Denon DP47-F won't stop

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Dan-M
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Denon DP47-F won't stop

Post by Dan-M » 06 Apr 2017 17:50

I'm new to the site and trying to repair an old DP35-f and DP47-f. They both have issues with the tone arm not returning at the end of the record, if you push the stop button or manually move the arm to the arm rest the platter won't stop until you power down. I have downloaded the service manuals for them to see if I could figure out the problem. I cleaned the tone arm position leds and photo sensors, the position cam seems to be solid and doesn't look like it would have moved out of position(both tables used to worked fine a few years back). I touched up any suspect cracked or cold solder joints without success. Reading posts here it seems this may be a common problem with older Denon tables and I've heard it suggested to change the photo (CDS) sensors. I called a Denon service center and they didn't think they would be available now but didn't check with Denon on that.
Does anyone know where I can order replacements from? Would a supplier such as Digikey have them? If so what part# or value are the sensors? Appreciate any help.

Dan-M
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Re: Denon DP47-F won't stop

Post by Dan-M » 09 Apr 2017 22:12

After reading more posts on the Denon forum I see the Digikey replacement part for the DP-45f CDS (photo sensors) is already provided by captmark- Thanks.
With my Digikey order for the photo sensors I will also follow the advice to recap and order the electrolytics at the same time.
Great Info Thanks!

captmark
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Re: Denon DP47-F won't stop

Post by captmark » 11 Apr 2017 05:20

When you hit start does the arm drop in the correct position for an album? If you manually move the arm past the inside normal end of side spot does it then work? If so the sensors are OK but the arm position adjustment is off (the cam you mentioned)
Make sure you mount those CDS sensors dead flat on the board and you most likely will have to readjust the VR's to correct for the new sensors (DVM needed not a scope)

Dan-M
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Re: Denon DP47-F won't stop

Post by Dan-M » 12 Apr 2017 15:17

Both tables find the beginning of albums when I hit start. I did adjust the start position (cam) on the 35f because it was dropping too early.
The "cam" I referred to as "solid" earlier I see is actually called the shutter in the manual which is a much better name and description for it, sorry for the confusion.
When I move the arm past (inside) the end position of the album it still doesn't return- it's not even trying to.
I will order and change the CDS sensors and see what happens, also will order the electrolytics at the same time.
When going over the boards to make a list of the required caps and comparing that with the parts list for the 47f manual they don't agree. The 35 f manual however seems pretty much correct, at least for the electrolytics.
Thanks for the help captmark!

captmark
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Re: Denon DP47-F won't stop

Post by captmark » 14 Apr 2017 09:28

Yes I've lamented many times how the Denon manuals (at least the versions here in the library) are off and sometimes WAY off when you crack open a table. My theory is they probably printed out "revisions" and sent them to service centers to just add to the back of the binder kind of thing, and the pdf's here are all Ver 1.0

The good news is your PC board is marked on both sides which makes the recap mucho easier,

Try this to see if it jives with your table-there only six or so different values-spend $5 more and get a few extra of the non power cap values and you'll be covered just in case... the numbers after the values are voltages...

C32 10uf 16
C35 1000uf 25
C36 1000uf 25
C38 10uf 16
C45 10uf 16
C47 10uf 16
C48 10uf 16
C50 100uf 16
C51 10uf 16
C53 10uf 16
C55 1uf 50
C63 47uf 16
C64 220uf 16
C66 1uf 50
C67 1uf 50
C68 100uf 16
C69 47uf 16
C77 10uf 16
C79 10uf 16
C80 47uf 16
C87 10uf 16
C202 10uf 16

Dan-M
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Re: Denon DP47-F won't stop

Post by Dan-M » 18 Apr 2017 22:42

My DP47-f has 36 electrolytics on the main board and a lonely one on the servo board.
They are as follows;
47uF @10V- C21 C22
47uF @16V- C80 C69 C63
10uF @16V- C47 C45 C53 C51 C48 C87 C28 C77 C38 C23 C31 C32 C79 C6
1uF @50V- C55 C66 C67 C18 C10 C12 C3 C20 C17
100uF @16V- C50 C24 C27 C68 C9
220uF @16V- C64
1000uF @25V- C35 C36
also a 10uF @16V at c202 on the servo board

I didn't make a list for the DP35-f, the service manual jives with my board pretty much other then I have a c71 and c72 and no c3 or c10.

Dan-M
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Re: Denon DP47-F won't stop

Post by Dan-M » 25 Apr 2017 01:11

The new CDS sensors from Digikey fixed the auto stop issue (or lack of it) on both turntables. I also recapped both tables after getting them working.

It's been years since I have done much soldering but still feeling confident with my abilities I started with recapping the DP-35F.

I was using a good quality butane iron and a solder sucker tool but found that the butane iron was too bulky and gave off too much stray heat where I didn't want it.
The stray heat was a real problem when changing the CDS sensors with the tone arm wires being so close and so fine, the insulation began to melt on some wires.

So I got my temperature controlled electric soldering iron back I had lent out a couple of years back and armed with a new tip finished recapping the 35f and then tackled the 47f.

A proper soldering/desoldering station would have been better then a solder sucker
but if careful it can be done, I think (see disclaimer below).

However, when I tested them, the 35f has lost sound in one channel. At this point I haven't looked to see what the problem might be, I've been enjoying albums on the 47f instead and its working great.

I appreciate the info this site has provided!

Dimal
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Re: Denon DP47-F won't stop

Post by Dimal » 25 Apr 2017 13:06

Desoldering braid works a lot better than a sucker in my experience.
Produces a much cleaner site for soldering new components too... 8-)

Mal.

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