Has anybody definitively identified the BOB (Blob On Board) in the attached
photo? One forum says it is a Hitachi HD66710

(http://www.hardforum.com/showthread.php?t=761414)

After tracing the board and looking at the data sheet for the HD66710, I
can't
reconcile the chip pinout to the actual circuit. I believe the BOB has at
least
110 pins if one begins counting vias where 78 & 79 are screened. Since 110
isn't evenly divisible by 4, I'd guess that not all the pins are brought
out.

Thanks in advance...

"Lord Garth" wrote in message
. ..
Has anybody definitively identified the BOB (Blob On Board) in the
attached
photo? One forum says it is a Hitachi HD66710

(http://www.hardforum.com/showthread.php?t=761414)

After tracing the board and looking at the data sheet for the HD66710, I
can't
reconcile the chip pinout to the actual circuit. I believe the BOB has at
least
110 pins if one begins counting vias where 78 & 79 are screened. Since
110
isn't evenly divisible by 4, I'd guess that not all the pins are brought
out.

Thanks in advance...

The blob shape looks Epson(ish).
Probably a custom built 'pixel' graphics controller chip special for that
particular display. I'll bet absolutely no details are available. Anyway,
character set pixels would have to be supplied by yourself.
There's a nice article on interfacing to a Nokia phone, serial drive, colour
graphics LCD, on the Elektor magazine site.



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On or about 2007-05-11 22:09, Lord Garth is reputed to have said:
Has anybody definitively identified the BOB (Blob On Board) in the attached
photo? One forum says it is a Hitachi HD66710

(http://www.hardforum.com/showthread.php?t=761414)

After tracing the board and looking at the data sheet for the HD66710, I
can't
reconcile the chip pinout to the actual circuit. I believe the BOB has at
least
110 pins if one begins counting vias where 78 & 79 are screened. Since 110
isn't evenly divisible by 4, I'd guess that not all the pins are brought
out.

You're assuming that the die is square. Die shape is determined by
minimizing the die area within the constraints of the layout and the
packaging. Your part could easily be a 27x28, 25x30, 20x35, 15x40, etc.
In the picture, the blob looks oblong so a rectangular die is probable
-- I'd guess at 25x30 from the shape.

"A.Nonny Mouse" wrote in message
news:0Yt1i.13088$g63.8289@edtnps82...
On or about 2007-05-11 22:09, Lord Garth is reputed to have said:
Has anybody definitively identified the BOB (Blob On Board) in the
attached
photo? One forum says it is a Hitachi HD66710

(http://www.hardforum.com/showthread.php?t=761414)

After tracing the board and looking at the data sheet for the HD66710, I
can't
reconcile the chip pinout to the actual circuit. I believe the BOB has
at
least
110 pins if one begins counting vias where 78 & 79 are screened. Since
110
isn't evenly divisible by 4, I'd guess that not all the pins are brought
out.

You're assuming that the die is square. Die shape is determined by
minimizing the die area within the constraints of the layout and the
packaging. Your part could easily be a 27x28, 25x30, 20x35, 15x40, etc.
In the picture, the blob looks oblong so a rectangular die is probable
-- I'd guess at 25x30 from the shape.

The scanner didn't resolve that level of detail well enough. I am looking
at the
chip imprint within the epoxy and it does appear square.

I hope that this display is reusable but if the BOB can't be identified, it
will be
useless.

"Lord Garth" wrote in message
t

The scanner didn't resolve that level of detail well enough. I am
looking at the
chip imprint within the epoxy and it does appear square.

Even a square chip might not have the same number of pads on each side.


I hope that this display is reusable but if the BOB can't be
identified, it will be
useless.

Can you determine the pinout of the connector?


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"Tom Del Rosso" wrote in message
...
snip

Can you determine the pinout of the connector?


Not yet Tom but you can see that I traced most of the connector contacts
to the vias they pass through and therefore the pin numbers based on the
silk screen. This is where it doesn't jive with the pinout of the
controller.

"Lord Garth" wrote in message

"Tom Del Rosso" wrote in message
...
snip

Can you determine the pinout of the connector?


Not yet Tom but you can see that I traced most of the connector
contacts to the vias they pass through and therefore the pin numbers
based on the silk screen. This is where it doesn't jive with the
pinout of the controller.

Are the chip pin functions mixed up compared to the data sheet or only
shifted? The COB might have different pin numbering just like different
package shapes do.


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"Tom Del Rosso" wrote in message
...
"Lord Garth" wrote in message

"Tom Del Rosso" wrote in message
...
snip

Can you determine the pinout of the connector?


Not yet Tom but you can see that I traced most of the connector
contacts to the vias they pass through and therefore the pin numbers
based on the silk screen. This is where it doesn't jive with the
pinout of the controller.

Are the chip pin functions mixed up compared to the data sheet or only
shifted? The COB might have different pin numbering just like different
package shapes do.

My next step is to try to get the service manual for the HP 4500 series
laser
printer and see what it may indicate. Fortunately, there is a place near me
that services HP and I should be able to get the manual there. The owner
has let me take stepper motors and such from printers he was salvaging
for resellable parts.

"Lord Garth" wrote in message


My next step is to try to get the service manual for the HP 4500
series laser

I've found some of their service manuals online, but they didn't have
connector pinouts.


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