Trying to Crack a Pocket Computer Tape | Sharp PC-1251 |Adventures in Archiving 2|

[@RetroMels]

I went a bit overboard with the music this time, there is a no music version available you can find it here: kzbin.info/www/bejne/pZXMfqWZoqmLr7c

[@AMPProf]

[@Chris_In_Texas]

I had the Tandy / Radio Shack version of this, the PC-3. It was a great little computer at the time back when I was young in school. 👍🤠

[@StupidusMaximusTheFirst]

That's just amazing!!! A small computer running BASIC programs with a tape deck and a printer !!! wow.

[@RetroMels]

Agreed! I always wonder what it was like back in the day to have one of those…

[@DavidHembrow]

​​@@RetroMelsIt was pretty cool, but as most people didn't know what it was they weren't impressed. I had (actually, I still have) a PC1245, which is like your machine but with a shorter display and half the RAM (2K). I never had the expensive printer/cassette add-on. The PC8201a which I also still have and which also still works was more impressive to people. I guess it's not obvious that it's an actual computer and not "just a calculator".

[@RetroMels]

Oewh PC8201 very nice! I have the TRS-80 model 100 which has a similar form factor.

[@scottlarson1548]

I thought it was cute, but the thing that blew me away was the Radio Shack Model 100. That was actually usable as a computer and a word processor.

[@StupidusMaximusTheFirst]

@@DavidHembrow You can tell it's more than a calculator - it's got an alphanumeric keyboard. I didn't expect it to do BASIC though either.

[@kc8485]

Marvellous work! I Have a Sharp PC1251 which was used by my late father back in 1986/87 to run insurance premium calculation in the field. I later used it to program for my engineering degree.. That program listing at about 15 minutes in, is very similar to a software program I had that was used by radio amateurs to calculate the antenna bearing required for transmitting from your home station to an overseas location where you knew the latitudes and longitudes. I will have to resurrect my Sharp and see if I can confirm the listing from the snippets shown! Many thanks for the nostalgia!

[@RetroMels]

How cool!!

[@sideburn]

I’ve minimal luck loading or saving from computer. Micro cassette works flawlessly but digital audio is extremely finicky I’ve found with my two pocket computers. The trs 80 pc-2 and the sharp 1500

[@amtsgedicht]

How cool! I remeber reading a sailing book from Bobby Schenk (Germany). He was one of the first Sailors using this kind of pocket computers for navigation. He published the codes in his book and made even a ROM for the SHARP-PCs.

[@martinb.770]

My Sharp 1260 still is on the shelf right of me. I remember, when a friend found a book of advanced stuff and internals on them, in 1991. At that time, these computers were so simple, you could work on register level, say PEEK/POKE, if you had the docs.

[@jamescorvett]

i learned basic back in 1979 when it first came out, i was only 9 yrs old. A friends parents had the TRS80 desktop pc and i had the TRS80 pocket pc. Both devices came with manuals on how to learn basic but the big TRS80 desktop manuals were much larger and had a lot of stuff I didnt get with my pocket pc version. We spent 5-6 month clicking away every spare minute and had the majority of basic programming down. Within a year i was making graphic programs and these were super long codes, this is where the tape drive came in handy so you didnt have to rewrite 500+ lines of code every time we wanted to work on something. I still have my TRS80 pocket computer works like new, though i do worry about that screen issue. I myself was looking into purchasing a replacement but i agree prices are a little steep. A few yrs later Radio Shack came out there the Ti-99/4A which was a LOT more affordable for consumers, and it had games on cartridges, which used basic code...basically. It didnt take me but a couple days to write code for full screen animated color graphic which totally blew my teachers minds that i knew basic programming and they knew nothing. Lol Though i gave them and other students a crash course in basic for a class 6 week project. Also, look up how to load the tape code to the pocket PC. If Im not mistaken there is a button or control code xx that activates the pocket pc to start loading(listening) to the tape when it starts playing. And i guess worst case there could be something wrong with the docking station, or maybe its connections(pins)?

