I have already had some help from members in the past for which I am grateful, however I am still stuck 🙁.
After resoldering the power supply and NEON power supply, and measuring the voltages, Q701 (2SC1431) doesn't have the right values (resp. B=36v, E=53v, C=240v). According tot the service manual it should be 155v, 157v, 220v. I suppose that's the reason Q413 doesn't measure right either.
Does anyone have an idea what might be wrong? 😱
After resoldering the power supply and NEON power supply, and measuring the voltages, Q701 (2SC1431) doesn't have the right values (resp. B=36v, E=53v, C=240v). According tot the service manual it should be 155v, 157v, 220v. I suppose that's the reason Q413 doesn't measure right either.
Does anyone have an idea what might be wrong? 😱
Just discovered that the R706 resistor (33kOhm) is open (can see black mark on body). All the other resistors to this point in the power supply measure fine. Should I just replace this one or all the others as well as a safety precaution?
You're right, but kind of difficult for me to trace down. The situation is that a couple of years ago a repair service center in the Netherlands repaired my TT after some transistors started to smoke and it stopped working. It took them more than a year to repair the damage (2 transistors were burnt and the PCB traces around it were damaged). I assumed that they would do a full recap as the bill was a 1000 EU, but this wasn't the case. At one stage the strobe light stopped working (and the platter turns backwards a bit when I pressed stop). I decided this time to do a full recap to avoid future problems. I had hoped this would solve the strobe problem, but alas. Anyway, after help on this forum I decided to further investigate and came upon this burnt resistor. The other resistors in the power supplies all measure fine. I hope by replacing it, this will solve the low voltage on the transistors that follow.
Long story... 🙂 Of course there is a risk that one of the other components caused the resistor to fail.
Long story... 🙂 Of course there is a risk that one of the other components caused the resistor to fail.
In the one of the previous posts I uploaded a part of the diagram. You can download the service manual here Free Service Manuals
That way you can zoom in. Page 12 and 13 show the a PCB layout and diagram.
Thanks for helping out 😃
That way you can zoom in. Page 12 and 13 show the a PCB layout and diagram.
Thanks for helping out 😃
It's indeed just a snippet as it's a rather large diagram. Also, it was posted before I found the burnt resistor 🙂
I think after replacement of R706 you can switch on again.
Do not use a tiny type, because more than 50 V can be dropped here.
If possible do a quick check of Q701 and Q702 also.
I have heard that the PS-X9 neon lamps fail frequently.
Do not use a tiny type, because more than 50 V can be dropped here.
If possible do a quick check of Q701 and Q702 also.
I have heard that the PS-X9 neon lamps fail frequently.
I have only 'diode tested' the transistors as my component tester is broken. I surely hope the neon lamp is still okay as they are impossible to find.
