Thermal Printer PHP 1900 Repair Advice

[CosmicBoy]

Does anyone know how to fix a Thermal Printer PHP 1900.

 

The printer is only printing 2 rows instead of the text (see picture)

I used a different printer top/head from a working printer with the same effect so i guess the motherboard is not working.

 

someone already had the same problem and was able to fix it

 

 

[+acadiel]

Printheads.  Those three screws down there - take them out and (gently) remove the print heads.  Clean the contacts and reinstall them.  Be very careful, they're ceramic and fragile.  I've repaired two units that way.

 

The other option would be the connector to the motherboard where those print heads connect.  Check all of those and make sure there's none that are broken.

 

[CosmicBoy]

5 minutes ago, acadiel said:

Printheads.  Those three screws down there - take them out and (gently) remove the print heads.  Clean the contacts and reinstall them.  Be very careful, they're ceramic and fragile.  I've repaired two units that way.

 

The other option would be the connector to the motherboard where those print heads connect.  Check all of those and make sure there's none that are broken.

 

I have already done that.

 

I used a working printerhead from a working printer and have the same print with the original printerhead.

So i guess the printerhead works.

[+acadiel]

Here's the schematic...

 

thermal_printer_1979.pdf

[CosmicBoy]

18 hours ago, acadiel said:

Here's the schematic...

 

thermal_printer_1979.pdf 12.31 MB · 9 downloads

 Oha ?

Danke

[fabrizio]

Grazie mille. 

[fabrizio]

Thanks to the schematic I repaired mine, it had a faulty uln2003.  Simple enough since it drives the engine, now the problem is that it doesn't print well in the center, only by pressing lightly I can print.  Wonder if anyone had the same problem ...

Edited December 8, 2020 by fabrizio

[fabrizio]

On 12/2/2020 at 11:15 AM, CosmicBoy said:

Qualcuno sa come riparare una stampante termica PHP 1900.

 

La stampante stampa solo 2 righe invece del testo (vedi immagine)

Ho usato una parte superiore / testina di una stampante diversa da una stampante funzionante con lo stesso effetto, quindi immagino che la scheda madre non funzioni.

 

qualcuno aveva già lo stesso problema ed è stato in grado di risolverlo

 

 

It may not be a connector problem but a control circuit problem ... The eprom could be faulty.. 

Edited December 8, 2020 by fabrizio

[+acadiel]

4 hours ago, fabrizio said:

Thanks to the schematic I repaired mine, it had a faulty uln2003.  Simple enough since it drives the engine, now the problem is that it doesn't print well in the center, only by pressing lightly I can print.  Wonder if anyone had the same problem ...

 

Is the printhead spring providing enough tension (pulling back the printhead toward the platen)?  

[fabrizio]

I think that's just the problem, but I also have too old paper is yellowed, I would like to try new paper. 

[+acadiel]

34 minutes ago, fabrizio said:

I think that's just the problem, but I also have too old paper is yellowed, I would like to try new paper. 

That is why we modified the DSR - to allow narrower paper to be used.  (78.38mm or 3 1/8”).   It just narrows the print area by removing two characters.

[+Schmitzi]

On 12/9/2020 at 7:37 PM, fabrizio said:

I think that's just the problem, but I also have too old paper is yellowed, I would like to try new paper. 

 

If you find a source for paper here in Europe, please let me know