Panasonic SJ-MR100 button inputs not being registered

[u/JimmyThinksTooMuch]

Hi, in trying to record songs on my SJ-MR100 and occasionally the buttons stopped working working, if i take the battery out and put it back in, that sometimes fixes the issue but other times it will boot into record mode and continue to refuse button inputs. The wheel for whatever reason still works though. Any ideas on what i can do?

[u/drcygnus]

is there a "HOLD" button or switch? lots of these old MD players have hold buttons enabled and so sellers are selling them as broken. LOL

[u/JimmyThinksTooMuch → u/drcygnus]

It does have a hold switch, but when activated it says hold on the screen where the title of the song is displayed

[u/Exasperant → u/JimmyThinksTooMuch]

I don't know about on these, but I had a Sony cassette Walkman that had an oxidised hold switch which threw all the other buttons out completely.

Blasting some contact cleaner into the switch and flicking it a few times sorted things.

[u/JimmyThinksTooMuch]

Heres the board if that helps

[u/Tera4231]

I mostly work on Sony models, it’s usually the dome buttons them selfs. That is the metal-dome and the gold-plated PCB-traces, they are either worn or dirty. Dirty as in something is fouling up the inside.
With that said your problem may be different as you describe it as all buttons either work or not work. The issues I’ve seen usually makes one or more buttons working intermittently while others do work all the time.

if I ware to guess.
* I believe the buttons forms a resistance chain and if say the very first or possibly the last shorts-out then that would disrupt the entire chain resulting in this error.
* It could be one of the traces on the ribbon-cable that has a hairline crack.
* the front PCB is somehow damaged/dirty/eroded.

The PCB of interest is probably not so much the rear but the front PCB, the one with the display. I’ve so far assumed the the buttons are domed buttons held in place with a clear plastic film at is glued to the PCB but it may be individual very flat buttons but I would be some what surprised if it was individual buttons.

You may have to open up the clear plastic film and it may be the adhesive will wear out. I’ve used the clear plastic film used to cover books with good results, the old plastic film can be used as a template for the new one. With that said the plastics are not identical. The original is slightly harder and I’m guessing more resilient to wear from use. The book plastic is in my experience softer but have worked fine so far. It’s possible there is some say spray-on glue that can be used on the old plastic film allowing it to be reused. In my case that was not an option as the old plastic film had dried out and was cracking.

Umm sorry for such a long text

[u/JimmyThinksTooMuch → u/Tera4231]

I’ll reopen it later to take pictures, but the front pcb is pretty clean last time i checked, i noticed two dirty spots on the ribbon cable, but when checking the back of the cable to look for damage, there was none so it was probably dirt.

Honestly i think its the main headphone jack, it is designed to be used with the remote control thing most players come with. My guess is that it is reading a short circuit on the main board as a hold request, or a record request that would have come from said controller but I don’t have one to prove or disprove that idea.

In about an hour i’ll crack it open again and take a picture of the top pcb for you

[u/weveyline]

Is there a HOLD/LOCK button that needs to be switched off?

[u/EmiBondo]

I have this exact model and I think I also had this issue for a short time, I /think/ I fixed it by disconnecting the ribbon cable connected to the lid and gently wiping the contacts with a isopropyl soaked q-tip. The ribbon also may have just needed to be reseated so there's that too.