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Reel To Reel All discussions pertaining to reel to reel decks. These include general usage, recording, playback, and service questions. For subjects related to tape itself, see the Open Reel subforum under this one. Obscure service subjects that don't quite fit go in the Help and Do It Yourself subforum.

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  #1  
Old 08-13-2017, 01:58 PM
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Neville Neville is offline
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Reelstop Studer A810 Battery Replacement

Hello to everyone! I'm blatantly after some advice!

I have recently acquired something I've wanted for many decades (well, since the 1970s!) - a professional open reel machine! I am now the proud owner of a Studer A810 - it's in superb condition with butterfly heads, etc. I thought direct-cut vinyl was as good as it gets, until I heard master tapes playing on the Studer - it's quite amazing! Anyway, I have looked at the microprocessor board and see it's had a replacement battery - a NiMH that was changed in 1996, so I'm guessing I should replace it (I've measured it and it's about 3.8V, so all OK). I've seen some people talk about a Lithium battery, others a NiMH - what would you experts recommend and what would be the model number of the battery? Attached is a photo of my card.

Also, I have saved the data to a tape (using a serial lead I made up using the connections shown in the manual) and it worked (and verified) first time! However, when in record and playback, the VU meters were hard over to the right - should I fit a 50 ohm resistor across the pins to reduce the o/p level? I'm assuming if the data gets lost when I change the battery, I can restore it from the tape I made? However, I also have seen that I can keep the memory alive by temporarily wiring up a battery - would a little holder with two AAA batteries work and where should I solder them on the circuit board? Or what would you suggest?

Lastly, I use IPA for cleaning the heads, guides, etc. but how should I clean the pinch roller? I have a translucent pale yellow one (not black rubber)? Again, I have seen some suggest a dry cotton bud held against it as it's playing.

I have also pulled out the signal boards and seen the dreaded Frako caps in there - I know I should get them changed, but I will probably send the boards to someone as my eyesight is not as good as it was 20 years ago and I really don't want to risk damaging a perfect, working machine! BTW - my Avatar is a photo of my machine

So many questions - I bet you wish you hadn't read this Many thanks in advance for any advice,

Neville
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Last edited by Neville; 08-13-2017 at 03:00 PM.
  #2  
Old 08-13-2017, 03:23 PM
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Tinman Tinman is offline
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Hi!

Well.... if the battery measures good and has NO sign of any corrosion, leave it alone for now. It is already a better battery.

I am the one that uses a lithium battery and remove the charging resistor.
I would suggest that in the future, as these batteries hold their charge longer and generally don't leak.

The pale roller is probably from Athan. Grossly overpriced if you HAVE to buy one, so be happy you have it. Soap and water to clean it. Just take it off the deck and wash it, pop it back on.

The caps on the audio boards.

Well, at some point you really SHOULD re-cap the deck for maximum performance. But if it runs fine....

The important one's are on the stabilizer board and the main backplane board. If anything, you should do those before even touching the cards themselves. DO NOT let the wrong "tech" work on that deck! They will likely just ruin it. The A810 is a very complex, highly tuned machine. If you need it serviced, find someone that specializes in Studer and Revox gear. Not a shop that can fix the occasional Teac reel to reel.

You are in a different league now.

Otherwise, fantastic machine, isn't it?

Enjoy it.
  #3  
Old 08-13-2017, 04:27 PM
vintagepc vintagepc is online now
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I would not replace a NiMH with lithium without extended study and care that it will work. They are different technologies and need to be charged in different ways.

In applications like this NiMH is probably better, they are much happier being mostly topped up and constantly float-charged than Li cells. If you've ever had a laptop in a mostly stationary location for a long time (years) and then go to unplug it, your battery will probably be flat in a matter of minutes even if it's never had a single discharge cycle.

To retain the memory while swapping the battery, you simply parallel in the correct voltage as mentioned; then you can remove the old battery and place in the new one without power loss and memory. It's a pretty common technique with car batteries so you don't have to go to the stealership to have your stereo/MCU reprogrammed etc. Of course, a sound backup is still good insurance just in case.
  #4  
Old 08-13-2017, 07:31 PM
Knasty Knasty is offline
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I have used lithium batteries on my 3 A810 MPU boards for years.
When you install them you lift a resistor to prevent them from being charged.
All they are doing is powering one chip that holds the calibration settings, last for
years with much less chance of corroding and damaging the board.
Google "3.6 volt 1/2 AA battery with leads" fits perfectly.

