DCC951 no sound from digital

[chartz]

Hello,

This will probably be my last attempt at obtaining a functional DCC player!

I just got a 951. It will play an analogue cassette (tested briefly) but no sound at all from my DCC tapes unfortunately.

When I insert a DCC tape it will display ‘reading’ forever then stops. I can see the track number when I FF +1, but no sound from either sides.

The message ‘clean head’ has appeared after cleaning the head! It looks fine though.

The capstans look oxidized, I’ve never seen that before.

Do I give up?

Regards,

Jacques

[Jac]

Try giving it a good cleaning. For starters, use a Q-Tip and some isopropyl alcohol (90+ percent pure) to wipe off the head, in up/down direction. You can’t really see whether the head is clean or dirty so keep scrubbing for a while. Also put the recorder in service mode and play a DCC tape; preferably a prerecorded one with a brown pressure pad. Check how many tracks are showing “00”. If they all show FF, there’s a chance that the head is defective but if you’re getting analog sound, there’s a chance it could be salvageable. Clean those capstans too.

Also check the pinch rollers; those are often an issue on 3rd gen recorders. DCC is very sensitive to speed variations such as the ones caused by worn out pinch rollers. They can be easily replaced and aren’t very expensive.

===Jac

[chartz]

Hi,

Thanks for the pointers.

I gave the head a thorough and lengthy clean with IPA and Revox pads – it was very, very dirty, but no cigar. It counts and sees tracks though!

I wouldn’t get any DCC sound with hardened pinch rollers then?

They don’t have the holes but yes they are a little hard.

I’ve cleaned both capstans with Brasso, they look ok now.

No wow with analogue tapes (classical music).

Also I’ve noticed that the three SMD caps at left on the headboard get very hot. This can’t be right, can it?

Edit: found that thread, no news.

Philips dcc 951

Problem with dcc head shows 10001001… Try to clean no success… Capstans was very dirty… Sometimes shows after 30sec first zero… And others but no sound… Capacitors on first board 10mF 60v are go hot 52 Celsius and chip is hot 52C. Is this normal… Or this caps are dead? No leaking… Clean board as new? Do you have new heads for dcc 951? Thanks. [IMG_20240716_221554] [IMG_20240716_121009]

Voltages are ok, 5, 8 and 10 V.

I don’t get the 900’s dreaded FFFFF but there are errors, two or three ones. They change when I try another cassette! See photo below.

Jacques

[chartz]

Let me precise that the ones are not solid, they keep blinking from 1 to 0. Odd.

Original gear, not cracked. Amazing.

[chartz]

Hi,

No ideas then?

I have ordered new pressure rollers from Laureen, but I’m not holding my breath. We’ll see.

Dismantlement of rollers is super easy, by the way.

[Jac]

During playback in service mode, the digits should mostly stay at zero for the recorder to play (and record) sound. If all tracks are 0 but one track is constantly 1, you may hear some fragments of music but 1/8th of the stream gets lost when one head isn’t working, and that’s exactly the limit of the error correction circuit.

Try it with multiple tapes and don’t just test the start of the tape. The start of the tape usually is a bit more sensitive to wear. Try fast forwarding to at least a minute into the recording.

If most tracks are zero most of the time, there’s a good chance that the head is just dirty. Keep scrubbing with a Q-tip with isopropyl, going up and down (not left-to-right). The digital heads are near the top of the head assembly and the first track is closest to the top edge of the tape. That should give you an idea of where to scrub.

If you can, you should test with a prerecorded tape. That way you don’t get fooled by a tape that was recorded on a machine with dirty or bad heads. A dirty head will keep the bits from reaching the tape, and no amount of scrubbing will improve anything with a tape that has a track with nothing in it.

Good luck!

===Jac

[chartz]

Hi,

Thanks Jac.

Most tracks do stay at 0, with one or two tracks flickering and no sound at all, not even fragments.

Unfortunately I do not have prerecordeds.

I’ll keep trying to clean, and insist at the edges.

[Henrie]

Hi Jacques,

Did you try listening through a headset? Just to rule out a very common dry joint solder defect at the RCA outputs on the PCB.

Kind regards,
Henrie

[chartz]

Hi Henrie,

Yes I always test via headphones on the workbench.

Analogue works fine anyway!

Jacques

[chartz]

Update: no change with new pinch rollers – as expected.

Same errors, same flicker on three digits. Sometimes I even see all zeros very briefly. Analogue is still fine, not better, no wow.

Cassettes work on DCC 600 and 900.

When I clean the head, it sometimes shows more errors, next clean, fewer errors but never zero.

Pressing the cassette angles does nothing at all.

The head is kaput I guess.

Since the head is so easy to remove, would anyone here have a good spare for me to try out?

Cheers,

Jacques

[chartz]

Hi,

The player is in the attic, last stage before the tip.

So I’ve got a 900 that works from time to time… it works perfectly for hours until it doesn’t (no sound all of a sudden).

I’ll bin it too I think. Shame because it is near mint.

Both players replay analogue cassettes absolutely fine, by the way.

And the 600 that keeps working fine!