john
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thank you Marcel, a great starting point, I will pull the images down today
br
john
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The unit with the 38.667 MHz x-tal is a FET 2 meter converter.
Is was publiced in UKW Berichte.
Here you can find some information? about it:
Br Marcel
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
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Good day All.
My Ebay lucky-dip FRG7 has arrived, and its what I hoped it would be, see pics below.
There are a few things that Im struggling to identify, so if anyone has any input, that would be great, thank you.
?
The serial number has extra digits, so if anyone recognises the number, please shout up.
Serial number: 17 8M 240615
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The PCB marked DL6 SW 004 is power from the DC rail, it 'seems' to have an SO239 on one side and a BNC on the other side, no connection into the unit itself at all. SO239 SW2 is no longer connected to SW1 or BC. Does anyone know what this is please.
The XTAL is 38.66667Mhz
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There is something that looks like an additional modulator marked astec, does anyone have any info on this please.
?
At the moment, its powered up, white noise when AM is selected, the lock LED will go out above 15Mhz ish but wont go out below.
Putting a TinySA outputting at 25Mhz with 100Khz AM-mod near the antenna plugs induces the signal at 25Mhz and is auditable.
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That's about as far as I've got so far.
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Br John.
<20250207_111134415_iOS.jpg>
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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
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On 7 Feb 2025, at 19:32, reeferjon via groups.io <reeferjon@...> wrote:
?
Good day All.
My Ebay lucky-dip FRG7 has arrived, and its what I hoped it would be, see pics below.
There are a few things that Im struggling to identify, so if anyone has any input, that would be great, thank you.
?
The serial number has extra digits, so if anyone recognises the number, please shout up.
Serial number: 17 8M 240615
?
The PCB marked DL6 SW 004 is power from the DC rail, it 'seems' to have an SO239 on one side and a BNC on the other side, no connection into the unit itself at all. SO239 SW2 is no longer connected to SW1 or BC. Does anyone know what this is please.
The XTAL is 38.66667Mhz
?
There is something that looks like an additional modulator marked astec, does anyone have any info on this please.
?
At the moment, its powered up, white noise when AM is selected, the lock LED will go out above 15Mhz ish but wont go out below.
Putting a TinySA outputting at 25Mhz with 100Khz AM-mod near the antenna plugs induces the signal at 25Mhz and is auditable.
?
That's about as far as I've got so far.
?
Br John.
<20250207_111134415_iOS.jpg>
<20250207_111141341_iOS.jpg>
<20250207_113818883_iOS.jpg>
<20250207_113824507_iOS.jpg>
<20250207_113834949_iOS.jpg>
<20250207_113858010_iOS.jpg>
<20250207_113924758_iOS.jpg>
<20250207_122654286_iOS.jpg>
<20250207_111150996_iOS.jpg>
<20250207_111219072_iOS.jpg>
<20250207_111234523_iOS.jpg>
<20250207_111242302_iOS.jpg>
<20250207_111251875_iOS.jpg>
<20250207_111258468_iOS.jpg>
<20250207_111301496_iOS.jpg>
<20250207_111349568_iOS.jpg>
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Sold as seen not working, spares or repairs
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Hi John,
What is a "lucky-dip"?
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73 Roger VE7LB
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Good day All.
My Ebay lucky-dip FRG7 has arrived, and its what I hoped it would be, see pics below.
There are a few things that Im struggling to identify, so if anyone has any input, that would be great, thank you.
?
The serial number has extra digits, so if anyone recognises the number, please shout up.
Serial number: 17 8M 240615
?
The PCB marked DL6 SW 004 is power from the DC rail, it 'seems' to have an SO239 on one side and a BNC on the other side, no connection into the unit itself at all. SO239 SW2 is no longer connected to SW1 or BC. Does anyone know what this is please.
The XTAL is 38.66667Mhz
?
There is something that looks like an additional modulator marked astec, does anyone have any info on this please.
?
At the moment, its powered up, white noise when AM is selected, the lock LED will go out above 15Mhz ish but wont go out below.
Putting a TinySA outputting at 25Mhz with 100Khz AM-mod near the antenna plugs induces the signal at 25Mhz and is auditable.
?
That's about as far as I've got so far.
?
Br John.
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Re: Digital Display for FRG-7
Hi Steve
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Thanks for doing that...I just couldn't make the numbers out. I spent ages trawling data books I have and looking for TI mixers on-line, but nothing came up.
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According to Google, it became the TL442.
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I'll check it out though...hopefully the one I have is okay.
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It appears the previous owner did what Pentagrid suggested and referred to the MSM5525 data sheet when connecting it up; at least in part! The DFC-7 uses a 9-0-9 volt transformer, and gets the 3v for the display filament, by using a resistor from the supply. Said previous owner used an 18-0-18 volt transformer for some reason, and used its 3v AC winding for the display filament.
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Somewhere I have a spare counter chip...probably not a mixer, but you never know. The counter chip will go in a socket and I'll see what happens.
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Thanks very much for all your help Steve, and I appreciate everyone else's input too.
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Regards
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Simon
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Re: Digital Display for FRG-7
So painfully true. I was thinking of Kat on Deutsche Welle today.
