Author Topic: Tektronix 7603/7613 Repairs  (Read 38244 times)

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Offline guido

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Re: Tektronix 7603/7613 Repairs
« Reply #75 on: April 19, 2016, 06:16:49 pm »


 :-+ :-+ :-+ :-+ :-+

Thanks for making these available. I'm running a 7603 with 7A13/7A22/7B53 and a 7623A with 7L5+TG. I am not doing a complete overhaul like you, but changing the caps was needed.

I also have some spare mainframes, one also with a recapped supply. So when one fails i just swap and repair later  :)
 
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Offline dave_k

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Re: Tektronix 7603/7613 Repairs
« Reply #76 on: April 19, 2016, 10:30:55 pm »
Looks very neat  :-+
 

Offline Uselesss

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Re: Tektronix 7603/7613 Repairs
« Reply #77 on: September 20, 2016, 06:20:11 pm »
Hello Guys,

I'm trying to repair an 7613, I have changed all the Powercaps (thanks for this nice boards) but my scope is stille broken, as you see on the Picture.

The points (I think they are the Overlay informations) change number an posistion according to trigger an Amp. Setings.
The Test generator works fine.

What should I do now?
best regads from Gemany.
 

Online tautech

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Re: Tektronix 7603/7613 Repairs
« Reply #78 on: September 20, 2016, 07:20:17 pm »
Hello Guys,

I'm trying to repair an 7613, I have changed all the Powercaps (thanks for this nice boards) but my scope is stille broken, as you see on the Picture.

The points (I think they are the Overlay informations) change number an posistion according to trigger an Amp. Setings.
The Test generator works fine.

What should I do now?
best regads from Gemany.
Welcome to the forum.

You don't say what documentation you have.  :-//
This one is handy along with the Service manual:
http://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf
Avid Rabid Hobbyist
 

Offline Uselesss

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Re: Tektronix 7603/7613 Repairs
« Reply #79 on: September 20, 2016, 07:44:03 pm »
 tautech Thank you for your fast reply until now I just had the service manual, I think the troubleshooting guide will help me allot.

Do you(or someone else) have an clue for the actual problem? How can I test the readout Unit?.
An vertical horizontal deflection ?

Best regards
 

Online tautech

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Re: Tektronix 7603/7613 Repairs
« Reply #80 on: September 20, 2016, 07:55:17 pm »
tautech Thank you for your fast reply until now I just had the service manual, I think the troubleshooting guide will help me allot.

Do you(or someone else) have an clue for the actual problem? How can I test the readout Unit?.
An vertical horizontal deflection ?

Best regards
I'm not overly familiar with the 7k series but just looking at the pic you posted the dual pot for intensity also controls Readout, does it not? The outer knob is in the Off position.

There's a good # of members with these scopes, give it a day or so and others will come to your rescue.  ;)
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Offline Uselesss

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Re: Tektronix 7603/7613 Repairs
« Reply #81 on: September 20, 2016, 08:04:44 pm »
Theater is why I'm posting here.

You're right with the internsety Poti, but this doesn't affect the result ??.

EDIT:

I managed to get the Scope working . But the Readout Signal is still mesedup. I will follow the debug instructions in the service Manual to find the resaon for this behavior.
Do you have an clue what reason this could have?

best regards
« Last Edit: September 21, 2016, 08:13:42 am by Uselesss »
 

Offline wine+dine

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Re: Tektronix 7603/7613 Repairs
« Reply #82 on: September 27, 2016, 07:39:10 am »
It's hard to tell from one picture and no description of the state & conditions.

Did you first check and align the vertical amplifier independently of the readout?  Unplug the readout Y cable at the V amp and go through the alignment checklist.

Next I would put the readout into diagnostic (there's a transistor you pull out, see manual) so it shows digits in all locations, as in http://w140.com/tekwiki/wiki/File:7000-readout-diagnostic.jpg.  Then use another scope to check that the readout board X and Y outputs make sense - the stuff is DC coupled into the Y amplifier so it can mess up a lot if the levels are off.
Take it from there and let us know how it goes.

Just for ideas, the readout on my 7904 failed a while ago and it turned out it wasn't dead but just some 20-30 Div off screen (I "found" the readout display by unplugging the blanking signal and shifting the V amp offset around).  Culprit was an emitter resistor (in the readout blanking IIRC), value was nominal but the stage would never turn off anyway - probably the transistors had higher beta than what was designed in in 1970.

There's also a description of a "cute" readout error and its repair at http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_mainframe/rep-und-kal-7603/Reparaturbericht%20TEKTRONIX%207603.htm that might give you an idea.

(Oh and before you do any of the above, please double-check that ALL supplies are nominal both in DC and ripple.)

 

Offline wine+dine

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Re: Tektronix 7603/7613 Repairs
« Reply #83 on: September 27, 2016, 11:28:34 am »
I just looked it up, the transistor to pull for the diagnostic display is Q2225.  Also check/replace the tantalum caps on the readout board, for example in one case C2115/2117/2119 caused me some grief.
 

