Hp8711 firmware help

[ovenqin]

Hi all, Thanks lot for help. Report a good new in here, A3 unit and CRT is ok now. This is a little good step for this challenge.
Scope man you are right , this is 8711a ,the oldest version. I program the bootload which Picturber provided, unfortunately it's 8711b.
Who could upload 8711a bootrom of 28F010? please give some advice.
  73! BD7TQ

[ovenqin]

Hi all, I search HP8711a with google,  Sp2xdm provide the 8711a bootprom flash files in his website www.lewcuk.pl
wish have a good luck tomorrow! 

[scopeman]

Give me a little time and I will upload a binary of a bootrom with your actual serial number in it.

If I read it right your serial is US36360171

I will also send you one with the options turned on that you can try. Some A models it will work with some not.

The hard part with these instruments is finding SIMM Memory modules that will work.

I will also send you the JED file for the Ibasic GAL (burn into a 16V8)

PM Me with your email address and I will see if I can get this done this evening.

Sam
W3OHM

[ovenqin]

Hi W3OHM,thanks. My email :ovenqin@sina.com
73! Bd7tq

[ovenqin]

Hi Sam, today I busy for find old disk drive and 1.44 disks. Eventually by many times test, I found a good driver and a 1.44 disk. Install Msdos6.22 and format the disk , then run your file. It work make me come back to old time.  after reload the 8711a firmware, the machine can run and check the other units.  This challenge work is too excite,I will continue this challenge,  thanks Sam. 73!
   

[ovenqin]

Hi all, I have the other curious thing today, it's about RESET signal of CPU. when I use A3 unit which out of machine with external regular +5V, it run and work well. But I put A3 unit into the machine , It halt. So I look for Reset IC U17 TL7705a, I connect pin2 to GND of U17, the Cpu reset and work. I replace the C12 10uF capacitor, the situation is the same(Halt), Maybe The U17 IC have some problem. But why I use the +5V external power for CPU, the reset is ok. I will check it again.
  BTW: It look like the Hp8711a need SIMM DRAM to run the system, It's really difficult to find some 30pin SIMM DRAM 
 73!

[scopeman]

Oven,

I have not had the chance to look through the documentation on this (and I have never had to do any troubleshooting on these particular power supplies other than to replace caps) but I suspect that it might be that the system expects all of the supplies to be up and in tolerance and there may be a power good signal required or perhaps a power supervisor signal of some sort. I do not recommend powering a complex device like this from anything other than the HP supplied power supply. I would suggest that you get that totally working before proceeding farther.

Sam
W3OHM