[@MotownBatman]

I wanted a Micro-Cassettee Tape Recorder so bad as a Kid, 8-10ish, The Ultimate Spy Toy! But I was p00r, so I carried my Radio Shack Tape Player/Recorder with its 4 C Batteries & Microphone Everywhere lol, best $5.00 at a Yard Sale

[@TechnoTinker]

Thanks for the video. As a teen, I got the Tandy PC-8 and the printer/cassette adapter when it was on its way out. It's basically what you have here, except that the PC-8 has a smaller display (fewer characters) and the printer/cassette adapter doesn't include the actual cassette player, but had mono plugs to connect to an external cassette player. It was a neat little computer. My dad had a PC-7 which was very different than the PC-8, but I later learned it was because Casio made that one, and Sharp made mine. I grew up programming with BASIC, mainly on various TRS-80s and the Apple II (and a clone).

[@RetroMels]

Oeh cool!!

[@summerlaverdure]

this video is amazing! i love pocket computers and preservation, subbed!

[@JohnCompton1]

I think the 25 theory is also effective because it's a quarter of a 100, wheras 20 is fifth. Maybe just enough to start some mental gymnastics...Thanks so muchh for sharing!

[@NozomuYume]

Have you tried adjusting the playback frequency of the WAV file? The drive in the dock might be running the tape at a different speed than the portable player you used. Obviously you also need some sort of manual adjustment of amplitude when feeding it back into the dock.

[@RetroMels]

Good advice! I used the faster speed on the portable player. The loudness of the recordings was similar to the known working file. But playing around with those settings is a good idea!🙏🏻

[@TechnoTinker]

@@RetroMels Although volume is important on the recordings (loud enought without clipping), pitch is probably the most important indicator. If you have a known good WAV file, you can compare it to yours. You can probably get it close enough by ear, or you can add your track in Audacity and compare the spacing of the peaks. Cassette motors weren't the most accurate things back then either, so it should have a little leeway. Great work! I love seeing people rediscover the old tech using the newer tech.

[@lwilton]

Just tripped across this video. Good job! A few suggestions: 1. Try some lemon juice or white vinegar on a swab to clean up that battery acid. I've had decent luck with that. Obviously swab off the area with clean water and a paper towel a couple of times after to get rid of the acid and any dissolved battery goo bits. 2. When tinning a wire, put a little fresh solder on the iron, then touch the bare wire to the top of the iron for a few seconds to heat it up, and then apply fresh solder to the wire itself. Doing it the way you did by just using the solder on the iron, you don't really have enough flux, and won't get nearly as good a tinning job. You can see in your solder joint to the chip leg that the solder wasn't as fresh as it could have been. Doing it the other way should make soldering easier and give you a better result. A little practice and you will be doing perfectly well soldering. 3. When wrapping stranded wire under a screw head, it is best to strip, twist, and then tin the wire. Without tinning the strands can separate and fray out, and possibly end up shorting to something near the screw head. You can see frayed wires sticking out of the head in the video. No harm was done this time, but a simple bit of tinning on the wire will produce a better result. You are doing great, keep up the good work!

[@RetroMels]

Awesome tips! Really helpful, I’ll keep those in mind for my next soldering endeavor!🙏🏻

[@andrewwasson6153]

Wow! I bought the PC1251 and docking station brand new in 1982 from a fellow who travelled to Japan frequently for work. Mine still works but I have to replace the LCD now (I have a modern replacement). If you have a dead screen, you can test the functionality of a PC1251 or one of the variants by using the beep command. BEEP X will output X number of beeps from the tiny speaker in the computer so BEEP 5 will beep 5 times. Also, the printer is a 4 colour printer. I’m surprised that the pens have not dried up. Mine has spent a lot of time in a box in storage but the cassette still works and it loads and saves just as one would expect it to. It’s a very resilient little computer. With a Z80 CPU, 24K RAM and a fairly powerful BASIC.

