eptheca Posted October 25, 2011 Report Posted October 25, 2011 (edited) My Mb SID synth has started to "freeze" now and then and shows strange screens like this does anybody know what could cause this? Edited October 28, 2011 by eptheca Quote
sneakthief Posted October 25, 2011 Report Posted October 25, 2011 (edited) Try a different psu. Edited October 25, 2011 by sneakthief Quote
Wilba Posted October 25, 2011 Report Posted October 25, 2011 Does the synth itself stop playing notes, or just the LCD doing strange things? IT could be just the LCD, so check the connections, solder joints on the LCD pads, the headers, the PIC, etc. Quote
eptheca Posted October 25, 2011 Author Report Posted October 25, 2011 the psu is top, so I don't think it's that the whole synth freezes, not just the LCD I was thinking it could be that I power the 260mA backlight over the 5V reg on the core module the PSU is a 12v 1A linear regulated 90$ industrial quality, should be fine for this job I only have a minimal with stereo SID Quote
eptheca Posted October 26, 2011 Author Report Posted October 26, 2011 (edited) Hey Wilba I was thinking I could modify my core from SmashTV to use your "High-power backlight" circuit. Would it work to: -feed 12V regualted power straight from the psu to B+ on the LCD -change the T1 transistor BC337 / 25 to a BC337 / 40 like in your sammichSID -change P1 trimpot from the 10K to a 50K Do I need another resistor in addition? It looks like R3 on the sammichSID pcb is part of the baclight circuit and that R4 is the same on both pcb's Your "High-power backlight" circuit works great on my sammichSID with 4x20 lcd even if I don't really understand why it's ok to feed 12V to a 5V LED :) I think this could be why the synth konks out now and then, because the 5V reg gets too hot Edited October 26, 2011 by eptheca Quote
ilmenator Posted October 26, 2011 Report Posted October 26, 2011 the psu is top, so I don't think it's that Is it also top for the use case at hand? Quote
eptheca Posted October 26, 2011 Author Report Posted October 26, 2011 Ja 12V 1A linjært regulert Mascot psu topp norsk kvalitet :) en guru i Norge? jeg er ganske ny her Quote
ilmenator Posted October 26, 2011 Report Posted October 26, 2011 Look, you are using a 12V reg power supply to feed a 5V backlight - this is why I asked to consider your use case. I am not questioning the built quality of the power supply itself :smile: . Maybe you could replace the 5V reg on the core module with one that handles higher currents? Quote
eptheca Posted October 28, 2011 Author Report Posted October 28, 2011 I went ahead and modified my core so I can power the backlight on my 4x20 250mA LCD with 12V used Wilbas sammichSID "High-power backlight" circuit. -fed 12V regualted power straight from the psu to B+ on the LCD -changedd the T1 transistor BC337/25 to a BC337/40 -changed P1 trimpot from the 10K to a 50K works perfect the 5V reg. was getting too hot both regulating down from 12 to 5V and powering the 250mA backlight Quote
ilmenator Posted October 28, 2011 Report Posted October 28, 2011 Good to hear and thanks for letting us know what did the trick for you! Quote
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