ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Please also see following topic: https://archivedforum2.beoworld.org/forums/p/44287/322363.aspx
while trying to fix an arm that would not go down every time I misplaced two new Transistors (TR9, TR10)
I blew the power supply fuses after doing that. I have fixed the position of the transistors with new ones and replaced the fuses. Now the arm goes down immediately when plugging the power cord in the socket.
Any ideas what might be broken in this circuit.
1IC4 shorted?
Martin
I don't really know. I have replaced the 1IC4 with another one. A BD898H was installed and I replaced it with a TIP125. Both give same result
I have checked the soldering and I thought there might be a short between Base and Emitter, so I have soldered it again make sure these were no shorted on the PCB.
When I now measure with an Ohm meter I measure 500 K between B and E, 15k between B and C, 7k between E and C. (This is with P4 not plugged in, if I plug that in the values are different)
If I measure the TIP125 with an Ohm meter the 15k is the same but between B&E there is 4m and between E and C can't measure. I do not understand enough of the schematics to judge wether this is okay or not.
Thanks, Eric
This is solved now: I need better reading glasses because `i mounted a wrong TR9 (BC307 instead of 207).
And now I have another problem, the arm does not move to the platter when pushing start. It reacts like it hits the end-stop immediately after starting to move. It moves 2mm and moves back and stops.
Any suggestion where to look?
I have solved this, another transistor was blown