Repairing a Phaser 850 printhead (jet stack) thermistor. Is it doable?

[PanamonC]

I have a Phaser 850 and the left jet stack thermistor is bad.

I have disassembled the head and found where the thermistors are embedded and where the signal emerges on the ribbon cable.

Does anyone know what brand (prob Tektronix proprietary) and type of thermistor is used and where one might get one.

I figure I could Dremel out the old one and embed a new one.

Since the head is (by the book) toast, I want to give a repair a shot no matter how invasive the procedure might be.

Plus, for some sick reason, it sounds like fun to me.

Any help is appreciated.

Thanks,
Joe.

Please refer to my previous post for background on this problem.

http://www.tek-tips.com/viewthread.cfm?qid=1511920

 

[ferengie]

Hi;

yo you have a component ID on the print.
Can you give it to me, maybe I can read on my transistor, which type it is and find a similar one

regards
ferengie

 

[PanamonC]

The thermistor is embedded in epoxy. There is no way to read the markings on it, if any.

Thanks,
Joe.

 

[ferengie]

Hei Joe;

sorry; can you explain me a little bit clearer on which print the transistor is.
Maybe - if i can fiind it - i find out anything
regards
ferengie

 

[PanamonC]

I am sorry, but I do not understand what you mean by "which print the transistor is"

Are you asking me what circuit board the thermistor is located on? If so, it is on the back of the printhead jet stack itself.
The back of the jet stack is normally hidden from view. To get to it you have to separate the printhead jet stack from the ink reservoirs by removing the 5 screws along the bottom which are hidden behind silicone and the two screws on top that allow the spring loaded clamp to come apart.
The Thermistors are then located towards the left and right sides of the jet stack. They are embedded into small indentations in the back of the jet stack and are further sealed into it with a tough, brown (possibly thermal) epoxy.

Thanks,
Joe.

 

[ferengie]

Hi Joe;

I am sorry; i do not realy understand you.
I got a "Service Manual" for 850 but i cant find what you ment.
I removed the INK-Reservoirs with 4 screws and see a circuit board which is fixed with 2 screws.

Is ith the circuit board with the red arrow? (attachment)

regards
ferengie

 

[ferengie]

Joe;

also see

Can you give me feedback
regards
ferengie

 

[PanamonC]

Thanks for your help ferengie.

Like I said not easy to get to and is hidden from view.

The "Printhead Drive Board" is not it. However, the jet stack, where the ink shoots out, is the shiny silver plate on the opposite side of the ink reservoirs. It is connected to the Printhead Drive Board by that wide flexigle orange colored ribbon cable that goes under the ink reservoirs.

I too have the service manual and it does not detail or even mention the electronics located behind the jet stack. With the exception of the error codes referring to the thermistors and the instructions to trash the printhead whenever anything goes electrically wrong.

Thanks,
Joe.

 

[ferengie]

Joe;
you wrote:
...To get to it you have to separate the printhead jet stack from the ink reservoirs by removing the 5 screws along the bottom which are hidden behind silicone and the two screws on top that allow the spring loaded clamp to come apart....

The point is, i have removed the ink-reservoirs, like in picture, but I cant find any "silicon" in my printer, do you have a photo?
Is the "ink load assambly" that what you described as "ink reservoirs"?
regards
ferengie

 

[PanamonC]

Ferengie,

There is a picture of the the silicone coverd screws on page 3-108 of the manual where it compares a good cap/wipe/purge vs a bad one.

At the bottom of each picture you will see the 5 hidden screws along the bottom of the head. They show up purplish/gray in the top picture and are black in the bottom one because they are covered in ink.
You have to drive your torx bit into the silicone to unscrew these. Along the top of the head are the 2 screws that release the spring mechanism used to hold the top of the head together.

(The picture you sent is really small and I can't make any detail.)

Thanks,
Joe.

 

[ferengie]

Hi Joe;

on my page 3-108 is a drwaing with the vacuum assambly.
hey do you have skype? now it is 21.05 CET, try to give me a call "ferengie" or "ferengie_in_gsi". (I'm not 100% sure)

regards
Ferengie

 

[ferengie]

let's try this picture

 

[ferengie]

hey Joe, i think i got it!
It's on my page 3-107

You are talking about the green marked screws in this picture:

 

[ferengie]

picture

 

[ferengie]

OK; I have opend this thing ;-)
it is a "Chromalox 119-5983-00 100V 150W".
On

http://www.chromalox.com

i cant find anything about such "heater"/ thermistor.

I think, you can not open the thermistor to repair it, it is like a soldering iron.
Once I tried to repair such iron, but was not successfull.

Maybe someone in this forum has a not working Heating-Unit with a working one in it.

sorry for such "bad news"

regards
ferengie

 

[PanamonC]

Well, that is certainly something!

Where did you find the markings that allowed you to identify the heater?

Thanks,
Joe.

 

[ferengie]

Hello;

sorry, that it took so long;

ok in the heater is:

Chromalox CSIR-3025
119-5983-00 100V 150 W 338PL

Producer: Chromalox
Model: CSIR-3025

Voltage: 100 V
Power: 150 W

What "338PL" means I dont know, also "119-5983-00"
I dint find anything on the web with such technical data.
But it may be that there is an alternative produkt.
(These data are on the metalcylinder which includes the heaterwinding)

Maybe here you will find a "Replacing-Part"

http://www.tamayatech.com/partsindex/part6037.htm

regards from Austria

Ferengie