HP 9825A with DC 100A tapes


I've heard that the write head electronics has to be modified with a resistor (I believe that may mean increased write current). Does anyone know this to be the case and if so what the exact change is. I have tried 3M DC100A's (no longer made even by Imation) but I believe them to be too old, or maybe the resistor is necessary. In any case I need some recently manufactured tapes to copy some programs for long term storage. (5 to 10 years). Any help is appricated.


I use 3M DC 100A cartridges with my 9825 & 9815 without problems.

I did not modify the write head electronics in any way so I'd guess your own 3M might be to old, these things degrade quite often on the long run.

My 3M were purchased in a batch on Ebay 2 years ago and they work fine.

John's site has an excellent tips section dealing with tapes here.

At the bottom of the page, you'll notice that the head modification is only necessary with Athana brand tapes.

Did you succeed in writing at least one tape on your 9825 ?

Can you elaborate on the symptoms ?


Edited: 6 June 2006, 1:01 p.m.


Yes the 9825s are good working machines. We have only used 98200As in the past. Since these are no longer available new, we are looking for a replacement. 3M (Imation) no long makes DC100A, apparently due to lack of demand. The company I work for has decided to implement better control and thus means if the tape is over 5 years old it can not be relied upon to last another 5 years. Therefore copying onto newly manufactured tapes is required. John's site dealt with the HP85 so I was unsure about the HP 9825 needing the head current increase. Athana must be using magnetic particle that require more magnetism to change but would last longer in use without fading.

My problem with the 3M was with the transport and folding of the tape back onto the spooled tape. This one may be due to old tape becoming slightly sticky and not moving smoothly. In some cases after I wrote block (reserved it) and then tried to write a different length right behind it, all I got were errors and an inability to find the first file.


3M shrink-wrapped DC-100A do appear regularly on Ebay and this is my main source.

However, if you do need **recently** manufactured tapes, Katie had positive experience using DC-1000 (yes 3 "0"s) on her 9825 as you will find in this thread and this one.

It appears that the DC-1000 were more recently manufactured than the DC-100 and would not need the write head modification.

Good luck.




re: "This one may be due to old tape becoming slightly sticky and not moving smoothly"

Did these tapes ever get hot? I know (from sad experience) that the particle binder on overheated mag tape can get soft and sticky. (Although, as I remember from almost 20 years ago, I think that it was really a problem only when the tape was hot. If you let it cool down, things were better.)


Only if you consider a warm office environment (around 75 to 76 degrees F). But I believe them to be old tapes since 3M quit making them when they became Imation(1996), then Imation quit making DC100A tapes around 2000 (due to lack of demand) according to the 3M people. Unless tapes are held at low temperatures (around 60 deg. F) and low humidity (around 30 percent) the binder will asbsorb moisture and become sticky (and life limited to around 10 years). Tapes still sealed my reduce that but no quarentees.

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