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Belated Happy New Year!
Finally spent a bit of time on my non-functioning 1000PX. Here's where I am so far...
The unit comes on, but does not boot. All I see is black blocks on the upper row of display. Tried hard reset and test mode. Nada...
Checked solder joints on bottom of power supply board where transformer connects. All looks good (I remember fixing these a while ago). Backup battery had been replaced at that time also. Showed a solid 3v on meter. Re-flowed the solder, all is tight, no cracks, voltages are present. Power transformer secondaries give me 16-32 and 7-14 volts.
Power supply is working. DC voltages to motherboard are + and -12v, 4.3v and 5v. Seems like pretty standard values.
Went through and exercised any socketed ICs in their sockets. I don't have a chip puller, so didn't pull them all the way out to clean pins.
No change, so I put it back together... Looking for any info or suggestions from the group. Many thanks!
--
peace,
Frank Dickinson
90 East Productions
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Sounds like the relay. Give it a decent (but not excessive pop) on its cover and see what happens. The tap will work for a while, but if this is it and you still have it open it's good to replace it. See K1000.net for suggested part replacement.
Sent from my HAL 9000 in transit to Jupiter
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Frank D via groups.io Sent: Wednesday, January 20, 2021 12:27 AM To: [email protected]Subject: [K1000-K1200] 1000PX - not booting Belated Happy New Year! Finally spent a bit of time on my non-functioning 1000PX. Here's where I am so far... The unit comes on, but does not boot. All I see is black blocks on the upper row of display. Tried hard reset and test mode. Nada... Checked solder joints on bottom of power supply board where transformer connects. All looks good (I remember fixing these a while ago). Backup battery had been replaced at that time also. Showed a solid 3v on meter. Re-flowed the solder, all is tight, no cracks, voltages are present. Power transformer secondaries give me 16-32 and 7-14 volts. Power supply is working. DC voltages to motherboard are + and -12v, 4.3v and 5v. Seems like pretty standard values. Went through and exercised any socketed ICs in their sockets. I don't have a chip puller, so didn't pull them all the way out to clean pins. No change, so I put it back together... Looking for any info or suggestions from the group. Many thanks! -- peace, Frank Dickinson 90 East Productions Our "lockdown" videos <>
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I have a K1000 with exactly the same symptoms as your 1000PX. ?
I?did everything that?you mentioned (following the tips in K1000.net)?and still got?solid blocks on the display. ?
I replaced the OS chips and the synth was?able to do?some (but?not all) of?the diagnostics functions,?but it still does not?boot.
Joey
On Wednesday, January 20, 2021, 7:01 PM, Nicole Massey <nyyki@...> wrote: Sounds like the relay. Give it a decent (but not excessive pop) on its cover and see what happens. The tap will work for a while, but if this is it and you still have it open it's good to replace it. See K1000.net for suggested part replacement. Sent from my HAL 9000 in transit to Jupiter -----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Frank D via groups.io Sent: Wednesday, January 20, 2021 12:27 AM To: [email protected]Subject: [K1000-K1200] 1000PX - not booting Belated Happy New Year! Finally spent a bit of time on my non-functioning 1000PX. Here's where I am so far... The unit comes on, but does not boot. All I see is black blocks on the upper row of display. Tried hard reset and test mode. Nada... Checked solder joints on bottom of power supply board where transformer connects. All looks good (I remember fixing these a while ago). Backup battery had been replaced at that time also. Showed a solid 3v on meter. Re-flowed the solder, all is tight, no cracks, voltages are present. Power transformer secondaries give me 16-32 and 7-14 volts. Power supply is working. DC voltages to motherboard are + and -12v, 4.3v and 5v. Seems like pretty standard values. Went through and exercised any socketed ICs in their sockets. I don't have a chip puller, so didn't pull them all the way out to clean pins. No change, so I put it back together... Looking for any info or suggestions from the group. Many thanks! -- peace, Frank Dickinson 90 East Productions Our "lockdown" videos <>
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Thanks, Nicole!
Will give it a try and report back...
--
peace,
Frank Dickinson
90 East Productions
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Check every electrolytic capacitor with a magnifying glass.? These units are very old and some of the caps go bad and, if so, they usually leak.? The leak corrodes the traces and or contacts under or around the cap.? Repair is sometimes possible. Good luck Dennis
------ Original Message ------
Sent: 1/20/2021 6:16:12 AM
Subject: Re: [K1000-K1200] 1000PX - not booting
I have a K1000 with exactly the same symptoms as your 1000PX. ?
