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Sony MDS-E12/MDS-E10 transplant/repair (project)

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7 hours ago, kgallen said:

Were you using monitor mode? I'm kinda surprised that the Copy Bit setting doesn't affect that, although I guess in reality I'm not that surprised as I guess they wouldn't want to make SCMS defeat too easy. I suspect even having this function on these decks was somewhat a compromise from the RIAA...

 

I suspect actual recording will be the same behaviour as monitor mode. But I'm just as likely wrong...!

Monitor mode, yes. My guess is that as this is a kind of pass-through, the signal remains unchanged. Perhaps a schematic would depict the path. As to during actual recording—that is, output via opt/coax while a disc is inserted, not monitoring without one—not sure I tried that. I will note that my HHB BurnIT CDR exhibits that same behavior with monitoring.

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6 hours ago, bluecrab said:

Monitor mode, yes. My guess is that as this is a kind of pass-through, the signal remains unchanged. Perhaps a schematic would depict the path. As to during actual recording—that is, output via opt/coax while a disc is inserted, not monitoring without one—not sure I tried that.

I think the signal path for both is the same - through the ADC, into the DSP, loop back out of the DSP, through the DAC. Delete ADC and/or DAC if using digital I/O.

 

So this includes going through (at least part of) the DSP. Whether or not this includes the Copy Bit reassignment logic is the question. Results from your experiment suggest not.

 

Service Manuals tend to not include a detailed block diagram of the DSP chip - which we must remember since CXD2654 (ATRAC 4.5) - includes pretty much all of the digital audio chain in one chip - sample rate converter, shock memory, ATRAC enc/dec, ACIRC error correction enc/dec, EFM enc/dec, plus servo control. These functions were largely in separate ICs if we go back to the first machines, even one chip per stereo channel in the case of ATRAC.

 

Minidisc is not like a 3-head cassette deck. When recording, what you’re hearing/monitoring is not being read back from the disc. Indeed the disc writing will somewhat lag the real time audio due to the encode/decode process latency and the buffer/shock memory.

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  • 4 months later...

Update: this mash-up machine is still going strong. I’ve been using it daily for listening whilst working from home. It sits nicely under the laptop! Disc write still works - I’ve not recorded audio using this machine recently but I’ve done lots of disc edits - titling, divides etc as it’s so easy with the keyboard. Most of my MDs at the moment I’m dubbing from CD using my MXD-D4.

 

The rest of my racked machines from the photo above had to go back into the workshop (missus rules!). They didn’t get their outing in January - panto cancelled (Wales COVID rules…)

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  • 4 months later...

Tonight I’ve mostly…

 

Just replaced the ML2020 battery in my E12(in E10 case) machine. After a few hours the machine would run ‘Initialize’ on boot because the battery wasn’t retaining the config.

 

Replaced with a newer ML2320 cell. RS part number 669-0517.

 

Sorted. Just had to play some Steely Dan to ‘test’ it 😉

 

54FC1A73-E884-4624-97CE-18867FF77E87.jpeg
 

8F6F8529-80DB-4F08-ADF4-D4AA28A5D210.jpeg

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30 minutes ago, BearBoy said:

Was that a solder job, @kgallen, or did it just slip in?

 

Looking at the Service Manuals, all of my decks have lithium batteries. Kind of surprised none of them have failed yet given the age of the kit (at least, they don't seem to initialise when turned on).

Yes, it is. Main board has to come out to desolder and solder in the new one - they are rechargeable cells not the CR2030 type of primary cell that are usually in holders.

 

This is the only one of my machines that has genuinely needed a new battery - and I have a 1999 MDS-JE520 thru' to 2002-era MDS-E12 machines (and quite a few as you know! 😁). I did replace this battery in my forever-broken E10 to see if it was part of the problem, but it didn't help, so even the battery in that one was good. They do seem pretty robust. However I note that in the lower-end machines it's a smaller capacity version of this cell, so I'm surprised we don't hear about more of them failing.

 

I don't think there is a huge downside, it just means the machine does that "Initialise" phase but it's only a couple of seconds - but it forgets any user settings you might have made (it doesn't lose laser config or anything critical). In the case of the MDS-E12 it has a real time clock which forgets and there are other settings that get forgotten like calendar format, parallel and serial I/O config and Resume settings. So as I'd bought a couple of spares I thought I'd change it. Initially I couldn't find the right mounting type with the pins both on the bottom (I'm sure I must have pictured the one I put in the E10 - it had the pins at a right angle and I had to add a wire). But RS started stocking the right one, or at least a newer version of.

 

What I should probably point out, as I was a bit dismissive above, is this battery retains RAM contents in the machine. This RAM contains the data that has been read from the disc TOC, or has been modified during record. If you had a power cut during record, or during TOC write, then the machine should be able to recover the TOC (at least in newer machines). Also it's the information that means when you turn a machine on with the disc still in, it already knows the disc contents and titles, so can display them on the machine immediately, rather than needing to read the disc. So in this respect the battery is a little more key, and if it starts to fail, this is probably the stronger reason to replace it.

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1 hour ago, kgallen said:

they are rechargeable cells not the CR2030 type of primary cell that are usually in holders.

 

Ah right, didn't realise they were rechargeable!

 

According to the Service Manuals for my decks:

  • MDS-JE500: BT301 / 1-528-739-11 / VL2020 3V
  • MDS-JB940: BT701 / 1-528-887-11 / BATTERY, LITHIUM SECONDARY
  • MDS-JB980: BT404 / 1-756-121-11 / BATTERY, LITHIUM SECONDARY

Given that they all seem to be trouble free at the moment I think I'd be better off leaving them be, rather than risk breaking something with my ham-fisted attempts at soldering. Unless you think there's a risk of leakage or anything with such old batteries?

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11 minutes ago, BearBoy said:

Given that they all seem to be trouble free at the moment I think I'd be better off leaving them be, rather than risk breaking something with my ham-fisted attempts at soldering. Unless you think there's a risk of leakage or anything with such old batteries?

Yea leave 'em be if they are working. They aren't a type that will leak (we leave that to Duracell Procell when they are in expensive equipment).

 

They'll explode if you wire 'em across the mains though! (It's ok, your MD deck won't do that!).

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