Philips AF877 Reject issues

[goldswimmerb]

Hey guys, so I'm trying to fix up a Philips 877 turntable but am kind of stuck.

I already replaced the LED for the stupid auto return mechanism, though that worked just fine to begin with.

The issue I am having is that the Reject function doesn't work properly and the SM does not detail how that works.

When the turntable gets to the end of the record it works as expected, bringing the tonearm to rest and stopping the table.

The problem is, if the reject button is pressed (before the record reaches its end) the table brings the arm back to where it is supposed to, but the table never stops spinning and the player just repeatedly lowers and raises raises the arm.

Does anyone have and ideas? I've never seen one of these where the reject doesn't work but auto return works perfectly.

 

[Craterranch]

Hi there. Wondering if a solution was ever found for this problem. I'm currently working on a Philips 887 (same as 877 but without pitch adjust) and it has the same problem. I also replaced the LED, and I cleaned and adjusted the small pots on the circuit board hoping that would help. Well, there is some improvement because now the autostop works correctly, but still no joy when rejecting manually (before the record ends). Cheers.

 

[Craterranch]

I worked at it another day and was able to get both the auto-stop and reject to work correctly. Mostly it was a matter of cleaning and adjusting the two small pots on the circuit board that control the voltage of the LDR and 11v settings. I did replace the LED on the LDR, but I'm not sure it was necessary in my case.

 

[wazymk]

I worked at it another day and was able to get both the auto-stop and reject to work correctly. Mostly it was a matter of cleaning and adjusting the two small pots on the circuit board that control the voltage of the LDR and 11v settings. I did replace the LED on the LDR, but I'm not sure it was necessary in my case.

im having a similar issue with my 887 - the reject switch works but the turntable and i have no idea why but on some LP'S the auto return works and on some it doesn't - the tone arm just sits at the end of the LP and wont auto return - ill look into these small pots and see if i can clean them and see what happens - thanks for the post !

Wazy

 

[Nashou66]

I think the return at end of play works by the speed the arm moving at the end dead wax.
Some Lp's the run out grove is shorter therefor moving the arm faster triggering the
return circuitry.

But......I may be mixing this up with another player.


Nashou

 

[pjrengineer]

My auto return works after replacing the led but the rej button does nothing. All other buttons function. Anyone else have an idea?

 

[DantroniX]

My auto return works after replacing the led but the rej button does nothing. All other buttons function. Anyone else have an idea?

Hi, replacing the LED on my 877 didn't help, I found that if you switch the LED off briefly while the tonearm is moving to the rest position, the turntable switches off reliably for the end position and for the reject button operation. No adjustment to potentiometers necessary, just mount a microswitch next to the yellow part and switch contact normally closed in series with e.g. red wire from the LED, that's all

Übersetzt mit DeepL https://www.deepl.com/app/?utm_source=android&utm_medium=app&utm_campaign=share-translation

 

[DantroniX]

 

[pjrengineer]

Mine ended up being when my hands were really dry the touch buttons didn’t work. Odd. Now it works normal. Interesting fix.

 

[Jens Sinding]

I had the same issue with the turntable not stopping and the arm keeping going up and down after returning, when using the reject button.
It turned out to be caused by the trip pawl that sits on top of the main gear not being held in place (out of the way of the shaft cog) by the small electromagnet, and thus causing the return cycle to be reactivated again and again.
After manually moving the pawl about, pushing the electromagnet as far forward as possible in its holder, and cleaning with compressed air the mechanism works and the issue is solved.

In the center towards the top you can see the little electromagnet keeping the trip pawl in place. If the mechanism is dirty the magnet may not be enough and you get the incessant cycle issue.
Now I need to sort out the LDR.

 

[Jens Sinding]

Sorting out the LDR proved easy enough. Remove the bottom plate and prop the turntable on a suitable support. Ensure that no stray light reaches the LDR, either by working in a very low light situation or shading the area with black plastic or fabric. I did the former with lights out, shades down on an overcast day. With the turntable running and arm in the support, measure the DC voltage between the white and the orange wire from the LDR. It should be 3 +/- 0.2 v, but in my case it was 9 volt. Now adjust the VR 472 so that you measure the correct voltage.
If this resolves the issue all is well.
In the picture you see a group of three solder points on the angled piece of the board closest to the LDR VR. The left (under the reversed T) and right ones are the measuring points



Here you see the hole for adjusting the LDR VR, you also see one of the measuring points, the second solder blob from the top left.

It turned out that I also had to adjust the position of the switch off bracket to achieve 4 volts with the stylus 60 mm from the spindle center, it was only 3.3, but now it works perfectly

 

[Jens Sinding]

I just measured wow. The speed locks at 33.24 rpm and wow is 0.03% weighted. Very respectable.
The speed could probably be adjusted but I’m not sure how.