Reg
On Saturday, January 25, 2025 at 06:39:03 PM CST, Mark Feltham via groups.io <dodacarem@...> wrote:
If only Dxing existed anymore John The broadcast bands are high powered China or Romania now Everyone’s gone over to internet… Its a shame My radio is a beauty but sadly nothing to listen to any longer The tropical bands are dead too It’s sad that? We knew it was coming with the WWW… The king is dead, Long live the king..
73 M
On 25 Jan 2025, at 21:37, John Hudak via groups.io <hudakjm@...> wrote:
? For what it's worth I've got a Communications Concepts Inc. (CCI) digital display for my FRG-7. It sits on top. No longer available of course but if you can find one I can highly recommend it. It's easy to program for the FRG-7 and it works very well. DXing with the FRG-7 and this display is a lot of "old school" fun. ? Cheers, John
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Re: Digital Display for FRG-7
If only Dxing existed anymore John The broadcast bands are high powered China or Romania now Everyone’s gone over to internet… Its a shame My radio is a beauty but sadly nothing to listen to any longer The tropical bands are dead too It’s sad that? We knew it was coming with the WWW… The king is dead, Long live the king..
73 M
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On 25 Jan 2025, at 21:37, John Hudak via groups.io <hudakjm@...> wrote:
? For what it's worth I've got a Communications Concepts Inc. (CCI) digital display for my FRG-7. It sits on top. No longer available of course but if you can find one I can highly recommend it. It's easy to program for the FRG-7 and it works very well. DXing with the FRG-7 and this display is a lot of "old school" fun.
?
Cheers,
John
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Re: Digital Display for FRG-7
For what it's worth I've got a Communications Concepts Inc. (CCI) digital display for my FRG-7. It sits on top. No longer available of course but if you can find one I can highly recommend it. It's easy to program for the FRG-7 and it works very well. DXing with the FRG-7 and this display is a lot of "old school" fun.
?
Cheers,
John
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Re: Digital Display for FRG-7
Thanks Pentagrid…I thought it might be one of those myself, but the pin out doesn’t match. As previously mentioned, it looks like a TI logo on on of the images, and SN something or other for the part number. Sadly, the image is just to low resolution to make it out.
It is indeed an elegant solution. A friend and I used a similar method with Deltahet and G3PDM receivers.
Regards, Simon.
Sent from my Interocitor
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Re: Digital Display for FRG-7
Hi All,
When I looked carefully (pic time_step-01.jpg in files/DFC-7), the mixer is definitely Texas Instruments, and I thought I could make out "SN7651?". Did a search and came up? with a data sheet for a SN76514 balanced mixer. Function and pin-outs match the schematic for the DFC-7, and part was around when the FRG-7 was produced, so I'm calling this as THE part number for IC1.
Have put the datasheet in files/DFC-7.
Cheers,
Steve
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Re: Digital Display for FRG-7
By memory I think you will find the mixer is a CA3028 transistor array or similar. Look in any 1970s? American? radio constructor books for details of these chips, they were used often before the days of LSI.? Three transistors, long tail differential pair in a round case with 7 legs
Basically, the oscillator into the? base of the long tail, signal into one base of the differential pair. The two products are available at the output. The LPF will remove the high product 3.455 +2.455? to? 3.455 + 3.455 = 5910 to 6910, leaving the low product 3.455 - 2.455 to 3.455 - 3.455 = 1 to 0 megs, this product passes to the counter module. This is a very elegant way to do this, as it also automatically reverses the count.....? the FRG7 actually tunes backwards. The second IF is below the first IF, and the first IF is above the signal frequency, that is the basis of drift cancelling...... both first and second signal mixers using? the same VFO....?
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Re: Digital Display for FRG-7
Enjoy it stock. Not worth the effort.
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On Jan 21, 2025, at 1:13?AM, Mark Feltham via groups.io <dodacarem@...> wrote:
? Don’t fit the digital display gents, it looks terrible and completely ruins the whole feel visually of the radio. The whole beauty of this radio is its retro appeal and I urge you to not be tempted to fit the aftermarket hideous digital display unit… It really does not do the radio any favours whatsoever. Thank you 73 On 21 Jan 2025, at 02:16, Steve Quigg (VK2TUM) via groups.io <stevequigg@...> wrote:
? Hi Simon,
Have attached a data sheet on the MSM5525 plus a couple of pics re the DFC-7.
Enjoy
<MSM5525_6.pdf> <time_step-04.jpg> <time_step-03.jpg>
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Re: Digital Display for FRG-7
Thanks everyone for your help on this...I've put Steve's diagram and instructions through PaintShop Pro and uploaded the results into the 'files' section on the group.
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Pentagrid - I've spent most of my life working on equipment without diagrams. Data sheets are of course a great help, but it's much easier if someone has the original manufacturer's diagrams and PCB layout, as I'm sure you will agree. The metal round IC, a mixer chip, isn't identified on the diagram...and the numbers have been removed from the physical part. I thought it might be a 'Birkett Special' Plessey SL640, but the connections don't match. I don't recognise the pinout and connections; is it familiar to you?
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The original owner had used an 18-0-18 volt transformer, with a separate 3v winding to feed the filament of the display. I'm fairly sure the counter chip is faulty, but believe I have a spare one 'somewhere safe'.
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I would never dream of installing it in my receiver, but will re-box it and sit it on the top.
?
Cheers
?
Simon M5POO
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Simon Robinson