I have a card reader and it seems fine mechanically, it pulls through the cards and does not leave any messy deposits on them.
However after appearing to record a file it will not verify and I always get CARD ERR immediately.
It does the same on both my 41CV nd 41CX.
I don't know if it is not recording or not reading the cards as I have not got any recorded cards.
Can anyone help by offering to send me a pre-recorded card with a small program on it? (I am in England). I can then at least check if it reads ok.
Also any other offers of help to diagnose the problem are welcome. I am an electronics engineer and could pull it apart to check signals on the record head etc, but I want to do as much diagnostic work as possible before dismantling it. I do already have the excellent repair articles which have been published on this site.
Thanks.
HP-41 Card Reader - HELP
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09-24-2002, 08:20 PM
09-24-2002, 10:19 PM
Hi; Let me get to the problem. Forgive-me if I ask a silly question: what are you doing, so you record data in a magnetic card? When you mention record a file on it, you mean any of the possible data - program, registers, status or all information? Or an specific data type? The CARD ERR appears anytime you attempt to read or record or only when reading? I have not seen CARD ERR when recording cards, only when trying to record on bad magnetic cards. Did you try the VER (verify) function? I'm an Electrical Engineer, and I just want to focus on the possible problems. Best regards.
09-25-2002, 10:28 AM
Two possible problems: 2) Readers that write but do not read are almost always caused by a defective tantalum bypass cap on the reader chip power supply. It is usually a small blue dipped tantalum that has developed a high ESR. It usually tests good, but replace it anyway. There are two other caps on the read head windings. They are probably OK. Some readers have a fourth tantalum. It is probably good also.
09-26-2002, 08:06 PM
Dave, thanks for your help.
09-26-2002, 08:17 PM
Hi, here is a clearer explanation:
09-26-2002, 10:22 PM
Hi; After the description, I must agree with David. He is right (he's been right since the beginning; I was the one who did not understand the problem): you should disassembled the reader. I have done it myself for at least five times; it's a safe procedure, be confident and check for the contacts and capacitors. I have not done it yet, but I'd do it, based on our experienced contributors' (valuable) guidance. In fact, I have done so many things based on them, the last one being the upgrading to 32K RAM in an HP42S - Thank you, Randy! -, that I'd do without hesitation. Success!
09-27-2002, 01:53 PM
Apologies for not replying sooner... I am in the UK, and have a working HP41 system (with card reader). I would be happy to write a couple of cards for you and post them. Or I can see if I can read cards that you've written on.
09-27-2002, 02:46 PM
Hi Tony, thanks for you kind offer.
09-27-2002, 03:22 PM
Hi Dave, if you email me I will be able to reply to you and attach a picture of the card reader. I have added an arrow pointing to the cap I think you mean, but I would like to check with you that it is the right one before trying to change it. Also, can you give me some advice on the best way to remove the psu board?
09-27-2002, 04:34 PM
My view is that you should never use 'lucky dip' methods of faultfinding/repair and that at this point you haven't collected enough evidence to decide if a particular capacitor is faulty or not. However, I can tell you how to take the thing apart.
09-29-2002, 08:00 PM
Your help is very much appreciated, and if I could get to the HPPC meeting I certainly would. I agree that I should diagnose the problem before doing anything and if you are willing I will continue to use email to try to pinpoint the problem.
09-30-2002, 07:57 AM
Hi Tony,
slightly off-topic,
Does the LogicDart have an HP-48 display? Regards, Raymond |
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