Hello everyone, I got this fine machine today, the Sony TCM 4040. Everything worked perfectly in the beginning, but now I suddenly have no sound from the tape anymore. The Drumpads are still working. Does anyone have ideas what could have happened? I didn't drop it or anything. Could it be the capacitors? Thanks in advance!
some more information: - the player doesn't have any switches to change the signal source - no apparent bad connections or loose cables - no mechanical issues (tape transport, forward and rewind all work) - recording also works
Did you try it with a different tape? Sometimes the felt pad that pushes the tape onto the machine's head falls off and the tape doesn't touch the head. Is there a headphone jack?
Yeah I've tried different tapes, nothing worked unfortunately. It doesn't have a headphone jack either.
There is a service manual available on Elektrotanya for this device: https://elektrotanya.com/sony_tcm-4040_cassette-corder.pdf/download.html Looking at the schematic and based on information available so far, TA7628 IC works fine (since drumpads are working). Signal from drumpads marked in red. Potential culprits are: - head preamp (Q101 and adjacent components): not getting power or other failure; - S101-2 not making a good connection on playback; Caps don't fail suddenly unless they fail short-circuit. This is a possibility that some capacitor shorted and a voltage supply rail is low or missing because of that. First thing I would check is if the 5.3V rail is present at blue circled point. This rail is generated by ripple filter inside IC101. S101-2 could also not make a connection in play mode, although less likely.
Thank you so much for your time to look into it and narrowing it down! Unfortunately I'm not very good at reading those schematics. At least I think I found the circled spot. I already had the area Q101 in mind but I didn't see anything wrong there. Would it be enough to check the areas you mentioned for continuity with a multimeter and use this method to look for any short circuited capacitors as well? Thanks again! [UPDATE] !!! Oh my god! I checked the paths you mentioned for continuity and I realized there was in fact something off with S102. It showed some continuity but not enough. I cleaned the area and now it plays MUSIC again. Thank you so much!! Can I buy you a coffee or something haha. Do you have any recommendations on how I could learn to find out how to read schematics and find out the things you pointed out myself? Thank you thank you, you made my day.
It just takes a little time but it's pretty easy to pick up the basics. There's all kinds of websites, https://www.circuitbasics.com/how-to-read-schematics/ https://learn.sparkfun.com/tutorials/how-to-read-a-schematic/all Alot of us, as kids, had these Radio Shack Kits which was really helpful in building cool electronic projects.
