My god, you still use such old instument? 8080A cpu?

30 years? thats why they refuse to serve for you now.

Im afraid you cannt buy such cpu now. why dont change a new one instrument to substitue the old one?

8080A cannt store any code only in ianother momery.

you can check that eprom or eeprom.

I can buy such vfd, but Im afraid it will not match yours. such old type may stop to sproduce .

Yes there is still demand for old stuff. We have customers that want to keep these old machines running. The big surprise is they are used used in the semi conductor industry. This is a 8080A cpu, the programs are stored in Eproms. We do not have the code for the programs. The Programmable peripheral interface 8255A-5 outputs to the display. I am trying to make a 2*40 display work but not having much success.

Thanks for the reply. These machines still have about 100 units being used in the semi conductor industry. It is an 8080A cpu with programs on Eproms. We have no problems getting replacement cpus, eproms, lasers, ic's, motors or other components. We are having lots of problems getting a display that will work. The display is driven by a programmable peripheral interface 8255a-5. We are trying to use a 2 * 40 display now. We can copy code from eproms to eproms but cannot read it or change it.

Its not difficault to read out and change it. but you neednt to do it now.

the forst you do is check your vfd to see if its fault. if the filament is fault, you change one new. if not, you hve to change your 8255 and buy new one. you cn buy it on market. no problem.

check power supply to see if it still suit to the filament. and anode voltage. etc.

you can substitute 2x40 to old one. but you have to match lead pins.

read carefully the specification. and ask an electronic engineer for help. its a not difficaut job for him.

[if you require, I can encode you a disply code, howver, I dont think its neccesssory]

Hi cnpower. The problem is in the display panel itself. We cans see that they are gassy or burned in the panel. They are old and are often left on all the time.

I still am no closer to a replacement. A guy that worked on these machines long ago told me they had a way to display the text on a monitor. If that is the case I should be able to connect it to hyperterminal in a computer.

The machine uses 9 data lines [Not WRITE (WR)] and Data bits 0 - 7

The Data bit 6 line is labeled [not CLEAR]. DATA 0 is LSB, and DATA 7 is MSB.

It is powered with 5 volts.

If anyone could give me a way to wire it up to a computer for hyperterminal that would be great.

post a pic here so that we can understand where the failure is?

vfd displany need not only 5v but more high voltage!!! 12v 24 oe 44v erz. and it needs filament power, ad or dc. check it.

I told you displace one good to the faulure board one by one. to confim whcih one is bad. you hve 100 for selection.

to lead signal to a computer from it is a bit difficulty. you need change code and communication with pc. you need dissamble an d then assemble. or even add a 232 interface and programm.

the man who tolod you he can do , why dont ask him for help?

what is not write? is it non write lead pin? this siganal is neccessory.

is the vfd dots or digital number? do you confirm its vfd not led or lcd? if only 5v work, it willl not be fvd.

are you from south asia?

you hve 100 units, you can substitute one by another to see where the wrong is?

once you fix the problem inform us so tht we can also know how to resolve it and share experience.

Can you substitute for a different brand VFD?

Try FUTABA http://www.futaba.com/products/displays/general_info/features/index.asp

If you cannot find 1 x 40, can you use two units 1 x 20?

Check also for surplus stocks held by traders.

Mark

Thank you. I am trying Futaba.

8080 does not have internal code memory to hold code inside, so it must be somewhere outside in a ROM/EPROM. Display data using 8255 must be segment decoded and you can take that data through a translation ROM into LED display.

That sounds easy ;-). How would I do it. I have the manual for the display IEE So3601-42-040, the data sheet 8255A-A, and the schematic for the circuit. But no programming information. I assume it is Intel ascii with an 8 bit word.

We have the bad panels in a New Jersey shop. I am in Phoenix, AZ USA, so I can't get a pic now. But the segments in the display are burned. The display segments that are most used are faint to dark. If you look at them without power you can see some characters that are always turned on burned into the display

They have 5 volts in and use DC to DC converters to get the much higher voltages required. The way the displays are made it would be almost impossible for us to unsolder them to take them apart and switch parts. But the power supplies aren't our main issue.

The guy that said he saw the machines putting out data to a monitor didn't know if they had some module between the display and the computer. He just saw it being done.

The good news is that Futaba got back to me. They have a 1 X 40 display M40SD04GR that looks like it is the same in form, fit and function. Most of the character codes are same. The only question now is if they can support our low volume. And can I get one to try it.

Thanks very much for the help I have received.