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Denon DN-951FA alignment procedure?

K

kthelen

Does anyone out there have a copy of the service manual for these beasts? I have one here that's putting up Error 85, which I understand means it might need to be re-aligned.

I can't find the procedure itself anywhere, but I hear tell that it involves an oscilloscope, can be rather tedious, and may have included some broken English.
 
I couldn't find it in my doc's. I do remember that once I say 85, that unit had very little life left in it.

I am surprised anyone is still using such a thing. I don't even have CD Players at all in the studio anymore.
 
I am sure I have a copy of that manual in storage. The last time I saw one was 1992!

I can tell you the two most common issues with these machines are:

1) low RF output from the optic block assembly = laser worn out

2) worn spindle bearings

Do you know the history of the machine? I'll check the lock-up this weekend and post back if I find the manual.
You are correct in believing that set-up does require the use of a scope. It's mainly to set the FOS and TOS of the optical block.


chriscollins said:
I don't even have CD Players at all in the studio anymore.
Click to expand...

A studio isn't a studio unless it has lots of buttons and flashing lights ;D
 
I had a couple of the 961's, one with the error 85. I sent a pair back to a third party servicer who claimed to have fixed them and they both came back with an error 85. I sent them back to Denon who repaired them correctly. One of them told be it possibly related to a ground inside the unit but it's been some years since I dealt with them so I can't say for certain.

I never acquired the manual for them which is why I decided to send them out.
 
Studio1 said:
I am sure I have a copy of that manual in storage. The last time I saw one was 1992!

I can tell you the two most common issues with these machines are:

1) low RF output from the optic block assembly = laser worn out

2) worn spindle bearings

Do you know the history of the machine? I'll check the lock-up this weekend and post back if I find the manual.
You are correct in believing that set-up does require the use of a scope. It's mainly to set the FOS and TOS of the optical block.


chriscollins said:
I don't even have CD Players at all in the studio anymore.
Click to expand...

A studio isn't a studio unless it has lots of buttons and flashing lights ;D
Click to expand...

The D75 has plenty of pretty lights. Now that my secondary PC's in the control room have full backup of the Audiovault on it, I see no reason to waste two Digital pots and the rack space for CD players.

We are in the process of pulling out all of our unused channels and putting the (very expensive) blank panels in there place. Lot's of spare D75 parts going into anti static bags on the shelf. Makes me smile at night...

I'm an IT man, but I am also a PD and jock, so the rooms are designed for maximum usability and simplicity. No reason to have all those pots running and hanging out in the board if they are not in use.
 
Studio1 said:
Do you know the history of the machine?
Click to expand...

Nope. Never seen it work - came to me with a bunch of other equipment that was supposedly working when removed.
 
The optical pickup is less that a hundred - considerably less if you ship around. The bearibngs are like $7 last time I bought a bunch - which was years ago. I've never done anythibng to one of them beyond those two, and usually the bearings are sufficient. Be sure the spindle height is set correctly (.050 gap)
I forget the slignment oprocedure but it's in the book. Requires a scope and a plug for the four pin test header on the bottom board. If anyone remembers the young lady's name who used to run Denon support (and who I believe married an engineer), call her and she can tell you how over the phone. She gave her presentation to our SBE chapter amiong others back when the 951s were the weapon of choice for music formats. I have half a dozen in storage for sakle, make me an offer for the lot.
 
As I recall. the laser reader is really a Sony. That is usually the problem. Denon used to want a kings randsome, but you could find it on-line for about $10.
 
Lasers on these machines lead a very hard life. And your error most likely means your laser is about to go Tango Uniform. Denon in my world means Darn Equipment Never Operates Normally, alas. This CD player was an exception. If you can find a replacement laser, you'll be fine a few more years of use.
 
Ok, I hunted the lock-up but only managed (so far) to find the manual for the DN-950FA - and it doesn't mention
anything about fault codes so I suspect it's a different machine internally to the 951.

I did find some notes however, and code 85 is 'Focus Error'. This *can* be caused by a dirty lens on the optic block.

On that basis I'd try cleaning the lens carefully first and see if it improves the situation.
Otherwise, it probably means the optic block is worn out and needs to be replaced. The part number is KSS-240A, there's plenty of them on EeeeeeeBay :)
 
We still have a couple DN-951FA's hanging in there.
Not much use. Several dead ones too with bad optics.
When cleaning the optics don't do like one moron did and spray it with contact cleaner
swiped from the shop.
Did notice that the consumer Denon players we also had the same optics but none of the problems with alignment.
 
I had over 15 of the DN-951FA's at my last cluster with a couple being spares. Great DJ-proof machines with the CD condoms, plus we had adults on the air who were not abusive with the equipment at all. It was easier and more cost-effective to drop a couple off at Denon when they were in the LA area and pay $75/ea. to repair them than attempt to order parts & fix them ourselves in a hectic environment. Once repaired, each would last 1-1/2 years in constant 24/7 service. I could tell when the laser was about to give out by the length of time it took to access track 99 from track 1 on my test CD. (If it took over 3 seconds, and would skip when bumped, it was time for the shop.) I even had one in a PD's office to preview incoming CD's from Mexico as occasionally these would not meet spec, but that was extremely rare. They are now just for emergencies as we maintained a CD library even after we upgraded AudioVault storage to accommodate the libraries. Also, the "loudness wars" swept thru and affected even the "romantica" CD's we were airing as these overlimited CD's would cause the A-D converters to clip on the AES outputs, and would overdrive the analog outputs from where our long-time house standard was set. Even so, with 3 decks in each air studio, I never had a crisis. Sometimes they had to get by on 2 machines over a weekend until I could swap in a spare, but CD players were the least of our headaches.

ps: If you have DN-950's, you have a reliable doorstop. Not the same animal at all.
 
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