AIWA LCX-AC1mini system, tape amp problem

B

b

Guest
this AIWA LCX-AC1 stereo works in all modes but cassette. when play is
pressed you get a thunderous crackle and hiss. This unit does not have
thre traditional rec-pb slider switch, which is usually the cause of
these faults; it seems to be done electronically.

the noise persists even with the heads disconnected from the main pcb.
I have tried heating and cooling the area to no avail. there is one IC
I suspect, labelled 4560 0695 , 8 pin and is smd. can't find
references to it.
Anybody have a schematic? or any other suggestions.
cheers,
-B
 
b wrote:
this AIWA LCX-AC1 stereo works in all modes but cassette. when play is
pressed you get a thunderous crackle and hiss. This unit does not have
thre traditional rec-pb slider switch, which is usually the cause of
these faults; it seems to be done electronically.

the noise persists even with the heads disconnected from the main pcb.
I have tried heating and cooling the area to no avail. there is one IC
I suspect, labelled 4560 0695 , 8 pin and is smd. can't find
references to it.
Anybody have a schematic? or any other suggestions.
cheers,
-B
Click to expand...
That IC is an op amp and I'd put that high on the list of parts to replace.
In fact, you could try removing it and check to see if the noise disappears.

Good luck.
--
David Farber
David Farber's Service Center
L.A., CA
 
b wrote:
this AIWA LCX-AC1 stereo works in all modes but cassette. when play is
pressed you get a thunderous crackle and hiss. This unit does not have
thre traditional rec-pb slider switch, which is usually the cause of
these faults; it seems to be done electronically.

the noise persists even with the heads disconnected from the main pcb.
I have tried heating and cooling the area to no avail. there is one IC
I suspect, labelled 4560 0695 , 8 pin and is smd. can't find
references to it.
Click to expand...
Remove the wires from the capstan and/or take up motors and
see if any change?
 
b <reverend_rogers@yahoo.com> wrote in message
news:e84bff61-eb40-4a88-94b0-c036fab6210f@21g2000yqj.googlegroups.com...
this AIWA LCX-AC1 stereo works in all modes but cassette. when play is
pressed you get a thunderous crackle and hiss. This unit does not have
thre traditional rec-pb slider switch, which is usually the cause of
these faults; it seems to be done electronically.

the noise persists even with the heads disconnected from the main pcb.
I have tried heating and cooling the area to no avail. there is one IC
I suspect, labelled 4560 0695 , 8 pin and is smd. can't find
references to it.
Anybody have a schematic? or any other suggestions.
cheers,
-B
Click to expand...
Any small relay anywhere and soft or dirty contacts
Assuming you don't have an oscilloscope try a crystal earpiece and needle
probe.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
On 17 dic, 03:26, "David Farber" <farberbear.uns...@aol.com> wrote:
b wrote:
this AIWA LCX-AC1 stereo works in all modes but cassette. when play is
pressed you get a thunderous crackle and hiss. This unit does not have
thre traditional rec-pb slider switch, which is usually the cause of
these faults;  it seems to be done electronically.

the noise persists even with the heads disconnected from the main pcb.
I have tried heating and cooling the area to no avail. there is one IC
I suspect, labelled 4560 0695 , 8 pin and is smd. can't find
references to it.
Anybody have a schematic? or any other suggestions.
cheers,
-B

That IC is an op amp and I'd put that high on the list of parts to replace.
In fact, you could try removing it and check to see if the noise disappears.
Click to expand...
I did bit more searching. I came up with BA4560, JRC4560 AND NJM4560
as references for the IC. these seem to be the standard DIL version
though.

I will desolder it anyway and see what happens.though I suppose that
might not prove definitively if it is the chip at fault, since any
component related to it simply may be out-of circuit when the ic is
disconnected....
..-B
 
b wrote:
this AIWA LCX-AC1 stereo works in all modes but cassette. when play is

Anybody have a schematic? or any other suggestions.
cheers,
-B
Click to expand...
Search for LCX-337 on eserviceinfo. It's a similar set.

--
Adrian C
 
b wrote:
On 17 dic, 03:26, "David Farber" <farberbear.uns...@aol.com> wrote:
b wrote:
this AIWA LCX-AC1 stereo works in all modes but cassette. when play
is pressed you get a thunderous crackle and hiss. This unit does
not have thre traditional rec-pb slider switch, which is usually
the cause of these faults; it seems to be done electronically.

the noise persists even with the heads disconnected from the main
pcb. I have tried heating and cooling the area to no avail. there
is one IC I suspect, labelled 4560 0695 , 8 pin and is smd. can't
find references to it.
Anybody have a schematic? or any other suggestions.
cheers,
-B

That IC is an op amp and I'd put that high on the list of parts to
replace. In fact, you could try removing it and check to see if the
noise disappears.

I did bit more searching. I came up with BA4560, JRC4560 AND NJM4560
as references for the IC. these seem to be the standard DIL version
though.

I will desolder it anyway and see what happens.though I suppose that
might not prove definitively if it is the chip at fault, since any
component related to it simply may be out-of circuit when the ic is
disconnected....
.-B
Click to expand...
In the realm of part failures, it's more likely that the IC is causing the
problem than anything else in the neighborhood. By the way, is the crackle
and hiss coming out of both channels?

Good luck.
--
David Farber
David Farber's Service Center
L.A., CA
 
On 17 dic, 17:29, Adrian C <em...@here.invalid> wrote:
b wrote:
this AIWA LCX-AC1 stereo works in all modes but cassette. when play is
Anybody have a schematic? or any other suggestions.
 cheers,
-B

Search for LCX-337 on eserviceinfo. It's a similar set.

--
Adrian C
Click to expand...
Many thanks for that tip Adrian - got the schematic now. It has made
me review my line of diagnosis - the BA4560 seems to be the rec
amplifier, whilst the rec-pb switchers are Q305, 307, 308, 309, 310.
transistors are all 2SA 1993F.
Given the crackle and interference reminds me exactly of the old
slide-switch problem in older tape decks, I suspect one of these has
gone. They seem to be SMD, not sure if there are standard
equivalents...anyone know?
here's an extract from the diagram:
http://www.fileden.com/files/2007/6/4/1143893/aiwastereo%20cass.jpeg
regards
-B
 
b wrote:
On 17 dic, 17:29, Adrian C <em...@here.invalid> wrote:
b wrote:
this AIWA LCX-AC1 stereo works in all modes but cassette. when play
is Anybody have a schematic? or any other suggestions.
cheers,
-B

Search for LCX-337 on eserviceinfo. It's a similar set.

--
Adrian C

Many thanks for that tip Adrian - got the schematic now. It has made
me review my line of diagnosis - the BA4560 seems to be the rec
amplifier, whilst the rec-pb switchers are Q305, 307, 308, 309, 310.
transistors are all 2SA 1993F.
Given the crackle and interference reminds me exactly of the old
slide-switch problem in older tape decks, I suspect one of these has
gone. They seem to be SMD, not sure if there are standard
equivalents...anyone know?
here's an extract from the diagram:
http://www.fileden.com/files/2007/6/4/1143893/aiwastereo%20cass.jpeg
regards
-B
Click to expand...
IC302 of the similar model shown above is a BA4560 too. And that is the play
side of the circuit. If I were fixing it, I'd start with that.

Good luck.
--
David Farber
David Farber's Service Center
L.A., CA
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top