Re: 82143a printer



#9

Hi;

it seems you have a short-circuited current booster OR a burnet-out head "driver".

If you have paper in the right position and pull it up a little, you'll probably see a vertical black line right ounder the middle of the head (the burners are there). If the current boosters are shortened, almost all power supply is over the head burners (do not let the printer ON or the head will be definitely lost), what explains the ZZZZ (from the power supply) and the "there's_something_hot" smell.

If you want to try, open the printer (five screws, one under each rubber feet and another close to the battery compartment) and carefully detach the flex circuit connector that connects the printer head to the mainboard (there is only one flex circuit). You must use something to move the conector's contact (mainboard) away, because they "pinch" the flex circuit connector tabs. I use a small antistatic piece of plastic so it fits between the contacts and the flex circuit connector. I push it in and carefully pull the flex circuit connector, then I pull the plastic out.

Then you can briefly switch the printer ON and simply verify if the BATT LED is off and only POWER LED is ON. Take care not allowing the flex circuit to touch other components and do not attach the printer to any HP41 door.

I can have a look in my 82143A and try to identify the head components, but you should also wait for other posts to help more.

Cheers.


#10

I remove the flex near connecting the head and then it stop getting hot. And yes you are true, if i hand throw the paper when on it leave a black trace on it. I change 2 capacitors but i still get the BAT allert and the power on light is not very bright. Without the the flex plug, i can hear the noize only 1 second when i put it on. Another hint : if i push the advance button, the on light get brighter, the bat light get darker and i hear the "capacitor like" noize till i release the button. I think the noize come from the AZTEC "chair like" big part.


#11

Hi;

let's get this thread, then.

I have once my own 82143A with a problem closer to this one. Mine is an earlier model, and it has a problem: if the AC adapter is connected without the batteries (or at least one low-voltage reference), one of the printer's IC (Integrated Circuit) seems to burn out. I found it out by doing it! Inadvertently. I simply connected the AC adapter and turned the printer ON. It worked for less than 20 seconds and stopped with the BAT indicator ON. Then I saw the battery outside the compartment (I used to take it out when I was not using the printer for a long time). Bye-bye printer...

At that time, HP still repaired this model (198x) and I sent it to the Brazilian repair center.

Maybe you have a related problem, because a lot of them appeared as I insisted using the printer that way. After a few minutes switched to ON the BAT LED lit even with the AC adapter plugged in. Then it printed unsual characters and, suddenly, an all-black "banner" in all lines. At that point I switched it off. I believe if I insisted I would have the drivers and/or the current boosters burnt out. Maybe that's what happened to yours.

I'd try an old 82143A and replace one particular IC that seems to be the one that burnt. The IC I'm referring to is right between the Vac input connector and the interface connector and it's code is 1026-0287. At least this was the only component HP repair center replaced. I draw a single PCB layout with all components and compare with the printer after it returned (I waited for twelve months till warranty expired): the only one change was this one. Even the power supply was the same (the little printed circuit board you're probably comparing to a chair).

You should expect other posts about this subject to confirm what I experienced once. Not too much probable, but maybe it's a big coincidence, who knows.

Hope you have success.

#12

I locate the component but there is no replacement for that chip i think :-(

Where can i find a schematic of the electronic for the printer?

It's sad to say but i think i'll nedd another printer. where can i find one, i really use if often at my job and don't want a Notebook-PC with a battery operated printer it's too big and lees programmable... I heard that there is a infrared printer available at HP now, is it plugable to my calc with some sort of hp-41 IR output?

Probably i'll nedd to upgrade to hp-49 or 48 :-( with the infrared printer But i don't really need all these graph and speciality mode I LIKE MY "vintage" 41 SYSTEM. i have one intensively use CX and one printer now dead :-(((.. probably i'm too retrograde and need to evoluate! As a proof is i reach help on a museum site for obsolete technology!!! Is Texas instrument, sharp or Casio manufacturing a key-programmable calculator with printer? What other solutions do i have???


#13

Hi, Frederic;

does the chip ID # match? If so, maybe yours is already an upgraded 82143A. Let's check for serial #: mine is 2141S40xxx (Singapore, 1981). Is yours earlier or newer? First two digits + 60 gives the tens for the year (21 + 60 = [19]81). You should keep waiting for any other suggestions, my tips are based only in my own printer.

Anyway, have you checked if the IC is getting hot? Any of them? A few (not custom) chips used in some HP equipment have commercial replacements. I doubt calculators have, but let's consider the fact the 82143A is a thermal paper printer. There are other.

About schematics, I'd like having this one, too. If you find it... please?

Cheers. Sorry not helping the way I'd like to.

Success.

#14

Frederic,
Is trying to fix your printer fun for you ? If not, may I suggest you try a upgrade.
I am sure Luiz can help you substitute your 41cx+printer for a 42s+IR printer - both are more reliable than what you have now, and programs are compatible.
Even if you manage to fix it now, it will sure fail again in the future.


#15

Hello, Renato;

thak you for the add-on and support

In fact, Frederic, I can also help you even upgrading your system for an HP48 + 82240A or B, it's up to you.

If you have programs written for the HP41 system and need their version for any of the systems, I'll translate them for you. In fact, from the HP41 for the HP42 we can face some difficulties with the X-Functions (mostly ASCII files) and both time functions and some peripheral devices, not available for the HP42S. Anyway, in most cases, tese functions may have their counterparts in the HP42S system (except time functions). If not, they can be simulated by extra programs. There is no I/O facilities in the HP42S, what makes it impossible to emulate a complete HP41 system.

About the HP48... well, if you are willing to upgrade to an HP48, let's talk about it as soon as you want to.

Cheers.

#16

The 82143A printers tend to be fairly reliable. You can find them on Ebay almost any day. Typical sell price for a bare machine is around $25. Most problems found are dirty drive mechanisms, stretched out drive belt, etc. Other common faults can be bad print heads and broken battery contacts. Machines you find on Ebay always have bad or missing batteries and most are missing the power plug and manual.

Is your machine the one type with the silver timing wheel that is driven by the belt, or the black one on the other side of the machine from the belt? I may have a replacement electronics board in the junk pile.


#17

2133s40362 is the serial number of my printer. There is a belt and a wheel with metal pinch very cute... Probably for the detector just up these pin wheels.

#18

Yes it's the same board! I you don't need your extra one you can sell it to me!!! :)


#19

I am still looking for my board. It wasn't where it should have been. There are two types of boards used in these printers. One is where the toothed timing wheel is near the belt, the other where it is on the other side of the printer from the belt. Which version do you have?


#20

The timing-teeth wheel is attach to the strap to another smaller pulley connect directly to the motor.

#21

The 82143 power supply is rather complicated. The battery voltage is stepped up to abo ut 18V for the printhead (the actual voltage is set by the intensity switch) by the 0950-0408 module.
This voltage is then regulated down again by a switching regulator to give +5V for the logic.
The printhead elements are driven by the 75473 (8 pin) chips. Perhaps one of those has failed, or perhaps the custom-programmed 3870 microcontroller is malfunctioing.
Disconnect the printhead flexiprint, and try the printer again (it's OK to connect it to the HP41 with the printhead disconnected. If it works (obviously it' won't print, but if the paper feeds correctly, etc) then most of the microcontroller is working. I would then check the 75453 chips, etc (oops, I meant 75453, not 75473, a few lines earlier!)


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