ADC Accutrac 4000 Stylus Setup Help

[mcaddie7]

Recently bought this turntable. It actually worked too with finding the spaces between each track. That was until I put the stylus on.

I took the turntable apart, cleaned all boards, buttons, and contacts, and replaced the capacitors on the motherboard. However now it doesn’t sense tracks properly. It’ll kinda go near the track I selected (pretty off though) and then go back to the rest, and just play at the beginning of the record.

Do I need to adjust the small screw on the head shell left, right, or center when the stylus is installed?



I also want to measure the voltages for the sensor. From what I gathered, I’d measure the voltages at T7, at the collector for shiny / full markings and adjust? Any info is greatly appreciated!

 

[Beobloke]

Do you have the correct stylus fitted? You can only use the RLMA-1 type on this.

 

[mcaddie7]

Yes, I ordered that model “new” old stock on eBay. When I take the stylus off it still is acting funky.

Any idea if the sensors on the catridge should be adjusted left, right, or center with the tiny screw on the head shell?

My other thought is maybe I funked things up by replacing the caps? I used the same values but hey.

 

[Beobloke]

I think what you've actually got there is an LMA-3 cartridge, which was original fitment on the Accutrac +6. The correct LMA-1 for the 4000 has a small lever that sticks out of the front which allows you to adjust the set-down position of the stylus by moving the sensor.

That said, it shouldn't matter so, yes, adjusting that screw on the front of the cartridge should adjust the set-down position left or right.

As to capacitor changes, my golden rule is - if it's working, then leave it alone! It would be worth triple-checking that you haven't made a little mistake when changing them - we've all done it!

 

[mcaddie7]

I think what you've actually got there is an LMA-3 cartridge, which was original fitment on the Accutrac +6. The correct LMA-1 for the 4000 has a small lever that sticks out of the front which allows you to adjust the set-down position of the stylus by moving the sensor.

That said, it shouldn't matter so, yes, adjusting that screw on the front of the cartridge should adjust the set-down position left or right.

As to capacitor changes, my golden rule is - if it's working, then leave it alone! It would be worth triple-checking that you haven't made a little mistake when changing them - we've all done it!

Just checked on ebay from the buyer and I do in fact have the RLMA-1 installed. It has a little fork on the front of the opto sensor. I can adjust that screw you mentioned and it either moves it to the right, left, or center above the stylus. Any tips? My guess is it should be directly center but I could be wrong. NOTHING in the service manual about this; ugh.

From a different post I'm going to try doing this following troubleshooting:

"
Testing:
- Both speeds are set dead-on after slight adjustment. All buttons and pots on the front work.
- I can see both sensors under the tonearm responding properly. Checked as per waveforms on LS-1 and LS2 test points under the tonearm.
- I can see the voltage waveform from head sensor changing (on jumper connected to TR4 transistor collector). It is around +6V DC on shiny parts and +2V DC on dull parts (tracks) - when I move the tonearm manually over the record.
- I do not have the reflective/dull gauge to set the voltage on TR4 collector with gauge installed to -19V DC. But I can see VR2 operating smoothly, and (without reflectivity gauge) installed, voltage at TP2 can be adjusted from +1VDC to +19VDC"

I'm guessing if I don't see the +6 / +2 V for the dull and shiny parts of the record then know something is off with the caps I chose, given that it was working beforehand.