MPC60II blank display - possible blown resistor - need advic

I'm trying to help a dude with his MPC60II, he bought it without a display, now he has a display for it and it's totally blank. But everything else on the machine works. I don't have an MPC60II and this dude is about 1,500 miles down the road in the Ukraine so we are trying to resusc... recuss.. recus.. fix this thing remotely

The problem - the -12VDC and the other negative voltage for the display contrast is missing. These voltages should be on pins 9 & 10 of the display connector. So I think a resistor has blown (we have checked all the fuses).

The resistor I'm looking for I think is going to be about 33 ohms, it's the resistor that (i think) limits the -12V supply to pin 9 (and so to the contrast pot and pin 10 too). I only have the MPC60 mark 1 schematics so I'm trying to figure this out from photos of the board, and some Akai S1100 schematics I have (I think the display circuit is gonna be pretty similar on both machines).

Does anyone have the MPC60Mk2 schematics and could perhaps have a look for that resistor, and check what value it should be? Or measure R69 and R70, I think it might be one of those two... I'd be grateful and will return the favour if I can.

Matt

The MPC60II schematics don't appear to have been uploaded for the benefit of the wider community. It would be great if that were done or if a link were identified. God knows I searched for it enough times; didn't know it actually existed until recently.

Clint wrote:The MPC60II schematics don't appear to have been uploaded for the benefit of the wider community. It would be great if that were done or if a link were identified. God knows I searched for it enough times; didn't know it actually existed until recently.

(possibly aimed at me?)

I only have them as a printed manual. Might see if I can find some time to scan them in and create a PDF to upload (not sure where to upload to?).

Is a PITA, due to the fold out pages being approximately A2 size, and not having access to an A2 sized scanner, so they need to be scanned in multiple passes and joined together. Being so large, and with some pages having colour (red print overlay), to have enough resolution for the schematics to be usable, the files will probably be very large.

Also have a factory photocopy of the ASQ10 Service Manual, which has a few pages of factory service bulletins (factory changes/mods after release), would love to see these for the MPC60/60II/3000 as well.

And if I can get hold of an original MPC3000 Service Manual, would like to rescan the schematics, as the version that I have found online is unreadable in parts due to not being a scanned at a high enough resolution.

The resistor you need to change is R69 (33 Ohms).

Resistors like R69 that are not mounted flush with the PCB are done this way as they are good testpoints for troubleshooting.

MPCHunter: Thank you sir! R69 it is. I wondered why they mounted some that way. I assumed it was because they could get hot

Simon: Agree there, hard to scan these things properly, would like to get an original 3000/60/60ii service manual for the fine details. I ordered some schematics for some other gear, and my anus is still badly injured from the reaming I took on the postal costs. Nearly $80 shipping for a few sheets of paper . Maybe a few of us could split the costs sometime and get a few manuals.

Problem with original 60/60II/3000 manuals is that they are out of print, and not necessarily readily available, I doubt that you would find enough in stock anywhere for multiple people to split postage costs on them, they are the sort of thing that if you find one you should just buy it.

It sounds like the reaming you took was more from the seller not shipping with a slow/cheap shipping method, it shouldn't cost that much for some manuals.

That's what I thought at first about the reaming situation. So I had them shipped to a buddy in the USA so he could ship them on to me. He got a couple of quotes and that's when I heard the faint cry 'Let the fisting commence'. It's like you get special treatment for sending documents.

SimonInAustralia wrote:

Clint wrote:The MPC60II schematics don't appear to have been uploaded for the benefit of the wider community. It would be great if that were done or if a link were identified. God knows I searched for it enough times; didn't know it actually existed until recently.

(possibly aimed at me?)

I'm sure you're not the only person on earth with a hard copy; anyone who has these elusive documents and may read this could also help. I wouldnt be surprised if they were on sale at Forat or VST Service. Shouldnt really have to pay for service manuals, but thats capitalism for you.

Good luck with the resistor change MrWhite and friend.

MisterWhite wrote:Does anyone have the MPC60Mk2 schematics and could perhaps have a look for that resistor, and check what value it should be?

MPCHunter wrote:The resistor you need to change is R69 (33 Ohms).

Resistors like R69 that are not mounted flush with the PCB are done this way as they are good testpoints for troubleshooting.

J4...


Lower left of B1...

Hey Simon! Thanks man, I really appreciate that, they are crystal clear. We are getting there with this 60MKII, just a few more issues to figure out. PM heading your way shortly.

No problem at all Matt.

Sorry, only just re-read your initial post, and realised that you are diagnosing and repairing remotely, I would have put them up earlier if I read it properly the first time.

If you need any more schematics, or parts of the service manual, to sort the remaining issues, just let me know.

That is the sort of clarity that I think you need to make them useful when troubleshooting, many of the available online manuals are unreadable in the fine detail, and without the colours for the double sided PCB layouts.

I'm not really setup to do it properly, and to my level of OCD, would like them to be flatter, straighter, and the large foldout pages scanned in single passes, for less distortion, but is the best I can do at the moment with the photocopier I have access to. Would also help if I cut the spines off of the manuals, to allow the pages to the placed flatter and straighter in the photocopier, but without a second original set of manuals, my OCD will not let me do that.

I think I have most of it scanned now, just need to join the separate scans of the other large foldout pages together, rescan any that are not scanned straight enough, play with optimising resolution/file size/etc. for smallest file sizes while maintaining clarity, measure up the original page sizes, and get them together into a single PDF.

Did you fix this in the end? I had the same problem, and it turned out to be the resistor. Note that it's *fusible*, for protection - you can short it to test (be sure everything is connected correctly!), but you should replace with the same type.

SimonInAustralia wrote:I think I have most of it scanned now, just need to join the separate scans of the other large foldout pages together, rescan any that are not scanned straight enough, play with optimising resolution/file size/etc. for smallest file sizes while maintaining clarity, measure up the original page sizes, and get them together into a single PDF.

What's up Simon, did you manage to produce the PDF in the end? Cheers.

Hi,
Good point. To be honest I can't recall if I told the guy that it was fusible. I know it's definitely working now. I'll let him know about it. There's a bit of a language barrier - I was doing this fix by email. I guess the resistor was blown as a result of plugging in a display connector incorrectly.
But yes, one MPC60II rescued from the boneyard

PacificState wrote:Did you fix this in the end? I had the same problem, and it turned out to be the resistor. Note that it's *fusible*, for protection - you can short it to test (be sure everything is connected correctly!), but you should replace with the same type.

MisterWhite wrote:But yes, one MPC60II rescued from the boneyard

God bless ya!