I?did everything that?you mentioned (following the tips in K1000.net)?and still got?solid blocks on the display. ?
I replaced the OS chips and the synth was?able to do?some (but?not all) of?the diagnostics functions,?but it still does not?boot.
Joey On Wednesday, January 20, 2021, 7:01 PM, Nicole Massey <nyyki@...> wrote: Sounds like the relay. Give it a decent (but not excessive pop) on its cover and see what happens. The tap will work for a while, but if this is it and you still have it open it's good to replace it. See K1000.net for suggested part replacement. Sent from my HAL 9000 in transit to Jupiter -----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Frank D via groups.io Sent: Wednesday, January 20, 2021 12:27 AM To: [email protected]Subject: [K1000-K1200] 1000PX - not booting Belated Happy New Year! Finally spent a bit of time on my non-functioning 1000PX. Here's where I am so far... The unit comes on, but does not boot. All I see is black blocks on the upper row of display. Tried hard reset and test mode. Nada... Checked solder joints on bottom of power supply board where transformer connects. All looks good (I remember fixing these a while ago). Backup battery had been replaced at that time also. Showed a solid 3v on meter. Re-flowed the solder, all is tight, no cracks, voltages are present. Power transformer secondaries give me 16-32 and 7-14 volts. Power supply is working. DC voltages to motherboard are + and -12v, 4.3v and 5v. Seems like pretty standard values. Went through and exercised any socketed ICs in their sockets. I don't have a chip puller, so didn't pull them all the way out to clean pins. No change, so I put it back together... Looking for any info or suggestions from the group. Many thanks! -- peace, Frank Dickinson 90 East Productions Our "lockdown" videos <>
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Scanning the schematics, the DC supply voltages are:? +12V,? -12V,? +5V and +5V backup (present with power off)
I don't see a 4.3V supply that you measured - unless this is the +5V backup voltage (low battery ?)
If 4.3V is the +12V supply, then you may focus on that part of the power supply (regulator, capacitors, etc)
Also, see that the RESET signal is low for normal operation.? It will go high briefly at power up.
At the CPU, it is inverted as RESET* - should be active high in normal operation.
POWER_OK* should be low? (0V) in normal operation.
if you have a oscilloscope or logic probe, check clock input,? address and data pins on the CPU - are they active?
If yes, then the CPU is attempting to run code - which is a good sign.
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Thanks so much for the tips! Will get back into it tomorrow.
I no longer have a 'scope, but can perform the other tests.
--
peace,
Frank Dickinson
90 East Productions
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OK, I went back in...
The 4.3vdc readings at the power supply are present when the PS is connected to the motherboard. If I pull the Molex connector from J4, 5vdc is present at the same pins. Seems that the power supply works correctly when not connected.
Looking at the PS schematic from k1000.net, I can not see any reference to pins 9 and 10. The rest of it is a bit hard to read. I also found a small AC voltage present at pin 9.? 4.3 v is reaching the CPU at pin 14.
Here's what I have at the connector:
Pin# - VDC disconnected - VDC connected
1.???????? gnd???????????? gnd
2.???????? gnd???????????? gnd
3.???????? +5 ???????????? +4.3
4.???????? +12 ??????????? +12
5.???????? -12 ??????????? -12
6.???????? -0.5 ??????????? 0
7.???????? +5 ???????????? +5? (backup)
8.???????? +5 ???????????? +4.3
9.???????? +1.9 (2.2vac)?? +1.2 (1.5vac)
10.??????? +5 ???????????? +4.3
If anyone can interpret this or give any suggestions, I would truly appreciate it. Many thanks!
P.S. I'm also curious about the relay which Nicole mentioned. Seems like its function is to prevent a pop on the outputs during power-up. In any case, I do not hear it click. Is that a clue?? ;-)
--
peace,
Frank Dickinson
90 East Productions
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The +5V supplies that you measure at +4.3V when connected is a problem.? K1000 won't likely boot.
Digital logic of this era needs at least +4.75 V to operate properly.
Some component is dropping this voltage under load - either on power supply itself or on main board.
