• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Need help with SL 1700MK2

Zodia

Zodia

Super Member
I recently acquired a Technics SL-1700MK2, it had the usual problems (sticky power button, and no cue/auto return), cleaned switch and replaced belt, however, the cue and auto return still doesn't work, i am pretty sure the problem lies in one of the IC chips, but...I can't find any replacements, so my question to you expert folk, is, is there any compatible IC that i can use as a replacement or is this unit FUBAR?
The platter spins, it holds speed, tone arm is good, it's missing the feet, but i am not worried about that,as i plan on doing my own.

Any help is appreciated, as always.

John.
 
Register to hide this ad
If it's a chip, you'll need a donor unit.

I'd be more inclined to think of it being a bad wire or solder joint perhaps.
 
I thought of that too, i spent nearly 6 hours resoldering every single solder joint, and checked every wire for continuity...
oh well, $20 dollars for a manual 1700mk2...meh.

EDIT: nope motor is good.
 
I have one with the same problem. I had the ICs replaced in the early 90s, and they failed again this year. I'm always on the hunt for a parts unit.

The sucky thing about this is there is no manual cueing on this table, so it's a full manual and takes a stead hand!
 
Zodia said:
I thought of that too, i spent nearly 6 hours resoldering every single solder joint, and checked every wire for continuity...
oh well, $20 dollars for a manual 1700mk2...meh.

EDIT: nope motor is good.
Click to expand...

Bummer.


Shoot me your number in a PM when you get a chance.
 
Mine is temperamental - it cues fine, but no auto-lift and return. I've been hesitant to try to fix the return on the chance it is chips. If the return motor is just going bad, are there replacements?
 
wank said:
Mine is temperamental - it cues fine, but no auto-lift and return. I've been hesitant to try to fix the return on the chance it is chips. If the return motor is just going bad, are there replacements?
Click to expand...

It's a 12v dc motor, i am sure you can fit one in there.
The most important factor in choosing a replacement motor is the RPM's, you wouldn't want the tonearm to go flying off the table.
 
I'd thought the Technics ICs understressed and generally robust. The problems with my SL-1600 MkII were all mechanical related to hardened grease and oils preventing the mechanism from working properly as well as the usual belt problem.
 
It's worth noting that most Japanese motorized devices use brush type dc motors and they "fail" due to oxidation of brush contacts. My fix is to shoot some contact cleaner into any opening, like screw hole and then spin the motor manually. I've done this with hundreds of motors over the years and most go back to working for several years.
 
Pio1980 said:
I'd thought the Technics ICs understressed and generally robust. The problems with my SL-1600 MkII were all mechanical related to hardened grease and oils preventing the mechanism from working properly as well as the usual belt problem.
Click to expand...

I've only run across a few that had problems- often ones that were abused, stored in damp basements or hot hot attics, or had damage like power surges or lightning strikes.
 
There is a little micro switch activated by hi and lo spots in that white disc the worm gear spins. If it is dirty or hanging, could cause the issues you are experiencing.

I would not suspect the motor unless you have tried putting 12v dc to it and it fails to spin.

Scott T.
 
That was actually the first thing i did, i unhooked the motor from the opto sensor board and tried it with a 6 volt source and it spun good, had it had dirty or oxidized brushes it would have hesitated or not spun at all at that voltage, so that was my first test, I didn't see the micro switch though...i must have missed it, i'll have a look at it again, probably tomorrow, when i take it over thedelihaus.
 
Have one that suddenly smoked the arm control PCB, or some portion thereof. Cue up/down and auto-return functions are completely dead. STOP raises the cue and returns the arm, but the motor refuses to run in reverse to lower the cue. Quite sure it's the PCB as I smelled it myself. :sigh: I'm just thankful that's it's still usable as a great manual table, AND I just found another that hasn't lost it's mind (yet..) :thmbsp:
 
I had one once that did that. It turned out to be 3 small black transistors located towards the bottom of that board. Luckily I had an extra from a 1700 that died from a thunder storm. Funny all the other electronics died except that board.
 
Although the specialized chip that controls the cueing mechanism is NLA, the service manual describes the theory of operation and relevant truth tables for sensors and motor functions in such detail that a dedicated DIYer might be able to replace the faulty electronics with a PIC processor.
 
Do you know of any one that could build one?
That would be incredible.
I can solder, and i can replace components, but to build something from scratch?... I just don't possess the knowledge to do so.
 
I'd be interested in a project like that. The logic is simple and well-documented, it's just a matter of duplicating what the ICs do.
 
You must log in or register to reply here.
Back
Top Bottom