Problems with Grundig Satellit700
Josefa Cabral
listen to short wave, everything will come in clearly for about an hour,
then the radio will make a staticky noise for a few seconds and will then
not receive any shortwave or AM signals, and this will last a few days, when
suddenly the radio will work again and receive shortwave. Does anyone have a
clue as to what is happening or can you recommend a good repair shop. I am
in the New York area.
Chris
Peter Maus
The simple solution is the antenna connection to the input board.
The antenna is mounted to the back of the radio. The input is on the
board mounted into the case. To bring the antenna into connection
with the input, there is a metal tang at the input that comes into
contact with the antenna when the case is closed. This tang is under
considerable tension, as it should be. But this tension tends to
loosen both the soft solder connection to the input, and the bent
tabs that hold this tang to the input board. Open the case,
reposition the tang, resolder the connection with silver bearing
solder (higher tensile strength than the factory solder for this
connnection) You'll not have this problem again.
If it's not this metal on metal connection, you'll have to look
for cold solder joints on the motherboard.
The FM system uses the antenna as well...but at VHF frequencies, a
direct connection to the input is not required for decent FM
peformance. The capacitive coupling of proximity alone is
sufficient.
AM/SW however DO suffer when this connection opens up.
I"ve had to do it to both my Sat 500 and Sat 700 displaying the
same symptoms as you describe.
Not had a problem since.
Ruud Poeze
To my best knowledge also the Sat 700 (as the Sat 500) uses a ferrite
rod antenna for AM/MW (and LW) reception.
When also AM fails another cause might be considered; see my other
reply.
Ruud
Ruud Poeze
Hi Chris;
First check out if the radio stil receives FM signals when AM reception
fails.
I had a problem with a Sat 500 where all reception stopped, indeed after
some static sounds (only on AM).
The cause of this was a Crystal oscillator in the synthizer section that
stopped oscillating due to a faulty trimmer.
After a day or so the set functions again when the short cut in the
trimmer is temporaly lifted. But only for a short time.
When this happens you have no reception at al, not even from the
stronges signal.
When there is a problem with the antenna - print connection via the back
lid, you must still have FM reception AND medium wave (and LW) recption:
since in this mode the ferrite rod is used and not the whip antenna.
Also an external antenna must stil provide for "normal" reception on all
bands.
Even when the whip antenna is completely removed (by removing the back
lid)_some SW reception on the hihger bands must be possible of very
strong signals.
Ruud
Monty Python
You might want to check and see if you turned the
AGC knob off of auto and turned it high enough for
the radio to go deaf. I did that when tuning in the
dark one night and I also thought the 700 died on me.
monty
Ruud Poeze
>
> Rudd you're right!
>
> Additional I have suggest as followed:
> Topic: Single superhet / double superhet --->signal conversion.
> #1 Satellit 700 = double superhet at s/w
> Stage 1 = 54,5 MHz
> Stage 2= 450 kHz
>
> #2 Satellit 700 = single superhet at AM (MW/LW)
> Used stage (#2 as above) = 450 kHz.
AM also is double conversed.
>
> If AM and SW fails, then Stage #2 fails, because Stage #1
> not in use under 1,611 kHz.
> In other words, Signal conversion broken (as Rudd said).
>
> Try this: enter 150 kHz (Longwave band), take a second receiver, set
> it
> to 600 kHz and bring both radios much near together (really close).
> Tune the Satellit 700 some kHz up and down. If 2nd receiver gets some
> "silent points" then Oscillator stage #2 (450kHz) at S 700 is OK. If
> not, Stage #2 as listed above fails.
>
> To proof stage #1 (54,5 MHz) you need to have a radio able to receive
> at least 84,5 MHZ ( highest s/w frequency S 700 provides = 30 MHZ +
> oscillator #1 frequency 54,5 MHz = 84,5 MHz ).
>
> If Oscillator stages are OK, often the "near by" filters (bandwidth)
> fails. Manufactor is MURATA. SFR 450 J and SFR 450 H used here. Both
> available.
> If not in US, I am able to support "ya".
>
> hope you're able to understand my "overseas-english"....
>
>
> Thomas
I'm dont know how a 700 works, but I do how a 500 handles the signal.
I guess that the principles are more or less the same.
I'm afraid I dont agree with you that the 700 only has one conversion
stage for MW/LW.
All AM bands are double conversed.
The mixing frequency is generated by a synthesizer.
In the 500 this synth also produces the mixing signal for FM. (single
conversion)
(to check if the synthesizer works try a second FM receiver next to the
Grundig. Tune the Grundig to say 90 MHz. The second receiver must pick
up a signal on 90 + 10,7 = 100,7 Mhz.)
When my 500 failed I had NO reception at al.
All AM bands, but also the FM band was deaf.
In the schematic diagram I found that the synth. is driven by a 7475 kHz
Crystal oscillator.
After opening the set I held a second SW receiver tuned to 7475 kHz next
to the Grundig. As long as the Grundig was able to receive I also
detected the 7475 signal on the second receiver.
At the same moment the Grundig stopped; also the 7475 signal diappeared!
Most likely cause was the X-tal oscillator or better, the trimmer next
to it.
Why: because many Color TV's stop producing color when the sub-carrier
oscillator (3.38 or 4.43 MHZ) fails. Always caused by a faullty trimmer.
And indeed: the trimmer meusured a few 100 kOhms.
After turning the trimmer slightly the short disappeared (infinite) and
yes: the Grundig received again!
You have to replace the trimmer: alternatively with a fixed C.
But turning it and putting it back to its original position might cure
the set temporarely.
So: beware of faulty trimmers in X-tal oscillator sections.
Ruud
Thomas Baier
>
> I'm dont know how a 700 works, but I do how a 500 handles the signal.
> I guess that the principles are more or less the same.
> I'm afraid I dont agree with you that the 700 only has one conversion
> stage for MW/LW.
> All AM bands are double conversed.
Ruud,
Satellit 500/700 are single superhet at AM (MW/LW).
450 kHz IF-stage only. Go to www.satellit700.com
regards,
Thomas Baier
Homburg,Saar / Germany
mrta...@gmail.com
Pekka Hasu
Pekka Hasu
I bougth a very beatiful radio on a flymarked. The problem is that only FM works.Mw and Lw oly make a scratching sound. A second problem is that you can´t put of the ligth.
Could somebody give me a clou to solve these problems?
ric...@norris964.fsnet.co.uk
Radio Tech
> Hi!
> I bougth a very beatiful radio on a flymarked. The problem is that only
> FM works.Mw and Lw oly make a scratching sound. A second problem is that
> you can´t put of the ligth.
> Could somebody give me a clou to solve these problems?
Yes, It sounds like you have an ethnic shortwave receiver.
FM on your radio is like white people, It works. Medium wave and shortwave on
your receiver are like Niggers, it's hard to get them to work.
Thanks for the excellent question. Happy to help.
Radio Tech