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ImageWriter II - one pin does not work

rollmastr

Well-known member
Hello everybody,

I hope I am not the only one tinkering with old printers. I got an ImageWriter II to match my Mac Plus, SE or SE/30 and while the printer cleaned up quite nicely there is one problem that I was unable to fix so far and that is annoying me very much.

The middle pin does not work, see this picture from the self test:
IMG_9883.jpeg

What I've done so far without any change in behavior:

- replace the ribbon
- check and clean the connector to the print head PCB
- replace the flexible cable with with a tested good one (I checked every trace with a multimeter)
- replace the print head with a used one. I measured all nine coils with a multimeter and verified that none are open. I then took apart the original print head and all pins look fine. I switched them around, reassembled the print head and the missing dot remained at the same place.

I would appreciate any ideas. Thank you.

/edit: I forgot to mention that all capacitors look fine. No leakage or corrosion whatsoever.
 

Johnnya101

Well-known member
At this point, wouldn't the last suspect be the logic board? Not really familiar with the ImageWriters.
 

Iesca

Well-known member
Check out page 239-240 of Macintosh Printer Secrets. Maybe this is it?
 

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rollmastr

Well-known member
Thank you! Unfortunately that's not it. I did suspect a bad print head so I got a used one. I then took the old one apart, thoroughly cleaned it and inspected all the pins, switched them around and nothing changed.

I think @Johnnya101 must be right that either the logic board or the psu board is faulty and not actuating one pin. I was hoping someone could give me some hints on how to troubleshoot the PCBs. Unfortunately no bad components are visible and also the capacitors look great. I did reflow the pins of IC6 on the driver board, but it did not do anything.
 

trag

Well-known member
Thank you! Unfortunately that's not it. I did suspect a bad print head so I got a used one. I then took the old one apart, thoroughly cleaned it and inspected all the pins, switched them around and nothing changed.

I think @Johnnya101 must be right that either the logic board or the psu board is faulty and not actuating one pin. I was hoping someone could give me some hints on how to troubleshoot the PCBs. Unfortunately no bad components are visible and also the capacitors look great. I did reflow the pins of IC6 on the driver board, but it did not do anything.

@techknight did a thread on a full rebuild of an IWII a while back. You might look that up and see if htere are any relevant portions.
 

jajan547

Well-known member
Hey there if you can be patient I have the full apple service manual on these with an original wiring diagram schematic. I ordered a scanner and can have it uploaded tuesdayish.
 

techknight

Well-known member
Hello everybody,

I hope I am not the only one tinkering with old printers. I got an ImageWriter II to match my Mac Plus, SE or SE/30 and while the printer cleaned up quite nicely there is one problem that I was unable to fix so far and that is annoying me very much.

The middle pin does not work, see this picture from the self test:
View attachment 43310

What I've done so far without any change in behavior:

- replace the ribbon
- check and clean the connector to the print head PCB
- replace the flexible cable with with a tested good one (I checked every trace with a multimeter)
- replace the print head with a used one. I measured all nine coils with a multimeter and verified that none are open. I then took apart the original print head and all pins look fine. I switched them around, reassembled the print head and the missing dot remained at the same place.

I would appreciate any ideas. Thank you.

/edit: I forgot to mention that all capacitors look fine. No leakage or corrosion whatsoever.

it is probably the driver IC to the printhead. there is a driver for each pin.

the drive transistor for the coil probably failed. I dont recall if all of the pin drivers are in a single IC or not, and if so, change the IC.
 

rollmastr

Well-known member
In case you're wondering about the print head... This is what it looks like taken apart.

IMG_8930.jpeg

IMG_8941.jpeg

Reassembly was quite fiddly, but it still worked except for the middle pin even though I switched the pins around. Next I got another print head and the printer showed the exact same behavior. I also measured all nine coils and verified that none was open.

So... since the theory of the blown driver IC seems more than plausible I got another beat up ImageWriter II to salvage parts from, however upon arrival I discovered it's the third revision (which Apple calls ImageWriter II/L) that is quite different from the older models. My malfunctioning ImageWriter II is the second revision.

IMG_0394.jpeg

While it's a bummer that thos solution will not fix my cosmetically beautiful IW II the good news is, after some elbow grease the II/L not only works, but it also cleaned up decently. It will definitely need some retrobright though since it not only is yellowed, but the yellowing is uneven as there were some stickers on the panels.

First I planned to just swap parts from the case, however I discovered that nothing fits! Compare the feet of the Rev 3 on the left vs. Rev. 2 on the right.

IMG_0408.jpegIMG_0403.jpeg

I just placed an order for a jug of peroxide...

/edit: Here's a comparison of the labels on the underside. Rev 3 on the left, Rev 2 on the right.

IMG_0396.jpegIMG_0407.jpeg
 

jajan547

Well-known member
Hey there I finally uploaded a huge binder describing all troubleshooting and diagnostic/hidden service modes. This guide covers the ImageWriter and ImageWriter II, I hope it can shed light on your problems. Link is HERE.
 
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