freakyooota Posted June 8 Share Posted June 8 (edited) No identifiable blown capacitors or burned PCB. There is a little sound, especially in the higher octaces - but its faint - and i mean its really faint. - Jack tested. - Fuses all good (replaced one). - Key-ribbon looks good. - Correct voltage set I will attach pictures maybe it can help. Thank you folks. https://postimg.cc/gallery/8FRTSBC Edited June 8 by freakyooota photos didnt upload Quote Link to comment Share on other sites More sharing options...
Chas Posted June 8 Share Posted June 8 (edited) 6 hours ago, freakyooota said: No identifiable blown capacitors or burned PCB. There is a little sound, especially in the higher octaces - but its faint - and i mean its really faint. - Jack tested. - Fuses all good (replaced one). - Key-ribbon looks good. - Correct voltage set I will attach pictures maybe it can help. Thank you folks. https://postimg.cc/gallery/8FRTSBC Congratulations on acquiring a vintage Casiotone! Those are lovely old keyboards with warm tones and analogue percussion, and are well worth having and using. Also of interest is that it is one of the models that includes the now famous "Frog" preset famously used on Michael Jackson's "Thriller" song! With regards to yours and its issues, looking at your pictures the first things that come to mind are the following: In the picture below I've arrowed a small rectangular yellow capacitor, known as a RIFA film capacitor. These are notorious for going kamikaze by popping and producing a lot of smoke when they do, though yours looks fine. My understanding is that they are used as a noise suppressor in the PSU circuit. They can be cheaply and easily replaced with modern equivalents. I've also arrowed two missing fuses. Have both these been replaced, and why were they missing in the first place? Another possible culprit is the Power Amplifier module arrowed in the picture below. Could also be an issue with circuitry and components around it: Lastly, have you checked both the headphone out and line outs to see if they both suffer from very faint volume? When you switch the keyboard on, can you hear a small 'pop' sound from the speaker? Can you start and hear the rhythm section playing when activated (even faintly)? Do the LED lights respond when you press switches on the front panel? Starting with the basics, try wiggling the volume control back and forth, and try it at various positions to see if an oxidized/ dirty potentiometer might be the issue. Also try the doing the same thing with the balance control. Quite often volume issues are caused by volume potentiometers not working correctly. If all the above doesn't produce any results, it's time to use a Service Manual and dive in deeper. I managed to find one online and will upload it into the files section of the forum. Good luck, and I hope you manage to get your 401 singing again 🙂 Edited June 8 by Chas 1 Quote Link to comment Share on other sites More sharing options...
Chas Posted June 8 Share Posted June 8 (edited) I uploaded the 401 Service Manual to the Downloads section of the forum. Here's a direct link: https://www.casiomusicforums.com/index.php?/files/file/1599-casiotone-ct-401-service-manual/ Edited June 8 by Chas 2 Quote Link to comment Share on other sites More sharing options...
IanB Posted June 9 Share Posted June 9 Excellent comments from Chas above. The RIFA looks ok (they normally fail apocalyptically) and aren't required for circuit function anyway (you can just remove it if you want tbh, it's there to comply with regulations basically). It certainly won't work with missing fuses! 1 1 Quote Link to comment Share on other sites More sharing options...
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