Philips DCC730 don't start

Recorders, Players, etc.
1

I have a problem with may Philips DCC730.
When I turn on the play button, the tape deck does not start. You can hear the switching of the relay (coil) from the mechanism, but the tape does not start. Below is a link to a video of what it looks like. Do you have ideas what is not working, what should I check first?

2

Could be the belt.
Have you replace it?

3

Belts are ok. I have replaced all belts.

4

What about the pinch rollers?

5

Pinch rollers are ok. It’s seems that the motor don’t start.

6

Maybe you can try and remove the motor and put some voltage on there (start with 3V upwards) to see if it spins.
Ralf

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7

The Main question whether the main motor starts after you press play. You can mention it by observing if capstans start to turn after you press play.

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8

Just my two cents:
Remove any cassette and power off. Remove the cover.
Then, while viewing the capstans, press power on. The capstans will run for about 3 seconds.
Then you’ll now if the electronics and motor are working.

By the way, that’s how I do a quick cleaning of the capstans.

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9

Hi, I am having exactly the same problem. The solenoid can be heard but the capstan motor does not start. I’m pretty confident that the capstan motor is okay so could it be the tape transport control board. Does anyone have a 730 or 951 tape drive control board I could buy/borrow to rule this out. Or has anyone successfully repaired one in the past.
P.S. I too have ruled out the belt.
Hope someone can help. Best regards, Dave.

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10

@Windmill_PL did you find any solutions to your issue? I am having the same problem with my 730. :worried:

11

Thank you all for the suggestions that I can check. I checked all the motors, by connecting the 3V directly, all motors are spinning. I enclose a link to the video how it looks from the bottom side.

Do you have any suggestions for what I can still check? I note that I am not a specialist and I do not have specialized tools.

12

Hi @Windmill_PL This is exactly the issue I have seen on three DCC730 machines. Unfortunately I think it is an issue with the Tape Drive PCB (pictured). On one machine I was lucky enough that @Richard_Symes supplied me a spare working PCB which when fitted resolved the issue straight away. I have another machine with this issue that I am looking into at the moment with the help of @Jac . From the test results I have so far it looks like there could be an issue with the 74HC4066D ic and/or the transistor at pos 7542. I have ordered some ICs and will fit when they arrive. I hope to provide a detailed post on here for future reference once the repair is complete. I have also circled two more transistors that are worth testing. I believe the issue may have been caused in my case by the belt being stuck to the capstan motor spindle, then repeated attempts at pressing PLAY have possibly caused an overload in the circuit? BTW your belt looks quite thick in your video? Hope this helps, :wink:

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@saturn5 did you fix the issue already? I seem to have the same problem with a DCC951. Belts and gearwheel already replaced. Al motors work, also the one that drives the capstans. Tapes do rewind and forward wind, but the capstans never seem to move. When I apply 8V to that motor, the capstans and tapehead mechanism do move. Also, I do measure 10V on the pins that lead to the motor. Could this be the same issue here?

14

Good morning @Langley78 , welcome to the forum and so very sorry for my late reply. In short yes, replacing the transistor 7542 successfully repaired this issue on two boards ( I also have a third board I am yet to repair but am confident changing 7542 will also repair this board).

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I purchased the transistor from little diode on ebay. I paid about £4 each for the transistors which is very expensive but they were advertised as being Philips brand. The transistor you need is a BC808-40 in a SOT23 package, if you are not bothered about brand you could get them for a around £1 each or maybe a strip of 10 for £1 if you can wait for them to be delivered from China.
As for measuring the voltages, with the motor connected to the board none of the voltages were consistent with those given in the service manual.
With the motor disconnected I was getting 10 volt on test point 19 (1504-2 CAP+) when in STOP, pressing PLAY would see this value drop to ZERO volts - This is the exact inverse of the behavior you should see according to the manual.
Hope this helps. Must also give credit to @Jac for his assistance.

5 Likes
15

Hi @saturn5, thanks for your detailed reply and the warm welcome here. My soldering skills are not that great, so I am going to ask someone with more than enough skills to do it for me.
Hopefully this will save another DCC deck!

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17

I have a DCC951 with the same issue. The service manual explains how to remove the Digital board. But how do I remove the Tape drive control board?

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18

Hi @hermanelenbaas , you have to bend two metal tabs back gently to release the board. Im at work at the moment so can’t get a pic for you to help.
Regards.

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19

Thanks saturn5. I got my my DCC951 which had the same issue repaired with the successor of the Philips BC808-40, the Nexperia BCX18. Nexperia is former Philips Semiconductors, former NXP. The BCX18 is easier to get. For example at Mouser . The data sheet is available at the Nexperia website BCX18

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That’s brilliant news @hermanelenbaas :grinning:
Glad I could help out :+1:

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21

Good news, great work!