Need Info on C118 on MPC2000XL 8 Outputs Board to Replace It

My MPC2000XL has the 8 outputs upgrade board, but outputs 1 and 8 were barely audible for some reason. I recently opened it up to inspect the board and re-seat the connector cable, and in the process, C118 broke off like it was made of paper (it's right next to one of the screws, and the screwdriver lightly grazed it -- I didn't even notice it had touched it until it fell off).

C118 was apparently vital as the entire machine won't power up properly with the 8 outs board connected now, so I'm currently back to just stereo. Can anyone help me find the specs for this component so that I can solder in a new one and hopefully get the board working again?

There are 2 numbers printed on the cap: voltage and capacitance in yF.
You can usually guess from the numbers which is which.
F.e 100 means micro Farad, because 100V doesn‘t exist in such circuits.
6 or 16 is likely a voltage figure because 6 or 16 micro Farad are very unusual.

Telefunky wrote:There are 2 numbers printed on the cap: voltage and capacitance in yF.
You can usually guess from the numbers which is which.
F.e 100 means micro Farad, because 100V doesn‘t exist in such circuits.
6 or 16 is likely a voltage figure because 6 or 16 micro Farad are very unusual.

Hi, thanks. Unfortunately, it was so tiny that I didn't even recognize it as a cap and wouldn't have known what it was if "C118" hadn't been written on the board. Could not read any numbers on mine.

If anyone knows these values, it would be a huge help.

Updating with a few new pieces of info.

The component (C118) that the screwdriver scraped off is in the corner in this image, by the screw. I added a penny for scale. It's tiny:

I also got two possible leads:

1) I found a link to a service manual which actually does list the IB-208P board. Mine is the IB-M208P, but it still probably is relevant. However, mostly the manual seems to deal in Akai part numbers rather than generic electronic components values, so there might be an extra step there in trying to decipher it. I also have not actually been able to locate C118 on the diagram at all yet: https://elektrotanya.com/akai_s2000_s3000xl_s3200xl_eb16_ib-208p_service_manual.pdf/download.html

2) Big Noise Radio does an "audiophile cap upgrade" of the IB-M208P, so maybe if I ask nicely, they'll tell me what C118 is: https://bignoiseradio.com/product/akai-mpc-2000xl-ib-m208p-8-output-capacitor-audiophile-upgrade/#

The service manual you linked is limited and it references a version of the 8 out board that is using a design about 10 years earlier than yours.

Your 8 out board is the final revision that Akai released. As far as I know, there are 4-5 different 8 out board designs I've seen over the years, some not even made by Akai.

To answer your question, If you own a multimeter - test the capacitance of the neighboring surface mount capacitors around C118, it's very likely it has the same value.

I tried searching around online for good pictures of other iterations that use C118 but have not had much luck so far.

Here's one version where I can see C118, I do not imagine that Akai or Mutek would be using multiple surface mount capacitors of differing values:







Right click on the picture and open in a new tab to view larger image.

My suggestion again, test the neighboring surfacemount value with a multimeter.

richie wrote:To answer your question, If you own a multimeter - test the capacitance of the neighboring surface mount capacitors around C118, it's very likely it has the same value.

Thank you for all the info. I do have a multimeter and will test the others near it.

Page 61 of that service manual has the schematic for the 8 output board, though the labels are different.

I think C635 is the equivalent which is 47nf. Most of the non polarized caps are 47nf in the circuit anyway so its a pretty safe bet it would be that value, at least in this older version of the board.

I doubt the values were changed. You could test one of the similar looking caps you have, but you'd need to remove it first to test out of circuit, which could cause more problems!

From your photo it looks like an 0603 size. It may be 0805 which is slightly bigger. Voltage wise I would say 16v would cover it. Voltage rails would either be +-12 or +- 15. You can go higher for voltage without issue, just don't go lower!

So my best guess is you need an 0603 47nf cap rated at 16V or higher. That's 0603 imperial, DO NOT get 0603 metric as that is ridiculously small and will never fit! You could get 0805 as well to be safe, get a bunch of each as it will only be cents and you're paying way more for postage.

All that aside, the cap you knocked off looks to be between two grounds. I'm not sure that would stop the whole MPC from powering up. Double check there's nothing touching that shouldn't be. Maybe a bit of foam or plastic insulation isn't where it should be and something is shorting to ground on the expansion card?

jimmy_p wrote:Page 61 of that service manual has the schematic for the 8 output board, though the labels are different.

