Wednesday, January 11, 2017

Sharp PC-4500

Sharp PC-4500 (4502)  

Restoring History

Manufacturer: Sharp Corporation (Osaka, Japan)
Release date: October 1987
Reference: PC-4500
Processor: Nec V40 at 7.16 MHz or equivalent (compatible with i80188)
Memory: 256 KB or 640 KB RAM expandable to 1.6 MB Including 1 MB of EMS memory
Display: CGA compatible monochrome LCD display (Backlit on models 4502 and 4521)
Storage: 1 or 2 floppy drives 3 "1/2 of 720 KB
Original Add
Or 20 MB hard drive according to models.
Interfaces: Parallel
1200 baud modem and optional external CGA
Software: Ms-Dos 3.2 Sharp

Particularity: Announced at Comdex Spring 1987 and marketed from October of the same year, this entry-level PC compatible PC is sold at a rather competitive price. The compatibility is good but the performances are not extraordinary. Note that it requires a version of Ms-Dos of origin Sharp to start.

3 versions ever existed:

PC-4501, 256 KB with 1 drive, LCD not backlit
PC-4502, 256 or 640 KB with 2 drives
PC-4521, 640 KB with 20 MB hard drive

My machine is a PC-4502, 2 Floppy disks, no HDD, back-lit display.

I got this machine 2 weeks back of the internet from a guy who said that it does not know if the machine is in working condition.

I am not very happy that I did not make any pictures how the machine looked when I got it but I can rate it a 5 out of 10.... and I will show you why.


1) The DC IN connector and wiring is missing.
2) The DC POWER BUTTON is missing.
3) The Floppy drives power connectors are missing. Power cables from the Power Supply to the motherboard are damaged and a few blown capacitors.
4) Missing bolts and screws
5) Cracked case
6) No AC Adapter

1) The DC IN connector and wiring is missing

This unit was completely butchered by someone who has no idea how electronics work. It seems the unit had some problems booting so someone just messed with the cables.

I had to rebuild the whole POWER CONNECTOR SOCKET!

Parts Used: DC Connector (from an old Toshiba notebook), piece of black thin plastic, soldering gun, poxipol-plastic welding, superglue and a LEGO piece :)

I started by cutting a square piece of plastic with a hole inside, same plastic as a credit card and fitting it into the unit with a drop of super glue, just so it would hold on when I will apply the other stuff. I needed this in order to mask the DC connector so when the unit will be assembled it will look like the original does.

Thin plastic square with a hole for the DC IN Connector
I needed to find a way to mount the DC connector a little higher so it will perfectly fit like on the plastic squares hole. 

So I found a permanent fix: LEGO! 

Bringing the base at the right size so the DC connector will perfectly fit the hole

I had soldered the + and - wires on the DC connector. THE SYSTEM BY FACTORY HAS THE CENTER PIN AS NEGATIVE. As I have a more modern Power Adapter I will use the center pin as + . 

DC Connector - Not Original one
Again I used plastic welding and fitted the connector on the LEGO piece.


2) The DC POWER BUTTON is missing

This unit has no power button so I googled but I can`t find much on this units insides to see what power button it originally had!!!

Lucky me I found this YouTube video of the inside of a PC-4521 machine....

So as you can see on the video the Power Button is similar with what you will find in an old laser pointer. And ...I still have some laser pointers in a shoe box in my storage.
I had cut the laser board with the some of the board around in order to fix the button on the original surface.

And this is the Output of 20 minutes of hard work :)

3) The Floppy drives power connectors are missing. Power cables from the Power Supply to the motherboard are damaged and a few blown capacitors

Looks like the one of the previous owner had tried to "repair the unit" by cutting half of the wires in order to power the motherboard from another power supply. I had spent some time figuring out what happened so here`s what repairs and fixes I had done:

Replaced marked in RED capacitors. It seems the power supply did not start because of those.
New wiring for the Floppy Disk units.
New wiring for the Floppy Disk units.




1 out of 2  Drives are only present. Date is 10 of September 1987

The weird thing is that the Keyboard is PASSED as test but no keyboard is attached at this moment...

