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Sony 2251 and/or 2250 owners thread

Hello!
I took measurements. I provide a report.
In normal operation (starting the motor), measurements are not possible, since the motor rotates at high speeds; the voltage on its winding is 60 V !!! (took measurements in the first 3-4 seconds). Of course, such a mode of operation of the motor is contraindicated !!!
Conditions for carrying out work and measurements: cut off the power supply to the motor, open the wire from the transformer winding.
To take oscillograms, the motor was rotated by hand.
12V and 9V power supplies are normal.
The measured operating modes of the elements (control points) are in accordance with the manual given in the table. A huge question about the modes of the transistor Q3.
The signal from the FG of the desired shape is stable.
Oscillograms (all except pin11 CX-032) fully correspond to the manual in shape, amplitude, frequency; stable. On pin11 of CX-032, the required waveform appears for a very short time (0.5 seconds) at the moment the motor starts rotating and just before stopping. During the rotation of the motor - signal - "straight line".

TEST.jpg
 

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60V - yes, with disc installed.
All other measurements - the disc is removed; rotation (to receive the FG signal) by hand.
 
I'm glad I found this thread.
I have a quick question... I recapped the PCB a couple of years ago.
I just rewired the original tonearm, and decided to take a look at the PCB.. then I noticed I missed the two big caps.
4uf 250v and 16uf 50v.
From my understanding the 4uf 250v might be paper in oil (I might be wrong), I was planning on leaving that cap.
The issue is with the 16uf 50v... I don't get if it's bi-polar or not. There are no polarity symbols on the cap, nor any BP info. The manual online doesn't specify any information in regards to polarity.

If anyone can clear up this for me, I greatly appreciate it.
Elna cap.jpg
 
Electrolytic cap = polar. Prolly need to pull it, to find the (+) and (-) posts.

index.php
 
Mr Boochie said:
Electrolytic cap = polar. Prolly need to pull it, to find the (+) and (-) posts.
Click to expand...

Thanks,
Just removed the cap from the clamp... no symbol.
What's throwing me off is the "AC" part. Since back then things weren't completely standardised. Company could name things what ever they wanted.
 
Cesari0 said:
Thanks,
Just removed the cap from the clamp... no symbol.
What's throwing me off is the "AC" part. Since back then things weren't completely standardised. Company could name things what ever they wanted.
Click to expand...


Can you take a photo of the tabs, where the wires were soldered? Must have polarity sign somewhere? :idea:
 
My bet is the black line is negative. With unit off and unplugged, try testing the black lead site to ground and see if you get continuity with a DVM (on ohms setting).
 
Last edited:
Mr Boochie said:
My bet is the black line is negative. With unit off and unplugged, try testing the black lead site to ground and see if you get continuity with a DVM (on ohms setting).
Click to expand...

Humm... on both leads I get one "beep" and a reading... both readings are pretty close.

Is it starting to look like a BP cap?
 
Yeah, I suppose so. Like two electrolytic polar caps tied in series (-) to (-). ELNA should have stamper "BP" on the cap. Not AC or Electrolytic in big letters. :idea:
 
Mr Boochie said:
Yeah, I suppose so. Like two electrolytic polar caps tied in series (-) to (-). ELNA should have stamper "BP" on the cap. Not AC or Electrolytic in big letters. :idea:
Click to expand...

Just went to eevblog... and this is what I got from there:

"AC capacitor does not have polarity, but the constructions are generally based on films without any kind of electrolyte. The capacitor has a big volume/capacitance and is expensive also.
Dc Capacitors are based on an electrolyte, that makes a very low capacitance/volume but works only on DC voltage because the electrolyte can't isolate on both direction"

So I guess that settles it.
Also settles the fact I don't have to replace it since it has a construction based on film capacitors.
 
Yes, use a non-polar film cap of similar mfd and voltage rating. Those back-to-back electrolytic NP caps have the same issue as regular electrolytic caps. They all dry out over time. :(
 
Hi! Reviving this old thread. Does anyone know of a replacement dust cover with correct hinges? Is there another Sony model that uses the same one, opening up my chances of locating a dust cover?

Thank you.
 
I lift mine on and off, it's a generic cover.The hinges are hard to come by,I had a pair once and sold them to a member that says he'd been looking for a long time for a set to come up for sale.Patience and a WTB post should help.Love my 2251.
 
koksrevda said:
Hello!
I took measurements. I provide a report.
In normal operation (starting the motor), measurements are not possible, since the motor rotates at high speeds; the voltage on its winding is 60 V !!! (took measurements in the first 3-4 seconds). Of course, such a mode of operation of the motor is contraindicated !!!
Conditions for carrying out work and measurements: cut off the power supply to the motor, open the wire from the transformer winding.
To take oscillograms, the motor was rotated by hand.
12V and 9V power supplies are normal.
The measured operating modes of the elements (control points) are in accordance with the manual given in the table. A huge question about the modes of the transistor Q3.
The signal from the FG of the desired shape is stable.
Oscillograms (all except pin11 CX-032) fully correspond to the manual in shape, amplitude, frequency; stable. On pin11 of CX-032, the required waveform appears for a very short time (0.5 seconds) at the moment the motor starts rotating and just before stopping. During the rotation of the motor - signal - "straight line".

View attachment 2138441
Click to expand...

Hi, did you ever fix the issue? I have the same same issue on my 2250 and expect the cx032b is bad and can't find a replacement or even a datasheet for the ic.
 
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