Technics SL-1610 MkII arm lift problem

[carlosfm]

Hi,

Maby someone knows this turntable...
I have this at around 10 years (I bought it used at the time), and it developed a fault that I could never repair.
I use it completely manual, because the arm litfting doesn't work.
Yes I've replaced all the electolythic caps some years ago (Technics/Panasonics always fail here) and that didn't solve the problem.
I even connected a small transformer to the arm motor and it works, the arm lifts and goes down (reversing the polarity).
So...
Must be something on the control board, I don't know...
So much electonics to put a disc turning.
Any help?
Thanks.

 

[peranders]

If noone can help you here maybe you could ask the germans at http://www.analog-forum.de/ (english is OK).

 

[Netlist]

I even connected a small transformer to the arm motor and it works

Assuming the Cueing Switch S403 works, check the voltage at
TP908: (Collector of Q905) +5V
TP909: (Collector of Q906) 0V
TP910: (Kathode D905) 0V

If these are not correct, check IC401 (MN1400PA) and IC402 (SVIM53217P) Difficult to do without Service Manual, which I have.
If TP908...910 are OK, check Q901…Q906 and D901…D906 (MA150)
Q901/Q902: C: 12V, B: 1V, E: 0.4V
Q903/Q904/Q905/Q906: C: 0V, B: 0.2V, E: 0.4V

(I guess) the +5V at Collector of Q905 will be 0V in normal condition or +5V in working condition (motor working or not)

Hope this helps.

/Hugo

 

[carlosfm]

Hugo, your post is impressive.
I knew I would fin help here.
Do you have any chance to mail me the service manual?
One of these days I'll open this thing again, gotta finish some things first.

Anyway, I forgot to say that the arm doesn't work, and the start and stop buttons at the front don't work too.
Sometimes, if I touch them, it starts working and suddenly the arm stops in the middle of the lifting.
The turntable gets completely blocked, I have to take the platter out and the inside cover to get access to the arm motor and rotate it by hand to it's initial position.
To prevent this, some years ago I took the arm motor belt off, this way no hangs up.
Maby this is a clue.

 

[Netlist]

Sometimes, if I touch them, it starts working and suddenly the arm stops in the middle of the lifting.

This would make me pick up the iron for a major resoldering session. Let us know what you measured at the mentioned transistors.
It could be the buttons but as they only are impulse switches this is unlikely.
Mail me. I'll see what the scanner can do and try to supply you with the section you need. You have a big mailbox?

/Hugo

 

[carlosfm]

Thanks, Hugo.
I think my mailbox will handle it.
Anyway, compress the files if you can.

I don't know if the service manual has many pages, the ideal would be to have it all.
Anyway, I think that the problem may be on the right-side board, where (almost) all the connections from the arm go.
S' much electronics to lift an arm.

I'll send you a mail now.

 

[Netlist]

I just scanned to complete manual.
Turns out to be 62Mb.
Expect something like 70 to 75Mb in your box.

Anyone who might be interested, mail me.
I'd like to send this thing only once.
Hotmail accounts will not work.

Greetings

/Hugo

 

[carlosfm]

Waaaaait!
62Mb?
I take it back, my mailbox will not handle it.
Do you have PDF Writer?
Or convert the files to Jpg?