Definitely do the Frakos on the backplane and stabilizer board, and the Rifa X2
caps (they really stink if they let loose).
  #5  
Old 08-13-2017, 10:00 PM
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390FE 390FE is offline
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If I were in need of replacing that batt I would replace with the same or similar as they are still readily available on Ebay & other places for cheep.

NOW if the batt was hard to get and/or expensive I would then do something similar to what you were suggesting.

Though if it is hard to get at or have to disassemble a lot to get to it then I would mount a holder on the chassis easy to get at also with some insulated disconnects on the leads for easy disassembly if needed.
  #6  
Old 08-13-2017, 10:33 PM
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Quote:
Originally Posted by vintagepc View Post
I would not replace a NiMH with lithium without extended study and care that it will work. They are different technologies and need to be charged in different ways.
I think you didn't read the part about lifting the charging resistor. You can most certainly NOT use a rechargeable lithium as is, OR a primary cell without disabling the charge circuit.

But using a lithium primary cell is the longest and safest memory retention we currently have as an option for maybe rarely used decks. But the above all is not having to worry about the battery leaking. NiMH need to be charged more often, due to higher self discharge. So you COULD loose all your settings if you stored your deck a little too long. So "OK" but not "Ideal" for the occasional use in the home. I used to have to remember to actually turn my deck on just to top up the battery!

MY next move will be using a FRAM chip in place of the SRAM and removing the battery altogether. I am already doing this in some oscilloscopes that use an old DALLAS chip with no problems whatsoever.

Read up on this, it's pretty cool. It's also now being used to convert battery backed ram in old arcade games, etc. Retention is supposedly ... well, longer than WE will live.

Lastly, maybe someday we can develop a new MP board for these decks based on a modern platform which would allow a vast extension of the storage and calibration parameters of this machine.

I THINK... (correct me if I'm wrong) we are looking at only 16 address lines and not nearly enough storage. Imagine toggling between ... say 16 different tape configurations using the tape A/B button and having the display show the setting number and then returning to counter.

All possible. Alas... I am a tech, not a PIC programmer.....

Anyone up for a challenge? The card itself and the bus is pretty simple.

Anyway, back to the regular scheduled programming...
  #7  
Old 08-13-2017, 10:36 PM
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Quote:
Originally Posted by 390FE View Post
If I were in need of replacing that batt I would replace with the same or similar as they are still readily available on Ebay & other places for cheep.
Yes, cheep. Do read the date codes on those batteries being peddled for "NEW".

Be careful with that! "NEW" as in "never used, old ass stock"
Stay off ebay for memory batteries if you plan on getting one that lasts more than 4 months.
  #8  
Old 08-14-2017, 12:36 AM
tapefanatic tapefanatic is offline
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Can you use multiple MP boards to store multiple parameters? You put in the 2nd MP board if you want the tape types 3 and 4? Might be a stupid question
  #9  
Old 08-14-2017, 03:01 AM
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Neville Neville is offline
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A huge 'thank you' to everyone for all these really helpful comments. I hadn't appreciated the Lithium option was a long-term fixed cell that shouldn't be charged. I'll probably stick to replacing with a NiMH for the time being - bought from a reputable source!

As for the Frakos and the backplane, I'll not attempt doing that myself as that will clearly require dismantling the unit to remove the backplane, not just pulling a card. The machine is running beautifully, so for the time being, as you suggest Tinman, I'm just going to enjoy it

Neville
  #10  
Old 08-14-2017, 04:25 AM
vintagepc vintagepc is online now
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Quote:
I think you didn't read the part about lifting the charging resistor. You can most certainly NOT use a rechargeable lithium as is, OR a primary cell without disabling the charge circuit.
Almost... I did read it but misinterpreted "remove" as bypass. My bad.
  #11  
Old 08-14-2017, 01:57 PM
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Quote:
Originally Posted by tapefanatic View Post
Can you use multiple MP boards to store multiple parameters? You put in the 2nd MP board if you want the tape types 3 and 4? Might be a stupid question
You COULD do that....