Offline Uselesss

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Re: Tektronix 7603/7613 Repairs
« Reply #84 on: September 27, 2016, 12:25:27 pm »
Hello wine+dine thank you for the input.

I removed Q2225 and the result is showed in the picture. On Every possible location an dot appears.
I checked the X and Y Signals from the read  out-ROM to the Format Generator Signals are present.
I checked all Voltages the look god (measured on test points against Chassis GND).
Is it necessary to use Tantalum Caps, or could I use low ESR Electrolytic Caps as well?

On the Picture https://www.dropbox.com/s/kt68a9ihquj5l1g/readout_mit_werten.png?dl=0 I wrote down my measurements in the maintenance Mode.

Thanks for the Help best regards
 

Offline wine+dine

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Re: Tektronix 7603/7613 Repairs
« Reply #85 on: October 02, 2016, 09:05:32 am »
Looks like things are OK from the character position signals all the way to the CRT, but the per-character X and Y signals are missing or much too small. 

Since both X and Y are affected, which are generated in the analog character ROMs by steering emitter currents (see http://w140.com/tekwiki/wiki/7000_series_readout_system), I'd suspect the driving side. 

Do you see a triangle signal at TP2129?  At pin 16 of U2126? Does turning R2128 have any effect? Are the ROMs being strobed (Pins 9 U227x)?
 

Offline David Hess

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Re: Tektronix 7603/7613 Repairs
« Reply #86 on: October 02, 2016, 03:39:58 pm »
I removed Q2225 and the result is showed in the picture. On Every possible location an dot appears.

Good, that is roughly what is suppose to happen although it should be displaying zeros rather than dots.

Quote
Is it necessary to use Tantalum Caps, or could I use low ESR Electrolytic Caps as well?

I doubt the tantalum capacitors are the problem but low ESR aluminum electrolytic capacitors will work fine.  Use 2 to 4 times the capacitance to get the same ESR.
 

Offline peekpt

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Re: Tektronix 7603/7613 Repairs
« Reply #87 on: October 20, 2016, 08:36:11 pm »
I happen to have a partially working  tek 7603 to restore in my lab. :-BROKE
I will start with the Pwr Supply, so caps need to get tossed out.

I pick @dave_k adaptors idea and made a multi adaptor instead of two.
I want to ask you if you can review it before I order the pcbs. Thank you in advance.
Feel free to use the design. It's ready to upload to any pcb maker.


https://oshpark.com/shared_projects/hpUFRhHC

https://github.com/peekpt/tekcaps
« Last Edit: March 04, 2017, 06:55:07 pm by peekpt »
 

Offline danmc

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Re: Tektronix 7603/7613 Repairs
« Reply #88 on: March 28, 2017, 12:34:37 pm »
stupid question... Got any good tips for getting those big cans off the board?  It's been 25 years since I touched anything other than surface mount. 

I like the adapter boards.  Very slick.

My other question is if you had to desolder the transformer to get that board out.  My 7613 went belly up last time I turned it on.  Looks like I have a shorted diode and one of the caps is shorted.  I figure the others can't be far behind and  I might as well recap the whole board while I have it apart. 

Thanks
-Dan
 

Offline danmc

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Re: Tektronix 7603/7613 Repairs
« Reply #89 on: March 28, 2017, 01:00:39 pm »
Have you ordered those dual adapter boards?  I just cloned your github repo and looked at the gerbers.  I have two questions

1)  Why is the Tektronix logo (pretty by the way) on the soldermask layer?  I would have expected it to be in silk?

2)  The bottom copper looks kind of weird.  There aren't thermal reliefs on the 4 outside pads (where the pins to connect to the Tektronix board would go) but the ground circle isn't exactly unbroken either. 

I've not picked which caps to buy yet and checked pin out and drill sizes.
 

Offline peekpt

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Re: Tektronix 7603/7613 Repairs
« Reply #90 on: March 28, 2017, 03:42:31 pm »
1) It will be shinny this way  ;)  golden if you order from oshpark
2)Not thermal relief was an option since some of pads are jumpers and drive a lot of current. The bigger pads are for the pins, you can get triangular or square shape. 10mm apart for the capacitor's pins, some have an extra pin
 

Offline peekpt

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Re: Tektronix 7603/7613 Repairs
« Reply #91 on: March 28, 2017, 03:46:57 pm »
stupid question... Got any good tips for getting those big cans off the board?  It's been 25 years since I touched anything other than surface mount. 

I like the adapter boards.  Very slick.

My other question is if you had to desolder the transformer to get that board out.  My 7613 went belly up last time I turned it on.  Looks like I have a shorted diode and one of the caps is shorted.  I figure the others can't be far behind and  I might as well recap the whole board while I have it apart. 

Thanks
-Dan
this is yet on my todo lis  :-[t, but if you unsolder transformer it will be easier to work, not a big deal if you have a good practice
 

Offline WastelandTek

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Re: Tektronix 7603/7613 Repairs
« Reply #92 on: June 22, 2017, 04:33:33 am »
Hey folks,

These little adapter boards are brilliant!  I am working on a couple of 5000 series scopes and some other D10 chassis and these are just the thing.

