You just have to fault find based on the situation as it stands now. If it is in protect mode (so I'm assuming all outwardly OK but speaker relay not connecting) then you have to begin with things like looking for DC offset and so on.
I've got it working. The broken front board is a later revision than the other. There was a dead cap I missed right at the top. It's an anomaly because it was a 100uf 16v and all the other electrolytics are 22uf 50v. Even in the service manual it should be a 22uf 50v although if the board is a later revision then it might be legit.
Having replaced two of the main micros on this particular model (and micro's on many other products) I would have to disagree..😉 - it does happen, but of course one should always check the vitals, supply, clock , enable and reset first.
There is also a bulletin about the processor on this model, the original 4bit variant was superceded by an 8 bit, but both were still available for service (that might have changed today though lol) - the bulletin was dated 2007
There is no compatibility between the two variant processors.
4 bit variant - 4822 209 15719
8 bit variant - 90M-HU100750R
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Well done
that's great news.If it is a part that has a proven track record of failure then that is fair enough 😉 It becomes a stock fault related to that model.
My own experience working in a large service dept as both bench tech and also supervisor and so overseeing the work of others was that in the majority of cases the uP was usually the last thing to suspect... or I suppose more correctly was the easiest to suspect but was rarely the cause of the fault.
That doesn't mean they never fail but it was pretty rare for it to be so.
It's becoming more common for customers to say "my mate think it's the power supply that's gone ...." or "it's just a capacitor"
Where's it gone then ? 🙄😀😀
Just tell me the symptoms and let me get on with it 🙄😛
I am looking for a diagram for the front panel of this amplifier with an 8-bit processor. is there even a service manual for this type of processor?
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The processor is 'generic', the 6B40 marking is the unique program (like firmware) burned into the chip to make it applicable to the item it is used in.
So you need not only the correct main type number but crucially the 6B40 part as well. The other numbers are just production codes.
So you need not only the correct main type number but crucially the 6B40 part as well. The other numbers are just production codes.
yes, that's clear to me. I have an original processor with burned firmware, unfortunately it is 8bit and cannot be exchanged for my TMP47c200BN, which is 4bit. they are irreplaceable. The PCB probably went through a revision where Marantz started to mount new 8bit chips. I can't find a newer service manual anywhere... thanks
Does anyone have a wiring diagram of this 8bit processor in the front panel of the amplifier please?
thanks Mooly i have this schematic it is for 4 bit tmp47... actually i want to upgrade this schematic to 8bit microprocessor
I just want to convert this board to the newer 8-bit microprocessor, because the 4-bit tmp47c200 is no longer available.
if there is at least someone who has this board with the PM7200 front panel 87c846 processor that would take a photo of it for me from both sides, then I would try to make a schematic out of it. thank you very much for your help
Hi everyone,
I know it's an old thread, but for the ones stumbling across it having similar issues, if you still can't find the newer SM, which seem to be unavailable, here's a tip - lookup the PM8200 SM - uses the 8-bit micro, but interestingly, it doesn't use the S808. Perhaps a safe option would be as suggested here earlier to remove and bypass it, although the S808 is still available as replacement in case the problem was there.
@bandisrandi attached are a couple of photos if you still haven't found them and need them, but likely the PM8200 covers most of the schematic or a good approximation.
I know it's an old thread, but for the ones stumbling across it having similar issues, if you still can't find the newer SM, which seem to be unavailable, here's a tip - lookup the PM8200 SM - uses the 8-bit micro, but interestingly, it doesn't use the S808. Perhaps a safe option would be as suggested here earlier to remove and bypass it, although the S808 is still available as replacement in case the problem was there.
@bandisrandi attached are a couple of photos if you still haven't found them and need them, but likely the PM8200 covers most of the schematic or a good approximation.
Cheers