I think C635 is the equivalent which is 47nf. Most of the non polarized caps are 47nf in the circuit anyway so its a pretty safe bet it would be that value, at least in this older version of the board.

I doubt the values were changed. You could test one of the similar looking caps you have, but you'd need to remove it first to test out of circuit, which could cause more problems!

From your photo it looks like an 0603 size. It may be 0805 which is slightly bigger. Voltage wise I would say 16v would cover it. Voltage rails would either be +-12 or +- 15. You can go higher for voltage without issue, just don't go lower!

So my best guess is you need an 0603 47nf cap rated at 16V or higher. That's 0603 imperial, DO NOT get 0603 metric as that is ridiculously small and will never fit! You could get 0805 as well to be safe, get a bunch of each as it will only be cents and you're paying way more for postage.

All that aside, the cap you knocked off looks to be between two grounds. I'm not sure that would stop the whole MPC from powering up. Double check there's nothing touching that shouldn't be. Maybe a bit of foam or plastic insulation isn't where it should be and something is shorting to ground on the expansion card?

Thanks. A poster at Gearspace said the same thing about C118 appearing non-essential from the schematic, and sure enough, I plugged the data cable back into the system, and the MPC powered up fine. No idea why it didn't before. But it still doesn't produce sound.

I'll be ordering those caps and testing them out. Will report results.

That's good the MPC is powering up with the expansion board connected. If the headers aren't boxed that you are plugging the cable into watch out that you aren't out of alignment one way or another.

Looking again at your photo, the ribbon cable doesn't look right. Was there another bit of black plastic over the top holding the cable in place?

At the moment I can see the spikes that cut through to make the connection, but the cable would be free to move, possibly losing one or more wires. Losing one of those signals would definitely stop the whole card from functioning so look at that.

Your initial problem of channel 1 and 8 not working, in my experience a likely culprit is the output opamps failing, with the output permanently at the positive or negative rail. You can check this quite easily, assuming there is still power to the board!

Turn MPC on with nothing playing. Plug a TS cable into the output you want to test. With a multimeter in DC voltage mode put negative on the sleeve and positive on the tip at the other end of the cable. It should read around 0v. If you are getting a constant positive or negative voltage the opamp has failed and needs replacing.

jimmy_p wrote:That's good the MPC is powering up with the expansion board connected. If the headers aren't boxed that you are plugging the cable into watch out that you aren't out of alignment one way or another.

Looking again at your photo, the ribbon cable doesn't look right. Was there another bit of black plastic over the top holding the cable in place?

At the moment I can see the spikes that cut through to make the connection, but the cable would be free to move, possibly losing one or more wires. Losing one of those signals would definitely stop the whole card from functioning so look at that.

Your initial problem of channel 1 and 8 not working, in my experience a likely culprit is the output opamps failing, with the output permanently at the positive or negative rail. You can check this quite easily, assuming there is still power to the board!

Turn MPC on with nothing playing. Plug a TS cable into the output you want to test. With a multimeter in DC voltage mode put negative on the sleeve and positive on the tip at the other end of the cable. It should read around 0v. If you are getting a constant positive or negative voltage the opamp has failed and needs replacing.

Thanks. I finally got around to ordering the surface-mount caps, so we'll see in the next couple of weeks if that fixes the 8-outs board.

About the ribbon cable, I haven't removed any plastic covering from the board end, so it was working fine as pictured previously even with the spikes exposed. I tried wiggling it to see if anything was loose as you suggested that that might be a problem, but they're completely snug and won't budge, so I don't think that's the problem. I also tried reseating it on the main board side again, where it clamps in, but there's still no sound on the 8 individual outs. Do you know if there's an inexpensive generic replacement cable for it I could order from somewhere just to try that?

Also, thanks for the tip about the opamps. At this point, I'd be very happy just to have the six working outs back, but if I get the power restored to the board, I'll try your multimeter testing suggestion.

I finally got the surface-mount capacitors. 0805 was the correct size; 0603 was way too tiny. I soldered one on, and...nothing. The MPC powers up, the stereo outs and everything else work, but the 8-outs board is still silent.

Well, at least the rest of it still works.