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Birthday Present! Denon DP-1200

fizzgig

fizzgig

Well-Known Member
:thmbsp:

Father in law brought me a DP-1200 from Iowa for my birthday! what a pretty table! included an Audioquest Sorbothane platter mat and a DL-160 cartridge, but minus the stylus. :thumbsdn:

Also, she's not spinning. So I gotta open her up.

Magnetic head looks ok with a quick glance.

I'd like to get her up and running so I can compare to the Pioneer PL-518x.

He also brought me a Harman Kardon T-20, which is a cute little thing, but not my style.
 

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I have that same model, and from the picture it looks like your start/standby switch is in the out or standby position. Push it in to the start position and see if it works then.
 
fizzgig said:
Wish it was that simple buddy, but nope.
Click to expand...

Oh well, it was worth a try.

Does the motor spindle spin easily when you try to spin it by hand with the platter removed?

When diagnosing something like this, I personally try to eliminate the obvious things first. You might also want to try and DeOxit all the switches and the speed control pot. It is pretty easy to do, and it won't hurt anything to do it, as they probably need it anyway.
 
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No reaction from the platter when giving her a little help. I'll pop it open tomorrow and do some diagnostic work. Deox the speed pot and the like.
 
Hey Treker, would you mind posting a picture of the bottom side of your platter from the dp-1200? I need to make a comparison.
 
I hate to be really "doh" about it, but it is a semi-auto deck (you know this I'm sure) and it won't start turning until the arm is moved out to position. That and what Treker said. I had one a few years ago and spent a few minutes after I brought it home thinking it was dead.
 
Correct, the arm is over the platter, start button in, drop the switch to play/on, and nothing, not even a jiggle.

I do know this model uses a magnetic pulse speed system. The magnetic head has to "read" a pulse from the underside of the platter. There should be some sort of "tape" or something on the underside, inside the lip of the platter, right? If the magnetic head senses no signal, then the thing just won't turn, correct?
 
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Also, my second table is a pioneer pl-518x, so I'm not just a manual idler snob! :D I know how auto tables work. :yes:
 
fizzgig said:
Also, my second table is a pioneer pl-518x, so I'm not just a manual idler snob! :D I know how auto tables work. :yes:
Click to expand...
I had actually never owned anything not completely manual before I got the DP-1200. On the other hand mine did start up once I moved the arm over. Sorry that yours isn't co-operating. I suppose it could be just a dirty switch. I know from experience with a Technics table that it sure doesn't take a whole lot of oxidization to stop them dead in their tracks. Apart from that maybe a cap in some circuitry has gone south or something? It is a very nice table when up and running.

Hmmm, what about the switch that senses when the arm is in place to start things? Could that be dirty and causing the issue?
 
fizzgig said:
Correct, the arm is over the platter, start button in, drop the switch to play/on, and nothing, not even a jiggle.

I do know this model uses a magnetic pulse speed system. The magnetic head has to "read" a pulse from the underside of the platter. There should be some sort of "tape" or something on the underside, inside the lip of the platter, right? If the magnetic head senses no signal, then the thing just won't turn, correct?
Click to expand...

Actually, I just checked this, and the platter does not even have to be in place for the motor to run. All you have to do is have the start/standby button in the start position, and move the play lever to the play/on position. The tonearm also has to be in the rest position, not the lock position. When you do this, the motor starts running and the strobe light comes on, even with the platter removed.

Good luck in getting your DP-1200 running. This really is a very nice turntable. I have owned once since 1979 when I purchased my first one, and it is currently my primary deck.
 
Hopefully it's a simple fix, although opening a turntable up is already treading into "medium difficulty fix" territory.

1zc1t0l.jpg


As I learned, the arm moving to the "rest" position (or further towards the platter) hits a switch inside the TT that completes the circuit and gets the motor spinning. Have a look to see if it is out of place, disconnected or needs deoxit' ing
 
jkilla said:
Hopefully it's a simple fix, although opening a turntable up is already treading into "medium difficulty fix" territory.

1zc1t0l.jpg


As I learned, the arm moving to the "rest" position (or further towards the platter) hits a switch inside the TT that completes the circuit and gets the motor spinning. Have a look to see if it is out of place, disconnected or needs deoxit' ing
Click to expand...
That would be the first place I'd be thinking about if the other switches are clean. It strikes me that the motor being sick is the least likely issue on one of these somehow, but what do I know?
 
FYI
Take care running certain TT without their platters mounted as it can cause
the speed control systems to overload quite quickly with being "loaded".
 
totem said:
FYI
Take care running certain TT without their platters mounted as it can cause
the speed control systems to overload quite quickly with being "loaded".
Click to expand...

The motor will likely run full-on and is not rated to do this for long AFAIK.
How 'bout a pic of the underside of the whole works?
 
I believe it is the switch (marked #2 in the previously posted picture) that is causing the issue. I noticed it was not opening the circuit when I moved the arm back, and the LED for the return was going off when the switch engaged.
I opened the switch up, reset it back to open position and then powered on. Once I had the main power switch on, I closed the circuit in this little tone arm switch by depressing the button. A small spark inside the switch was seen when it engaged. At that time the tone arm LED went off.

The little tone arm switch seems to be shorting out when engaged. Then it won't disengage automatically via the internal spring and has to be manually disengaged.

What would happen if I bypassed the tone arm switch?
 

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Pio1980 said:
The motor will likely run full-on and is not rated to do this for long AFAIK.
How 'bout a pic of the underside of the whole works?
Click to expand...

I only ran mine for a few seconds to see if it would run without the platter in place, so I'm sure I did it no harm. However, from my experience with electric powered radio control aircraft, running a motor unloaded is a lot less stressful on them than running them loaded, especially overloaded. I am pretty convinced that this will in no way harm the motor, but whether or not it may harm the speed sensing and control system is another matter that I do not have enough experience to comment on.
 
So, I finally deox'd all switches and pots. Still no joy. Checked output of CN3 (voltage to motor) and all is good there at 120V according to my multimeter. So I know the motor has power going to it. But no life in the motor. I'm not sure I have a way to check the motor itself. The spindle moves freely so I'm sure it's not locked up.

At a loss at this point.
 
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