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Birthday Present! Denon DP-1200

good luck gentlemen. i look forward to seeing pics of this table playing happily away. too nice of a table, in good cosmetic shape to junk.
 
Hey guys. I'm in the midst of a bunch of other projects right now and will be out of town until Saturday. I plan to pick this back up then. So if you think of any other things to try before then, go ahead and post here and I will try them when I get back.

Again, THANK YOU for spending time on this with me. I'd love to get this thing up and running! :thmbsp:
 
Hey gents,

I'm back after a very full weekend. Seems the misses had other things planned for me.

After I pull the yellow wire and test the Zener (d4) in diode mode, I get 605/718. Prior to being installed on the board I got 910 and open (1) on this same diode.
 
fizzgig said:
What is the best way to test this? Look for continuity between which connections?
Click to expand...

Yeah just continuity from one though-hole to the next on the same trace, and IIRC check for any suspiciously high resistance along the traces (someone with fresher experience with electronics than me can jump in and say for sure, I'm kinda rusty).
 
I'll be back with some suggestions later, I'm having to take a break to rethink this and get some other stuff squared away for another guy and myself.
 
updates

ok gents, I reached out to a local tech that I've used successfully in the past and he helped me over email to do some more troubleshooting. 84 emails later and we are still not working, but he believes it is a problem with the Servo IC. Below is a full rundown of the steps taken.

1) Checked DC across R19 with W14 (orange) disconnected. Results were 42.5 which signaled a possible short on the tonearm pcb. Reconnected W14 and tested R19 VDC on 200. Result, nothing.

2) Pulled and tested D6 on the arm pcb and got beep both ways, shorted. Replaced D6. Tested DC across R19 again. Result 34.4.

3) Connected yellow wire (was still disconnected) and tested R19 again. Result 33.6. Connected motor for a test, no joy.

4) Tested solenoid by measuring the resistance across D6. Result: 230.

5) measured R20/R24. Result: 592ohm.

6) Measured voltage on D4. Result: 6.2.

7) Measured voltage across R18. Result: 000.

8) Replaced Tr3 and Tr4. Still no go on the motor. R20/R24 still get hot to the touch. Tr3 and Tr4 had corroded leads before replacement.

Last impressions from my tech friend:

I think we've reached the limits of my know-how on this. The only other thing might be the servo IC. You might post an update on Audiokarma and see if anyone there has any more ideas now that you've replaced that shorted diode. You've got 6.2v going to the servo IC now. I'm sure someone there has experience troubleshooting this IC.
 
Just to recap and correct me if I'm wrong: the motor works, but the switching circuitry does not, correct? At this point I'm just a bit confused as to how far along the chain you're getting power to at this point?
 
I get a full 120v at the motor connection, but no spin. Motor was tested at diode bridge (d3) and got full speed out of the spindle.
 
fiddlefye said:
Just to recap and correct me if I'm wrong: the motor works, but the switching circuitry does not, correct? At this point I'm just a bit confused as to how far along the chain you're getting power to at this point?
Click to expand...

The spindle motor can run if the control throttle diode network is bypassed, so it is good. The problem is in the control ckt somewhere and I think we've covered the obvious stuff, so it's something we've likely overlooked.
 
Pio1980 said:
The spindle motor can run if the control throttle diode network is bypassed, so it is good. The problem is in the control ckt somewhere and I think we've covered the obvious stuff, so it's something we've likely overlooked.
Click to expand...
A bit like following a murder mystery. One keeps thinking one knows Who Dunnit only to have that character get killed of.... :D
 
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