Blowing the head of DCC 730 and DCC951

Yesterday it was the 3rd time I blew a head of a 3rd gen DCC player. And now I’m afraid of doing anything else on a player other than replacing pinch rollers and cleaning the head.

I really don’t know why this happens. Normally I replace the caps when needed and apart from that everything remains roughly the same. I have a lot of experience in electronic repairs (and I am certified).

The player can play DCC cassettes for many hours (I test them on my desk while I am working), and without hick-up, or any other distortion.

But then it happens: after making 1 (yes only one) recording, the player will never play a tape again (i.e. no sound). I switched boards and cables from other, perfect players, and it seems like he head is gone. There’s no sound whatsoever. And after playing the recording on another DCC player, there’s also no sound.

Has anyone seen this happening? I’m stunned this happens so often. Can someone explain what happens? Is it a broken read/write board, or chip?
I do not dare to try the probably defective read/write board in another player, risking I blow that head too, while making a recording.

Thanks for sharing your experience :wink:

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Oh my word! What a tragedy!
Did you replace the heads on the recorders? When playing back all is fine, as soon as you record the head blows…

As far as I know every head has it’s own specific recording current. It is written on a sticker on its leads. For playback it doesn’t matter. If your read write board is giving too much current to the new head I figure that might me the cause… but ai in no way an expert… maybe @drdcc or @Jac can give you the correct reason why…

After refurbishing, each player played perfectly for a long time, 100% and without any errors. I rarely record music on DCC tapes myself.

After breaking down after recording, I set the mechanics and electronics aside and replaced it with another block. The new mechanic and read/write/digital boards still play and record perfectly.
So there seems nothing wrong with the power supply and/or main boards.

I did not replace the heads of the possibly faulty read/write board, for I was afraid of damaging the replacement head too. I once placed the ‘blown’ head in a working machine and it didn’t play. So I suspect the read/write board for 99% being faulty. Measuring and comparing with other read/write boards didn’t show any differences.

This happened to me for the 3rd time now. I was just wondering if it’s only me…

I never measured the head, because they are so sensitive to static electricity.
So if the head ‘blows’ this way, should I be able to measure that?

We have done only a few of them. Never had that problem. I agree however that it cannot be a coincidence.

@Jac and @drdcc
Before I say something silly… the only possibility of blowing a recording head is if the recording current is exeding the limit of that particular head… is that right? Apart from static energy that would be the thing right?

So after recapping a third gen dcc player would it be possible that the factory determined and regulated current may have changed? If that is the case that might have something to do with this problem.

Since 3rd gen recapping is not common (yet) it might be worth looking in this problem, to prevent damage in the future?

Hope this helps!

Dear Henrie,
I found this in my old manuals. Mabe your heads suffer from a construction fault which has been fixed later. "Qoute
SYMPTOM: DCC head defect, no recording, several isolation shorts on DCC head.
CURE: Isolation shorts are caused by ESD. To protect against ESD replace (or bridge) C2999 on Read/Write panel by a 4k7 resistor (4822 051 20472). It is advised to introduce this in all sets with which will be offered for repair, and the modification has not yet been implemented yet. Implementation date: In R/W boards from production week 9540 onwards. Unquote”

Mabe there are a lot of hypersensitive units out without the protection.

Bye Michael


Thanks so much Michael!

My apologies for the late reaction, this message was still in concept!I

So I opened up several units, even one from 9544, and did not see (or measure) the modification.
First thing I now do when opening up is mounting this resistor. It’s an easy fix to prevent static discharge to the heads.

If you want to share more of these tips from your manual please let us know :wink:

Thanks again!



Meanwhile I experienced the same mysterious defects on two third generation recorders , one 951 bought in spring 2013 and one bought on kleinanzeigen this year in an attempt to fix the 951
The first died after rewinding a few freshly bought tapes for storage. I assume there was a build up of static electicity from the tapes which killed the head.
The second one came with defective head as a ripoff from kleinanzeigen but shows the same fault on service menu . In both units the service menu showed 1 for more than three channels.
Replacemant of all capacitors on the first one showed no results.
So the heads die due to a construction fault which they tried to fix later but none of my units had this modification.

I recommend the following :slight_smile:

Never ever loose connection between head and board on the third generation decks !
Apply described modification
Never ever try running the recorders or tapes when arriving from the cold. A video recorder survives humidity but not the DCC.

By Michael

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Thanks for these great tips Michael!

In meantime I studied the circuit diagram, and the modification for static discharge only seems to concern the tray parts. But it sure could help preventing static buildup from the tape.

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Same here, except my issue was with a 2nd Gen DCC600. I bought it for cheap as a non-working spares/repairs deck and boy did it have loads of issues - which I posted about elsewhere on the forum! After I had fixed it all, I too found it would play and not record. The reason for this was that two of the record head coils (which are in series) were open circuit when buzzed out with an ohmmeter. Now, whether this damage was caused by me during the other repairs or was always there I don’t know. I did have the head unplugged for extended periods and took no ESD precautions being ignorant of this at the time. I toyed with the idea of shorting out the two open circuit coils to see if the deck would record with two of them missing, but in the end I bought a faulty DCC730 instead. Needless to say I was super careful to avoid trashing the 730 head during the recap of the digital board. I now use the 730 for recording and the 600 for playback to preserve the head on the former. Interestingly the 600 plays the 730 tapes perfectly but won’t read the track name data.

P.S. I stand to be corrected but having thought about this a great deal I think that the problem with setting the correct record current is less to do with damaging the heads and more to do with getting the correct recording “depth” onto the tape. Too little current and the previous recording is not erased, too much and the recording is too deep and cannot be erased subsequently. It doesn’t make sense to me that they would design a head that could be damaged by its own driver chips!! I think this damage is only down to ESD issues when disconnected.