I have an HR-16, and a bunch of Alesis gear from that era. The first thing I do on those machines, just by way of good practice, is to recap (especially power supply stuff), change power regulators, change the battery, check diodes, and remove all chips and deoxit sockets and pins and reseat. I'm sure you checked a bunch of this stuff but Alesis kit from this era is notorious for these issues and doing the above will put you in a good position to troubleshoot further. From memory the power supply is AC (rare for a lot of stuff with a wall wart) and people can damage units by plugging in the wrong adapter. The HR16 is a great sounding machine (possibly the samples plus that DAC) and prices are climbing.
Dear fellow Necromancer, I have been repairing a few of these lately and have some thoughts. Firstly, it should be mentioned that the Power Supply for these units is an AC adapter, rather than the usual DC that powers most gear like this. The behavior at the beginning of the video is similar to what I've witnessed can occur when using a DC adapter instead of AC. This AC is used in the reset circuit and comparator circuit to compare to regulated positive 5 volts. However, you got the machine to sort of boot so I would suspect one or more of the voltage regulators. The 7805 providing 5+ volts is probably ok and that circuit drives the display and the 12mhz crystal that drives the processor. The negative 12 and positive 12 volt regulators are probably not putting out the correct voltage that is needed for one of the chips (Eprom - ROM, RAM, or SRAM) in this revision of the circuit board. Everything else is awake, but data isn't correct. Later revisions only used only a 7805 5v regulator probably to avoid this false startup. In other words, check the voltage regulators 7805, 7812, 7912. Good luck to you!
Hi I'm a fixer for my own stuff but that's due to costs and not extensive technical training. I do have ESD soldering skills and a station, but it's never been a passion just hobby. Can ask you a question? When it comes to SRAM which is what's bad in my HR-16, How much of a variable is the chip number? The chip I need to replace is the cxk58256pf-12L 7K90 C90. Is there any part of that number that is just a variable or newer series of the chip? Or do I need the exact chip with the exact same numbers? I've also heard Hitachi has chips which are better but need to know what number chips those would be unless they're the same chip under Sony. Any help would get me on the right track. I also just bought another HR-16 that also has the ramp chip bad. ALSO, you may find this of interest. both when doing a self test show midi I/O error. Maybe that's inicative of something related to the Sram, not sure. i'm suspecting ram chip since they're not saving data even when the power is turned on. (i.e. changing a voice, save, switch patterns and back to the changed patter, all saved vanishes even while under power. Also I tried ordering a chip thought to be the same, a cxk5864pn, (which I think is wrong now) and that threw jumbled characters on the screen. just like yours. so maybe that chip that was in yours could be incorrect. All my characters came back when I put the OLD Sram chip into it, but it still doesn't save. At 8:52 of your video it looks like the same chip as mine. Maybe my SRAM just isn't saving and your 58256 is more compromised, but I did see a it return with my original non-saving SRAM. And yes both HR16's, I replaced the NEW SRAM (5864) and got the same messed up characters yours got, AND all words return when I reinstall the SRAM. Also both machines in self test say Midi I/O Error. Maybe your machine does as well which may or may not indicate a pattern. Thanks if you have any insight to share!
hi i'm not that familiar with the RAM compatibility so may not be able to help. The 6116 RAM chips can be replaced by other Toshiba chips so generally if you get one with the same spec say 2k 8 bit then the timings should not be super critical.
Hello, I have the same problem in mine, I already changed the capacitors and current regulators, do you think that replacing the eprom and ROM chip could help?
I'm sure you'll put the pieces of the puzzle together in time. What's your technique for getting chips desoldered? It's something that I have had some difficulty with.
hi get a good desolder tool. preferably a gun with a heated element that can heat and remove solder. Also good solder wick for a board like this. Chemtronic is the only one I have found that works reliably
I have an HR-16, and a bunch of Alesis gear from that era. The first thing I do on those machines, just by way of good practice, is to recap (especially power supply stuff), change power regulators, change the battery, check diodes, and remove all chips and deoxit sockets and pins and reseat. I'm sure you checked a bunch of this stuff but Alesis kit from this era is notorious for these issues and doing the above will put you in a good position to troubleshoot further. From memory the power supply is AC (rare for a lot of stuff with a wall wart) and people can damage units by plugging in the wrong adapter. The HR16 is a great sounding machine (possibly the samples plus that DAC) and prices are climbing.