But not enough to blow a fuse from excessive current (short circuit)
This low voltage would prevent boot.? I would closely inspect the power supply capacitors on +5V.
Some ideas:
1)??If you have a bench power supply with +5,?output (sufficient current > 3 amps? ), you could substitute for the K1000 supply +5V.
Must make sure to tie supply grounds together.?
2) Use a triple bench supply (+5, +12 and -12V)? or maybe an old PC power supply with these output voltages?
3) Test the? K1000 power supply with a?resistive load (power resistor 10 ohms -> 500mA current, 2.5 Watts) on the +5V supply to see if voltage drops to 4.3V
If voltage drops, then power supply is problem (capacitors are first to check).
The relay is as you describe- protects from output 'pop' on power up until K1000 is fully booted.
Good luck.
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All good suggestions. As previously mentioned too much load could be bad caps on mother board or other load not on Power Supply. If you have not done so, I would check the traces and solder joints on the Power Supply.? If corroded, the normal load will pull down the voltage.? Sometimes the solder joints corrosion is really hard to see - re-solder if in doubt.??
The relay is closed by the processor after the boot, so if it does not boot, the relay will probably not close.?
------ Original Message ------
Sent: 1/25/2021 9:47:06 PM
Subject: Re: [K1000-K1200] 1000PX - not booting
OK, I went back in...
The 4.3vdc readings at the power supply are present when the PS is connected to the motherboard. If I pull the Molex connector from J4, 5vdc is present at the same pins. Seems that the power supply works correctly when not connected.
Looking at the PS schematic from k1000.net, I can not see any reference to pins 9 and 10. The rest of it is a bit hard to read. I also found a small AC voltage present at pin 9.? 4.3 v is reaching the CPU at pin 14.
Here's what I have at the connector:
Pin# - VDC disconnected - VDC connected
1.???????? gnd???????????? gnd
2.???????? gnd???????????? gnd
3.???????? +5 ???????????? +4.3
4.???????? +12 ??????????? +12
5.???????? -12 ??????????? -12
6.???????? -0.5 ??????????? 0
7.???????? +5 ???????????? +5? (backup)
8.???????? +5 ???????????? +4.3
9.???????? +1.9 (2.2vac)?? +1.2 (1.5vac)
10.??????? +5 ???????????? +4.3
If anyone can interpret this or give any suggestions, I would truly appreciate it. Many thanks!
P.S. I'm also curious about the relay which Nicole mentioned. Seems like its function is to prevent a pop on the outputs during power-up. In any case, I do not hear it click. Is that a clue?? ;-)
--
peace,
Frank Dickinson
90 East Productions
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That is exactly the function of the relay, and much joy has been had in the past with giving it a tap. I've also found in the past with my machines that powering the unit up and getting the blocks then doing a fast power off and back on often resolved this issue, at least for the moment. (I have to do something similar with my Matrix 6r)
Sent from my HAL 9000 in transit to Jupiter
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Frank D via groups.io Sent: Monday, January 25, 2021 10:47 PM To: [email protected]Subject: Re: [K1000-K1200] 1000PX - not booting OK, I went back in... The 4.3vdc readings at the power supply are present when the PS is connected to the motherboard. If I pull the Molex connector from J4, 5vdc is present at the same pins. Seems that the power supply works correctly when not connected. Looking at the PS schematic from k1000.net, I can not see any reference to pins 9 and 10. The rest of it is a bit hard to read. I also found a small AC voltage present at pin 9. 4.3 v is reaching the CPU at pin 14. Here's what I have at the connector: Pin# - VDC disconnected - VDC connected 1. gnd gnd 2. gnd gnd 3. +5 +4.3 4. +12 +12 5. -12 -12 6. -0.5 0 7. +5 +5 (backup) 8. +5 +4.3 9. +1.9 (2.2vac) +1.2 (1.5vac) 10. +5 +4.3 If anyone can interpret this or give any suggestions, I would truly appreciate it. Many thanks! P.S. I'm also curious about the relay which Nicole mentioned. Seems like its function is to prevent a pop on the outputs during power-up. In any case, I do not hear it click. Is that a clue? ;-) -- peace, Frank Dickinson 90 East Productions Our "lockdown" videos <>
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Hi Frank, ? As a EE I¡¯d suggest putting a separate resistive load on those off nominal Vsupplies & ideally look at them with a scope. If the supply collapses with that load you¡¯ve already separated the rest of the system from the PSU which always makes me happy. ? Note a DVM isn¡¯t ideal to diagnose problems once you see something other than the rated output (esp under load). A failed cap for example (likely) could be revealed by higher freq switching/modes that the meter tries to average poorly esp if it¡¯s not a true RMS meter. ? Hope that helps. ? Bill 
Embedded Systems Engineering - Product Development ?
