Dead HP97



#14

Got a defective HP97, thought it was the battery, but it works fine.
When switching on, some '0' (not always the same) light up for some milliseconds, but then the display remains dark.
(When shifting the printer head by hand, it returns to its initial position and when disconnecting the printer pcb, some '0' stay lit)
Checked all contacts, and wanted to figure out whether the power supply circuit works and all ICs get their correct voltage, but without any documentation...

Is this a typical failure with simple solutions or has anyone some info e.g. required voltages or signals (clock generator) on special pins or info on the used ICs? (pcb is the same as on http://www.hpmuseum.org/97intern.jpg)

Michael

Edited: 2 Nov 2003, 5:30 p.m.


#15

The complete service manual is on the MoHPC DVD... :-)


#16

> The complete service manual is on the MoHPC DVD... :-)

No need for the ":-)". Now that I know about it, I'd really like to order the CD or the set.
But could someone please confirm, that this manual contains something more than simply "how to replace the battery", "cleaning the keys" or "removing paper from the printer feeder"... 8-) (someting like a circuit diagram and signal descriptions)

Edited: 3 Nov 2003, 9:52 a.m.


#17

Quote:
could someone please confirm, that this manual contains something more than simply "how to replace the battery", "cleaning the keys" or "removing paper from the printer feeder"...

Of course there's more than that. It also shows you how to turn it on and off. 8^)

Seriously, though, it contains diagrams galore, information to a level of detail that I don't really understand (my expertise in electronics is very limited). I believe it will help you get the 97 repaired or, at the very least, help you diagnose the problem.

The CD set (or DVD) is an incredible resource. You should get it ASAP.

-Ernie

#18

Quote:
But could someone please confirm, that this manual contains something more than simply "how to replace the battery", "cleaning the keys" or "removing paper from the printer feeder"...

That would be in the users manual...

Honestly, you get pointed to the most valuable resource you'll even find to fix a 97 and all you can respond with is a flame about me putting a happy face on end of my message?

You asked for information, I gave you the source.

You're welcome, in spite of your comments.

BTW - make sure the battery is indeed good under load. A print head that doesn't return to the home position is either a dead battery or a locked up printer. It's common for the battery voltage under no load to measure good but it can't deliver much in the way of current, and 97's love their batteries...

Edited: 3 Nov 2003, 11:08 a.m.


#19

> and all you can respond with is a
> flame about me putting a happy face
> on end of my message?

Please excuse me, that is in no way what I wanted to express. I am not a native speaker of English, and what I wanted to say is that I got the hint that there is a way to support hpmuseum.org, what I really would like to, as it is a nice place to get information, contact, and quick help like your's.

> You're welcome, in spite of your comments.

In future I will be more sensitive.

Michael


#20

Then lets call it a complete misunderstanding and get on with your 97 repair efforts!

Edited: 3 Nov 2003, 12:09 p.m.

#21

The 97 service manual on the CD set contains block diagrams, disassembly instructions, parts lists, test procedures and partial schematic diagrams, but not a complete schematic. It's quite useful however and should at least help you in determining what's not the problem.

Edited: 3 Nov 2003, 5:15 p.m.


#22

The HP97 service manual schematic is quite complete... it is just spread out over several sections.


#23

David,

I stand corrected. It is all there along with parts placement diagrams as well.
Thanks for pointing that out!

-Katie


#24

Thanks for your information. I already ordered the DVD on tuesday, and as it is shipped on thursdays, I expect it to arrive next week.

Michael

#25

The HP97 requires the printer circuit board to be installed... it contains the CPU clock generator. Also you need a GOOD battery installed. Also the printer needs to be operational (or at least have the head at the HOME position).


#26

The print head returns to its home position on its own, when shifted by hand, so I suppose the battery delivers enough current.

>it contains the CPU clock generator

So if the LEDs stay lit without and become dark with the printer pcb, that could mean that the CPU starts its reset-routine but gets stuck somewhere (or that the printer pcb contains the power on reset circuit, which also clears the display buffers...)

As soon as the DVD arrives and if I get my oscilloscope fixed (another case...), I'll do some measurement on the voltage drop and the clock signals.

Michael


Edited: 7 Nov 2003, 12:59 p.m.


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