Dear fellow Necromancer, I have been repairing a few of these lately and have some thoughts. Firstly, it should be mentioned that the Power Supply for these units is an AC adapter, rather than the usual DC that powers most gear like this. The behavior at the beginning of the video is similar to what I've witnessed can occur when using a DC adapter instead of AC. This AC is used in the reset circuit and comparator circuit to compare to regulated positive 5 volts.
However, you got the machine to sort of boot so I would suspect one or more of the voltage regulators. The 7805 providing 5+ volts is probably ok and that circuit drives the display and the 12mhz crystal that drives the processor. The negative 12 and positive 12 volt regulators are probably not putting out the correct voltage that is needed for one of the chips (Eprom - ROM, RAM, or SRAM) in this revision of the circuit board. Everything else is awake, but data isn't correct. Later revisions only used only a 7805 5v regulator probably to avoid this false startup.
In other words, check the voltage regulators 7805, 7812, 7912.
Good luck to you!
appreciate the very helpful insights and info on this classic machine
That's a shame. RAM would've been my guess when I saw the garbled text on the display. Hope you get it sorted.
Hi I'm a fixer for my own stuff but that's due to costs and not extensive technical training. I do have ESD soldering skills and a station, but it's never been a passion just hobby.
Can ask you a question? When it comes to SRAM which is what's bad in my HR-16, How much of a variable is the chip number?
The chip I need to replace is the cxk58256pf-12L 7K90 C90.
Is there any part of that number that is just a variable or newer series of the chip?
Or do I need the exact chip with the exact same numbers? I've also heard Hitachi has chips which are better but need to know what number chips those would be unless they're the same chip under Sony.
Any help would get me on the right track. I also just bought another HR-16 that also has the ramp chip bad.
ALSO, you may find this of interest. both when doing a self test show midi I/O error. Maybe that's inicative of something related to the Sram, not sure. i'm suspecting ram chip since they're not saving data even when the power is turned on. (i.e. changing a voice, save, switch patterns and back to the changed patter, all saved vanishes even while under power.
Also I tried ordering a chip thought to be the same, a cxk5864pn, (which I think is wrong now) and that threw jumbled characters on the screen. just like yours. so maybe that chip that was in yours could be incorrect. All my characters came back when I put the OLD Sram chip into it, but it still doesn't save. At 8:52 of your video it looks like the same chip as mine. Maybe my SRAM just isn't saving and your 58256 is more compromised, but I did see a it return with my original non-saving SRAM.
And yes both HR16's, I replaced the NEW SRAM (5864) and got the same messed up characters yours got, AND all words return when I reinstall the SRAM.
Also both machines in self test say Midi I/O Error. Maybe your machine does as well which may or may not indicate a pattern.
Thanks if you have any insight to share!
hi i'm not that familiar with the RAM compatibility so may not be able to help. The 6116 RAM chips can be replaced by other Toshiba chips so generally if you get one with the same spec say 2k 8 bit then the timings should not be super critical.
We got one drum voice that doesn't get any sound out of it, any idea?
possibly a bad pad / switch, try it over MIDI
Monitors didn't pick up the 3pan position. Pan to zero solved ✊🏼
Hello, I have the same problem in mine, I already changed the capacitors and current regulators, do you think that replacing the eprom and ROM chip could help?
hi I would check/replace the RAM chip and then give the machine a full reset. Also check the powersupply rails.
I'm sure you'll put the pieces of the puzzle together in time. What's your technique for getting chips desoldered? It's something that I have had some difficulty with.
hi get a good desolder tool. preferably a gun with a heated element that can heat and remove solder. Also good solder wick for a board like this. Chemtronic is the only one I have found that works reliably