Sounds like something in the tracking circuit went wrong.
Either the lamp/sensor/interrupter (loose on the spindle ?) assy at the foot of
the carriage or some electronics on the main board related to the tracking.

The fingerwheel trimmers losing contact is a wellknown problem. Well done !

Martin

Hello Martin

Thanks once more🙂

I'll have another look and see what I can find.

Will advise asap.

Regards

andre/dauphine

Hello

This is what I found and will replace them tomorrow. Hope renewing these will cure the problem. The clamp holding the slotted plate around the arm base is tight and the area around there is clean.

Regards

andre/dauphine Login to view image 

What is it, you would like to replace on that board ?
I suggest you check the tracking circuit and related mech. as mentioned above.

Martin

Hi Martin

Both of the parts on the underside of the board shown above have signs of 'bubbling'. I take it then these have nothing to do with the arm dragging problem? I will have to re-study the manual and familiarise myself with the tracking circuit.

Regards

andre/dauphine

I wouldn't worry too much about anything on that board.
I suggest you check the tracking circuit and related mech. as mentioned earlier.
It drags towards the left because it is fed a wrong signal from the tracking sensor, either
the interrupter has become lose from the tonearm base spindle, something went wrong with
the sensor or lamp assembly or the electronics are somehow misbehaving.
The tracking electronics are on the main board.

Martin

Hi Martin

I really appreciate the advice and clues as to where to look. I got the same advice about the board I showed in the pic from a friend more qualified than I am.  He advised those little bubbles on the 2 caps are just wax - nothing to worry about.

The present symptoms are dragging of the arm to the left and the tonearm traversing much too fast.

I had to take a short break but will return to the problem this evening and tomorrow.

I already had a thorough look at the interrupter which is held with a clamp to the arm base spindle? and everything is tight and clean there.

The cover plates are still off so I think I will take a close look at the main board incase I see a broken track or anything else under a 60X stereoscope I have.

The sensor arm's lamp is OK and I've got Menahem's LED + resistor installed inside the black cover. That also worked after installation and there's another UV? LED-like device with bent wires somewhere around this area which I'm not sure how to test.

I understand one can photograph it in the dark with a digital camera to see if it is emitting light, which I will also check this evening.

What is so strange about this problem is that absolutely everything except the 45rpm speed worked fine for weeks after I installed the main board after getting it back from Menahem. 

I'll post here if I have news.

Regards & a fine weekend.

andre/dauphine 

Ambient light may confuse the sensor (at least the original sensor - I am not sure what is in there now).
Have you tried with all surface panels fitted ?

Martin

Hi Martin

Thanks, I know about ambient. The plates at one stage was completely fitted and the problem still showed up. Initial tests after fixing the 45rpm speed was done with the covers fitted. I was working in my workshop and with bright  fluorescent directly above. I also had a 100W worklamp above which I switched off as soon as I saw what was happening.

During the weeks I played without problems, the plates were first just loose on top, then fitted properly and the light above were from  5 40W incandescent lamps. At this time, the platter was still not properly level and flush with the plates.

So after the 3 weeks or so while I 'rested' before tackling the 45rpm speed problem, all worked OK, despite the platter dipping slightly at 12 o'clock.

The other change I made was to insert the coil of brass shimstock and changed to another lubricant in the spindle bearing.

Therefore, 3 parameters changed. The 45rpm speed got restored, the platter is now perfectly level and flush with the top plates and, the bearing hole has been shimmed.

There must undeniably be a little more spindle bearing friction because of the shim. With the belt and top platter off, I can still spin the platter with a finger flick although I had to make small + adjustments to the speed pots.

After receiving your earlier comment about the original spindle bearing tolerance where I could move the platter say at 3 o'clock and 9 o'clock and observed (perhaps wrongly) excessive bearing sideplay as compared to my other turntables (Micro, Micro Seiki and Garrard 301's) - I think I will also remove the shim incase this could be causing a problem.

Except for the 45rpm repair, I think I will restore all revised settings to as close as possible to what it was when everything worked.

And of course look and double-check all the other possibilities you mentioned.

I'll let you know what I find.

Regards

andre/dauphine