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Well, when I check it in diode mode, it shows the short. when I turn it on. When I check the voltage, it comes up with really strange numbers. Flip the multimeter and it shows the same only negative.alland wrote:I do not understand, what signals you are describing - just +5 and +12? If so, then those voltages seem to be good.mkeschinger wrote:Looks like we have 0 when plugged in but not turned on and then +5.03 like we should and it goes to 11.99 for the 12v at the 12v connection on 3005. Is there enough of a tolerance for that? I will check out the mute chain next. At least the haystack is getting smaller right?Thanks!
Rather interesting would be what does MUTE_A (on board KLM-3005, see page 20/21 on Korg maintenance manual)?
Do you mean measure it at that connector when it's plugged in or remove it to see what voltage it is getting?KK wrote:I just completed my 5-year ownership maintenance on my K2, so took some pics. Look for that tiny connector with two wires - purple and grey. You have to measure voltages with everything connected.mkeschinger wrote:I will check out the mute chain next.
1) Yes, you should measure voltages while connector connected. One wire (+5SB) should be contact #1 and must be +5V all times when Kronos plugged to power (even no swithed on), another wire (Power_OK) should be contact #3 and must be 0V when power switced off and go to +5V when switching Kronos ON. If these voltages are OK, then your PSU seems to be good in terms of your failure and you should investigate further on Analog Audio board (whatever KLM number it has)mkeschinger wrote:Do you mean measure it at that connector when it's plugged in or remove it to see what voltage it is getting?
Also- how did you get a pic on the forum?
You should measure Mute_A as following (after you ensured that +5SB and POWER_OK signals behave correctly (see my another post about that)mkeschinger wrote:Well, when I check it in diode mode, it shows the short. when I turn it on. When I check the voltage, it comes up with really strange numbers. Flip the multimeter and it shows the same only negative.
My probes are too big to fit in the small opening. :/alland wrote:1) Yes, you should measure voltages while connector connected. One wire (+5SB) should be contact #1 and must be +5V all times when Kronos plugged to power (even no swithed on), another wire (Power_OK) should be contact #3 and must be 0V when power switced off and go to +5V when switching Kronos ON. If these voltages are OK, then your PSU seems to be good in terms of your failure and you should investigate further on Analog Audio board (whatever KLM number it has)mkeschinger wrote:Do you mean measure it at that connector when it's plugged in or remove it to see what voltage it is getting?
Also- how did you get a pic on the forum?
2) Here was one of many photo uploading and linking services used : https://postimages.org/ - Upload your photo, post a link and incude this to forum post.
ok- when I connect to the ground and the collector of the q606 when it is turned of- it measures under 1 volt. .017 to be exact.alland wrote:You should measure Mute_A as following (after you ensured that +5SB and POWER_OK signals behave correctly (see my another post about that)mkeschinger wrote:Well, when I check it in diode mode, it shows the short. when I turn it on. When I check the voltage, it comes up with really strange numbers. Flip the multimeter and it shows the same only negative.
1) Measure voltage, set your multimeter 20V range. Do not use "diode" mode, it's just for finding shortcuts or determining diode polarity.
2) Turn Kronos OFF but leave plugged.
3) Connect multimeter black probe to Kronos ground.
4) Connect multimeter red probe to MUTE_A signal (find it according the schematic somewhere on Analog Audio PCB)
5) Measure and raport this voltage, should be somewhere below +5V (keeps muting transistors opened and any output muted/silent.
6) Turn Kronos ON and see, what happens to MUTE_A signal - supposedly MUTE_A should go to zero or even negative, if your multimeter does not automatically recognize polarity, then reverse the probes and measure again. Report MUTE_A signal behavior aiimediately after turning Kronos ON.
These measuremets should tell, if MUTE_A driving transistor Q606 is working properly.
1) First please measure and tell what "+5SB" and "Power_OK" gives to you when Kronos switched OFF and when switched ON.mkeschinger wrote:ok- when I connect to the ground and the collector of the q606 when it is turned of- it measures under 1 volt. .017 to be exact.
When I turn it on it measures 3.9 at the collector. switching the electrodes just makes it negative.
Sorry, when I check the voltage of they keyboard turned on with the negative electrode at ground and the positive at the collector, it says 3.9 volts.alland wrote:1) First please measure and tell what "+5SB" and "Power_OK" gives to you when Kronos switched OFF and when switched ON.mkeschinger wrote:ok- when I connect to the ground and the collector of the q606 when it is turned of- it measures under 1 volt. .017 to be exact.
When I turn it on it measures 3.9 at the collector. switching the electrodes just makes it negative.
