My amazing grandfather's HP 45 calculator, from 1973, rides again. What a beautiful machine! It took a few hours to restore the calculator and a month to process the emotions and make a video worthy of his life.

I still use my HP-22 business calculator given to me by my father long ago. 1975 vintage, had to have a whole new battery setup as the old removable battery along with part of the case, the contacts, and about an inch of trace from the circuit board had been yanked off. But the new battery pack fits and holds a charge, and I love using this thing because 1) I'm proficient with it, but also because 2) it turns heads. People think it's from another planet!

Thanks for this, I bought my HP45 in my senior year in high school, 1974, and paid an entire months of summer full time work to get it. I continued to use it thru the 80's and sadly dont have it any more. It was an amazing machine for the times, and your video brings back many memories of my college and engineering career.

I still have - and USE - my HP-45 from my college years in the 1970s. It's great that one can find aftermarket replacement battery packs for these. Great video, what a cherished heirloom you have!

My go to calculator is my HP-45. Had to recently disassemble it as power switch stopped functioning, and clean it up. It’s nice to see you honouring the history of the calculator, nice mix of history and restoration. I was just being silly when I filmed the disassembly of mine (post temporary fix, and prior to proper cleaning).

I bought my HP35 in spring 1973 for $395. Big bucks but so worth it. It saved me so much time in my physical chemistry class, and it carried me through grad school. After it had been in storage for 30 years due to intermittency, I decided to try the procedure in this video. I found that the power slider switch was really gummed up with debris entering around the slider. The rest of the contacts were not too bad, but I cleaned all with contact cleaner, used soapy water to clean the plastic keys and the housing, and put it all back together. It works reliably!!! I'm charging up my battery pack now to see how that will go. Thanks for the video!

You may have identified it by now, but that little plastic piece you couldn't identify at the beginning is part of the battery door....specifically the latch on the left side. Look closely at the other latch, and you'll see the little t-shape that retains the latch in the door. These frequently break off, and allow the latch to 'fall out' of the door, as clearly visible on yours at the 8:00 minute mark. (Great calculators. I've still got mine on my desk, and a few backups in case it dies.)

Great video but next time you have to dismantle a machine in the "classic" series, please use a hairdryer to soften the label on the back. It damages it far less when you remove it and if done right, once it's back in place you honestly cannot see that it has ever been removed. I have an HP 67 that has had a similar treatment. Also, consider *not* putting back the screws that are under the label. They are not needed mechanically because there's a plate on the inside keeping the PCB with the key domes up against the keypad, and it avoids having to remove the label again if you need to go back into the calculator for any reason. Both my 67 and my 45 are missing those middle screws and they still work fine.

I just found my HP41c that I got in 1979. I put new batteries in it, but for some reason, the batteries started heating up about two days later. Became extremely hot. The batteries still worked afterwards and the calculator still powered on, not sure what happened but it was like it when into thermal runaway.

Wonderful video, your granpa would be proud

Wow.. Loads of work putting this together.. Nice video!

❤️

You may want to look into a contact burnishing tool, it is an ultrafine file for cleaning contacts.

Your little [TAN]gent was amusing, after my initial [R]!, I [SCI]'d a little. A crude joke but it's no [SIN]. Although, I can't [RCL] in my [log] the [LAST x]'s I've seen such. Rather than let it [/] me, I [STO]'d my opinion to myself and [CLEAR]ed my head. Hoping it would [+] up in the end, I pressed [ON] rather than be called [yellow]. Your little [FIX]es worked well. [OFF] to have some [pi] now. High [5]'s and [RAD] job!

very nice restoration job, your grandpa would be proud of you. i liked and subscribed :-)

just great. wonders about broken tabs. likes c64s. thinks rpn is normal. have to sub.

In time of making this calculators steve wozniak work for hp

RavenWolf - I have one of these. Do you know where there is a schematic for the HP 45?

Nice vid. I have an HP-35 that has a touchy power switch. I will try this. What is the pad that you are using to disassemble the unit on? A silicone mat of some sort? Nice for the small parts and order of reassembly!

1m52s - Does anyone know where those tabs go? I have a 35c (series 3), with no battery pack or battery cage. I had opened the battery door multiple times just to look and nothing happened. Then one time two tabs, just like those in the video just dropped and I can not figure out where they go. Any insight appreciated.

Amazing work! Doesn't the 45 suffer from cracking plastics, especially the screw posts? (like the 41 usually suffer). Keep it as your grand father legacy 🤗

Nice work, but new phone who dis?