chiplonkar

asked Sep 1, 2007 at 1:49am
Hp HP DeskJet 670C

encoder strip in hp670c printer

While troubleshooting on my hp670c, I have removed the encoder strip several times and it always worked whichever way I put it back. I mean the orientation.

Today I noticed that at both ends of the film are some small letters marked. When read through magnifying glass the letters turned out to be " EMULSION SIDE " and some code number.

What is the meaning of EMULSION SIDE ? Does it have any significance with orientation of the film ? I did not see any difference in the pattern of closely spaced black lines when viewed from either side.

Can any one throw some light on this ?

Chiplonkar
Emulsion, in this case, is the photo sensitive coating needed to produce the lines. Encoder strips are processed similarly to film based photographs.

I have worked on many 600 series printers and the orientation of the encoder strip has never seemed to make any difference.
by Bert on Sep 1, 2007 at 9:33am Add comment
Thank you very much Mr. Bert for immediate response second time!
You may recall that I had asked a question in this fourm about yellow LED blinking immediately after print command on my hp670c.

Problem has now shifted its focus to plastic flat cable running behind the color cartridge. I found that the gold plated domes making electrical contacts with cartridge(49)were damaged due to corosion. I guess ink leaked from somewhere has corroeded two or three contacts. I managed to get a new cable from a shop and now the symptoms have changed to worse.

Earlier, atleast, the cartridge carrier was moving smoothly in and out after opening the cover. Now, the carrier gives a jerk and printer trips ( Power ON and RESUME both leds flash alternately. Manual indicates this to be due to mechanical jamming of the carrier. Actually it is not. )

Some time during investigatins, I had expereinced this type of jerky movement when encoder strip was forgotten to be put in place. Now encoder strip is well in place and is good also.

What must have further gone wrong ? PCB ?

I have a lot of time. And patience is ample.


Any thoughts ?

Chiplonkar
by chiplonkar on Sep 2, 2007 at 8:39pm Add comment
Either the encoder strip is not detected or the carriage rod needs lubrication.

If you have not already, clean the carriage rod and lubricate it with very low viscosity oil. Lubrication that is too viscous can cause the carriage to bind.

Perhaps the new cable is in worse condition than the one you replaced or the encoder strip is not threaded through the sensor on the carriage. If the encoder strip is installed correctly, then the problem could be the carriage electronics, the carriage cable, or the main electronics.

I have repaired over one hundred Deskjet 600 series printers and found less than five that had failed electronically. The rest started working again after cleaning and lubrication.

by Bert on Sep 3, 2007 at 12:25am Add comment
Further Development :

I have found out the reason for cartridge-carrier giving a jerk and tripping the printer. From the begining, when these symptoms started appearing, I have been suspecting some connection with encoder, encoder strip etc. However, because I had changed the flat cable for COLOR cartridge when the symptoms appeared I was concentrating on that change.

Tody, I found that the falt cable which carries encoder signal was damaged near the gold plated connectors near the pcb. Only three or four contacts were cut open. I cut the edge of the gold plated connector by a cutter,by about 1 mm, and the cartridge movement became normal and smooth.

Actually, now I am back to original problem. I have following question:

When I run the printer utility program on pc, and open/close the cover of the printer, I get error windows appearing and disappearing as per the movement. However, behind that window another error window is present which says " INCORRECT INSTALLATION. TRY INSTALLING COLOR CARTRIDGE AND PRESS OK TO CONTINUE. "

If I put another bad cartridge, the message changes to " CARTRIDGE NOT FOUND "

With first cartridge it does not say the cartridge is not found, but it says that installation is incorrect.

Any suggestions ?

by chiplonkar on Sep 6, 2007 at 9:06pm Add comment
Install a known good cartridge.
by Bert on Sep 7, 2007 at 7:23pm Add comment
Thank you Mr.Bert for the suggesion. I will try obtaining a new dummy (blank) color cartridge and test. New one is costly and also I do not need COLORS.

Whatever this printer has taught me, I have put it on http://freeideas.bizhat.com/hp/hp670.htm

You may have a look.

Chiplonkar
by chiplonkar on Sep 8, 2007 at 3:45am Add comment