MPC 60 MKI SYNC PCB ISSUE

Hello, been searching this forum a lot over the last several months regarding 60 MK I maintenance. Purchased a unit a few months back and started working on upgrading/restoring it, have noticed throughout the process that I must have an older MK I because I havent found many good photos referencing this unit, and searching the service manual PDFs has been a headache, as I cannot locate a few of these components, let alone even identify what a couple are..

I have been replacing the caps, the inverter, the backlight, Gotek USB floppy, all tact switches, I have replaced most of the caps on the PSU (06H, 05H and 01H errors constantly) and now Sync PCB (mpc freezes when turned on and plug/unplug any midi cables) and CPU PCB, soon to replace caps on Voice and ADC PCB (crackling master volume pot and on 1 channel).. I have spotted a couple bad resistors, looks like the legs are oxidizing/burned so will swap these out, have identified thanks to schematics available.. Hopefully that will solve all these freezes and crashes but for now---

My main issue right now is identifying what is on C56 and TR1.. Machine would not turn on after replacing caps, reinspected and it looks like I broke off a leg of this component but I'm having an issue identifying it to replace it.. It is not a transistor on TR1, and to me it looks like a resistor with the coating/axial.. it has 1 brown/tan leg, the main body has 1 green band pointed toward ground, and the other leg is just the unpainted leg... I don't know much about reading schematics or electronics repair, basic soldering skills and do not have money to take to local repair in Chicago or ship off for repairs.. If I can replace this component myself I would like to, but I cannot identify what it is exactly.. Any help identifying is greatly appreciated! (don't mind the poor soldering job on C54 & C55)

Thanks but when I referenced the manual and common parts list, the component I am trying to ID does not look like that part, as stated before I am having an issue indentifying it. The service manual states a transistor, but that does not look like a Transistor on my board, and there are two of them side by side. Would rather replace w similar/indentical components rather than have to use something different unless it is recommended. Thanks.

ofmgk wrote:the component I am trying to ID does not look like that part

That´s sometimes the case.

When repairing my 2nd MPC4000 I had to change what looked like a resistor but was actually a capacitor. The fine folks from www.electronicspoint.com were very helpful.

Maybe post pics of the schematics there and see what they have to say...

Thanks for the quick reply, will send them a message and see what I can find out. Been trying to figure this out all day so I can finish my mouser order and resurrect this thing.. Appreciate the advice!

If it helps anyone in the future, the 2 components were identified as 0 ohm resistor links/jumpers.

Hi there....
Are u revering to an component that looks like an resistor? But with an single green band around it??
It's true that if u measure it, it says 0ohm.
This is an coil in resistor clothing B-)
Measured in "Henry's" and installed to smooth out the currency flow..
This is an common part in the sampler and if your measuremettool says its 0ohm then its fine,, if u don't trust it? Go to an shop and replace em, they don't cost much.

Greets
Danny

A pair of Glasses wrote:Hi there....
Are u revering to an component that looks like an resistor? But with an single green band around it??
It's true that if u measure it, it says 0ohm.
This is an coil in resistor clothing B-)
Measured in "Henry's" and installed to smooth out the currency flow..
This is an common part in the sampler and if your measuremettool says its 0ohm then its fine,, if u don't trust it? Go to an shop and replace em, they don't cost much.

Greets
Danny

Yeah that was definitely confusing me, I hadn't removed the resistor from the PCB and was getting measurements closer to 0.15 or .25 i think.. after removed it was measuring 0 ohm, so ordered a replacement from mouser that seems to be doing the job.. but still having issues with 06h error, usually about 2hr in, or close to 4-5hrs..
i notice the freezes happen faster (and ive read this is common), while using more than 50% avail RAM memory from samples.. (i know in general you don't want to max out memory in any electronics to retain performance speeds, but was hoping there would be a system message indicating low avail memory?). i have tested with the EXM unit disconnected, and it seems to happen almost twice as fast, so i'm guessing that's a sign of bad stock ram somewhere in the 6 stock RAM from what i've read in posts here, maybe ram refresh rate is culprit to how it freezes even when idle/no contact with board?

waiting for some new old-stock ram to come in to replace on the board as well as on my EXM unit.. if still no luck, then will try to use an eprom programmer to check conditions as i think both OP v1.1 and Voice1&Voice2 are dated '87 chip mfg date, and '89 encoded date... something i am wondering though is that reported life expectancy is 10yrs+ for eproms & 5-10yrs for ram, but is that factoring in usage time/cycles and not physical age of memory? i read moisture and rapid changes in heat (machine on & off) can do some unwanted contracting/expanding of the pins causing data to be lost/unreadable, so that's why i wonder if environmental conditions would play part in shelf life of old memory that has not been used in many years..

i purchased this unit back in september thru auction, previous owner had it kept in storage, did not seem to have any mods done to it or ever opened up by previous owner, and because of the good physical condition it leads me to believe that the unit had low usage/run time... i did notice a couple jumper cables under the cpu pcb and i think the voice pcb? has anyone else seen that or is that common from MFG? was not the ram daisy chain hack i've read about, not connected to ram.. looked like a couple pins were missing from the Intel chips and were connected at a few points underneath the PCB, not sure if those are just jumper cables needed to get the chips to work with the rest of the board... i don't know, this unit must be too old in production line, i think the OS chips i pulled out were old 2.02 chips.. i have been getting these error messages 05H & 06H since first using the unit, so i'm guessing these problems are somewhere on my board and not in the OS..

Also wondering if this is a common issue with anyone else with the MIDI ports I/O, and i assume the work around solution is 'just leave it alone', but is it normal for the 60 to freeze up as soon as plugging/unplugging midi cables either in idle or sequencer running? i notice as soon as i plug or unplug a MIDI cable into any port, i get the same 06H error and was hoping that new caps would have solved that issue.. i just leave every midi cable plugged in now incase i need to use more midi channels while working on a project.. most of the resistors looked fine on the Sync PCB, replaced all caps and have been checking for cold solder joints but besides 1 bad joint on PSU PCB i haven't seen anything else that could be shorting or causing issues.. just seems a little odd a 'midi production center' has a major problem with user making different midi connection choices while machine is on, to where it causes the whole thing to freeze up without warning..

after weeks of searching this forum & google, it would seem that the 06H error is just unresolved? running out of ideas on what else to replace besides ribbon cables and resolder all the ribbon pin connections.. but i guess at this point, there's not a lot of other PITA tasks left to perform.. if this is just how it is for a majority of users, i can learn to accept these limitations with workarounds and just expect potential issues, but i really believe that this thing should be operating more smooth once enough aged components are swapped out. i would love to be able to do long sessions with this unit as opposed to saving every 5/10 minutes, but i guess that's what everyone with these problems wishes.. suppose it could be worse.


Any feedback/comments are appreciated, thanks to anyone who read this far (sorry for the long post) and sharing of knowledge!

Hmmm.... Your problem is not normal. I can run my 60 for days without any problems, and I use it as an sampler and all of the midi ins and outs with multiple channels,, its really the center piece of my cabin,, and its doing it flawlessly. I've also never experienced the 05/06 error, what does the service manual says about this? It shouldn't freeze over when plugging in an midi cable (same error when the cable on the other side is disconnected??)
And there are some cable jumpers on the other side of the PCB's.
I don't think your voice chips got anything to do with your problem.
(did you change the o.s??)

Greets
Danny