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Replies... great!


OK, taking each in turn...  I have actually tried removing the RAM starting without to note response and was as expected from a PC not having RAM. Also tried replacement RAM but original symptoms remained. I have not tried updating the firmware, and not sure this can be done given that I am unable to access any on-screen menus on the printer. In the meantime, since trying the replacement Gamut Board, I find I am no longer able to access the printer via LAN connection. LED's are flashing over the main PCA LAN socket, but no response at hub end despite changing cables and hub port. Have probably killed the IP address.


The replacement Gamut Board did not come from HP, where it is well known in Australia that there appears to be a significant premium added to locally supplied HP components, rather it was purchased online from the US via that well known international website, as a used item. It did not come with an adaptor, but in my case I don't believe that mattered as original symptoms remained unchanged. Just normal power on startup, HP Invent display counting down to 1, then nothing further. Just a power light flashing green, fixed display and non operating buttons.  However, I too would be very interested in an adaptor!


Last night, I dismantled the original PSU again, this time to try to discover a little more about its workings. It appears to be divided into three basic sections, the main AC input and DC conversion, ATX supply for the main PSA, larger supply for the printer. This board then appears to have four seperate supply lines via switching and tranformers, producing the six different voltages required by the printer. I noted the colours of the PrintMech connector wires and the marked voltages expected to appear on each, which corresponded to previous tracings and findings from the PrintMech Board end. Voltages appeared correct values except the


The three display LED's above the main power switch, the sense/control lead from the Gamut board both connect to a vertical edge-mounted board, having some discrete and integrated components. Its location makes it very difficult

see just what is there. However, taking things very quietly and carefully, I first wanted to confirm that there was nothing else obviously wrong apart from missing 24V and 42V before going to the next step.


Having confirmed there is nothing else obvious faulty, I plan now to remove the printer supply section of the PSU from its frame, trace the 24V and 42V rails back to the transformers, then look more closely at the circuitry on the edge mounted board to try to determine its function. This will almost certainly require its removal, but that should not present a problem.


Now, if anyone has a schematic...  ?


Regards to all, Glenn




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Glen... your time is worth more than this plotter. 😄

I'm not sure your replacement Gamut board is operational. I had a similar problem with the lights and I purchased a replacement power supply and that was not the problem. The gamut board apparently directs and sends power to the other respective boads.


I do not think your issues are from the power supply. I had a journman electrician look at mine and he thought it may be the power supply and I purchased a replacement on his suggestion.


Have you tried diagnosing the problem using the lights on the boards?


I printed the manual and the trouble shooting steps are good.


I'll be putting a power supply on ebay in a week if you need it. 😄

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Hi laartistguy,


Yes, I also suspect that the problem is not the power supply and more likely the Gamut board, but at this moment, I have two power supplies, two Gamut boards, and two PrintMech boards... and still the same fault and no change in displayed symtoms! Before outlaying money on yet another board, I'm going to need a little more convincing.


After dismantling the PSU, the edge mounted circuit board on the printer section of the PSU is covered in surface mounted devices on the underside, making tracing or even repair challenging. It appears that there are six signal lines between the PSU and the Gamut board, connecting via a small plug to socket marked DC PSU. Of the six lines, two are 0V. The other four connect to series resistors and filter capacitors before disappearing between the layers.


Powered on, three lines measure almost 0V, but the other measures 3.3V. Disconnecting the plug and measuring the same line on the board shows approximately zero volts, suggesting the signal is incoming.


However, when tracing the line on the PSU edge mounted board, this line appears to connect to the positive input of a comparator. Of the other three signal lines, two wander about on the riser board but difficult to determine which way signals go, the fourth is connected to one of the PCB's mounting edge connector. Circuit tracing boards consisting of high density SMD's is difficult at best.


Very little learned from the exercise, except increasing suspicion that the replacement Gamut board may well have the same fault as the original.


For another couple of hundred dollars, I can get another Gamut board, used of course. I'll have a think about that unless someone can offer further suggestions.


Regards to all... Glenn





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Hi Glen,


You've done your homework and you certainly know a great deal on circirtry and electronics.


I'll reread your posts, but I think the issue is still the gamut board.


When you got your replacement gamut boards, did they come with an adapter to connect the trailing cable?


The replacement board I got freom ebay works, although I have not been able to source the connector. HP won't provide a part number, vendor or any assistance.... This particular machine would work with a $10 part.








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Hi laartisguy,


I am not sure which Gamut board you need but the one my printer uses has the connector designated as "replacement" (Rev C) in the pictures you posted, and the replacement and unuseable board is the one designated "original" (Rev B). I blame myself for the error when making the purchase in that I didn't check the connector type more carefully. At a glance, it looked the same. There was no converter plug offered within the listing and as the board was designated "used", it is unlikely one is available.


If your printer uses the "original" Gamut board, then we perhaps should discuss further out of the public forum.


Looking carefully through your posts, it appears then that the symptoms displayed by your printer are almost identical to mine, EXCEPT... that you have an error message displayed on the screen, whereas I simply have the HP Invent display with the bar-graph counter stopped at 1.


I would expect that the 24V and VPOWER2 LED's are not lit on both the PrintMech and Interconnect boards as is the case with mine, but do you have a lit green LED adjacent to the blue LED, above the main power switch?


While watching the count-down HP Invent display following power being applied, at what point does the error message appear?


The LAN access came back to life and I have been able to confirm the firmware is the latest version as provided by HP. I am reluctant to mess with firmware for any reason unless under very strictly contolled conditions as I've seen far too many laptops, desktops and mobile 'phones rendered "brain dead" after firmware upgrades that went wrong. Most devices don't like being re-flashed with the same version firmware anyway.


Regards... Glenn




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"I simply have the HP Invent display with the bar-graph counter stopped at 1...."


Glenn, I saw this elsewhere. I'll review your issue with all of our notes and let you know.


I'm happy to ship my old board to down under at no charge, althouh I'm certain this board was my problem.


I had a senario where we didn't get the counter as well. I'll see what I can do to reproduce the error.


Talk to you soon and thank you for your reply,


- laartistguy

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Hi laartisguy,


I have no problems shipping my board over to you as if it works perfectly in your machine, it then has been useful to me in eliminating a possible fault source.



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laartistguy offered the suggestion that I should replace the battery on the main PCA. It was something that I had thought of, but was concerned that in the process I may destroy settings within the CMOS and have no way of restoring them. However, with a dead printer having replaced the PSU, Gamut and PrintMech, there was now nothing to lose by trying a fifty cent battery from the local Two Dollar shop.


After an odd two-tone melodic chirp from the depths and a couple of other odd beeps, the printer burst back into life again!


I had created one problem for myself in the process. While the printer was dismantled, I used to opportunity to thorougly clean it out and replace the carriage belt with one purchased cheaply many months ago from China. I had actually tried replacing the belt previously without success as the printer would respond with an 86.01 paper jam error message as it attempted to check print heads etc. Lubricating the slides, and replacing the encoder strip (it had marks and stains aquired during its life before me!) made no difference. Restoring the old chewed up shredded belt made the printer work perfectly again.


A GENUINE HP belt is now on order, the printer works again, I've learned a lot and the backup HP 1050C can go back on standby.


Many thanks to all to who contributed and to laartistguy for the final solution!

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Well hot diggety dog!


Rock on! Sooo nice to know.


I had a feeling the solution would be super easy.


Glenn, you have a place to visit in Florida - anytime. This plotter is getting packed and is going to the sun!


Checkout my private message.


Best regards, Jeff

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