Hi to everyone,
I don't know why, but the CPU of my Cyrus III does not work anymore. No self tests are performed, and the front leds light up randomly.
I've tested all the other PC boards using another Cyrus III of mine, and they work correctly.
From what I've understood, that CPU (Z86E21F1, manufactured by ST Microelectronics) contains also an Eprom section able to store the firmware necessary to manage the amp logic correctly.
I remember that some years ago it was possible to read the firmware from a CPU of this kind and then copy it on a virgin similar IC. It's not difficult to find a new (or erasable) IC of this type, but unfortunately, I'm not able to retrieve who/what could do such a copy today.
Any hints about?
Thanks a lot in advance
I don't know why, but the CPU of my Cyrus III does not work anymore. No self tests are performed, and the front leds light up randomly.
I've tested all the other PC boards using another Cyrus III of mine, and they work correctly.
From what I've understood, that CPU (Z86E21F1, manufactured by ST Microelectronics) contains also an Eprom section able to store the firmware necessary to manage the amp logic correctly.
I remember that some years ago it was possible to read the firmware from a CPU of this kind and then copy it on a virgin similar IC. It's not difficult to find a new (or erasable) IC of this type, but unfortunately, I'm not able to retrieve who/what could do such a copy today.
Any hints about?
Thanks a lot in advance
@flambart try @David Nessim he can provide new IC's with firmware for the Cyrus 3. I have the same amp but a different fault, the power LED just blinks constantly so some other condition is apparent.
Have you watched Myalbatech on youtube? One of his videos is regarding faulty Cyrus 3 controller
Have you watched Myalbatech on youtube? One of his videos is regarding faulty Cyrus 3 controller
Hi @passive420,
thx a lot for your hints. I will contact asap @David Nessim.
In the meantime I've had a look at Myalbatech videos, so interesting.
Talking about the possibility of programming one of those ICs, I remember that some years ago (more or less 40, time flies...) it was possible to erase the Eprom contents using an ultraviolet lamp. Afterwards, there was a special device able to download and store a program from a source IC and then copy it into a virgin (or previously erased) similar IC.
I wonder if it is still possible to find one of those devices...
thx a lot for your hints. I will contact asap @David Nessim.
In the meantime I've had a look at Myalbatech videos, so interesting.
Talking about the possibility of programming one of those ICs, I remember that some years ago (more or less 40, time flies...) it was possible to erase the Eprom contents using an ultraviolet lamp. Afterwards, there was a special device able to download and store a program from a source IC and then copy it into a virgin (or previously erased) similar IC.
I wonder if it is still possible to find one of those devices...
Would you need something like the AVR Dragon? This may not be suitable for the STM chip, I haven't checked the datasheet but the MCU chip would have been pre-programmed with something similar.
Myalbatech is Duncan Boyd, send a polite email and he will likely give a few pointers for free, maybe he can consult for a small fee - myalbatech@outlook.com
Have you asked Cyrus support? They may advise for nothing to point in the right direction.
That's VERY interesting regarding UV wiping the Eprom.
Myalbatech is Duncan Boyd, send a polite email and he will likely give a few pointers for free, maybe he can consult for a small fee - myalbatech@outlook.com
Have you asked Cyrus support? They may advise for nothing to point in the right direction.
That's VERY interesting regarding UV wiping the Eprom.
The last time i used an UV eraser must have been around 1992. "Interesting" it was in the 70s.
Of course no UV erasable eproms in that Cyrus.
While a corrupted eprom is the most likely culprit, is the Z86 getting power and clock?
Of course no UV erasable eproms in that Cyrus.
While a corrupted eprom is the most likely culprit, is the Z86 getting power and clock?
Hi @analog_sa,
thx to you too for your kind reply.
In fact, it seems that the ST Z86E21 family had the chance to erase and re-program the 4k/8k internal eprom, while the equivalent Zilog ICs did not have this possibility, being one-time programmable. The glass window on top of ST IC was used to erase the internal eprom, by exposing the IC to an ultraviolet light for some time.
"At some point in the late 1980's the Z86 architecture was second-sourced by STM as a 4K & 8K UV erasable EPROM device (Z86E11 & Z86E21)".
Have a look here https://www.instructables.com/STM-Z86E21-EPROM-Programmer-Adapter/
The problem now, where is it possible to retrieve those Eprom programmers? Maybe in some prehistoric cave?
Thanks again to @passive420, your suggestions are so usefule and appreciated
thx to you too for your kind reply.
In fact, it seems that the ST Z86E21 family had the chance to erase and re-program the 4k/8k internal eprom, while the equivalent Zilog ICs did not have this possibility, being one-time programmable. The glass window on top of ST IC was used to erase the internal eprom, by exposing the IC to an ultraviolet light for some time.
"At some point in the late 1980's the Z86 architecture was second-sourced by STM as a 4K & 8K UV erasable EPROM device (Z86E11 & Z86E21)".
Have a look here https://www.instructables.com/STM-Z86E21-EPROM-Programmer-Adapter/
The problem now, where is it possible to retrieve those Eprom programmers? Maybe in some prehistoric cave?
Thanks again to @passive420, your suggestions are so usefule and appreciated
I'm tempted to contact directly ST Microelectronics, they are 30 km far from me.... Never say never
Gee, you are quite right, did not realise the Cyrus 3 was so ancient. Board says '95 and the part indeed does have a window under the sticker. UV erasable eproms are certainly more prone to errors than otp.
If this were mine i would think of replacing the micro with something more current, perhaps an ATMega in an adapter socket and programming it from scratch. Perhaps a similar amount of work, but at least with a guaranteed outcome. Or look for a front panel from an old Cyrus with a working chip.
If this were mine i would think of replacing the micro with something more current, perhaps an ATMega in an adapter socket and programming it from scratch. Perhaps a similar amount of work, but at least with a guaranteed outcome. Or look for a front panel from an old Cyrus with a working chip.
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It could be a good idea, thanks. I fully agree with you about the intrinsic weakness of EPROM memories.
Unfortunately, I'm not so clever, at least not enough to program an IC from scratch. Taking also into account that I don't know the original program steps/commands...
This is the main reason why I'm looking for a device able to copy the program from an Eprom to another one. Probably, mission impossible today.
I appreciate a lot your interest and your helping hand. Grazie!
Unfortunately, I'm not so clever, at least not enough to program an IC from scratch. Taking also into account that I don't know the original program steps/commands...
This is the main reason why I'm looking for a device able to copy the program from an Eprom to another one. Probably, mission impossible today.
I appreciate a lot your interest and your helping hand. Grazie!