DCC900 dead again after two years

Recorders, Players, etc.
1

Hi,

My DCC900 was repaired two years ago (full re-cap) and it had been working absolutely fine ever since.

But today, no sound from DCC and faint analogue sound (both channels) and a slight hum is heard too, from digital and analogue.

I don’t understand. Before digital muted completely, I could hear scratching sounds with full VU meter deviation (both channels) but no music.

Any ideas please?

Thank you,

Jacques

2

That’s awfully short! That shouldn’t happen so soon after a recap, unless a cap was missed two years ago and that started leaking or a bad cap was used as a replacement.

Immediately power down the player, and don’t plug it in anymore to make sure you don’t damage it any further.

Then have it checked by an expert in your region, unless you’re up to the task yourselves.

3

The old leaking caps might have damaged the copper wires and through-hole layer connections before replacement. In the mean time the chemical residu from the old leaking capacitors will have ‘eaten’ some of the pcb-tracks.

There’s a great chance that this is what’s now happening to you player.

Do not use the player anymore, or even power it on, or you might blow your DCC head.

Get the unit serviced. Your best bet: replace the read/write board by one from the DCC museum.

4

Hi,

Thanks for your inputs. I will remove the PCB and inspect it again, and test the vias too – those were good prior to re-cap. I used quality caps, no problems here.

I know that the best solution would be a new PCB of course! I’ll also test the heads.

I just have a faint hum I didn’t have before (amp volume pot right up) even with nothing playing or no cassette. When it failed I just tried the next song function which still worked!

Jacques

edit: I’ve just inspected the board and it turns out all the new SMD caps have leaked too. Dammit. Yet I had cleaned the board very thoroughly I’m sure.

PS: are you the Henrie that is friends with Laureen?

5

Too many vias have continued to be eaten, in spite of what I thought was very thorough cleaning, with untrasound bath and IPA after acetone surface cleaning. I did a few and then I gave up. Not worth it, too many of them!

I’m working on my second card (much cleaner, no heavy corrosion) and I’ve found two bad vias, near R135. The 8 V sense voltage was missing. What does it do?