The auto stop is out of adjustment on this. Does not work at the end of the record... I have the downloaded repair manual, but it's hard to see the adjustments for this from the pics and description...If I cue it up and move the tonearm over to say 2nd or 3rd track the table stops. If the arm is down it stays running....Id like to fix this or disconnect the auto stop and install a Q-UP auto arm lift.. Can anyone help in repair or disconnect the auto stop..?
Thorens TD320 Auto Stop Repair
- Thread starter gfreek
- Start date
Jadran
Off The Record
It is possible to fix the issue this way...
From the other forum;
However, that will work if no mechanical or other damage exists at the tonearm base!
From the other forum;
It's very easy to do it, since the chips have holders soldered on the board so pulling out the old one and placing the new one is a joke. New chip costs ...well.
However, that will work if no mechanical or other damage exists at the tonearm base!
Hi all, this is my first post here. I'm retired for some months so I got time to restart that TT TD320 I was offered for my 25th birthday.
I met the issue in the title of this thread.
I fixed it yesterday. The P3 variable resistor was set fully CW. As voltages were very roughly not bad *(see comment below about this) I didn't change any component on the board.
To dismantle the TT, I could not find any accurate guide on the net. Now I did it I can give some advises :
1srt of all, to get the TT horizontal upside up with the bottom metal bezel removed, you'll need 3 wood or plastic rods 4 to 5cm (2in) diameter (for stability) and 10cm (4in) length.
2nd, secure the arm onto its rest, remove the plexiglass cover and the aluminum 30cm platter.
3rd, lay the TT on its left side (front near you if you are right handed or rear near you if you are left handed, because you'll need your unskilled hand to keep the TT on its risky left side), remove the screw in the center of the bottom cover with a screwdriver in your skilled hand, then the 2 screws that attach the cover to the left side (which is now the bottom side
) and in the end, securing both the TT body and the cover with your unskilled hand to prevent it to fall, unscrew the last screw that is now upside in the solid corner.
4th: at this time you'd ideally need 3 hands, but I reached with only 2 and you will if you decided to access the PCB yourself: wires that are attached to the bottom cover to the TT body are too short to allow laying the cover flat on your working table, so slightly take the cover apart from the body so that with your skilled hand you will loosen the audio cable, supply jack and the ground lug from the cover. Throw the cover as far as possible so that it won't encumber you for next step.
5th: still securing the TT with your unskilled hand, roughly preposition the 3 rods, 1 for rear center near the suspension, 1 for left on left side of the PCB, 1 for right slightly behind the arm lift control knob. Approach the TT to the rods, making sure you won't drop the TT on delicate parts (PCB, lift knob mechanisme, rear suspension). With free fingers of each hand move the rods so that you can set the TT body onto them. The left one is quite acrobatic (no room enough for full sit). You did the harder. Do not make any wrong move that would lead to a TT 10cm drop onto a fragile part.
6th: as I said my tonearm never went up when going in the inner groove. You don't need to detach the PCB as 3 holes through it allow access to the actuators. P3 (the one that is alone on its own, the 2 others beside each other are 33+1/3 - 45tr/mn settings) being fully CW I only had to go forth and back in trial and error process to find the good setting. Sit down back the platter and mate and put a disk on it. Do not move the tonearm headshell too quickly near the inner groove as this would trigger the lift. To achieve more easily this repetitive process I found useful to lock down the the lift (so that I ear the mechanism to make sound on auto-stop) then lift the arm up with the knob to push it near the inner groove. When nearly set fine, precise setting could only be done with the needle in the groove very slowly pulling the arm towards to disk center.
Comments about this PCB. My TT is a TB320 (mk I aka no mk) bought brand new in fall 1987, supplied with the TP-16-mk-IV tonearm.
All IC's are on socket.
I found Z103 lift control supply, optic driver/detector and driver Op Amp was a LM324 as per the service manual page 10.
Z102 MC34001 differentiator was a TL071C (I or M with ceramic case would do the job the same way).
Z101 LF347 motor bridge driver was a TL084C (same remark as above).
Voltages "non bad" did I say. I just forgot to check TP7 for 1/2 TP1 as stated in table page 9. Only TP6 4.7V supply line was really good.
I never reached to get the 0.3V stated on Tome arm installation page 7.
I found the voltage at TP5 far too progressive when the arm running close to the inner groove when I hoped to get a forthright edge.
My TT being from the late 1987 when mains here in France was still 220Vac, the wall supply adapter was supplied accordingly. Now we switched to 230Vac (legal since 1986), all voltages in the service guide do not match anymore, particularly the ones stated for motor not running because there is no voltage regulation. We should find 230/220~5% higher voltages (don't forget the ±10% legal tolerance for mains delivery). This seems to have none or negligible impact on 33/45tr/mn motor rotational speed. Inserting 1N4001-4007 series diodes between + GR101 bridge and + C101 will drop TP1 voltage by 0.6-1V each.
