This manual is downloaded from the FoxTango site, Yaesu. FRG HF Receiver. Survival Guide. Revision 2 march. If you want to work on your FRG, it is a must to have the manuals and schematics. See: The manuals are very informative and deal. The purpose of this manual is to provide the reader with information critical to the nance of the FRG general coverage communications receiver.
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Close inspection discovered some more shorts between solder joints. With the help of this guide your Frog can survive the next 20 years and frg–7700. Well, as things go, this rx had also a display problem, the previous owner told me that he had used the receiving and PLL board himself for a swap, because the power supply of his had blown up, so I expected that I had just got a bunch of spare parts for my other receivers. For AM however, the displayed frequency is correct, if the mankal station is tuned in the center of the filter.
This guide is in the true boat anchor tradition, a collection of known faults and their solution, and a story of resurrection of a receiver at my workbench.
Another set of modifications are described on a very interesting Swiss internet site: Yaesu did it the cheap way here, a spray of manua paint over the plastic faceplate and that is a pity, because it is very difficult to repair.
Yaesu FRG-7700 Instruction Manual
Well, that was the only band with signals, but at least there was hope for the better. First I had to construct a new power supply, because the owner had thrown away the burned board, but fortunately had still the original transformer, complete with burn marks and burned wires. On this site are also modifications, pictures, descriptions and more. For a fully alignment you need a signal generator with attenuator and a range from 0.
Most sides of the front plate are heavily scratched, so Fgg-7700 will try to paint the sides alone, if there is then a small difference in shade, it will not be so obvious.
The highest resolution of the display is 1 khz, so there is always a frequency difference of khz between the true and the displayed frequency. I measured voltages between 1. Is the set very unsensitive, check first the semiconductors in the circuit, or there can be resistor or condenser failure, that is much more likely than misalignment… Closely check for abnormalities burnt or cracked components, bad soldering joints, bad connectors and other trouble spots.
This wire has to be some 10 cm longer than the others. The receiver is very rugged and, normal used, there are not much problems. After studying the circuit diagram I found that the Memory Fine manuall is nothing more than a voltage divider, the output is used to tune a varicap in the memory unit.
If your display goes weak, you can solve the problem temporarily by removing the orange filter in the display window. You find very much manuao stuff there about ham equipment and a lot of very good descriptions of ham equipment. The remaining problem was now the counter and the clock.
Try to make this adjustments very careful, often these voltages are too high, resulting in a loss of range or a failure to lock properly, with a high noise level as result.
Using the clock was no problem, but the switch could not change to the frequency mode, it still displayed the time. Your Frog has then a very bright green display, that will again last for years. If I got a spare, changing the IC was done in no time. These terms and conditions contain rules about posting comments.
So it is not recommended. Set the band switch at the 5 Mhz band and adjust T for a reading of 7.
Dial lamps are long lasting, but they have to be changed now and then. I saw one used!!!
YAESU FRG SCH Service Manual download, schematics, eeprom, repair info for electronics experts
One of my sets had a bad mode switch. The OM who worked on this receiver was clearly not qualified to work at this kind of equipment, and has a BIG soldering iron… After reinserting the board, I had now signals at all bands.
Change C uF to 47 uF, for a higher pitched audio. The main dial can be set exact enough, but not quick enough to follow quickly changing talk. The rag chewers are not always at exactly the same frequency, and constantly tuning with the main dial is no fun, because you easily overcompensate, losing all information. The set and memory module is very stable, but some changes improve the receiver considerably: D43 was defect and displayed a resistance of 5 K-ohm in both directions.
Again, I did not like the result, and changed C to nf. If the end point of each Mhz range is getting lower at the high side of each band, a re-alignment of the first PLL is necessary, receiver receives not higher than or so on the analog scale If only the end points at the 5, 12, 20 and 29 Mhz bands are too low, a re-alignment of the second PLL is necessary. After a squirt of contact spray and working the switch a couple of times, everything worked nice again. The cores are not interchangeable, so do one at a time.
I checked the resistance of the movement and even that was almost the same. The pages are in German, so I will give a translation of the mods, for the benefit of all of you who are not fluent in that language.
I have seen all kinds of junky stuff on e-bay, that was tampered mahual and sold for high ftg-7700, to the chagrin of the new owner. Painting the front is as a whole is almost impossible, the lettering is printed on the front and is easily damaged. After pulling the board out, I discovered that there was a solder connection between the power. This modification is very elegant, because there is no drilling or extra knobs necessary, simply undone if necessary, easy to use and has no side effects in stability of the receiver.
Yaesu FRV, Yaesu FRV VHF Converter for FRG
Follow closely the procedure in the manual, if the receiver is in a normal condition, the changes should be minor. This alignments are not difficult to do, you need a good counter, a VTVM, RF millivolt meter or oscilloscope and fitting plastic or ceramic tuning tools. If this is carefully done, you can put the switch back together again without problem. Just check for a Be careful if you buy from Internet, there are many guys who advertise with a receiver in good condition, but when it arrives it manuual a box full of junk.
A mode switch changes the display for frequency, clock, on-time, off-time and sleep function. MilliHenry, to form a DC path to unload antenna charges. There is not much difference between the first and the last receivers, the frb-7700 thing I saw was a different coupling of the frequency scale to the dial mechanism.