Marantz pm-82 microcontroller

[bernatvm]

I'm dealing with a "not that old" marantz domestic amplifier from the 90s. The exact model is pm-82. This piece uses a microcontroller to deal with all the input output routing, volume ajust, etc and I suspect is dead. The current behaviour is that the controller is sending voltage to all led indicadors output pins and routing none of the inputs to the main amp pcb.

The microcontroller is a TMP47C200BN-G928 chip. Anyone knows where I can find a replacement?

 

[gyraf]

That one has integrated (OEM-programmed) ROM, so replacing it won't do the trick.

https://www.digchip.com/datasheets/parts/datasheet/487/TMP47C200BN-pdf.php

Have you verified that it's not some exterior bus driver fail?

/Jakob E.

 

[bernatvm]

What do you mean by exteriror bus driver?

I've checked all the pins and the supply voltage is correct on the chip.

Also, I understand the "G928" on the name reffers to the program written on it, so maybe someone know where to source this chip with the correct program. It's officially discontinued.

 

[Newmarket]

There are likely other components in the circuit such as a 'driver' ic to drive the LEDs and analogue switches or relay drivers.
Do you have a schematic ?
I think it's unlikely you'll source a replacement microcontroller unless you find one of these amps for spares/repair (for other reasons obvs! )

 

[bernatvm]

Here's the link to the Service Manual: https://drive.google.com/open?id=1vWq_06-yTPgkJlBMXa71dYwWeqRpFXf1

I suspect the problem is in the microcontroller for two reasons:

First one is that in the front panel there are some leds to indicate which input is being used (cd, aux, fm...) and all of them are turned on by the controller at the same time, while non is connected to the amp board.

Second is that the motorized volume knob keeps turning up. Its motor gets the instructions from the micro controller too.

 

[s2udio]

Is the crystal oscillating ?

 

[bernatvm]

Is the crystal oscillating ?

How can I check it?

 

[bernatvm]

Can I replace the ceramic resonator with a quartz crystal as is, or do I need to modify some other components?

 

[bernatvm]

Just replaced the ceramic resonator and the problem persists. Any more ideas?

 

[bernatvm]

Its sad that this nice amp is lost because a microcontroller is malfunctioning

 

[bernatvm]

Update: replaced the controller with a slightly different one and... i just worked. Guess the unit where this other model was supposed to be soldered in is pretty similar.

This is what I bought: TMP47C200BN 1pcs New TMP47C200BN TMP 47C200BN DIP-42 DIP42 Ic Chips Replacement | eBay

 

[CJ]

do you know about this place?

https://audiokarma.org/forums/index.php?forums/marantz-audio.134/
feel my pain.
another stack just like it in the next room.




i feel like a prisoner,