I don't know which component wear due to age introduced this drift in lift trigger setting, maybe capacitors (BTW, each two 10µF caps were rated 50V), or the D201 LD271(A?) IR LED, or the D202 BPW34 photodiode, or T110 gain (never read anything about gain loss over years for our plastic sealed discrete transistors). Maybe only the difference in mains.
Please, anyone still having the genuine TP-16-mk-IV alignment cardboard template I lost would give a link to download a scanned copy with measurements ?
Thank you
I met the issue in the title of this thread.
I fixed it yesterday. The P3 variable resistor was set fully CW. As voltages were very roughly not bad *(see comment below about this) I didn't change any component on the board.
To dismantle the TT, I could not find any accurate guide on the net. Now I did it I can give some advises :
1srt of all, to get the TT horizontal upside up with the bottom metal bezel removed, you'll need 3 wood or plastic rods 4 to 5cm (2in) diameter (for stability) and 10cm (4in) length.
2nd, secure the arm onto its rest, remove the plexiglass cover and the aluminum 30cm platter.
3rd, lay the TT on its left side (front near you if you are right handed or rear near you if you are left handed, because you'll need your unskilled hand to keep the TT on its risky left side), remove the screw in the center of the bottom cover with a screwdriver in your skilled hand, then the 2 screws that attach the cover to the left side (which is now the bottom side
) and in the end, securing both the TT body and the cover with your unskilled hand to prevent it to fall, unscrew the last screw that is now upside in the solid corner.4th: at this time you'd ideally need 3 hands, but I reached with only 2 and you will if you decided to access the PCB yourself: wires that are attached to the bottom cover to the TT body are too short to allow laying the cover flat on your working table, so slightly take the cover apart from the body so that with your skilled hand you will loosen the audio cable, supply jack and the ground lug from the cover. Throw the cover as far as possible so that it won't encumber you for next step.
5th: still securing the TT with your unskilled hand, roughly preposition the 3 rods, 1 for rear center near the suspension, 1 for left on left side of the PCB, 1 for right slightly behind the arm lift control knob. Approach the TT to the rods, making sure you won't drop the TT on delicate parts (PCB, lift knob mechanisme, rear suspension). With free fingers of each hand move the rods so that you can set the TT body onto them. The left one is quite acrobatic (no room enough for full sit). You did the harder. Do not make any wrong move that would lead to a TT 10cm drop onto a fragile part.
6th: as I said my tonearm never went up when going in the inner groove. You don't need to detach the PCB as 3 holes through it allow access to the actuators. P3 (the one that is alone on its own, the 2 others beside each other are 33+1/3 - 45tr/mn settings) being fully CW I only had to go forth and back in trial and error process to find the good setting. Sit down back the platter and mate and put a disk on it. Do not move the tonearm headshell too quickly near the inner groove as this would trigger the lift. To achieve more easily this repetitive process I found useful to lock down the the lift (so that I ear the mechanism to make sound on auto-stop) then lift the arm up with the knob to push it near the inner groove. When nearly set fine, precise setting could only be done with the needle in the groove very slowly pulling the arm towards to disk center.
Comments about this PCB. My TT is a TB320 (mk I aka no mk) bought brand new in fall 1987, supplied with the TP-16-mk-IV tonearm.
All IC's are on socket.
I found Z103 lift control supply, optic driver/detector and driver Op Amp was a LM324 as per the service manual page 10.
Z102 MC34001 differentiator was a TL071C (I or M with ceramic case would do the job the same way).
Z101 LF347 motor bridge driver was a TL084C (same remark as above).
Voltages "non bad" did I say. I just forgot to check TP7 for 1/2 TP1 as stated in table page 9. Only TP6 4.7V supply line was really good.
I never reached to get the 0.3V stated on Tome arm installation page 7.
I found the voltage at TP5 far too progressive when the arm running close to the inner groove when I hoped to get a forthright edge.
My TT being from the late 1987 when mains here in France was still 220Vac, the wall supply adapter was supplied accordingly. Now we switched to 230Vac (legal since 1986), all voltages in the service guide do not match anymore, particularly the ones stated for motor not running because there is no voltage regulation. We should find 230/220~5% higher voltages (don't forget the ±10% legal tolerance for mains delivery). This seems to have none or negligible impact on 33/45tr/mn motor rotational speed. Inserting 1N4001-4007 series diodes between + GR101 bridge and + C101 will drop TP1 voltage by 0.6-1V each.
I don't know which component wear due to age introduced this drift in lift trigger setting, maybe capacitors (BTW, each two 10µF caps were rated 50V), or the D201 LD271(A?) IR LED, or the D202 BPW34 photodiode, or T110 gain (never read anything about gain loss over years for our plastic sealed discrete transistors). Maybe only the difference in mains.
Please, anyone still having the genuine TP-16-mk-IV alignment cardboard template I lost would give a link to download a scanned copy with measurements ?
Thank you
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