Hi,
Yes that is fairly normal.
Only the portables would be able to take that banging.
Oh no. After playing flawlessly earlier on, it’s now dropping out every few seconds, quite cyclically. I’m starting to lose any hope with DCC. I don’t know what more I can do with this machine. 
The heads can get dirty quickly. Try cleaning them again. Also pinch rollers could be the issue.
What does the Service mode say? You did not answer that question previously. Are the same tracks failing on the head?
Not yet tried service mode, will have to look that up! Don’t yet know how to do that.
It seems to play better in the B direction than A, but both drop out.
There’s still that one non-polarised capacitor on the digital board as well.
Are the red seals on the head still intact? Maybe someone has tried to adjust the head.
Service mode for the 900. Hold Stop and Play and then power on.
Ralf
The left hand screw (B?) seemed very tight and secure. The right hand screw (A direction I think) seemed to be slightly free to move.
I don’t have the remote but using the service mode to look at all channels, in B direction they are reading zeros fairly consistently, with 1’s appearing just momentarily. In the A direction there are much higher readings. I will very gently tweak the right screw to see if it gets the errors down. Otherwise, I suppose the A direction pinch roller is suspect. I don’t suppose they are available?
Thanks for all your help so far.
Regards,
Colin
In service mode, it’s apparent that the errors are happening in time with the left (A side) pinch roller rotation.
We have new ones in stock if needed.
Ralf
I think I will need a pair of pinch rollers. I’ve seen the video, they look easy to change. I’ll include this on my YouTube video too!
I will email you off list.
Thanks and regards,
Colin
1 Like
The new pinch rollers have arrived and I will install them today, though as it happens there are no errors from DCC today. Thanks also for the DCC recording.
I had mentioned that one of the head azimuth screws has not very tight, and though it is set for very few errors on DCC, I thought the best way to align it would be to tune for maximum treble on a good pre-recorded analogue tape. However I found that there is no analogue playback! Just a very faint “whirring” sound, which is reduced when Dolby is selected (so everything from Dolby circuits onwards is working). Have you ever encountered a lack of analogue playback? I suppose it’s not important but it would be nice to get the deck working properly.
Hi,
Yes around the pins (I believe 16-18) are on the read write board holding the flat cable and directly under The 68uF capacitor there could be connection problems from side a-b on the board.
Ralf
1 Like
Well done for that tip! One of those two pins was open circuit at the through-plated hole next to the connector. I patched it with wire and have put the PCB in an ultrasonic tank to hopefully clear any remaining capacitor gunge. I’ve also fitted the 2.2uF NP capacitor you kindly supplied.
Next is to fit the new pinch rollers, hopefully I can do that later this evening. All of this will be on my YouTube channel in due course.
All the best,
Colin
2 Likes
New pinch rollers installed, but that wasn’t so easy. The right hand pinch roller assembly got stuck and would not fully lift off, so I had to replace the pinch roller in-situ, which was fiddly. The left assembly came off fine, but removing the screw on the top cover assembly was hard. In the end though it was playing DCC tapes very well, delighted with that.
Analogue playback though didn’t go so well. I patched out the defective through-plate hole you had suggested, but still no analogue playback (the whirring sound may have stopped though). I checked for further bad through plating and may have found one, but one side is under the flat cable connector, so I can’t get to it. There’s another suspicious looking one next to a capacitor I had changed, and I suspect others on there too. It’s looking too risky to carry on. It works for DCC now and I think I should probably quit while I’m ahead and leave analogue playback, which I would never have used anyway.
However if you ever have a scrap read/write board which hasn’t been eaten too much by capacitor juice, do let me know.
I’ll be putting all my work on YouTube as soon as I have time to edit it all together.
All the best,
Colin
Normally, replacing pinch rollers should ge relatively easy.
glad it worked out. Unfortunately we do not have aboard that you would consider useable.
Looking forward seeing the video.
Ralf
It was certainly worth changing the pinch rollers. The left one, which was causing poor playback on side A, had a big dent in it. Someone had clearly switched it off when it had been playing a tape, and left it like that for a long time. The capstan had therefore dented the pinch roller.
1 Like
To be honest we don’t recommend using DCC players for analogue playback anyway as the claimed durability of the head is about half and they added a protection layer just to protect against the abrasiveness of analogue tapes.
By the way, as your offerings also include repair of damaged tapes, did you come across a DCC with dropouts or anything that could need additional error correction? I would love to read your opinion here: https://forum.dccmuseum.com/t/is-there-any-need-for-additional-error-correction/
1 Like
The DCC900 repair video will be released later today on this link:
Just love the last three letters of that random link URL!
Of course you are very much promoted in the video (and any back link would be appreciated too).
For your info: I was barking up the wrong tree with the lack of analogue playback.
I looked for and found a failed through-hole on the Digital PCB. You had told me to look at the read/write PCB. So, strangely, it would seem that both PCBs had the same problem on the same signals! However I’ve decided not to dismantle it and work on the read/write PCB at this time. It’s just that there’s always a risk with working on that PCB in particular, and since analogue playback will never be used, I’ve decided to leave that problem unless I have to work on the PCB again in the future.
There is still the DCC300 with no digital playback, but analogue works. But it’s lacking treble, so I wonder if there’s a clue. It doesn’t have the “slushy” sound of bad head azimuth though. What happens when the heads wear on DCC? I also need to find the test mode operation for the DCC300.
All for another day though, I have a bit of a backlog of other projects.
All the best,
Colin
3 Likes
Great detailed video.
Thanks for sharing.
The reason why the right pinch roller did not come out is that you would have to open the mechanism tray slightly. You can do that manually by turning the wheel on the right.
Ralf
1 Like
I’ll add that to the video comments.