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Wow, thanks for the great suggestions from everyone!? I implemented what I could with what I have on hand...
Coincidentally, I am also trying to get an Akai S1000 working again, and ordered a 35w 5v power supply (Meanwell LRS-35-5). The PS came today, so I rigged it into the circuit by pulling the pins from #s 3 and 8 on the Molex and tack-soldering leads. Same issue... the +5vdc is pulled down to 4.4, and blocks appear on the display. I figured this indicated a motherboard issue, but tried the other suggestion anyway and connected a 12ohm power resistor from the disconnected internal +5v supply to ground. This also pulled the voltage down to 4.4!
I suppose I could go into shotgun mode and replace all electrolytic caps (there aren't many). Traces on PS appear OK, I did not look under motherboard.
To Bill: My DMM (EEVblog/Brymen BM235) is true RMS, but does not have a separate RMS chip. I think that's fine for lower frequency measurement. Let me know if you think otherwise. (I'm not an engineer, I only play one on TV... ;-)
So... I toss this info out with great appreciation for y'all's responses!
BTW Nicole, I also have a Matrix 6R which is starting to act a bit wonky. Was planning (after this project and the S1000) to check PS, seat chips, clean ribbon cable connectors and such.
--
peace,
Frank Dickinson
90 East Productions
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This may be worthless as I¡¯m not as familiar with my KW insides as I should be. Everyone, but everyone, will tell you to ¡°replace the electrolytics¡± which is always good advice and you should always do when their lifespan is measured in decades like these KW units are.? Whether that¡¯s the cause of your troubles right now, or not, it WILL be. But in a DX7 there is a similar mantra of ¡°change out the tants!¡± There are tantalum capacitors, ¡°timing caps¡± they¡¯re called.? Tiny orange things that straddle some of the memory chips.? They don¡¯t leak.? They don¡¯t explode.? They don¡¯t even discolor.? They just don¡¯t work right and the result (again, on a DX7) is a no-boot condition and bad display. At an internal clock speed of 10 MHz or so, it¡¯s kinda hard to catch a glitch or two during boot. ? Anyway, before you go total shotgun, it might be worth a try. ? L. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Frank D via groups.io
Sent: Tuesday, January 26, 2021 10:39 PM
To: [email protected]
Subject: Re: [K1000-K1200] 1000PX - not booting? Wow, thanks for the great suggestions from everyone!? I implemented what I could with what I have on hand...
Coincidentally, I am also trying to get an Akai S1000 working again, and ordered a 35w 5v power supply (Meanwell LRS-35-5). The PS came today, so I rigged it into the circuit by pulling the pins from #s 3 and 8 on the Molex and tack-soldering leads. Same issue... the +5vdc is pulled down to 4.4, and blocks appear on the display. I figured this indicated a motherboard issue, but tried the other suggestion anyway and connected a 12ohm power resistor from the disconnected internal +5v supply to ground. This also pulled the voltage down to 4.4!
I suppose I could go into shotgun mode and replace all electrolytic caps (there aren't many). Traces on PS appear OK, I did not look under motherboard.
To Bill: My DMM (EEVblog/Brymen BM235) is true RMS, but does not have a separate RMS chip. I think that's fine for lower frequency measurement. Let me know if you think otherwise. (I'm not an engineer, I only play one on TV... ;-)
So... I toss this info out with great appreciation for y'all's responses!
BTW Nicole, I also have a Matrix 6R which is starting to act a bit wonky. Was planning (after this project and the S1000) to check PS, seat chips, clean ribbon cable connectors and such.
--
peace,
Frank Dickinson
90 East Productions
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Thanks, Larry!
I don't remember seeing any tantalum caps (I closed the unit up) but will take a look. There are other caps, but they might be ceramic.
--
peace,
Frank Dickinson
90 East Productions
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I know it's OT, but I just installed a Meanwell LRS-35-5, 5 volt switching power supply in my dead Akai S1000.
