Re: Thorens TTA-2000 DC offset
Ok, I disconnect this 33pF caps and measured some impedance 18k-1M.
New detections:
- if I measuring impedance in one channel (R or L), then no voltage on that channel RCA, only 0,1V, what is raising slowly. On second channel (no measuring) 15-18V every time. After turning off and on again, voltage are present on both channels.
- if amplifier is turned off, without power cable - I measured negative voltage on RCA (-15V and slowly descendig). That voltage are present on the top of the input caps, on others...
zoldi211
Member
Last Activity: 02-10-2022, 01:19 AM
Joined: 02-11-2016
Location: Kosice
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Re: Thorens TTA-2000 DC offset
There is not, I know. I dont have full circuit diagram or service manual....Leave a comment:
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Re: Thorens TTA-2000 DC offset
The polarity is ok too. I did not find any problem.Leave a comment:
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Re: Thorens TTA-2000 DC offset
All caps are ok, I replaced them all....Leave a comment:
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Re: Thorens TTA-2000 DC offset
The grounds looks fine.......Leave a comment:
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Re: Thorens TTA-2000 DC offset
The impedance beginning on 20k and raising up to 1M within seconds. There is a 33pF capacitor across RCA terminal.Leave a comment:
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Re: Thorens TTA-2000 DC offset
The voltage is set to 50V. If I increase the voltage, the DC voltage on the RCAs is also grows. How can I measure the impedance? All of the caps are replaced.Leave a comment:
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Re: Thorens TTA-2000 DC offset
Thanks for your answer. My Yamaha RX-V1800 have preout output and protection turned it off with DC overload, if Thorens are connected.Leave a comment:
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Re: Thorens TTA-2000 DC offset
Hi, I replaced Q1 Darlington transistor TP147, but DC raising with 2-3V on RCA terminals. Zener diode? Resistors are ok. Please help !!!...Leave a comment:
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Re: Thorens TTA-2000 DC offset
I have an another problem. On RCA terminals I measured high DC voltage - 15-18 V on both R/L RCA inputs !!! What is this? This is normal on this type of power amplifier?Leave a comment:
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Re: Thorens TTA-2000 DC offset
The test is done. With old speakers and 1A fuse, because I dont have suitable resistor. After turning on, the current disappeared. I measured only 0,04 or 0 mA.
A have a version with protection board with relay (1. photo in post #19).Leave a comment:
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Re: Yamaha RX-V467 power problem
Problem is solved. Faulty CPU on Digital PCB. After replacing Digital PCB, receiver working even today without any problems. Thanks for help.Leave a comment:
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Re: Thorens TTA-2000 DC offset
OK, thanks. What type of resistor is suitable for this test (value in ohms, wattage)?Leave a comment:
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Re: Thorens TTA-2000 DC offset
so do you think, i can use it normally with speakers?Leave a comment:
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Re: Thorens TTA-2000 DC offset
I haven't tried load on it, because I don't want to destroy the speakers...Leave a comment:
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Re: Thorens TTA-2000 DC offset
Yes, both channels are same. DC adjustment maybe not...Leave a comment:
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Re: Thorens TTA-2000 DC offset
Hi, schematic on german forum is incorrect. I found one in korean forum and this have only one error, R11 are before R12,R13. Some values are also incorrect, but there are only minimal differences. I measured input voltage: 71V, voltage after trimmer 53V. Voltage between R1 pins: 0,380mV. Heatsin after 30 min 60°C, but this is normal with this amplifier!...Leave a comment:
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Thorens TTA-2000 DC offset
Hi, I bought Thorens TTA-2000, but I am affraid connect speakers because DC offset between the +/- terminal are 2,5V!!! This is normal value on this "A" class amplifier or is this faulty? -
Re: Yamaha RX-V467 power problem
The measured voltages are filled to the attached pdf file, on page 111....Leave a comment:
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Re: Yamaha RX-V467 power problem
Sorry, the correct value on CB381 is 0,2V (not 2,54V)...
The R3702 and R3703 resistors are OK. The problem may be in the IC375 ???
After shorting AC-PWR to DGND on CB381, nothing changed - ACPWR-DET still 2,54V and PWSW - 0V.Leave a comment:
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