There are some jumpers on this machine and I found some info on some forums... I really hope I can get the second FDD working so I can put MS-DOS 3.2 on 1 drive and some CGA apps on the other :)

I got the Jumper settings for SHARP PC-4500 and 4502 from a forum:

Link here.

"Here are the settings my PC4500 came with on the DIP switch bank on the bottom of the unit:

3 ON
5 ON

I would guess that one of these switches defines the presence of the second floppy drive and perhaps the presence of a full 640K memory card (I have both in this machine)."

The settings above suggest 640k memory and 2 FDD installed.





This restoration of the SHARP 4500 was a true success! :)

Thursday, December 8, 2016

The world did not begin with the World Wide Web

The world did not begin with the World Wide Web
                                                                                   by Bogdan Tirziu

     The Internet is the biggest and the most advanced technology of this century. Its basically a huge amount of information and knowledge that opens up unlimited possibilities and opportunities to the masses.

     Today it is the biggest source of information to mankind. Learning and getting knowledge on thousands of topics has become an easy task. It just requires typing a single word on a search engine and retrieves thousands of search results that are close enough to your query. Internet has made the information just a click away. While you read this, routers, servers, converters etc. work for you to receive and send data. For the younger generations this seems normal and it seems that the world was like this for a long time.

    "The History of the Internet is begins with the development of electronic computers in the 1950s. Initial concepts of packet networking originated in several computer science laboratories in the United States, United Kingdom, and France.[1] The US Department of Defense awarded contracts as early as the 1960s for packet network systems, including the development of the ARPANET. The first message was sent over the ARPANET from computer science Professor Leonard Kleinrock's laboratory at University of California, Los Angeles (UCLA) to the second network node at Stanford Research Institute (SRI). Commercial Internet service providers (ISPs) began to emerge in the very late 1980s. The ARPANET was decommissioned in 1990. Limited private connections to parts of the Internet by officially commercial entities emerged in several American cities by late 1989 and 1990,[5] and the NSFNET was decommissioned in 1995, removing the last restrictions on the use of the Internet to carry commercial traffic."
                                                                                                                               source: Wikipedia

     So the Internet is about 30 years old and has been in a continuous change ever since. For example this is how the internet looked back in 1994. Information was growing, technology was growing, so this pages might seem primitive, back in 94` these were super sharp and fancy. You can compare with the 3rd image where you can see how the internet was introduced to people in the first place.

                           One of the first web pages

As stated in the title "The world did not begin with the World Wide Web", back in the late 60`s some Universities had a sort of communication between computers but that was not intended for the masses and it was more an experimental thing as the protocols of communication used were not yet a standard so everything was happening local.

Everything was about to change

Many years ago, long before the birth of the web, there was a time when France was the happening-est place in the digital universe.

"What the TGV means to train travel, the Pompidou Centre to art, and the Ariane project to rocketry, in the early 1980s the Minitel was to the world of telecommunications."

The Minitel was a Videotex online service accessible through telephone lines, and is considered one of the world's most successful pre-World Wide Web online services. Basically the French Telecommunication networks brought a FREE boxy thing to every home and presented the users the benefits. In 1982 almost every french person could access some awesome services for that time, users could make online purchases, make train reservations, check stock prices, search the telephone directory, have a mail box, and chat in a similar way to that now made possible by the Internet.
From 1982 to 2012 it was used by 25 million people (of a total population of 60 million). Developed by 10,000 companies, in 1996, almost 26,000 different services were available. Even with the expansion of the internet in France this service was available and used by 9 million until 2012!

The "boxy" thing

"Minitel used terminals consisting of a text-based screen, keyboard and modem. Simple graphics could be displayed using a set of predefined graphical characters. Aftermarket printers were available.[9]

When connecting, the Minitel integrated modem generally dialed a special number connecting to a PAVI (Point d'Accès VIdéotexte, "videotext access point"). The PAVI transmitted information to the servers of the appropriate company or administration using the Transpac X.25 network.
In February 2009, France Telecom indicated the Minitel network still had 10 million monthly connections. France Telecom retired the service on 30 June 2012."
source Wikipedia

Thanks to this weird monitor attached to the telephone, while the rest of us were queuing for tickets at the station, the French were already shopping and travelling "online". A small screen with a keyboard, the Minitel was a very basic computer that allowed users to access text-based data over phone lines. Other countries looked on this with admiration, and the French were proud. (proud nation anyway)...

