Studer A810 reel tables

[reelnut]

Does anyone know how to change the height of the reel tables on a Studer A810? I recently purchased some NAB hub adapters from Darklab. They look EXACTLY like the Studer originals I have (except that the slaves are bonded directly to the hub, rather than being a screw-on affair). But when using them they cause the tape pack in the reels to be way off-center. The tape packs about 1/16th inch, or less, from the front flange of the reel, so it's actually acceptable, but it sort of drives me reelnutty that I can't figure this out. I have disassembled the tables down to the motor itself and can't see how to correctly adjust anything. Placing a CD disc on the table before putting on the NAB hub provides the added height that I need, but this is an unacceptable solution. The original Studer hubs provide a perfectly centered tape pack.

[Tubes n tapes]

John,

The reel tables of the A810 and most all other Studer/Revox machines are adjusted by adding or subtracting filler washers on the reel motor spindle, right under the brake drums.

What I don't understand is how the Darklab adapters give you a different reel height than the original Revox ones. In both cases, the reel itself is pushed against the reel table and should therefore have the same height.

Are the reels pushed against the reel tables correctly with the Darklabs? If not, changing the reel table height would just be fighting symptoms, not solving the problem.

[reelnut]

Arian-
OK, I see what you're saying and you are absolutely right about the reels being pressed against the tables in both cases. But I noticed this misadjustment the very 1st time I used the Darklabs. I dunno what's goin on here, but I'm working on it and will get back to you on this! Thanks very much!

[ironbut]

Hi John, I hate to state the obvious ( oh heck, I take that back,.. if it weren't for that, I'd be virtually mute!) but it must be that the Studer adapters don't hold the reel against the turntable. I'd be interested how they do this and by how much.

[reelnut]

Arian & Steve:
Thanks for your interest in this. Arian opened my eyes to the obvious fact that the hubs could not affect the height of the reel. FYI I examined the Studer and Darklab hubs- they appear to be perfectly identical, except for the slaves. They appear to have been made in the same plant. They look like they come from the same mold. I don't know what to think. I did have both motors out of the machine roughly a week before I got the Darklab hubs, but didn't have the drums off of the motor shaft. I am certain the table height was correct prior to that point. Since the tape is packing about 1/16th inch from the front reel flange, that means the reel tables need to come up by approx. the thickness of a CD. Maybe some day I'll figure this out. Or, I could put about one precision machined washer on the shaft under the drum to shim it out correctly. Thanks to Arian for that info!

[Ki Choi]

Hi John:

Hope your supply and take up motor mounts were marked when you removed them so that you can place them back exactly as when they came from factory.
As you put your reel motors back and reassemble the brake assemblies, be very carefully of its position.  There are small play in three moutning screws.  A slight missplacement would cause you to lose brake control.

Ki

[reelnut]

Hi Ki Choi-

I'm not sure what you mean about getting the motor mounts back on right. There appeared to be only one way to put the motor back on. I don't think anything there would have caused the change in height of the reel tables, would it?

As for the small play in the 3 screws that hold down the brake chassis: Yeah!! Big 10/4 on that!! Apparently adjusting brakes on the A810 is one area where the skills of an experienced Studer tech really are needed! It took me about 2 weeks of tweaking to finally get the brake adjustment right after having removed the chassis! Fortunately, the brakes can be accessed by undoing only 3 screws at the top of the machine to let the top front panel come off- a real time-saver.

I have a thought regarding your attempts to calibrate VU meters to operating level on your A80 and will post it to you.

[Ki Choi]

Hi John:

Sorry for the confusion. I wasn't commenting on your reel table height fix but as you were disassembling the reel motors and brake assembly, I thought to mention - be careful with the realigning the motor positions - as you have already edured...

One of my A810s is still not well.  Its brake function is so touchy - it stops after play and FF/REW while placed on its back but will have jerky creeps before eventually coming to a stop on while in standing position... After playing with it for weeks, I have given up for a while but may get back into it over the holidays.

Thanks for your post on A80 UV meter setting.

Ki

[reelnut]

Hi Ki-
Here's a thought regarding your A810 brakes: The A810 servie manual states that brake pads can be roughed up with steel wool. You might try that- see if it helps. Also, did you touch the brake pads with your fingers? A810 service manual states emphatically DO NOT EVER touch brake pads. They can be cleaned by scrubbing with isopropyl alcohol, if necessary. Happy servicing!

[Ki Choi]

Actually, I did try cleaning and scrubbing the brake parts with no luck.  In addition, I had aquired NOS brake drums and replaced them...but still it coasted after stop.  I recently found another compelete brake assembly with mechanism, solenoids, bands, and drums and will be replacing them as a complete set to see if it makes any difference.  I still have a hunch that it's the finiky motor mounting issues. 

I obtained this deck as parts machine in not working condition to keep my other A810s in operation but when I received it, it had simple power supply issues that was fixed, and it was no longer parts machine.... 

It's one of few radio station decks in my possession and did have lots of hours on it - enough to wear down the brake drum.

Ki