These switches are working fine in case the tray is open/close.
Any other tip?
Have you checked service mode to see if the microcontroller agrees with you that they work? See my previous post.
===Jac
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I am a little bit lost!
I entered the Service Mode - Then push NEXT; now it should say SERVICE MODE. Then push RECORD (REC / MUTE!?) but this button did not work, because “HOLE TEST” didn’t appear. I pressed the REC / MUTE button serveral times - no reaction!
When I press “APPEND” → TRAY TEST" appeared.
Any idea?
Sorry I don’t have a DCC600 handy (it’s packed up in the garage). I wrote that from the flowchart on page 25 of the DCC600 service manual.
===Jac
Update - the fault is somewhere in the tape unit / device, because I put it in another case inkl. circuit board with the same error result.
And also there the push RECORD (REC / MUTE!?) but this button did not work, because “HOLE TEST” didn’t appear! → maybe this is another topic.
Issue can be closed.
I can’t just narrow down the cause of the error. I had another defective DCC 600 with defective mechanics in the slot. Then I only installed the drive unit (with all the microswitches) into the actual defective one. I continued to use the slot and the tape head unit. I found that the gear was broken and this one. I’ve now ordered a new one, because the other one is already a bit chipped.
It’s just running again! 
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Nevertheless, the service mode “Hole Test” does not work as described for the DCC 600 - neither of my two devices!
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Thanks! Good to know. It’s not unusual to have bugs in the service mode; obviously it’s not the most important part of the software so it doesn’t usually get tested before the factory starts making preprogrammed microcontrollers.
Next time I have one of my 2nd gen recorders out, I might investigate what’s going on, and if there is a workaround.
===Jac
Hello,
I’m new here because my DCC600 has the same problem.
I did the servicemode tests and it passed all hole tests and tray test ok.
At last I found out that there is another sensor in the red1 mechanism that checks if there is a tape inserted. The signal goes from the red1 to the mainboard an from the mb to the front board and it ends at pin 10 of the processor. It should be 0 volt if a tape is inserted but mine is 5 Volt. So the proc. says “no cassette”.
Thought of grounding the signal by hand, but this is a hack I only will do as last option.
First I will remove the mechanism and take it apart to find the broken switch.
Any hints how to take it apart and put it togehter again?
Forgot to say: The service manual has many errors, as wrong numbered pins and connectors and so on. Even the way how to do the service mode tests are wrong. For example: mark erase for key test, but it really is mark write.
Greetings
Ralf
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Hi @Bandsalat and welcome.
It might be that the switch is dirty as well.
Here is a video on how the take the mechanism apart. Hope it helps.
Hello,
no, the hole-switches are working. I tested them manually with the multimeter. And I checked if the signal arrives the processor correct. All OK except the cass in1 signal and the corresponding switch is in the red1 mechanism.
I’ll take a look at the video tomorrow.
Greetings
Ralf
Could you give us an update?
Hi, I’m having problems with the ‘no cassette’ message. Could you tell me where the switch is in the red1 mech? Thanks
Hello,
until now I had no time to disassemble it. It’s still waiting for repair.
Did you check the hole-switches by firmware testmode? Is it the same problem as mine, cassette is inserted and pin 10 at the proc ist 5v?
Greetings, Ralf
Hi all my name is Han, After changing the gear wheel I faced the issue “no cassette”. Executing the hole test (with cass tray open!) showed that all switches worked properly. To determine if the cass itself activates the most right switch of the four, turn the big left wheel on the side to move the tray in manually. Since still in the hole test, the switch was operated by the cass. After leaving the service mode, the error “no cassette” still occurred.
From the schematic I could see that there is a second switch that needs to be activated to determine the cass present. This switch is located on the most right side in the cass holder (if possible I will upload a photo to indicate the switch) This switch did not function properly since the pcb that holds the switch was a bit allocated. After readjusting the pcb the “no cassette” issue was solved.
4 Likes
Welcome to the forum, and congratulations on fixing it yourself! You can use the upload button or copy and paste them to post photos; there is no need to use an external service.
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Thanks Han for the photo. I encountered the same message (“No cassette”) after replacing the belts of my DCC380. I did not properly put the black cables back to their place. This interfered with the switch CASS_IN on the bottom of the photo. Putting the cable in the right spot solved it. I would not have figured this out without your photo.
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Thank you for this explanation! 
I had the same problem after replacing the gear wheel. But after re-adjusting the pcb with switches the message “no cassette was gone”.