Hello everyone,
I'm working on a Pink Triangle Anniversary PSU, I can't find schematics or any info on the design on this so its a bit difficult for me to fully understand its workings.
The PSU switches on but it drives the motor into runaway speed. The issue started after the 12V batteries have been replaced with new ones. This is for both 33 and 45 rpm.
My understanding of how the PSU should work is:
Mains supply power to the electronics inside the PSU, the motor is driven from the big 12V (6+6) batteries and the speed control is achieved by the AC tacho attached to the DC motor.
I did check the motor separetly and suppling different DC voltages results in variation in the AC feedback so I belive the motor itself is operating correctly.
I'm able to track the AC feedback signal through the initial quad op-amp, it gets amplified and then it goes through a pair(NPN, PNP) of medium power transistors BD135 and BD136 and then it gets complicated for me as there is a comparator circuit (LM393N) two logic chips (MM74HC00N, MM74HC02N ) and a precision timer/oscillator chip (ZN1034E). All the chips have 5V supply present at Vcc pins. The basis of the NPN transistor seems to be came the signal output of the logic chip MM74HC00N.
I have changed the ZN1034 and the MM74HC00N. The transistor right of MM74HC00N is a BC639 NPN.
The C of printed circuit board goes to the left relay.
I have replaced the precision timer chip however the issue remains, all the trimpots seems to be working fine. PSU is fully recapped.
Is there anyone who can send a schematic of the anniversary psu?
Thank you very much for your help
I'm working on a Pink Triangle Anniversary PSU, I can't find schematics or any info on the design on this so its a bit difficult for me to fully understand its workings.
The PSU switches on but it drives the motor into runaway speed. The issue started after the 12V batteries have been replaced with new ones. This is for both 33 and 45 rpm.
My understanding of how the PSU should work is:
Mains supply power to the electronics inside the PSU, the motor is driven from the big 12V (6+6) batteries and the speed control is achieved by the AC tacho attached to the DC motor.
I did check the motor separetly and suppling different DC voltages results in variation in the AC feedback so I belive the motor itself is operating correctly.
I'm able to track the AC feedback signal through the initial quad op-amp, it gets amplified and then it goes through a pair(NPN, PNP) of medium power transistors BD135 and BD136 and then it gets complicated for me as there is a comparator circuit (LM393N) two logic chips (MM74HC00N, MM74HC02N ) and a precision timer/oscillator chip (ZN1034E). All the chips have 5V supply present at Vcc pins. The basis of the NPN transistor seems to be came the signal output of the logic chip MM74HC00N.
I have changed the ZN1034 and the MM74HC00N. The transistor right of MM74HC00N is a BC639 NPN.
The C of printed circuit board goes to the left relay.
I have replaced the precision timer chip however the issue remains, all the trimpots seems to be working fine. PSU is fully recapped.
Is there anyone who can send a schematic of the anniversary psu?
Thank you very much for your help
please don't post duplicate threads in different areas of the forum.As a new signup all your posts need approval which means there can be a delay before they appear 🙂
It worked. Batteries were changed. It doesn't work.
I would go back to that battery change and see how that went wrong.
While unusual I received batteries from a UK company and inserting them into a piece of portable test gear they did not work .
It was when I checked the voltage and found it was over-voltage ,on phoning the company and speaking to a technician this was not the first time they had that problem and sent me ones with correct voltage which did work.
But PRR has a point something must have happened in the process of changing the batteries .
I still cant find a schematic for a PT Anniversary and I do remember some preferred a PT to a Linn Sondek it boiled down to sides being taken in "musicality " depending on which side of the fence you sat on.
Some complained of later PT,s circuit being "complicated " in relation to early versions and while some have ones that "go on forever " and sound good/great others say they breakdown too easily .
It was when I checked the voltage and found it was over-voltage ,on phoning the company and speaking to a technician this was not the first time they had that problem and sent me ones with correct voltage which did work.
But PRR has a point something must have happened in the process of changing the batteries .
I still cant find a schematic for a PT Anniversary and I do remember some preferred a PT to a Linn Sondek it boiled down to sides being taken in "musicality " depending on which side of the fence you sat on.
Some complained of later PT,s circuit being "complicated " in relation to early versions and while some have ones that "go on forever " and sound good/great others say they breakdown too easily .
Now, everything is ok 🙂
I reduced the voltage(17,8V) at the relays to 12V with two 392ohm parallel.
Last I changed the relays, one of the two relays was broken.
I reduced the voltage(17,8V) at the relays to 12V with two 392ohm parallel.
Last I changed the relays, one of the two relays was broken.
Mica 321
Hello there , for a similar problem to battery psu of my PTA, may I gently have your private email to discuss about the matter?
[REDACTED]
Thanks a lot
Massimo
Hello there , for a similar problem to battery psu of my PTA, may I gently have your private email to discuss about the matter?
[REDACTED]
Thanks a lot
Massimo
Last edited by a moderator:
Thanks for your kind reply. I ask, if possible without violating the privacy rules of the forum, how to get in touch privately with Mica 321 who some time ago solved my same problem with the PTA.
Thank you
Massimo
Thank you
Massimo