HP85 Integrated Computer... boot up sequence question - Page 1
Forum section: electronics / repair

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: November 01, 2020, 12:42:54 am
content: Hi, I've just got my hands on one of those 1980ish HP85. I've noticed it yesterday strolling through recycling center. It in beautiful condition, very clean and complete but without any modules on the back.When turned on, the CRT lights up but it doesn't boot. Wanted to know if it even boots without the ROM cartridge.I didn't do any research, just way to busy, wanted to pick your brains guys.Anybody out there that has any cartridges for it so I can check it out... or maybe there are some modern replacements I can get.Don't want to spend a fortune on any accessories.Ah... and if you want to know... it was about $100. Hard to tell, got bunch of miscellaneous crap... and the price was for all of it.

author: mag_therm
author_rank: Frequent Contributor
timestamp: November 01, 2020, 04:31:01 pm
content: I used one at the time.It runs BASIC.You will need a manual and I see they are available still.It looks for a program called autost on boot, if a tape drive is present.It can be used in a manual "calculator" mode if the tape drive is not present.Does it come up with a cursor?

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: November 03, 2020, 07:39:31 pm
content: No, I don't have anything on the screen when I turn it on. If I adjust the brightness with the pot on the bottom of the unit I can see the return lines on the screen so.. no signal coming in.

author: picburner
author_rank: Frequent Contributor
timestamp: November 03, 2020, 07:52:48 pm
content: HP Computer Museumhas the service manual with schematics.

author: Kean
author_rank: Unknown
timestamp: November 05, 2020, 01:24:42 pm
content: You want to join this grouphttps://groups.io/g/hpseries80/

author: Stray Electron
author_rank: Super Contributor
timestamp: November 05, 2020, 03:42:52 pm
content: The HP-85 has BASIC in ROM so it should be accessible. It's a dead certainty that the tape drive rollers have turned gummy and don't work, unless it has been rebuilt recently. Tapes are an odd size but are available, however the HP tapes were some of the very first small cartridge type tapes made and are BAD about shedding the magnetic media off of the plastic base. Not only does that corrupt the file at that location but the drive sees it as an End of Tape alert so it can't read any files beyond that point. Also they use a rubber band looking belt inside the tape case to drive the two tape rollers and those belts have long ago lost their elasticity and won't drive the two rollers properly. Long story short, forget the tape drive! If you're serious about wanting to save programs and data, then get an HP-IB controller, the optional Mass Media ROM and one of the early HP floppy or hard drives that understands the Amigo protocol. The HP-85 Mass media ROM only talks Amigo so the later HP hard and floppy drives won't work with it. FWIW there are a couple of groups that are working on reverse engineering the HP drives and are writing new and improved drivers and new hardware for them so they may have a better non-HP solution.

author: Kean
author_rank: Unknown
timestamp: November 07, 2020, 11:44:17 am
content: The old tape drives are only worth attempting to repair if you seriously want to try recover old data. Otherwise, something like the upcoming EBTKS add-on will bring new life to these wonderful old machines.http://www.fliptronics.com/HP-85_Adventures/EBTKS.htmlThere have been similar 3rd party add-ons, but not as advanced and apparently not readily available.But first, you may need some advice from experienced users, and the hpseries80 group is an excellent resource. I have a 2 or 3 HP-85A's and a bunch of modules, but they're all sitting in storage and I haven't worked on them in many years.

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: November 08, 2020, 04:33:40 pm
content: I've opened it up. The only sign of life is green LED by the keyboard and screen that lights up. Didn't have much time this week but have to check the power supply voltages...The machine is extremely clean, doesn't even have dust on it, so it was either stored in the "case" or it was covered. I wish they left the modules alone but obviously it was found to be not working and stripped of all the cartridges.