Going OT a bit (though I didn't start it ) to the Technics SL-PJ25. I found the service manual. In terms of transport and electronics, it's a very complex beast compared to the Philips ones. There are pots for adjusting eye patterns, PLL jitter waveforms etc that you simply don't have to worry about on the Philips. Given that the aim of both is simply to present the right bits to the DAC at the right time, they seem to have gone strangely overboard. Bits are bits after all. It does have the Technics MASH DAC though, which was well regarded at the time - I can't find the datasheets for the ICs though. I suspect that it is going to be something of a major project if it doesn't work!
The service manual is here... https://elektrotanya.com/technics_sl-pj25_cd_player_sm.pdf/download.html
Yep, there is a full row of orange trimmers right next to the track for the coil. Easy to spot on my pictures.
Yes I am sure it must be a lot of "fun" if one needs to fiddle with all of them to get the thing working to spec !
Will do my best to fix it, we will see how it goes...
That said if I fail to fix it, I would still keep it, as it's sucha uncommon and nice piece of engineering and build quality.
Nice to hear the MASH DAC is good... didn't even that "MASH" referred to a DAC !
The SL-PJ25 makes no mention of it on the front panel. However I have a couple other Technics players, a SL-PG200A and SL-P277A. Front panel look 90% similar. Both of them feature a huge "MASH3 markng on the tray face plate. Now I know what it refers to !
I first go the SL-P227A, which is a very sorry state. Very dirty outside, some rust on the chassis bottom plate, and a couple plastic bits broken from the transport... the clamping mechanism was dislodged and moving freely inside the cabinet... put it back together as best I could, and somehow it still reads CD's !
I kept it only because I noticed it had a swing arm, which surprised me. Also, a nice detail... it is the only player in my entire "collection" where the headphone output can actually play loud ! In all my other player, whether they feature a volume control or not, it won't play loud. I use the headphone output to fix all these players, as I have only one CD input on my amplifier, already used for my main player, the one I use to listen to music at the bench... don't know if one can connect another CD player (the device under test I mean) to the other inputs of the amp : Phono, Tuner, Tape1, Tape2... haven't checked the manual for the amp, but I guess each input expect a different signal amplitude and might apply some analog "processing" different on, each type of input. I don't know, maybe some filtering/bandwidth limiting tailored to each type of device... something like that...
Anyway, I intended to "restore" that player, treat the rust, give it a good clean, try to super glue the broken plastic bits back onto the transport... try to at least. Now that you are telling me that this MASH DAC is worthy, that's another reason for me to keep it...
The second player, 99% similar, also a swing arm, sold for part. What the seller did not say, is that the player clearly got dropped from the top of the Eiffel tower !
Wow... for parts it is indeed ! Though I could use it to help me fix the first player. Somehow, despite massive mechanical damage, it still powers up and the disc spins.. but it won't read it.
Toshiba : tried a Philips remote, indeed it works, hjust tried ! Good to know...
Luckily the player came with its original Toshiba remote control. First time I see a remote where you can select the "index". Don't even know what that means ! Maybe an audio track can be further divided in sub-tracks, and the "index" lets you navigate from one sub-track to the next.... don't know. Never had a music CD that had indexes ?! Maybe it could be useful for something like an audio book or something ? Lots of content so a track could represent a chapter, and you could further divide a chapter in sub-sections... dunno.
Anyway, "great" news : while trying the remote control(s) on the Toshiba, I eventually witnessed the player misbehaving ! YES, there is something that needs fixing in this player after all !
Symptoms :
- while the CD was playing, I could hear a weird noise coming from the cabinet, louder that I found acceptable. Thought oh no, the spindle motor is on its last leg, bad day ! But, I pulled the top cover and found that instead, the problem came from the DC motor that operates teh tray ! It was constantly running ! Tray was already closed, CD was being played, yet bloody motor was still trying to close the tray !
I stopped the playback, open the tray, closed it... and the motor stopped as expected. Did not misbehave anymore, hmmm.....
- Later, in the middle of playing, suddenly playback stopped, and the VFD displayed the TOC, as it does following the insertion of a disc ! So I had to press the Play button to get it going again.
- Later again, as I was operating the tray a few times to test it, it opened only 80% of the way then instantly moved back and closed ! So didn't have time to insert a CD.
It's all random and weird.. however it all adds up, makes a consistent picture, I think, if we had a dodgy micro-switch, the one that detects that the tray is closed. So might have to replace it. Looks like a bog standard tactile switch though, nothing special, soldered directly to the motherboard. Same kind you find for all the buttons on a front panel.