[@indy.b]

I still have my PC-1500 and the printer, so do a couple of good friends. We decoded the assembler language ourselves using the original manual's BASIC POKE example, and exhaustive/exhausting testing. BTW the printer is not a printer, IT IS A PLOTTER. It pushes the paper up and down and the pen (!!!) left and right.

[@RetroMels]

Oeh nice! The CE 125 manual refers to it as a printer. It is a different mechanism then the ones with pens. I have one of those plotters that works with my TRS-80 Coco’s.

[@TechnoTinker]

The printer that Radio Shack sold for my Tandy PC-8 was a thermal printer (definitely not a plotter), and looks very similar to the one in this video. It had a small head that would sweep over the paper, leaving the characters behind, much like a dot matrix printer, except thermal instead of impact.

[@FalconFour]

Funny thing, I have *exactly* this same setup, with almost exactly the same problems. I'd first recommend indeed YES actually replacing (not removing) the battery in the printer/cassette dock. These machines typically only use the AC Adapter to *charge* the battery, and the machine is designed to *run from* the battery as a cleverly-regulated DC supply. To charge the battery, they take the AC adapter DC voltage and run it through a resistor, then to the battery (which can be perpetually charged without issue, as long as it's a low current). It's a cheap and clever way to provide DC voltage regulation (a clean 5 volts, as this era's logic chips loved to run on), without large or wasteful DC regulators. So, definitely 100% replace the battery - running it on AC adapter alone is prone to degradation. (A modern NiMH pack is perfectly suitable to replace the NiCd pack - I just grabbed one on Amazon that fits and works great!) Next, the tape on mine needed a whole evening's worth of circuit diagnosis to figure out why it couldn't hear incoming signals. Some of the traces was eaten away by the battery acid, and I had to figure out which ones, and patch them. Though everything might appear working at a quick glance, subtle issues like that will arise. But given that the aux input jack is working, I suspect you may have dodged that bullet. I work with pocket-tools a lot, so maybe I can boot that interest back up and get back into it. I wore myself a bit out on pocket computers after refurbishing a whole box of the things. haha. Now I just need to finish selling them! (I'm not much a collector, just enjoy fixing things :) ).

[@RetroMels]

Awesome comment! Thanks for taking the time! Helpful tips I’ll keep in mind. In moving forward with my CE 125. I can relate to feeling a bit burnt-out after spending a lot of time fixing a certain type of product. Had that myself with trying to replace belts on a MZ-800 cassette deck.

[@xtevesousa]

If you found acid corrosion on the pcb you have to wonder how it got there. One path commonly overlooked is through the wires, yes the capilarity of the wires can wick the acid from the battery to the PCB. I would completely remove the 2 battery wires and place new ones. Check the other wires conected to the pcb + too, by pulling a bit on the insulation. Cheers.

[@RetroMels]

That is great advice! Thanks! 🙏🏻

[@SnepperStepTV]

I want one of that Sharp package. I'd get more utility out of it than a smartphone

[@RetroMels]

😂😂 and less stress probably!✌️

[@smallworx]

Noticed that RETROMELS has the same logo format as IBM

[@RetroMels]

Correct, I used a font called IBM logo. No cease and desist letters in my mail yet 😅.

[@hughaskew6550]

Isn't the battery leakage at least equally likely to be alkaline rather than acidic?

[@victorpalacios1017]

Excelent presentation of a retrocomputing, i still have a pc Casio FX-720p, from time to time i program something there just for fun, math solving ecations, Fibonacci and so on. I wish to have the printer and this video gave me good advice and was cool to see. Thank you very much.