As President Jacques Chirac said: "Today a baker in Aubervilliers knows perfectly how to check his bank account on the Minitel. Can the same be said of the baker in New York?"
Students were logging in to check exams and to subscribe to different activities, small business had all accounts linked with it and could see the balance real time. It was for sure a limited "Internet connection" but it was something mindblowing taht you could chat with your brother that is 3 county's away. The incomes of Minitel were tremendous, they were making more than 1 million $ per day as the most expensive service was 1 EURO in today's money. The most expensive and used service was... PORN. Yes... the french had dozens of notorious "pink" services. They usually employ a woman's name or baldly suggestive titles such as "Brutal Beach," "Perver" and "Cruella." Advertised on lurid posters and billboards all over France, the services offer a whole menu of options for the user, ranging from explicit sexual graphics to direct dialogue with another person.

Soon, Belgium, Brazil, Canada, Italy, Germany, Finland, UK, Sweden, Spain etc. had tried to adopt the system, but the Internet was already available so the war was lost.

I know it looks terribly old-fashioned by today's standards, but it was simple to use, you pressed a button and it did something, just like on a tablet today.

"The failure of Minitel was not one of technology," says Benjamin Bayart, head of France's oldest internet provider, French Data Network.
A recent Minitel set
Image captionThe design of the Minitel changed over time
"It was the whole model that was doomed. Basically to set up a service on Minitel, you had to ask permission from France Telecom. You had to go to the old guys who ran the system, and who knew absolutely nothing about innovation.
"It meant that nothing new could ever happen. Basically, Minitel innovated from 1978 to 1982, and then it stopped," he says.

As an old hardware collector, I really want to get my hands on one of this terminal computers. I think of them as an important part of the History of the Internet. 

Saturday, August 27, 2016

The Motorola MicroTAC


Today I want to share with you something from the past. Its one of the pioneers of the mobile industry. MOTOROLA Micro T-A-C Mobile.

This morning I went at a local garrage sale and I bought this phone:

It doesn't have a charger but battery is probably dead so I will store it as it is... anyway ...the Motorola MicroTAC was a cellular phone first manufactured as an analog version in 1989. GSM-compatible and TDMA/Dual-Mode versions were introduced only by 1994. The MicroTAC introduced an innovative new "flip" design, where the "mouthpiece" folded over the keypad, although the "mouthpiece" was actually located in the base of the phone, along with the ringer. This set the standard and became the model for modern flip phones today.

FUN FACT: it seems the engineers where much ahead of their time on the antenna design, the Motorola MicroTAC from 1989 had a fake external antenna because at the time people did not believe in internal antennas, so Motorola had to add a fake one in the outside even though it had an internal one! 

This phone had 3 breakthroughs and inovations:

- first flip design

- internal antenna

- fake antenna, just for public opinion 

The phone I got needs a 900Mhz full business card size SIM... could still run in some areas of my country... in the mountains there still are 2g and 3 g antennas. Does any operator still have such SIMS? :)

D1-Club by Motorola
This model was made for Telekom (model D1)
Very nice layout keyboard 

Wednesday, June 29, 2016

The Toshiba T1000 back to life!

Hi there,

As you know I got a Toshiba T1000 from a friend from Holland about 3 weeks back. I was posting on my Facebook page The x86 Generation that this machine dosen't even power up. That has changed dramatically in the past 3 weeks!!!


"The Toshiba T1000 was a laptop computer manufactured by the Toshiba Corporation in 1987. It had a similar specification to the IBM PC Convertible, with an 4.77 MHz 80C88 processor, 512 kB of RAM, and a monochrome CGA-compatible LCD. Unlike the Convertible, it includes a standard serial port and parallel port, connectors for an external monitor, and a real-time clock.

