Tektronix 4010

[Roland Huisman]

Last week I've picked up some nice old pieces of history. One of them was the Tektronix 4010.



Because it has collected dirt for 46 years, I first cleaned thoroughly.



And I don't want to sit on my knees when servicing this kind of electronics.
But now I bumped my head several times against the bottom of the terminal.



Slowly powered it up. A bridge rectifier already got quite warm with only 40V mains voltage (set at 220V mains).
And there was one fuse of 8A where a 2A fuse should be. Well, it really does not trip when it is necessary.
The cause of the hot bridge rectifier was in a shorted tantalum capacitor on the -15V supply line on one of the boards.

After some further measurements, the + 20V showed enormous ripple voltage. This was caused by a
dead filter capacitor. And what a worthless construction to get that cap out! So I thought
let me put that spare power in there which I got with it. It might save some time is that one works.
Unfortunately the 5V TTL power supply was faulty on that one. So I had two broken power supplies.

So I repaired the original power supply. Slowly turned up the mains voltage again
and POOF, there went that -20V fuse again! Now on another board a tantalum on
the -15V shorted. It remains old stuff of course



And I put everything back together again...



So meanwhile it is running DIR on PDP8 / F:

Now it would be nice to throw some graphics data to it.

Regards, Roland

 

[jdreesen]

Roland,

Nice find !

on ftp://ftp.dreesen.ch/TEk4014 you wil find plt.tar, which contains a lot of graphic demos for the 4014. Just send them down the serial port .
I believe they would also run on the 4010

Jos

 

[Roland Huisman]

Hi Jos,

Thanks, I will check it out!

The data cable is a bit messy. Only gnd, rx and tx are connected trough an old mains cable. :sad:
So I want to make it original again, but I can't find the cable pinout in the manual.
And I can't find this data communication card in the manual... It seems to be pretty old.
All chips date from 1971...



Regards, Roland

 

[nikola-wan]

Roland,

That was quick repair work on your 4010!

Now its time to start on your 4052

Please post a photo of the rear of your 4052 - I'm particularly interested seeing that 4-slot backpack, and any label on the back indicating any other factory options.

Congratulations on your 4010 repair!

Monty

 

[Roland Huisman]

Hi Monty,

Now its time to start on your 4052 Please post a photo of the rear of your 4052 -
I'm particularly interested seeing that 4-slot backpack, and any label on the back indicating any other factory options.

I will make a new topic for the 4052 and post some pictures from it.
I've made a lot of pictures of my 4010 and sent them to Kurt for the Tek WiKi.
Maybe he likes to place them there. My 605 and 611 are displayed there too...

Congratulations on your 4010 repair!

Thanks! In the meanwhile I found the part number for the Tektronix 4010 data cable.
Searching on that number lead to another document which describes
the serial data board and cable. So that is fixed as well...

Too bad that there are so few serial port settings on the board.

Regards, Roland

 

[djg]

The communications is an option so its in a separate manual
http://www.bitsavers.org/pdf/tektronix/401x/070-1458-00_4010comm_Aug81.pdf
Mine had the same card and I have the official cable if the manual isn't clear.

My 4014 had the same shorted tantalum capacitors.

From when I was playing with them I think some of the files in the tar file are 4014 specific but a number should work fine on the 4010.

 

[Roland Huisman]

The communications is an option so its in a separate manual
http://www.bitsavers.org/pdf/tektronix/401x/070-1458-00_4010comm_Aug81.pdf
Mine had the same card and I have the official cable if the manual isn't clear.

My 4014 had the same shorted tantalum capacitors.

From when I was playing with them I think some of the files in the tar file are 4014 specific but a number should work fine on the 4010.

That was the manual I found later indeed. The cable is now back to the original wiring scheme.
I will check out the plot files!

 

[Roland Huisman]

I have been playing a bit with my 4010 and there are a few things which I noticed...

When connected to a PC the 9600 baud seems to be too fast for the terminal to
accomplish all tasks in time before the next command arrives. Look at the differences
between the characters F, I and R in these pictures. The first is 4800 and second 9600 baud



I thought that my PC wasn't handling the DTR right, so I connected it to a PDP11/10.
Autsj! Many times, when the PDP11 is buffering from disk, the 4010 throws a glitch onto the screen...
I made the first picture on 1200 baud and the second at 9600 baud. The F, I and R are still ugly at 9600.
Bot this is nothing compared to the other mess...



Here another picture. First 9600 baud on a PC and the second on 9600 baud PDP11.


I thought this has something to do with RTS and DTR, but these are just looped back in the terminal.
The strange thing is that the serial board in this 4010 is very old compared to the rest. Maybe not original?

Are there some official Tektronix test programs which I can use on the 4010?
Maybe it has just something to do with a line draw function which does not work well?

Regards, Roland

 

[nikola-wan]

Roland,

I suspect the serial issues are due to lack of hardware flow control.

Here is an image of a couple of pages from the bitsavers 4010 Comm manual:

Looks like the 4010 has a jumper for communicating with a computer instead of a modem in Table 1-2.

Also looks like hardware flow control is on 4010 RS-232 pins RTS and DTR, so the jumper on these two pins in the cable may be your issue.

Only 4010 'plot' files that I have found are posted here:
https://github.com/rricharz/Tek4010

Monty

 

[Roland Huisman]

Hi Monty, thanks for your feedback

I suspect the serial issues are due to lack of hardware flow control. Also looks like hardware flow control is on 4010 RS-232 pins RTS and DTR, so the jumper on these two pins in the cable may be your issue.

I suspected that too... But flow control does not exist on the board.
The RTS and DTR, are just looped back in the terminal on the RS232 board.

Only 4010 'plot' files that I have found are posted here: https://github.com/rricharz/Tek4010

There seem to be a lot pictures which Jos has collected also.
But it would help if there were some tests for the Tektronix.

Another strange behaviour is with text... This image is made at 4800 baud from my PC.
No changed made in the setup. Just sending the same file again and again. Just compare the
text on top of the screen...



The terminal sometimes adds spaces between characters. In text mode it has the same problems btw...
Sometimes with typing a text like "Tektronix" appears like "T E K T R O N I X". The baud rate or other serial settings
don't seem to have any influence on this behaviour.

So there still seem to be something wrong in the terminal... :sleepy: I'm not sure if both problems have the same cause...

Regards, Roland