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Author Topic: Studer A810 fast forward problems‏‏  (Read 3026 times)

Offline Guglielmo

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Studer A810 fast forward problems‏‏
« on: December 03, 2013, 05:41:03 AM »
Hello to all,

please I would like to have your skilled help in fixing a little problem in my STUDER A810.

When the Left Reel (big NAB metal) is tape full I start the FAST FORWARD and the Right Reel (also big NAB metal) begins to take-up the tape. After 20-40 seconds the Right Guide Roller of the Tape Tension Sensor slowly goes to the lowest zone causing the STOP of the Fast Forward.

In principle I guessed that this was due to some "sticky" old tape and in facts restarting the FF several times (actually just 2 or 3 times because this problems occurs only at the begin of taking-up operation) the tape reaches the end and the next time in FF with the same tape the problem seems fixed or almost.

The doubt is that this happens also with new modern tapes so I guess that there is some adjustment to be made... I try to understand the Manual but it is very complex for me.

I have to underline that this problem is not present with small 7" reels.

I have noticed also that the sliding of Guide Roller makes a little "click" (like a spring or thin sheet noise) in the upper path just before the end-run.

Another clue is that the bearings of the Guide Rollers are slightly noisy so it could be that the tape tension along the path is not at its best. For that I am waiting for a new set of bearings.

Thanks a lot for useful help!

Cheers,

Guglielmo

Offline Ki Choi

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Re: Studer A810 fast forward problems‏‏
« Reply #1 on: December 06, 2013, 11:52:48 AM »
Hi Guglielmo:

Sorry to hear about your problems with A810.

There is a very good instruction in the service manual on setting REW and FF tension to increase torque.  However, if you have not replaced any of the components for the winding section, I would not recommend readjusting tension. 

Instead, I would start the normal process of troubleshooting by measuring supply voltages from the back of the machine with it in winding mode under load.  I would pay attention to the 24VDC section. 

These machines are in general 30+ years old...  more than 50% of the time, I see the bad filter caps in the power section and on basis board as causes of many problems.

Let us know what you find out on supply voltage measurements.

Good luck,
Ki
Ki Choi

Offline haiau

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Re: Studer A810 fast forward problems‏‏
« Reply #2 on: December 06, 2013, 08:59:05 PM »
hi Ki Choi,
the first, I've to say to thank you so much about your useful sharing on the forum. Some members have been successfully in backup data from eeprom of Studer, (such as IC10 (MCM2802) in A807; PG16811C in A810,...)

Because, I have 2 machines A807MK2, one of them with IC10 (MCM2802) of Tape Desk Electronics board (1.727.650.25) dies. I changed this IC (MCM2802) from the good machine to sure that IC MCM2802 dies.

Can you show me the how to read data from good eeprom mcm2802 and write to wrong eeprom mcm2802. Please email for me [email protected] the things you known, web address for help, circuit diagram for program tools, software for programming,....

Thank you very much

Regards,
HaiAu

Offline Guglielmo

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Re: Studer A810 fast forward problems‏‏
« Reply #3 on: December 10, 2013, 09:37:33 AM »
Hello Ki,

thank you very much for concurrence and helpful suggestions. I'll do those checks.

In the meanwhile please see my video here

http://www.4shared.com/video/SCeLvk7M/L1010120.html

As you may note the problem occurs with SX reel full of tape. I shoot just two of this events. This occurs about 3-5 times, namely the first 10 minutes of Fast Forward beyond that the fast run is correct.

I guessed also about mechanical problem: the dash-pot for instance because I noticed during playing at 15 ips that the RH tension arm roller has a slight flickering (not steady). Also the two internal springs of tension arm may have lost their original retention force... What do yo think?

Thanks a lot again!

Guglielmo