Looking for someone who could pull the firmware out of his (hers) PSA-1's eeprom. I've got faulty PSA-1 that fails to boot.
p.s. have a response from SansAmp guys that the'd try looking for one, but I'm afraid it could end with nothing (you know, besides digging in a pile of old design files and firmwares, guys have a job to do, lol).
see the post above with "PSA_1_27C64_fixed.pdf" - hint, it is not a PDF
Looking for someone who could pull the firmware out of his (hers) PSA-1's eeprom. I've got faulty PSA-1 that fails to boot.
p.s. have a response from SansAmp guys that the'd try looking for one, but I'm afraid it could end with nothing (you know, besides digging in a pile of old design files and firmwares, guys have a job to do, lol).
see the post above with "PSA_1_27C64_fixed.pdf" - hint, it is not a PDF
In case the repair with a new EEPROM does not work...
It didn't work for me, so I ended up replacing the entire MC68HC11 and EEPROM with an Arduino Pro Mini and an OLED display:
I bent back the original display, so this is not a permanent modification. Works a charm, but sometimesI have intermittent noise issues. This could probably be improved with a proper circuit board.
agung wrote: ↑23 Feb 2024, 14:15
Oke thanks.. Your update schematic look like different for value part and others with Stephanovitch layout.. Please tell me, which one we must follow?
actually Stephanovich edited the file, I just posted it.
There are still some wrong bits to the puzzle
There is no 47n followed by a 100k to ground between U9a and U9b in the "secret" section - U9a output connects directly to U9b input
I wonder what those 14 pin devices with the sanded tops are - they appear to be supplied by the +5 and -5v rails - some type of cmos switch perhaps ?
bajaman wrote: ↑23 Feb 2024, 23:48
There are still some wrong bits to the puzzle
There is no 47n followed by a 100k to ground between U9a and U9b in the "secret" section - U9a output connects directly to U9b input
I wonder what those 14 pin devices with the sanded tops are - they appear to be supplied by the +5 and -5v rails - some type of cmos switch perhaps ?
bajaman
see my first post, they are
100k DS1267 dual digital potentiometers
bajaman wrote: ↑23 Feb 2024, 23:48
There are still some wrong bits to the puzzle
There is no 47n followed by a 100k to ground between U9a and U9b in the "secret" section - U9a output connects directly to U9b input
I wonder what those 14 pin devices with the sanded tops are - they appear to be supplied by the +5 and -5v rails - some type of cmos switch perhaps ?
Looks to me like some of the unnecessary coupling caps and bias resistor were replaced with direct connections, aka, copper tracks. A value changed in the gain setting limit resistor to allow for even more gain. Guesses about the gooped module were REALLY good!
Looking forward to the final schematic!! This has been some AWESOME work, people!!!
Stephanovitch wrote: ↑13 Feb 2024, 11:26
Inside the mystery box
Compared to many, many threads online on a multitude of items but all with a dead end ""because I might break something..." I am amazed by the immense size of the balls some of the forummembers here have when it comes to performing possibly destructive measures to get more information. Respect!
Then, while looking at the -non-verified- schematic, may I suggest to be even more thourough in the definition/indication what is in the gooped module and what's not? As in. the Chrunch control, including the 1k series resistor are not in that module. The Drive Control and the 2.2uF cap aren't in the module either (and the input resistor appears to be a 1k, not a 3k3.) ast but not least the 100nF output cap is not in the module either.
