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ti 59 and pc100 repair

tilover

Member
Joined
Jul 30, 2022
Messages
21
Location
The Netherlands
Hello forum ,

i have 2 trouble makers which decided to rest on my workbench way too long .

So time for repair , but i need more info te get them going ;

- ti 59 ( and an ti58 ) suffer from internal smp powersupply fail .
the little unit does not generate the 2 negative voltages anymore .
i tried to find out the obvious ( tantaliums ) but the were fine , finally i found one broken resistor of unknown value .
so need to know what to use for the 3 transistors , and the value of that one resistor .

- pc100 ( a ? ) this is the type of which i could not find any schematics for , it is the early type with one single board
i noticed fading of the print and that ended in not printing or moving at all .


if you can help me with these oldies , highly appreciated .

regards,
tilover

m_IMG_3009.jpgm_IMG_2114.jpgm_IMG_3019.jpg
 
From the images you attached, it looks like you aren't using the service manual to help determine the problem. If you don't have it already, you can find it here:

http://ti58c.phweb.me/download/system/ti59-service-manual.pdf

It has a different schematic from the one you are using. Also, if you haven't already been there, that website has a lot of TI-59/PC-100 info:

http://ti58c.phweb.me/site/articles.php?langue=EN&smenu=The extensions

including two PC-100 schematics. One for the model "B" and another model (but I don't remember which one):

http://ti58c.phweb.me/download/system/ti59-pc100-schematic.pdf
 
Thanks for the info ,

the problem is that the pc100 schematic is for the newer models ( there are at least 3 versions ) , which have a totally different pcb .

the psm module is never put in a schematic as ti bought them as a sub assembly .
probably mexico or even far east , but with ti marking on the transistors
 
the problem is that the pc100 schematic is for the newer models ( there are at least 3 versions ) , which have a totally different pcb .

I wasn't sure which one it was. I knew there were "A," "B," and "C" models. Which one is the pc100 schematic for? I'm guessing that it's "C" since the site also has one specifically labeled "B."

the psm module is never put in a schematic as ti bought them as a sub assembly .

Oh, I didn't realize you were looking for the PSM module specifically. The rest of the power supply is in the service manual and I thought that's where your problem was. So, in your first post where your said "internal smp powersupply fail," did you mean "powersupply failure in the PSM?"
 
I've taken a closer look at the PC-100 schematic linked to above and it is a PC-100A. Still doesn't match the layout shown that we're trying to find a schematic for, though.

Regarding the TI-59 power problem, someone else had a similar problem and was able to fix things without touching the PSM. Maybe this other forum can give a clue as to what's wrong in your case:

https://www.eevblog.com/forum/beginners/replacement-ti-59-power-module-help/[URL]
 
i think mine is a pc-100 A , so an old one .

the problem is that at the moment no voltages are coming out anymore so as the transformer and bridge are ok , there must be one component failing as all voltages are gone.
-> too hot today to work on it .

the little psm module gave ghost on both repair ti's on my workbench .

the problem is that i could not find any info except the small schematic from sipke , who passed away in 2004

so the only schematic i have is in the picture with my finger on it .

right now my search gave no results .

regarding the powersupply , i am currently making the triple power test powersuply so i can verify if both ti's are salvagable ( and no other components have gone down with the powersupply )

most likely the previous owners ran them without the batteries , so burned parts of the little-guy


if there is any info please let me know ,

throwing away these old beauties is a waste
 
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correction ,
it is a pc-100 so the sr52/56 version .
thus even older as thought .

and the little powersupply could be manufactured by TDK
 
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i have found the patent , and there seems to be some info in that .

the search goes on ....................

there must be people out there who can say something about these old units ??
 
Have you checked over at the HP Museum? There is a topic in the forums there that includes a number of the recipients of the TI-59 mailing list. I vaguely remember an extended discussion on repairs of the PC-100 but the current mailing list archive doesn't go back far enough. Maybe someone there could remember the discussion and provide a good pointer towards the needed information.

It is a challenge to find a dead website on the Internet Archive without knowing what the URL was.

 
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