Philips DCC 175 rewind issue: gear grinding noise at tape start/end after new belt

Recorders, Players, etc.
1

I am looking for some advice about a Philips DCC 175.

Recently I replaced the belt, the SMD capacitors, and the capstan rollers/wheels. In general, the deck is working well again, but there is still one issue I cannot explain. ( i will try to upload a video of it)

When I rewind all the way to the beginning or the end of a tape, I hear a strange noise that sounds like a squeal, grinding, or mechanical resistance somewhere in the gear train. It almost sounds as if a gear is being forced too hard.

What is confusing is that I did not have this exact noise with a previous belt I installed (from MFBfreaks), but with that belt the deck had a different problem: it could not always rewind properly all the way to the end of the tape. That is solved with this new belt.
With the current belt (from the DCC Museum), rewinding does reach the beginning/end correctly, but this unpleasant grinding/cracking gear noise appears. The current belt is slightly thicker: 0.7 mm instead of 0.6 mm i used earlier.

My suspicion is that the belt may be slightly too tight, causing extra load on the mechanism during fast winding and forcing the gears, which then creates this destructive-sounding noise. I am worried that over time this could damage the transport or even break internal gears, especially since replacements are not easy to find without a donor machine.

Another thing I noticed: this seems to happen only with non pre-recorded tapes that contain an older recording and that I want to record over again.
With pre-recorded tapes, the deck slows down properly during the last part of the rewind and then stops normally at the beginning of the tape.

I have two DCC 175 machines, and the other one does not have this issue, which makes me think this is not normal behavior.

So my questions are:

  • Could a slightly thicker/tighter belt cause this kind of noise?

  • Could this point to a problem in the gearing, clutch, idler, or tape-end detection? Where is the issue located most propably?

  • Why would this mainly happen with non pre-recorded tapes, but not with pre-recorded tapes? Because of the tracking information so it knows where it is when spooling the tape?

  • Is this something that could damage the mechanism if I keep using it like this? Which gear is most vulnerable causing this sound?

I would really like to understand the exact cause before continuing to use the deck. I have several players here, so I can compare parts and test suggestions if needed.

Any ideas are very welcome.

Thanks in advance!

2

Due to the age of the machine and different specs, every machine ideally needs a 64mm x 0.6 mm belt. In practice this no longer works. We have repaired over 250 portables and with most 0.6mm belts the belt stretches immediately, because of the heavy lifting that one belts need to do.

When changing to a 0.7mm belt, that problem is gone.

The other problem is the slip mechanism, that has aged.

That mechanism makes the machine stop when rewinding to the beginning.

With original tapes, the player can determine very easily that it is near the beginning and will slow down and stop correctly. With empty or home recording it does not always work.

When the slip mechanism fails to work correctly, sometimes a bigger or smaller belt might help. Sometimes there is no ideal combination.

Ralf

1 Like
3

Thanks for your reply, Ralf. That does indeed seem to be the cause of this issue. Not meant in a derogatory way (I have great respect for all your work), but I’m also curious about the experiences of hobbyists and the things they’ve run into, which might help contribute to a solution or at least point us in the right direction.

The annoying part is that one DCC 175 has this issue while another doesn’t Although the same changes are made to the internal mechanism (Capstan wheels, belt and capacitors). You would expect that to be something that could be addressed somewhere in the mechanism, although I do of course understand that these players go out of spec over the years.

Very curious to hear others’ experiences and any possible clues toward a solution.

P.S. Where is the slip mechanism located? Maybe the cause can be found somewhere around there.

4

I looked at the service manual and can’t find a specific mention how it is to be located and how it operates. You can clearly hear the “slip” when it works fine. Sometimes it slips 4-5 times before it stops. I have a DCC170 here that also rattles when rewinding normally. FFW but always REW.

1 Like
5

Thank you for your reply Ralf. Are there other forum members who are familiar with the ratlle issue issue and solved it maybe? There must be a way hopefully.