I got KiCad on and I can look at all the (6?) art layers.  I got the Harwin pins in my Mouser cart.

I know I am being dense here...I can't figure out how to use iTead.  I figured out the answers to the questions under "Small batches 2 Layer PCB".  Got the 1.6mm board thickness from the Harwin pin spec.  Guessed default on most.  Guessing 3.8 cm size from the little text files in the zip...is that right?

So I got 20 of these in my shopping cart ready to check out

 Small batches 2 Layer PCB

PCB Qty
    20pcs
PCB Color
    Green
PCB Thickness
    1.6mm
Surface Finish
    HASL
Copper Thickness
    1oz
Panelized PCBs
    1
PCB Width
    3.8
PCB Length
    3.8


but I can't figure out where to upload all the .G** files. 

I know I am being stupid here, but what am I missing??


edit/ disregard, I found the other thread https://www.eevblog.com/forum/repair/making-dave_k's-capacitor-adapters-at-osh-park/ and that process is very user friendly indeed  /edit
« Last Edit: June 22, 2017, 05:09:11 am by WastelandTek »
I'm new here, but I tend to be pretty gregarious, so if I'm out of my lane please call me out.
 

Offline WastelandTek

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I'm new here, but I tend to be pretty gregarious, so if I'm out of my lane please call me out.
 

Offline mikepukmel

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Re: Tektronix 7603/7613 Repairs
« Reply #94 on: April 29, 2018, 03:36:29 pm »
Update: oops, sorry, just found that you had posted the files, thanks!!! 


Hi Dave,  This is a fairly old thread,  hoping you still check for posts from time to time.   Im not much of an electronics guy, learning.  I like to build and work on guitar amps.    I got a Tek 7613, from a friend that was saved from a spring cleaning effort (was headed for the dumpster).     Took a few weeks to get up the courage to power it  up,  but it started OK, no smoke or sparks and I get a trace (could roughly measure a 60hz test tone).      I started reading around, and it seems that most real tech's replace most the electrolytic filter caps, esp on the power supply board, like you did in your unit. 

Any chance you still have the ITEAD files to make those cool adapter boards, and wouldn't mind posting them? 

Also, in general, I read around other threads, and looks like you guys really go through and replace lots of components, out of tolerance resistors, and other caps.    How do you determine that a component is out of tolerance?    I didn't think you could measure values in circuit, i.e. you'd have to remove the part to figure out if it was bad or not.

Thanks!
Mike
« Last Edit: April 29, 2018, 03:41:36 pm by mikepukmel »
 

Offline jh15

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Re: Tektronix 7603/7613 Repairs
« Reply #95 on: April 30, 2018, 03:08:01 am »
Just don't go nuts. Look at posts for your unit.  If you can grab another scope or meter and look at ripple limits in the power supply. High quality capacitors can last a long time.

Shotgunning capacitors in an antique radio might be good, but in test equipment you might not do well if you are not an expert.

Haven't had it happen to me, but tantalum caps were the bees knees when I was into repairing tek, fluke, hp, wavetek sound technology, and all the broadcast equipment of yesteryear.  Guess I'll consider replacing the tants in my stuff.

Even scarier, is the fragility of multi-layer capacitors as Dave has shown.

Oh well it fits in with the planned appleescence one puts most or their money into besides a house or retirement.
tek 575 curve tracer top shape, 535 top shape, 465. 545 hickok clone, Telsa Model S,  Ohio Scientific c24P single board computer, many c-64 from my club days, Giant electric bicycle, Rigol stuff, Heathkit AR-15 receivers 2, Heathkit et 3400a trainer and interface,
 
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Offline mikepukmel

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Re: Tektronix 7603/7613 Repairs
« Reply #96 on: February 17, 2020, 08:52:45 pm »
Hi All,   Its been a long time since anyone has posted on this thread.  In case anyone is watching: 

A friend gave me a throw away TEK 7613 that has been sitting in his closet at home since about 1990.  it powers, displays a trace,  seems fairly stable.   

I found this thread after a long search on what to replace in these great old scopes.     

Found the link above,

https://www.ebay.com/itm/Capacitor-Adapter-Tek-Tektronix-7000-Series-Recap-6-square-1-triangle-adapter/272799971348?_trkparms=aid%3D1110002%26algo%3DSPLICE.SOI%26ao%3D1%26asc%3D225074%26meid%3D1a6579e933b2414b97a29fee05aa89d9%26pid%3D100008%26rk%3D2%26rkt%3D2%26mehot%3Dag%26sd%3D272740191627%26itm%3D272799971348%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100008.m2219


but the seller has several different listings.     I haven't had this unit apart yet, does anyone know if the kt above is the right one for this 7613 ps? 

Also, anyone happen to have a parts list for replacement ps caps?

Thanks,
Mike
 

Offline mikepukmel

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Re: Tektronix 7603/7613 Repairs
« Reply #97 on: February 17, 2020, 11:40:33 pm »
Thanks JH, will do.
 


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