OR... you could just hook up a PC to the deck and talk to it directly. These decks were designed to be remotely controlled, so you can in fact read out and back in any saved parameters you want.
  #12  
Old 08-14-2017, 04:48 PM
Knasty Knasty is offline
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some nifty programs to play around with if your A 810 has serial port
functionality.


http://pe9ghz.org/cmsms/index.php?page=studer-a810
  #13  
Old 09-12-2017, 01:22 PM
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Nakdoc Nakdoc is offline
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I repaired an A810 with an EE error on turn on. Several of the led status lights were out and the deck would not play. It turns out the battery was absolutely dead. Replacing it changed the readout to "PPP00". Pressing master reset restored all operations.
I am impressed with this deck. Everything you need to know is buried in the lengthy service manual. I found chapter 9 useful, covering firmware updates. For example, we learned that the play EQ (CCIR/NAB) button only affects 15 and 30 ips speeds, and will only change if you press and hold STOP, then press the EQ button.
Entry of the data is pretty fast.
  #14  
Old 09-12-2017, 03:17 PM
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Quote:
Originally Posted by Nakdoc View Post
I repaired an A810 with an EE error on turn on. Several of the led status lights were out and the deck would not play. It turns out the battery was absolutely dead. Replacing it changed the readout to "PPP00". Pressing master reset restored all operations.
I am impressed with this deck. Everything you need to know is buried in the lengthy service manual. I found chapter 9 useful, covering firmware updates. For example, we learned that the play EQ (CCIR/NAB) button only affects 15 and 30 ips speeds, and will only change if you press and hold STOP, then press the EQ button.
Entry of the data is pretty fast.
I'm sorry, but you are clearly in name violation to repair a Studer.

OR.... you can also change the jumper in the deck so you DON'T have to hold stop to change modes. Safety interlocks are for amateurs!
  #15  
Old 09-13-2017, 08:17 AM
dminches dminches is offline
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Which jumper do you change to eliminate the need to press stop to change EQ modes or other settings like tape 1/2?
__________________
Studer A810; Otari MX-5050 BII; Technics RS-1500; Revox PR99 MKII; Pioneer RT-707; Nakamichi Dragon
  #16  
Old 09-13-2017, 10:05 AM
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It is a dip switch setting. Brad has the manual.
Nakdoc moonlights sometimes! And hey, I once had an A77, currently have a B77, and bought a mostly working A700. Steve Smith and I worked together many moons ago before he was hired by Studer.
  #17  
Old 09-13-2017, 02:42 PM
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Quote:
Originally Posted by dminches View Post
Which jumper do you change to eliminate the need to press stop to change EQ modes or other settings like tape 1/2?
THAT Jumper is on the board for the speed control on the right. You have to unscrew the little front panel to get to it.

It's in the manual.
  #18  
Old 09-13-2017, 02:48 PM
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Quote:
Originally Posted by Nakdoc View Post
It is a dip switch setting. Brad has the manual.
Nakdoc moonlights sometimes! And hey, I once had an A77, currently have a B77, and bought a mostly working A700. Steve Smith and I worked together many moons ago before he was hired by Studer.
"Mostly working" A700, huh?

Kinda glad I sold mine. It was failing faster than I could keep replacing parts.
I started seeing IC and transistor old age failures. I do have one good VU meter set left over as well as the whole audio section.

My remaining decks are 2 B77's, a PR99MKIII, 2 Studer A810's and my MX-5050BIII. (All restored)
Sold everything else. I'm WELL covered with these.

I just moonlighted on a BR-20. I admit, it's a damn fine deck!
Just such a shame they didn't implement 1/4track option play like Otari.
  #19  
Old 09-13-2017, 03:18 PM
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My friend has a PR99 playback only deck modified so it has two play heads and no record head. A simple 2T/4T switch is mounted on the front panel. The PR99 has no meters, so it may actually be a special model. Seems like a good use for special transports.
  #20  
Old 09-15-2017, 01:43 PM
bracurrie bracurrie is offline
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Smile Thank goodness Nakdoc will help me.

Quote:
Originally Posted by Tinman View Post
I'm sorry, but you are clearly in name violation to repair a Studer.

OR.... you can also change the jumper in the deck so you DON'T have to hold stop to change modes. Safety interlocks are for amateurs!
Hey, it's ok Nakdoc moonlights. There is a serious shortage of Studer techs that will work on 2 track machines. Maybe Nakdoc can add to his talents. BTW I am an amateur.
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