Hp 97 print head problems-missing row

[teenix]

(06-11-2021 02:17 AM)kleinwaechterj Wrote:  I just aquired a Hp-97. I successfully repaired the card reader, working flawlessly again. The printer has the usual issue of flattened wheels but I am hopeful I will be able to fix that too. What is more of a problem is that the middle row does not print at all, leaving a blank horizontal line through all characters. Not unexpected, resistance of that element is high, all others read 11-12 ohms at the ribbon cable. Any hope this is fixable? Are there any sources for replacement heads? Any chance it is a loose contact on the other side of the cable connecting to the head)? Any suggestions would be very much appreciated, this calculator is otherwise in great shape and a real beauty.....
Thanks for reading...
Jk

If you measured the resistance with the ribbon cable in its socket, it may be the socket connection.

You need a tool to remove the cable or it will most likely be damaged permanently.

Otherwise it sounds like the head pixel is failing or the connection to it.

I think this type of problem is impossible to fix. You cannot repair the head, and the connection cannot be soldered due to the materials used in construction. HP knew this and had to stitch weld the connection together. This might be the point of failure.

The ribbon cable might also be faulty somewhere along its length (a partial break in the associated track) although I don't think this is repairable either.

Just an opinion - Hopefully I'm wrong :-)

cheers

Tony