Hi,
I have recently acquired a Technics SP10 Mk2 direct drive turntable from 1981.
It came from a radio station so I presume it has spent most of it's life in an air-conditioned studio.
It has a quartz lock system with a number of circuits including a quartz oscillator, frequency generator and phase control ciruits.These are based on (74xx) ICs and it has (x16) (74xx) IC's and (x95) transistors on 3 boards.
Recently I was attempting to connect some oscilloscope probes to check the control circuit as per the manual and slipped and shorted on the probe test points.
I got a fat spark where there shouldn't be one and the smell of transistors/ICs frying.
I have tested the transistors and found 12 bad so ordered replacements. After I replace the transistors I'll see if it works but don't hold much hope.
At this point I'm assuming a possible full IC replacement and have ordered a set.
The original Mitsubushi (73xx) IC's are rare and expensive but there are reports of successful IC replacement with modern (74HCTxx) CMOS ICs.
So while I have it apart and am doing this I would like to recap the boards. The original capacitors from 1981 are Panasonic EC in a purple/lilac colour.
My query is -
Are there any particular parameters that I should pay attention to in choosing capacitors to go on the boards in circuit with the (74HCTxx) IC's (i.e. high ripple current, Low-ESR, Low impedance, Not Low-ESR etc.)?
I would start with 105C rated but am not sure if there are any further requirements.
It seems that a lot of guys use Panasonic FC in recapping these units. I would guess because they are Panasonic like the unit manufacturer and also because Panasonic FCs are popular in the diy audio/hifi community. I am not particularly attached to any brand.
I have attached photos of the boards, the manual and a caps list (based on FC) compiled by someone else to indicate the values and quantities that are required for this job.
I may be overthinking this but I would appreciate any comments or suggestions that anyone may have on capacitor choice.
I have recently acquired a Technics SP10 Mk2 direct drive turntable from 1981.
It came from a radio station so I presume it has spent most of it's life in an air-conditioned studio.
It has a quartz lock system with a number of circuits including a quartz oscillator, frequency generator and phase control ciruits.These are based on (74xx) ICs and it has (x16) (74xx) IC's and (x95) transistors on 3 boards.
Recently I was attempting to connect some oscilloscope probes to check the control circuit as per the manual and slipped and shorted on the probe test points.
I got a fat spark where there shouldn't be one and the smell of transistors/ICs frying.
I have tested the transistors and found 12 bad so ordered replacements. After I replace the transistors I'll see if it works but don't hold much hope.
At this point I'm assuming a possible full IC replacement and have ordered a set.
The original Mitsubushi (73xx) IC's are rare and expensive but there are reports of successful IC replacement with modern (74HCTxx) CMOS ICs.
So while I have it apart and am doing this I would like to recap the boards. The original capacitors from 1981 are Panasonic EC in a purple/lilac colour.
My query is -
Are there any particular parameters that I should pay attention to in choosing capacitors to go on the boards in circuit with the (74HCTxx) IC's (i.e. high ripple current, Low-ESR, Low impedance, Not Low-ESR etc.)?
I would start with 105C rated but am not sure if there are any further requirements.
It seems that a lot of guys use Panasonic FC in recapping these units. I would guess because they are Panasonic like the unit manufacturer and also because Panasonic FCs are popular in the diy audio/hifi community. I am not particularly attached to any brand.
I have attached photos of the boards, the manual and a caps list (based on FC) compiled by someone else to indicate the values and quantities that are required for this job.
I may be overthinking this but I would appreciate any comments or suggestions that anyone may have on capacitor choice.
Attached Files
