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Epson QX-10 lives!

T

tezza

Veteran Member
Joined
Oct 1, 2007
Messages
4,731
Location
New Zealand
I got a nice looking Epson QX-10 off our TradeMe auction site.
http://www.trademe.co.nz/Browse/Listing.aspx?id=526934878

It came without a monitor cable so it was untested. Was expecting to have to make up a monitor but was astonished to find them for sale on the Internet!!!!???
http://www.connectworld.net/cgi-bin/cabled/L5205?

Anyway, I ordered one and it arrived today. I connected it to monitor and case, switched on and stood back. Fans whirred, drives spun, lights flashed on the keyboard.

The words "INSERT DISKETTE" appeared on the screen. IT'S ALIVE!! :D

I'm chuffed! I still need to make a book disk from an image but prospects look good. At the least the mainboard and screen are working and the drive spins!

I won't be able to work on it for a few days but I'll let the forum know if it successfully boots.

Tez
 
Ok, I've made some CP/M disks and have ascertained the disk drives work.


That's the good news.


The BAD news is after about an hour of use the power started to flicker on and off very quickly and erratically.


Oh well, it happens with these old machines. Could be a short just starting on the board, a cap or power transistor starting to go in the PSU or something as simple as a loose wire? Hopefully I can fix it.

I want to get a few more collection videos done so the machine is now in the queue for a repair project on a rainy day.

Tez
 
Hi Tez,

Congratulations on the QX-10! Hope you can get the power issue resolved. I got one a while back, which may have a related problem. The machine would sometimes simply not turn on when you turn the switch, but would then start working again after a time. Now it is just not turning on at all. Possibly just a bad power supply.
Anyway, best of luck getting yours healthy again.
 
Update on the power issue. Hmm..while investigating the problem the fuse blew on the PSU. Replaced fuse but now no sign of life at all. Found that a large 5W 10 Ohm resistor on the AC circuit wasn't allowing any current through at all. Replaced it. No sooner than I had switched on than that new resistor went the same way as the old one. From measuring 10 ohms across it to no connectivity at all. Hmm...something must be causing that.

Got hold of SAMS Computerfacts for the QX-10. In first sentence on troubleshooting power supply it says to check for a short across pins 15 and 11 on the STK-711 Power Switch IC in the advent of a blown fuse. Hmmm...sure enough these pins are shorted.

I've ordered a new STK-711. Hopefully that's the problem and it's not something else nuking all these components otherwise the pins might just short again when I plug the new one in!

We shall see I guess.

Tez
 
STK modules for some reason like to go boom after a decade or two. They were a common failure point in some Sony Betamax machines as well. Like most things, heat eventually does them in.
 
The replacement part seemed to do the job. I haven't tested it extensively but the QX-10 now appears to be working and stable.

All power to a scanned copy of SAMS Computerfacts. Without it it would have been tough to track the problem down.

I'm happy :)
 
Hmmm. I now HAVE tested this extensively and the original issue is still present. I must have zapped the power switch IC when I was testing the PSU, so I've repaired that but not the original fault. I suspect it's a cap somewhere on the mainboard going out of tolerance once fully warm and causing a short. Not an easy thing to diagnose!


Anyway, I've added it to my collection pages even though it's still technically in sick bay.
http://www.classic-computers.org.nz/collection/epson-qx10.htm
 
Hey Great buy!
I'm glad to see these things are still appearing from time to time - I hope you get yours officially out of sick-bay.
We got ours in 1981 and unfortunately it got stolen from where we put it into storage. As there were no disks with it I doubt it ever got used again either :(

We used it for all sorts of things, but the highlight was the QX Text word processor which Dad bought while on a business trip to Singapore.
While this was the infancy of WYSIWYG, it was state of the art at the time.

When QX Text booted (program disk in drive "a" and data disk in "b") a graphic would load and display the message "QXText is loading, please turn the monitor on it's side".
You physically picked up the screen and put it on its edge to get your A4 page. (Good thing the mono screen was quite light!)

Within the system you also had control of margins and access to all the 16 EPSON fonts (does your system have the multi-font card built in?). Of course it was designed to work perfectly with the Epson printers. It did a great job with our EPSON FX-80 but I remember when we got our first LQ (24 pin) printer, I was stunned by the quality of the documents.

Additionally, (talk about ahead of it's time) it managed file names internally so users weren't restricted by the CP/M 8.3 naming limits.... so cool. Left Wordstar for dead!

And all this with 192kb RAM and no HDD.

Anyway, I'm still on the hunt for one, but if you get yours going properly let me know as I've got some disks floating around somewhere - they may still work!

Happy Days! :)
 
Thanks. It's still is sick bay unfortunately. I really don't know where to start with this one. The fault is intermittent so hard to track down.

Tez
 
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