Picked up a reasonable Panasonic model - and it's got either build up or some surface wear as seen in pic below, tried alot of rubbing with cotton bud and isopropyl and does not seem to budge anything. I can't test anything yet as I need a new clutch and bands, but do you think I'll have trouble with playback with the head in that state? * edit - I managed to take some close up pictures:
It looks like corrosion, I'll let more experienced members chime in about fixing it but you may want to look at this head-lapping brochure. I don't know if you need to do this yet, maybe some stronger chemicals might work. https://stereo2go.com/forums/threads/nortronics-head-wear-manual.3935/ Nortronics (one of the world's largest producers of replacement heads) turned into Geneva Group and they sold this cleaning kit, the spray is Trichlorotrifluoroethane (TF Cleaning Spray) and it spit-shine cleans everything but might have been banned world-wide. You can still find the NOS boxes on ebay. https://www.ebay.com/itm/266753110359?
I edited initial post with better images. curious about this amber looking build up on the head - I've not seen that before, the only thing I noticed with a similar colour was the old glue that was used to stick the glass window to the lid - which seems to have aged and turned a similar colour.
There's one thing which is unclear: how deep does the corrosion go. If it's just surface, a polish alone might be able to get rid of it. Otherwise the head will require lapping. Depending on how cheap a donor unit is, simply swapping the head might be more convenient.
I assume a basic polish would require the head to come out? what's best method for polishing - dremel and soft cotton/wool buffing attachment? plus some sort of polish compound?
If you think it is corrosion from battery leak, use some vinegar to clean it first. Better than using physical method. It won't hurt the head. Do clean it after use, though.
Polishing doesn't hurt the head and it would be needed anyway in my opinion even if part of that corrosion cleans off with vinegar because the surface won't be perfectly smooth anymore. @Rossoe Yes, I would recommend taking the head out, not because it's strictly necessary but because chances are the polishing compound will get everywhere if you don't. As for the polish itself, a cotton swab mounted in a dremel (low to medium speed) and a fine polishing compound is what I recommend. Polish until the surface becomes mirror finish again, then clean the compound. If the corrosion is just on the surface, you shouldn't need much at all to make it like new again.
ok thanks guys, I will try some more cleaning. I guess I was trying to avoid taking the head out being nervous of adjustments needing putting it back in. how much tweaking is expected when reinstalling the head, I assume this had fixed azimuth as I can't see any adjustment screws? Also is it ok to lightly scratch the head with fingernail? or is that risky? I've heard of people mentioning checking if there is anything felt when passing fingernail over the head to check for surface wear.
It's ok to scratch it with fingernail, it's not that sensitive. Yes, ideally if the surface is perfectly smooth you won't feel anything with your fingernail. Reflections on the surface should also be even, but in this case the corrosion has made the surface matte. No tweaking is expected when re-installing it. Azimuth is indeed fixed on most of these walkmans with carriage mounted on the door, including all Panasonic RQ-S and RQ-SX series. The entire head bridge + REV pinch roller assy will come out after they're rotated 90 degrees. Alternatively, you can remove just the carriage.
It might be liquid, maybe somebody spilled Mountain Dew in there since the yellow extends down everywhere.
"crap i spilt me 'dew all over granpappys tape player tryina 420 mlg frag out on modee warfare 2" -some guy in 2009, probably lol if it doesnt come off with cleaning it might be corroded and need re-lapping, on the bright side if it is you cant make it any worse than it already is going off looks it does look like some soft drink though, i had a wm-f10 that looked like someone spilled soda on eons ago which was totally sticky and ruined, if it still works aside from the head being munted thats pretty impressive