Connected 4 leads, drilled one hole to accommodate mounting screws, and it fired right up! Floppy drive still works. External SCSI CD-rom still works. The only thing not functioning is the external 44MB SCSI SyQuest drive (remember those?) and LCD backlight is dim (of course...).
Very happy! Gonna take care of a few loose ends and list it for sale. I also have two matching drum trigger units for it. Both working as well!?
--
peace,
Frank Dickinson
90 East Productions
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Hi Larry,
Just opened up the 1000PX again... Are you referring to the decoupling caps? I'm pretty sure that's their function. There is one at each IC, most are K5M 104, which (if I am correct) = 0.1uf. There has to be around 50 in here and only around a dozen electrolytics.
At this point, I think I will spend a few bucks on new electrolytics all around. They are cheap enough. Changing them out will also refresh the solder connections to the PCB. I am currently making a list and will place an order tonight. If that doesn't do the trick, at least they will be eliminated.
--
peace,
Frank Dickinson
90 East Productions
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Hi All,
I ran the diagnostics on my non-booting K1000 and all tests pass, except for the Timer and UART. ?
Every time the K1000 starts?the Timer and UART test, I?immediately hear the relay click and then the screen goes blank (it doesnt even show?the blocks). I then have to turn off the unit and when I power up again, I hear a clicking sound that repeats indefinitely.?
Any clues as to what's the problem here? ?
I measured?5v, +12.1v?and -12.1v?at?the power supply and?4.9, +12, -12 at the IC pins.?
Thanks.
On Friday, January 29, 2021, 9:27 AM, Frank D via groups.io <rhythm4_4@...> wrote: Hi Larry,
Just opened up the 1000PX again... Are you referring to the decoupling caps? I'm pretty sure that's their function. There is one at each IC, most are K5M 104, which (if I am correct) = 0.1uf. There has to be around 50 in here and only around a dozen electrolytics.
At this point, I think I will spend a few bucks on new electrolytics all around. They are cheap enough. Changing them out will also refresh the solder connections to the PCB. I am currently making a list and will place an order tonight. If that doesn't do the trick, at least they will be eliminated.
--
peace,
Frank Dickinson
90 East Productions
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On Fri, Jan 29, 2021 at 10:08 AM, Joey Mastrili wrote:
?
I ran the diagnostics on my non-booting K1000 and all tests pass, except for the Timer and UART.?
Did you connect the Midi cable loop (input to output) before running the test? https://www.sweetwater.com/sweetcare/articles/perform-self-diagnostics-kurzweil-k1000/ ? -- peace, Frank Dickinson 90 East Productions
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Ha! ?You¡¯re asking me? Notta clue. Maybe they decouple, maybe not.? Maybe there¡¯s 50, maybe there¡¯s 5.? No idea. I just threw that out there because the DX7 came out around 1984 and the PX about 4 years later, maybe 3. So the DX guys are going strong on ¡°change the tants¡± because, unlike electrolytics, no one had their eye on tantalums failing, but over this much time, they do with some regularity in the digital timing circuits. Even my local tech was completely baffled by DX7 tantalums and he gave me the long ¡°wellllll¡ that DX7 power supply is a funny thing¡.¡±.? He¡¯s only been doing this stuff for 40 years and had to throw in the towel on my DX because he only considered the power supply. I fixed it myself changing the tantalum caps on a couple boards.? ? I haven¡¯t peeked in my PX in months, maybe years. ? L. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Frank D via groups.io
Sent: Thursday, January 28, 2021 7:28 PM
To: [email protected]
Subject: Re: [K1000-K1200] 1000PX - not booting? Hi Larry,
Just opened up the 1000PX again... Are you referring to the decoupling caps? I'm pretty sure that's their function. There is one at each IC, most are K5M 104, which (if I am correct) = 0.1uf. There has to be around 50 in here and only around a dozen electrolytics.
At this point, I think I will spend a few bucks on new electrolytics all around. They are cheap enough. Changing them out will also refresh the solder connections to the PCB. I am currently making a list and will place an order tonight. If that doesn't do the trick, at least they will be eliminated.
--
peace,
Frank Dickinson
90 East Productions
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Dennis Spanogle (Mr. Kurlewin K1000.net)