Do you have the manual with the alignment instructions? You need that and a nanoVNA and tinySA or two. The 2nd is for use as a signal generator. Connect CH0 of the nanoVNA to the antenna input attach a probe to CH1 and start tracing your way thru the radio doing the alignment. You'll either find or fix the fault in the process. At some point results won't match the instructions.
Key traits:
manual preselector
Barlow-Wadley loop circuit
use of harmonics of 1 MHz oscillator to change frequencies
A good white noise source (NOT a BG7TBL!!!) will let you check the performance of the preselector with a tinySA. In fact, if budget is tight a tinySA and white noise source will do everything you need for under $100. A search on EEVblog for user rhb should find comparisons of the two noise sources.
The one of this pattern
https://www.ebay.com/itm/265453613573
that I have tested is quite flat to 1 GHz and then starts to roll of. Over the narrow spans and frequencies you need to use it will be perfectly flat. I've posted 8560A screen shots of the performance. The noise source should have a 2nd voltage regulator as the MIMICs are being fed unregulated input power and it's particular about what you feed it. I plan to add a LiPo and charger.
My FRG-7 is on loan at the moment. It was the first radio I ever did an alignment on for the simple reason I didn't have the needed instruments. I very much enjoyed it. I redid it a 2nd time just to be sure I had it right and to catch any potential coupling problems between stages. Just make sure you have the correct adjusting tools as you don't want to damage a tuning slug.
Basic procedure outline
check the operation of the preselector with the noise source. You should see the peak back and forth on the SA. and it should be of uniform amplitude at the preselector output. Then check at the mixer input to see the signal amplitude is constant check the LO input to the mixer and the output. Then align the harmonic oscillator chain. Use a magnifying glass and check for craks or solder flux residue.
If you observe cracking or corrosion I recommend fluxing the entire board and reflowing it with a hot air gun. If there's one you, see there are many you don't.
Have Fun!
Reg
On Saturday, July 15, 2023 at 06:22:59 PM CDT, Chris Rogers via groups.io <crvee8@...> wrote:
I have a FRG-7 that has the following non working symptoms. The Mhz led can be tuned out on the upper shortwave bands only, and a few stations can be heard at very low volume. The Mhz led does not go out on the lower bands and and no stations are heard.?
Any clue on where to look for the fault would be appreciated.
