Help with a sony D-T66

Kostgeor

Hello mr Kaosun, I need your help with a sony D-T66. The radio is working fine but the CD does not do anything at all, just shows "00" and nothing else. I replaced all the capacitors but the problem still remains. there is no laser emitted and no motor or coil action at all. I suppose this is a power related issue. I read in other forums about a DC-DC converter  that generates +5v and -5v but I don't find the location to test it. I have the service manual but i need a little more guidance. I guess I don't have the +5v output. Any help will be greatly appreciated! Thanks in advance, please respond!

kaosun

+-5V is designed for very ols players like D5, D10, not for later D66/DT66. Your issue should be checking LD power supply circuit according to your SM. You'll also check your PCB, whether thoroughly cleaned the PCB when replacing the caps? You can find a post here regarding the repair of a D515 no laser.

Kostgeor

Thanks a lot for your help! with LD you mean laser diode? Also can this be a transistor problem like the D515 case? Also, this 515 had the exact problem(no motor action and no laser) or just no laser and everything else working perfect? thanks a lot!

Kostgeor

An other question: what ground should i use to test the voltages? battery ground should be ok? thanks for your time!

kaosun

Sure, negative terminal of battery is connected with ground.

Kostgeor

Can this be an IC problem? Have you ever experienced a dead IC501( CXA1271Q) or IC504 (NJM2107F)?

kaosun

Never seen any IC broken, seldom examples including DAC, RF amp. It seems like your CPU doesn't work? Does the LCD display? If no, check clock, power supply and reset signal. If yes, check motor driver MPC1716 sync signal.  

Kostgeor

Hello mr Kaosun, and thanks for trying to help me! The CPU is working fine, the lcd displays and changes tracks. The radio is also working fine so I assume that the CPU is ok. I will check the sync signal of the MPC1715. The service manual says that this pin(sync) should have 1.8v so I will check it. Is this the correct way to check it? It needs an oscilloscope in order to test it? Thanks a lot!

Kostgeor

Hello again mr Kaosun. I followed the sync line and I saw that goes to pin 75(C4LR) of IC601. According the service manual, this pin has a waveform so I grabbed my oscilloscope and tested this signal. The oscilloscope couldn't detect any signal. I opened my second T66 which has not the same problem , tested the signal, and the oscilloscope successfully detected the signal. What can I check next? Why the signal wasn't coming out of the IC601? Thanks for your time!

kaosun

You can replace the MPC1716 for test.