2) When reporting voltages (MUte_A for example) always refer voltage (positive or negative) against the ground. Statement like "When I turn it on it measures 3.9 at the collector. switching the electrodes just makes it negative" does not make much sense...
Are power supplies for these even available?Looks like we have 0 when plugged in but not turned on and then +5.03 like we should and it goes to 11.99 for the 12v at the 12v connection on 3005. Is there enough of a tolerance for that? I will check out the mute chain next. At least the haystack is getting smaller right? Wink Thanks!mkeschinger wrote:Sorry, when I check the voltage of they keyboard turned on with the negative electrode at ground and the positive at the collector, it says 3.9 volts.alland wrote:1) First please measure and tell what "+5SB" and "Power_OK" gives to you when Kronos switched OFF and when switched ON.mkeschinger wrote:ok- when I connect to the ground and the collector of the q606 when it is turned of- it measures under 1 volt. .017 to be exact.
When I turn it on it measures 3.9 at the collector. switching the electrodes just makes it negative.
2) When reporting voltages (MUte_A for example) always refer voltage (positive or negative) against the ground. Statement like "When I turn it on it measures 3.9 at the collector. switching the electrodes just makes it negative" does not make much sense...
Yep, as I previously mentioned, everything must be connected for those measurements. On the pic, the connector is undone because I was removing PCBs in that area for inspection, etc. About connecting probes to tiny hard to reach spots, simply use pieces of small wire that you temporarily attach to the points. I use a box of phone cable for such things (4 x AWG#22). In this case, with power off simply insert short pieces of such stripped wire in the needed connector holes, make sure they are stable and not shorting out other things, then if all is well turn power on and take your measurements. Don't forget to remove them afterwards. You should see a voltage variation once the Kronos finishes boot sequence.mkeschinger wrote:Do you mean measure it at that connector when it's plugged in or remove it to see what voltage it is getting?
Also- how did you get a pic on the forum?
great idea! I am sure I have some old phone lines I can strip.KK wrote:Yep, as I previously mentioned, everything must be connected for those measurements. On the pic, the connector is undone because I was removing PCBs in that area for inspection, etc. About connecting probes to tiny hard to reach spots, simply use pieces of small wire that you temporarily attach to the points. I use a box of phone cable for such things (4 x AWG#22). In this case, with power off simply insert short pieces of such stripped wire in the needed connector holes, make sure they are stable and not shorting out other things, then if all is well turn power on and take your measurements. Don't forget to remove them afterwards. You should see a voltage variation once the Kronos finishes boot sequence.mkeschinger wrote:Do you mean measure it at that connector when it's plugged in or remove it to see what voltage it is getting?
Also- how did you get a pic on the forum?
About pics on forums, I use PostImage as well. Simple, easy and fun.
Thanks!ok, well, #1gives me 5v when powered on, but not off. #3 well, that number seemed outlandish. I also checked the digital out board- but it is getting the correct voltage. Is it possible to have a bad power supply, but still get the right voltage to certain areas?mkeschinger wrote:great idea! I am sure I have some old phone lines I can strip.KK wrote:Yep, as I previously mentioned, everything must be connected for those measurements. On the pic, the connector is undone because I was removing PCBs in that area for inspection, etc. About connecting probes to tiny hard to reach spots, simply use pieces of small wire that you temporarily attach to the points. I use a box of phone cable for such things (4 x AWG#22). In this case, with power off simply insert short pieces of such stripped wire in the needed connector holes, make sure they are stable and not shorting out other things, then if all is well turn power on and take your measurements. Don't forget to remove them afterwards. You should see a voltage variation once the Kronos finishes boot sequence.mkeschinger wrote:Do you mean measure it at that connector when it's plugged in or remove it to see what voltage it is getting?
Also- how did you get a pic on the forum?
About pics on forums, I use PostImage as well. Simple, easy and fun.
What do you mean saying "#3 well, that number seemed outlandish."mkeschinger wrote:ok, well, #1gives me 5v when powered on, but not off. #3 well, that number seemed outlandish. I also checked the digital out board- but it is getting the correct voltage. Is it possible to have a bad power supply, but still get the right voltage to certain areas?
? How goes voltage of that pin (signal Power_OK) when you turn Kronos on?It was 71v.....alland wrote:What do you mean saying "#3 well, that number seemed outlandish."mkeschinger wrote:ok, well, #1gives me 5v when powered on, but not off. #3 well, that number seemed outlandish. I also checked the digital out board- but it is getting the correct voltage. Is it possible to have a bad power supply, but still get the right voltage to certain areas?
