HI,

My Pioneer amp and tuner developed some intermittent problem which I do not
know if it is the amp or the tuner. There is no sound from the speaker when
the tuner is selected(may be a faint hiss if the vol is turned up to max.)
and the vu display shows no signal at the input. Some times the problem
disappear for a while and then the sound will be gone again. Any clue? or
any one can point me to a schematic or even pin out and volage levels at the
ribbon cable going from the tuner to the amp?

Thanks.

Cheuk

Well, if you're referring to the signal strength meter, and it shows no
signal when the problem occurs, perhaps the antenna connection is loose or
connected improperly.

Mark Z.



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"Cheuk-Fai Wong" wrote in message
...
HI,

My Pioneer amp and tuner developed some intermittent problem which I do
not
know if it is the amp or the tuner. There is no sound from the speaker
when
the tuner is selected(may be a faint hiss if the vol is turned up to max.)
and the vu display shows no signal at the input. Some times the problem
disappear for a while and then the sound will be gone again. Any clue? or
any one can point me to a schematic or even pin out and volage levels at
the
ribbon cable going from the tuner to the amp?

Thanks.

Cheuk

Hi Mark,

I checked the Ant connections and they are fine(AM and FM terminals). The
meters I am referring to are the VU meters.

Cheuk

"Mark D. Zacharias" wrote in message
...
Well, if you're referring to the signal strength meter, and it shows no
signal when the problem occurs, perhaps the antenna connection is loose or
connected improperly.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Cheuk-Fai Wong" wrote in message
...
HI,

My Pioneer amp and tuner developed some intermittent problem which I do
not
know if it is the amp or the tuner. There is no sound from the speaker
when
the tuner is selected(may be a faint hiss if the vol is turned up to
max.)
and the vu display shows no signal at the input. Some times the problem
disappear for a while and then the sound will be gone again. Any clue?
or
any one can point me to a schematic or even pin out and volage levels at
the
ribbon cable going from the tuner to the amp?

Thanks.

Cheuk

In that case, there may be an intermittent fault in the tuner - bad solder
connections, for example.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Cheuk-Fai Wong" wrote in message
.. .
Hi Mark,

I checked the Ant connections and they are fine(AM and FM terminals). The
meters I am referring to are the VU meters.

Cheuk

"Mark D. Zacharias" wrote in message
...
Well, if you're referring to the signal strength meter, and it shows no
signal when the problem occurs, perhaps the antenna connection is loose
or
connected improperly.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Cheuk-Fai Wong" wrote in message
...
HI,

My Pioneer amp and tuner developed some intermittent problem which I
do
not
know if it is the amp or the tuner. There is no sound from the speaker
when
the tuner is selected(may be a faint hiss if the vol is turned up to
max.)
and the vu display shows no signal at the input. Some times the
problem
disappear for a while and then the sound will be gone again. Any clue?
or
any one can point me to a schematic or even pin out and volage levels
at
the
ribbon cable going from the tuner to the amp?

Thanks.

Cheuk

Dear Mark,

After inspecting the IC's used and downloaded their pinout and data sheets,
I proceed to chase the problem. When I look at the AM local osc I noticed a
100KHz higher/Lower(? I forgot) than expected when,say, I tuned to 1430KHz I
should expect 1430+450Khz but I notice the 100Khz difference. I think that
may be the problem. I could not measure the FM local osc because I do not
know where to measure. The unit uses LM7001(Sanyo PLL AM/FM synthesiszer),
LA1256 IF chip and AN7040 MPX chip. I do not have a local source to get the
LM7001 chip to replace so there is no way to prove my theory.

Thanks anyway.

Cheuk