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Products => Test Equipment => Topic started by: Charlie_90 on May 03, 2023, 06:47:50 am

Title: HP 4195A Reparation
Post by: Charlie_90 on May 03, 2023, 06:47:50 am

Hi all,

I've got an old HP 4195A.

At the beginning, it worked. Everything went fine and so on. The thing was that the floppy drive was so dirty and decided to clean it. Once I did it, I inserted a floppy disk and error message appear in the screen (something like cannot read the disk).

I tried to use other floppy drive units but doest not work and even made that the screen was on but black with a beep sound.

So, now...the HP 4195A does not "work". It starts up but cannot show nothing on the screen and the beep sounds is constant.

Any ideas?

Many thanks in advance!

Title: Re: HP 4195A Reparation
Post by: samofab on May 03, 2023, 07:04:36 am

Service manual with full schematics can be found on the internet - start there.

Title: Re: HP 4195A Reparation
Post by: fenugrec on May 04, 2023, 12:40:30 am

Quote from: samofab on May 03, 2023, 07:04:36 am

Service manual with full schematics can be found on the internet - start there.

+1.

You will then want to look at the power supply module (a few infamous RIFA caps), and the RAM backup battery on A6 or A8; a dead battery will cause boot failues (I repaired mine thus : https://www.youtube.com/watch?v=0VhyDC1DTCk (https://www.youtube.com/watch?v=0VhyDC1DTCk) ), and if it leaked out and corroded the board other weird problems could pop up.