I just got one of these to mess about with, the AM1 version, the volume gets stuck at about 11oclock when I use the remote (i can hear the motor working but the knob is sticking on something) and the power light and MD/Tape light aren't working, I f anyone knows how to fix these things I'd love some help.
Nice Tip: if you have no remote, Marantz amp remotes control the volume which is handy.
I'm new here.
Nice Tip: if you have no remote, Marantz amp remotes control the volume which is handy.
I'm new here.
Sorry for the delay i have been away for a while .. The volume control knob on the am1 amplifier has a status led built into it . There is a 3 wire ribbon cable connecting to these leds . if someone removed the volume control knob there is a good chance they damaged the ribbon cable . It has most likley wrapped around the spindle of the volume Pot.. i had the same problem... Best way to fix is remove the ribbon cable from the amplifier re dress and solder the cable to the volume knob led first then to amplifier last...
Yeah I saw that ribbon when I took it all apart, It wasn't the cause but when I saw it I though it would be. Not sure what else might cause that, I've sold it now though and I'm waiting for the old audio innovations one to turn up somewhere. They did make them in chrome too but where the A1 has a balance knob it had a record selector, it also had a power button which the A1 did not.
hi!
i am resurrecting this old thread, because i have an early iteration alto that has been dead for some years. it blows its fuse immediately when turned on. i am hoping this might be a relatively easy fix. also interested in upgrading/upsizing the caps as has been discussed. (and i am going to post this to the other alto thread linked here, as there's some other readers there.)
thanks,
doug s.
i am resurrecting this old thread, because i have an early iteration alto that has been dead for some years. it blows its fuse immediately when turned on. i am hoping this might be a relatively easy fix. also interested in upgrading/upsizing the caps as has been discussed. (and i am going to post this to the other alto thread linked here, as there's some other readers there.)
thanks,
doug s.
I have a MK2 version. Worked when last used but several years in the loft seem to have done it no good.
I intend to repurpose it - strip out the entire circuit board, keep the case & front panel controls & rebuild as an Arduino controlled preamp with relay input selection (or possibly an integrated amp with some class D boards).
The input select doesn't work - all LEDs are lit. Can anyone tell me how the bi-colour LEDs usually sequence? It is so long since I had it operational I have forgotten. I guess the selected channel lights RED for a second while the output is muted then GREEN.
It would be nice to maintain the correct lighting sequence.
I guess nobody has ever found a service manual for the Mk 2 version? I can't even find an operators manual online.
I intend to repurpose it - strip out the entire circuit board, keep the case & front panel controls & rebuild as an Arduino controlled preamp with relay input selection (or possibly an integrated amp with some class D boards).
The input select doesn't work - all LEDs are lit. Can anyone tell me how the bi-colour LEDs usually sequence? It is so long since I had it operational I have forgotten. I guess the selected channel lights RED for a second while the output is muted then GREEN.
It would be nice to maintain the correct lighting sequence.
I guess nobody has ever found a service manual for the Mk 2 version? I can't even find an operators manual online.
You are right of course and this is a possibility I have not yet rejected.
I'm assuming the 'rust' stains around the 2 main filter caps and a smaller cap near the processor chip are signs of leakage.
I might replace these and see how the unit functions before doing anything drastic - the filter cap near the processor might be causing the processor to not work correctly.
It would be good to at least have a benchmark before modding anything.
Not having a manual (I bought the unit pre-loved many years ago), I didn't even know until yesterday that the unit had remote capability.
My Marantz CD remote works the motorized volume pot. My other CD remote however does not.
I am intending to put the unit in service in my hobby room which fortunately is where the Marantz CD resides.
One reason for the proposed rebuild is that I was never satisfied with the sound.
It was very bass light. However it may suffice for bookshelf speakers in my hobby room.
The Mk2 version is very unloved.
The advantage of using an Arduino is you can program to use any remote.
I'm assuming the 'rust' stains around the 2 main filter caps and a smaller cap near the processor chip are signs of leakage.
I might replace these and see how the unit functions before doing anything drastic - the filter cap near the processor might be causing the processor to not work correctly.
It would be good to at least have a benchmark before modding anything.
Not having a manual (I bought the unit pre-loved many years ago), I didn't even know until yesterday that the unit had remote capability.
My Marantz CD remote works the motorized volume pot. My other CD remote however does not.
I am intending to put the unit in service in my hobby room which fortunately is where the Marantz CD resides.
