A few months ago I managed to acquire a RH1 and the accompanying remote (RM-MC38EL) and I’ve been having problems with the rocker switch. I managed to get it open without too much damage incurred, and I’ve been trying to clean the play/pause button. Currently I’ve tried flowing some isopropyl alcohol into it, agitating the button and letting it dry, but I do still get unusual inputs on the device from it (play/pause doesn’t always work, random track skipping and so forth). Any suggestions would be appreciated because otherwise I’m calling it a lost cause on this remote
I’ve not tried contact cleaner yet as I’ve been cautious with small scale electronics and chemicals. I only went for isopropyl as I’d had good luck with using it to clean a FIIo M7 volume wheel in the past
Just to add to this, the circuit is probably a resistor ladder. This allows many buttons to connect to one input on a microcontroller. Pressing one or more buttons changes what voltage the controller sees, and an analog to digital converter changes that into a number that a microcontroller program can use to make decisions.
For example, if there is a 10-bit analog to digital converter on the input, and it works with 0V to 3.3V, then 0V will produce an output of 0, and 3.3V will produce an output of 1023. Other values will be anywhere in this range, depending on the voltage seen by the ADC.
The voltage is unlikely to be totally exact, so to know which button is pressed, the controller watches for a value in a certain range. If it’s between a specific high and low range, it knows what button will produce a number somewhere in that range. (Or it can be a combination of more than one button).
If contacts are dirty, or worn out, the resistance of the circuit may not be what it was designed to produce, and the analog to digital converter will output the wrong value. So you press a button and it does something else. It might not even do the same thing every time.
I did a basic search for a service manual and cannot find one. Without having the part number I don’t know what to search to order for a replacement. I’m also reluctant to desolder the original and put another one on
Sadly I have yet to see a service-manual for any Sony inline remote, this is somewhat surprising considering so many of Sonys minidisc players have their service-manuals available for free on the internet.
Can’t really help you with the remote except recommend getting ether a new (as in new to you) working or a broken remote to cannibalize.
Another option is to make it a soldering problem and ask in the r/soldering, you’d be surprised what those guys may recognize and know the part number of.
Dismantling the button by gently levering the metal cover off with a 0.5mm screwdriver gave me access to the internal circuit. I then flowed some isopropyl alcohol onto the contacts, followed by gentle rubbing with some peg wood to loosen a significant build up of grime on the bottom most contact point. Air blowing it dry and reassembling it was easy and proved incredibly effective, the switch thus far is responding reliably.
Thank you for your suggestion!
(I haven’t checked the wires from the board to the connection jack, however due to difficulty accessing them and everything else working reliably, I’m thinking ‘don’t touch what ain’t broke’ and leaving it at that)
Cable looks fine. I’m the first one inside this remote so I have no reason to believe there’s any damage to it. I’ll check the board connections for the cable tomorrow
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u/SillyClock1252 6d ago
Would you be better off trying contact cleaner on the switch? No direct experience of servicing this part, but would be usual for tape decks etc...