[@RetroMels]

Thanks!🙏🏻

[@curtisnewton895]

this was pretty fucking cool at the time I guess wow

[@Starchface]

Very good video. I hope you finally can succeed in cracking the code. The PC-3 was made by Sharp and apart from cosmetics, is identical to the PC-1251. My PC-3 docking station has only the thermal printer and no cassette unit. Instead it has audio jacks that connect to an external recorder, using the standard cables. My 1251 is in excellent condition with the exception of the LCD. Despite being kept in a box, it began turning permanently black. The guy that makes the replacement LCDs charges the very reasonable price of $20 US but getting it here to Canada that turns into $35, or over $50 in our money. That seems like a lot but it's not his fault. No one seems to know how he makes the LCDs, but as far as I know he is the only source in the entire world. It suddenly hit me that he could retire, lose interest in the project, or die at any moment, and anyone who has been holding off as I was, will be out of luck. Their pocket computers will be instantly worthless. So, I ordered my LCD and received it in about 10 days. I'll install it next week.

[@RetroMels]

Hope the installation will be a success! 🍀 Agreed that the LCD’s are reasonably priced, shipping to Europe is what turns it into quitte the investment for me. Also I sort of fear I lack the skill to perform the replacment. Would be interested to hear how things turn out for you. Thanks!🙏🏻

[@Starchface]

@@RetroMels There are plenty of videos of the procedure being done. Hey Birt from the Ozark Mountains put up such a video a few months back which motivated me to get into action. It's not particularly difficult but cleanliness is essential. Good luck with yours!

[@ristopoho824]

I have Sharp PC 1262 and 1211 I like them. They are neat. I pretend it's a collection. If i find another i'm getting it but not too worried about it. Fiddled with them a bit but mostly i just like to have them. They are neat.

[@RetroMels]

Hope you soon will find a third one!✌️

[@paradiselost9946]

for some reason i want to now see win11 busted down to machine code and stored on vinyl...

[@RetroMels]

😂 With a little hologram in the middle as a collectors edition!

[@hurricane567]

A tape that says PROG on it, and its Yes and Alan Parsons Project

[@RetroMels]

Hahaha, wouldn’t be the first time hearing music instead of a computer program haha!✌️

[@hurricane567]

@@RetroMels otoh can't music be made with BASIC? Roundabout squeaking out of a speaker

[@RetroMels]

Wouldn’t surprise me if that is possible. I have seen a lot of music box programs written in Basic that can play certain songs.

[@greenefieldmann3014]

Marktplaats?

[@RetroMels]

✅

[@greenefieldmann3014]

@@RetroMels That's the Dutch Craig's List.

[@RetroMels]

Hahaha that’s actually an interesting point! Marktplaats is certainly less creepy then Craig’s list. Love this comment!😂🙏🏻 I always say Dutch version of Ebay because until 2020 they used to be owned by Ebay.

[@greenefieldmann3014]

@@RetroMels The last guy I bought a bike from on Marktplaats was way creepier than most of Craig's List's Casual Encounters ads.

[@alanarmstrong2323]

Nice job I have a trs 80 pc 2 !

[@RetroMels]

Oeh cool!

[@PleaseExplainMe]

Mocht je wat soldeertips willen ;) Geen probleem. Pas wel even op met het vloeimiddel wat je gebruikt, straks bouw je een zelf oplossende schakeling ;)

[@RetroMels]

😂😂, vloeimiddel en ik hebben een moeilijke relatie haha. Denk dat het al te laat is om er ooit iets van te maken haha. Maar toch bedankt!🙏🏻

[@hi-tech-guy-1823]

Need to Be careful with Data & Audio cassettes (Even Voice Micro cassettes Dictaphones Have the Worst Wow & Flutter ) Yeh Data cassettes have 0 tolerance to A Audio (music Human voice cassettes Deck Built on the cheap to Wow & Flutter) and music & Voice Have loads of that going on Data Decks Have very different motors (more Coils) and Bigger Pinch Roller Flywheels To Eliminate Wow & Flutter & motor interference even the motor has magnetic shielding and A Scrubber network to keep the power supply clean

[@lasersbee]

5:14... Use Goo-Gone or Goo Buster... It will not damage the surface but will dissolve the glue. 6:35... Use a Water/Baking Soda mixture to neutralise the Acid Residue.