MPC60 3.10 OS problem with sampling

Hey

I bought a used set of OS3.10 chips and put in my 60. Everything works great, but i can't sample anymore. I can not monitor when sampling, and when i record the recording sounds like a distorted mess, at every setting.

Evrything worked fine with the 2.10 chips.

So, before I go on a lengthy troubleshooting mission with chanching chips and whatnot, has anyone else had this problem ?

Seems strange that the eprom's could generate this problem since they are just sort of ram-memory for the processor and the audio signal does not go in to them.

Just looked through the service manual for the MPC60. Apperently i can trim the A/D using a testdisk, anyone has this disk and can share an image of it ? Google could not find it.

have you tried reseating any of the connectors? this seems like a likely cause, maybe something was loose, and after opening it up, it got disconnected. hmm.

Have you tried putting the 2.1 chips back in ?
That way you can tell if 3.1 is faulty .
I'd try that before you go trimming the A/D or anything.

3001 wrote:have you tried reseating any of the connectors? this seems like a likely cause, maybe something was loose, and after opening it up, it got disconnected. hmm.

this^

also, you must try the original eproms again to truly know... make sure you seat those in properly too.

Are you sure you have the Monitor toggled to "ON"?

Are you sure that your signal is not too hot? Too much gain introduced by either the software or the hardware on the MPC will cause distortion.

Trimming the onboard pots for the A/D is only going to give you more issues if you don't know what you are doing.

mikael__ wrote:Hey

I bought a used set of OS3.10 chips and put in my 60.

This sounds shady to me. Where did you buy the "used" chips from?

It's possible that:

The chips were already faulty (bit rot, bad burn) or
Physically damaged or
Removed improperly or
Stored improperly or
Shipped improperly or
Installed improperly or
You have a preexisting issue with your MPC that the new OS uncovers or
All of the above

mikael__ wrote:Seems strange that the eprom's could generate this problem since they are just sort of ram-memory for the processor and the audio signal does not go in to them.

Why does this seem strange? The OS chips are ROMs not RAM or memory. The OS sends the commands to the CPU and the A/D converters. So if the CPU is receiving garbage data or info from the OS then the MPC may not function correctly.

In a different thread you wrote:

mikael__ wrote: A long time ago i came over eproms that "could" be the 3.10 OS, put them in, got exactly the same error as you. Tried putting them in backwards etc. never worked. Put in my old 2.12 and everything worked.

Are these the same chips that you are using? And what was the soruce of these chips?

If you have worked on your MPC in a careless fashion (intentionally plugging chips in backward) you may have introduced new issues to your MPC that you were not aware of. You may have broken a trace or solder joint by moving and removing the chips with too much force.

The images for the OS versions are different. It may be possible that you have a lifted trace or broken solder joint on one of the data lines that is only apparent to you when you have the later OS installed.

You may want to pull out the CPU board and inspect the solder traces to look for cracked solder joints or damage. You may also want to reflow the solder joints for the chip sockets.

Thanks for the replies!

I ended up solving it by just lighty rotating the VR2 trimmer (that sets the ADC offset). This is ofcourse not recommended without the testdisk that lets you see the actual offset value. But i took the risk and to my ears it sounds like it should.

Guess there was a case of oxidization on the trimmer because it started working with just the smallest little nudge. Or it was something else entirly. Anyhow, i can sample again and i'm very happy for that.

Thanks for taking your time in replying.