Help Troubleshooting: Two Voices, Pitch/Mod Wheels

[ditabeardmemo]

Hi everyone:

I need some help troubleshooting two issues with my Emulator III 8MB keyboard. The keyboard was extensively serviced last year (it was rife with problems when I first purchased it), but there are a couple of outstanding issues that I want to try to resolve on my own because I believe they are software-based.

1. When monitoring from the main stereo outputs, voices 9 and 10 only play out of the right and left channels, respectively. They do not play in stereo. But both voices play normally when I monitor them via individual outputs 9 and 10. I tested this using both the Universal Sound Test disk and a new sample that I created on my own. In every instance, voices 9 and 10 sound normal when monitored through the individual outputs, but do not play in stereo when monitored via the main stereo outputs.

2. The pitch and mod wheels do not produce any effect. I calibrated them and also confirmed that the software is seeing information from them using the Front Panel Test. But when I play a sample a move the wheels, they do not produce any pitch or modulation changes.

I have access to the Universal Sound Test disk (courtesy of dvdborn), an oscilloscope and a digital volt meter. Can anyone (Dr. C?) give me some advice on where to start troubleshooting?

Thanks in advance!
DBM

[dr.c]

One of the flat cables going to the jack board may be bad.
Twiggle them when you play and you will find wich one.
DO NOT INTERCHANGE THEM

Also, a bad resistor pack, or as well, bad jacks because when you insert a jack in a independent output, it cuts the signal to the stereo aoutput.
So, if the female jack plusg is defective, the signal won't go to the stereo

[dr.c]

2. The pitch and mod wheels do not produce any effect. I calibrated them and also confirmed that the software is seeing information from them using the Front Panel Test. But when I play a sample a move the wheels, they do not produce any pitch or modulation changes.


Did you ASSIGN the modulation and picth wheel to the samples or presets ?

[ditabeardmemo]

Thanks Dr. C!

I will be sure to test the flat ribbon cables connecting to the jack board first. Are the ribbon cables grouped in a logical manner? For example, does the first ribbon cable connect to outputs 1-8, and the second cable to outputs 9-16?

Assuming that re-seating the ribbon cables does not solve the problem, how can I test for either a bad resistor pack or a bad female output jack?

I'll also test your suggestion for the pitch/mod wheels tonight. It may very well be an assignment problem...

One of the flat cables going to the jack board may be bad.
Twiggle them when you play and you will find wich one.
DO NOT INTERCHANGE THEM

Also, a bad resistor pack, or as well, bad jacks because when you insert a jack in a independent output, it cuts the signal to the stereo aoutput.
So, if the female jack plusg is defective, the signal won't go to the stereo

[dr.c]

Pfff.... if you play while having taken away one of the cables, you will see wich voices are concerned, uh ?

The cable at left supplies +5V to the realy, so if you put it at another place, you will send 5 volts at wrong places and kill circuits.

[ditabeardmemo]

So I powered on my Emulator III, loaded one of the Universal Sound Test banks with the first 16 keys assigned to the 16 voices, and here are the results (along with an image of the cables themselves):

1. When I remove CABLE D, voices 1-4 do not appear at the main stereo outputs.

2. When I remove CABLE C, voices 5-8 do not appear at the main stereo outputs.

3. When I remove CABLE B, there is a loud pop at the main stereo outputs. Voices 9-12 do not appear at the main stereo outputs, but the volume level of ALL voices drops precipitously and the output is barely audible. When I reconnect CABLE B to the jack board, there is once again a loud pop at the main stereo outputs, and the volume level for all voices returns to normal.

4. When I remove CABLE A, none of the voices appear at the main stereo outputs.

Is this information helpful? What should be my next steps in terms of testing the unit? I would appreciate any advice.

[dr.c]

If you have an FTP taking 17 megs, I can send the manual.

Part of the deal : other users must as well have access so its a benefit for everyone.

[ditabeardmemo]

Hi Dr. C:

If you mean the Emulator III service manual, I already have a copy. What specifically should I look for in it pertaining to my voice problem? I already read through much of it when I thought my problem was software-based...

Also, I do have an FTP site where I can share a copy of the service manual. Want me to send you the login information?

Thanks again!
DBM

[dr.c]

Look at the voice output (jack board) diagram. If the sound arrives by the separate outputs, it shoud be on the mix, unless the jack plus are bad, or the resistor packs

[ditabeardmemo]

Got it. The sound definitely arrives via the separate outputs on voices 9 and 10. Can I use a digital voltmeter to determine whether the resistor packs are bad? If so, what resistor packs should I check, and what readings should I look for? It looks like the resistor packs I want to test are RN4 and RN12, correct?

[dr.c]

Come on....

[ditabeardmemo]

So I take it there's no way to test RN12 and RN4 to see if one (or both) is obviously faulty? I'd really like to give my technician some direction on what to check the next time I take this unit in for service...

[dr.c]

I believe its the jack plugs !

These jack plugs (separate output) atr cutting contact to the stereo output when you insert a jack into it.
If an idiot wlaks on the cables when that are plugged, it may damage the jack plug, and when you take off the jack (male), the contact does not come back and it won't be on the stereo.
Note : if your tech needs these kinds of advices, change it !