One reason for the proposed rebuild is that I was never satisfied with the sound.
It was very bass light. However it may suffice for bookshelf speakers in my hobby room.
The Mk2 version is very unloved.
The advantage of using an Arduino is you can program to use any remote.
Hello Everybody!
I could use your help, please. I have the Alto mk2 CD-Tuner in my possession, and the display does not work. I understand, this is a common issue, and I'd like to ask, if anyone has been able to fix it, without spending a fortune on it.
I can't attach any pictures here, unfortunately, but I can send it by email to anyone, who thinks able to help me.
Any help would be greatly appreciated.
Happy Easter!
Tibor
I could use your help, please. I have the Alto mk2 CD-Tuner in my possession, and the display does not work. I understand, this is a common issue, and I'd like to ask, if anyone has been able to fix it, without spending a fortune on it.
I can't attach any pictures here, unfortunately, but I can send it by email to anyone, who thinks able to help me.
Any help would be greatly appreciated.
Happy Easter!
Tibor
Photo of stripped amp. Note how this 'Richer Sounds' version is totally different to the Mk1 (post #7).
Pic of leaking main filter cap, its neighbour is similarly afflicted.
Photo of filter cap by the processor chip.
The speaker relay is adjacent to the speaker terminals and operates every time the source switch is moved.
There is a second relay adjacent to mains in. I would guess the yellow transformer powers the processor and the relay supplies power to the main toroid once the processor is up and running. Possibly also standby & on functionality through the remote but I don't have an AI remote I cannot verify this.
The NJU7311 input select chip can be seen adjacent to the inputs followed by a pair of +/- regulators & op amp buffer. The signal must then go to the front of the board for volume & balance before hitting the power amp.
Pic of leaking main filter cap, its neighbour is similarly afflicted.
Photo of filter cap by the processor chip.
The speaker relay is adjacent to the speaker terminals and operates every time the source switch is moved.
There is a second relay adjacent to mains in. I would guess the yellow transformer powers the processor and the relay supplies power to the main toroid once the processor is up and running. Possibly also standby & on functionality through the remote but I don't have an AI remote I cannot verify this.
The NJU7311 input select chip can be seen adjacent to the inputs followed by a pair of +/- regulators & op amp buffer. The signal must then go to the front of the board for volume & balance before hitting the power amp.
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Try to see if the display still works if you point a flashlight or similar at it. The backlight bulb is known to fail, a small 5 or 6V thing if I remember correctly.
Testing so far -
Cap replaced near 5V regulator (pic 3). Though TBH I don't know if that is leakage or just icky glue.
All chips have 5V on Vcc pins.
Functions that work -
IR sensor.
Remote control of: Motorized volume pot. Mute (speaker relay).
Speaker mute when input selector is turned.
Functions that don't work:
Source LED (all lit).
Source selection (see below).
Speaker on RH channel - lots of hiss (volume dependent).
One source only working, cannot change source.
Speaker on LH channel - very quiet hiss.
No source working.
Having established the chips are receiving power, I am not capable of fault finding processor/logic circuits. In view of its faults and because it was unloved (hence being put in the loft) I am of a mind to gut it and go for the Arduino control option. The casework is the sort of thing you cannot DIY.
Cap replaced near 5V regulator (pic 3). Though TBH I don't know if that is leakage or just icky glue.
All chips have 5V on Vcc pins.
Functions that work -
IR sensor.
Remote control of: Motorized volume pot. Mute (speaker relay).
Speaker mute when input selector is turned.
Functions that don't work:
Source LED (all lit).
Source selection (see below).
Speaker on RH channel - lots of hiss (volume dependent).
One source only working, cannot change source.
Speaker on LH channel - very quiet hiss.
No source working.
Having established the chips are receiving power, I am not capable of fault finding processor/logic circuits. In view of its faults and because it was unloved (hence being put in the loft) I am of a mind to gut it and go for the Arduino control option. The casework is the sort of thing you cannot DIY.
Have you cleaned all that gunk Off form around the processor?
Could well be messing with the oscillator.
The balance control looks like it's taken a dunt from the front and has been dislodged.
The black cable feeding NJU7311 is serial Data one of those wires is chip enable to pin 13 and should be 5V.
Could well be messing with the oscillator.
The balance control looks like it's taken a dunt from the front and has been dislodged.
The black cable feeding NJU7311 is serial Data one of those wires is chip enable to pin 13 and should be 5V.