HP Thinkjet or Quietjet???

Chris that is excellent news - though I need the variant that has the RS232 interface. I think that's the 2225D model.

Where are you based - I'm in East Sussex

AWEM

Reply to
Andrew Mawson
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Andrew,

I think all the ones I have are either parallel, or hpib, but did check the spec for the 1651A and it should have an hpib port on the back panel. There should be an option in the menus to select which port to use for the printer. Then all you need is an hpib / IEEE cable, which you should be able to find on fleabay for 5 ukp or so.

Am off to the store this afternoon and will bring back the printers to see what state they are in. The print head ribbon cable is the usual problem, at the point where it contacts the ink cartridge. They contact points are gold pated, as are the ink cartridges, but they corrode over the years, especially if not used for a long time. I find inkjets more trouble than they are worth in general, which is why i'm using a thermal hpib model. Paper is expensive for the thermal models, but you can still find it and don't use much of it anyway. Can bring a thermal model back if it's of interest and you can use fax roll paper, though it won't have the form feed / top of page cutout detect. The nice thing about hpib printers is that they work out of the box with most hp test gear.

Phone here is: Oxford zero one eight six five seven five zero six eight one, if you want to take this offline...

Regards,

Chris

Reply to
ChrisQ

You might find a converter like:

formatting link
would fix that...

Reply to
John Rumm

Then again, I just looked at the price of some of the converters... the right printer would be cheaper ;-)

Reply to
John Rumm

If you really must do GPIB, ISA bus cards are cheap. You just need to find an old PC to put them in. I'm surprised there isn't a cheap microcontroller solution though - GPIB is just a slightly more complicated parallel port.

Theo

Reply to
Theo Markettos

No I need a SERIAL connected printer - the instrument only has a SERIAL interface

AWEM

Reply to
Andrew Mawson

I think the suggestion was serial into an old PC, and GPIB out, just using the PC as a standards converter (even if a bit bulky!)

Reply to
John Rumm

FFS if you are going that route. use your main PC equipped with a serial board and drive any damed printer you want any way you can.

Reply to
The Natural Philosopher

Don't know if you finally fixed it, but if not, a couple of things which may help. Ime, the most likely things to fail are the ram chips, cpu and eproms losing their charge and marginal 0/1 when warmed up. The first two are easy to fix. The eproms can often be coaxed into giving the correct data by running at the vcc margins (4.75 / 5.25v), or outside, while copying in a programmer. Have had quite a few bits of old test gear with that fault and was able to recover the data using that method...

Regards,

Chris

Reply to
ChrisQ

Well I'm making progress! I found (thanks to my HP Logic Analyser) a

74LS163 that was counting when it was supposed to be inhibited - changing that has at least got characters displayed on the screen, but they are random. As far as I can detect the CPU isn't writing to the VDU static ram so I'm tracing through the code following it's start up process. Fortunately I can capture the read and write cycles from the 8085 CPU and thus see what code it is reading from the rom and follow it's progress. Waiting for a 40 pin ic test clip to arrive (hopefully tomorrow) to more easily follow all 8 data and 16 address bits - it does seem to be reading sensible data from the ROM board. What makes progress slow is the lack of any circuit diagrams - so far I have belled out the circuit of the CPU card, Video Card, Video timing card, and the far from simple backboard - only six more pcbs to bell out and I'll have all the circuits. The pcbs range from about 25 to 50 ic's each!

AWEM

Reply to
Andrew Mawson

That's good - there are times when only a la will get the job done, but admit i've always baulked at the idea of tracing out schematics on multi device pcbs.

Another thing that sometimes works is to burn in the boards in an oven at 70C, (no more) as this will drive out any damp in the circuits. In the case of test gear with mos circuits, leave the thing powered up for a few days, which probably achieves the same effect. I have a 54112D scope that had been left out in a shed for a couple of years. 3 channels worked, one intermittent and noisy. Powered up for a week continuous and it's been fine ever since. It did only cost

40.00 ukp on fleabay and was well worth the effort.

Let me know if there's anything else I can help with...

Regards,

Chris

Reply to
ChrisQ

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