Unusually for an IBM compatible PC, the T1000 contained a 256 kB ROM with a copy of MS-DOS 2.11. This acted as a small, read-only hard drive. Alternative operating systems could still be loaded from the floppy drive, or (if present) the ramdisk.

Along with the earlier T1100 and T1200 systems, the Toshiba T1000 was one of the early computers to feature a "laptop" form factor and battery-powered operation."
                                                                                                                                        from Wikipedia

At the time of its release, circa 1987, critics hailed the Toshiba T1000 as a groundbreaking innovation. It was the lightest PC-compatible laptop ever released up to that point, and the press considered it the MacBook Air of its day.

Like the MacBook Air, the T1000 shipped with a solid state disk: It packed MS-DOS 2.11 on a built-in ROM chip so it would be available instantly when powered on. For $549 more, you could increase the RAM to 768K, and use a portion of that memory as an ultra-fast RAM disk that retained its data as long as the main system battery didn’t discharge.

T1000 : Disassembly, Day 1, cleaning the motherboard against the electrolyte from the caps and battery spill 

Dissembling the unit is an very easy job as all you need is to unscrew 6 bolts and pick up the upper casing. Anyway, as for some this could be a challenge you can download the USER MANUAL here.

After removing the screws gently put the display in Open Position and then just unclick the top from the bottom. After that remove the video cable and let the fun begin.

After doing so you get this:

 The next step is to unscrew the keyboard bolts, remove the battery, then the FDD drive bolts and finally you get to the Motherboard.

 How all you need is to remove the motherboard in order to clean it from that spilled acid. Why? Because that fluid is conductive and thats not good for the sensible components.

 If you look in the next images you will see the acid laying on the motherboard.

I had cleaned the motherboard using isopropyl alcohol and nicely spreading it with a paint brush.

 After doing so I let the motherboard dry under a 25W Lamp (not neon)


As electronics age, the second components to fail (after batteries) are usually electrolytic capacitors, which break down over time and either deform or leak.

The next step was to check if the caps are dead or not. I tested them with a multi meter and could see a linear discharge so they seem OK but as they were leaking I decided to put new caps. Lucky for me I had a T1200XE dead unit that had good caps. I don`t want to use new caps, as they are very poorly made.

VR2 and PJ23

The next step is to get this machine to its initial parameters. otherwise it won`t boot. 

  • Assemble your computer back, except for the display and FDD unit (you will have more space to operate).
  • Ensure you have a 9V, 1.1 Amps adapter plugged in.
  • Use a multimeter to confirm that the output voltages for the PJ 23 on the system PCB conform to the values given in the following table.
  • If the voltage conforms to the values given in the table, try changing the Batteries (4X1.2V).
  • If the voltage does not conform to that given in the table, adjust the VR2 on the system PCB by a Phillips screwdriver. 

As seen below i had used some wiring to adapt to PJ23 the Multimeter
Multimeter on PJ 23

The next step is to use Philips screwdriver to set the value of the multimeter to 2.18-2.19Vdc.

Important! Check if battery is dead or it still holds some juice!

If battery is dead: Change the battery pack or ensure you have a 6V Vdc on the battery pins.

If battery still holds some power, even for a few seconds you can still use it to start your machine.

In my case the battery pack seemed fine so I gave it a try....

AAAAAAND.................YESSSS!!!!! THE MACHINE IS ALIVE!!!!!!!!!

WHO HOO!!!!!!..................................................................................

Counting RAM to 768KB

MS-DOS, baby!!! (present on the ROM so no disk required)








DEAD!  :(



...the machine just powered OFF... It looks like the Battery pack has died for good, so now I am looking for a drilling machine 6Vdc battery pack in order to use the cells to get this thing working again.

So for all there users that can`t get this machine running... just make sure you have 6VDC on the Motherboard, 9V, 1.1 Amps as supply, clean the motherboard very good, adjust the voltage using a multimeter and BOOT your lost love once again!

THE END..... for now!