Tektronix 7603 with 7B53A and 7A26 plug ins

[Refugee]

The thing I need that would help me the most is an extender card and I bet those are extremely hard to get hold of.

[Nick]

What part number? I have a number of Tektronix extenders - certainly got a TMS500/5000 one and may have a flexible cable for a 7000-series.

I'll have a look...

[Refugee]

When I worked in a test equipment repair shop they had a flexible cable with an empty plugin chassis to slide into the main frame and make contact with the edge connector.
Would that be what you have?

[Nick]

When I worked in a test equipment repair shop they had a flexible cable with an empty plugin chassis to slide into the main frame and make contact with the edge connector.
Would that be what you have?

No - I have a genuine Tek TMS5xxx extender and had a third-party 7xxx one as described in http://ko4bb.com/dokuwiki/doku.php?id=te...000_series - basically a flexible extender using ribbon cable and about 6 RG174 cables - worked fine.

It's possible that it went along with the last of my 7xxx scopes some years ago - I'll have to locate and dig through the remaining 7xxx spares boxes I have.

If you can wait until the weekend, I'll be able to look then...

John Griessen used to sell a DIY version that was very cheap - http://ecosensory.com/tek/ - he should be able to be found on the Yahoo! TekScopes list - drop him a line?

Jamma Boards sell a cheap TMS500 extender kit: http://www.jammaboards.com/store/?subcat...cts.search - not much use to you, but I'm putting that here for reference.

[Refugee]

That would be very useful and I am not in a huge hurry as there are other chores to do right now.
Cheers for looking.

[Refugee]

Sunday was officially bad FET day.
The FET is Q596 and I got a reading a little over 700 ohms between source and gate.
It was shunting the resistor section of the timebase switch so that the only change was seen when a capacitor was switched.
   
   

Lifting the FET out of the socket cleared the short from pin 8 of U580 and disabled the delayed timebase.
All the main timebase steps came back.
Next session is to try a 2SK43 in it to get the delayed timebase back again.

On screen displays next.

[Refugee]

I have put a 2SK43 in place of the faulty FET and now both timebases are working correctly.
I will now start looking at the on screen display parts in the frame so it is now fast TTL time for me.
Also that spike on my pulse generator is going to have to be looked at now I have a fast enough scope to tackle it.

[pwdrive]

Well done so far refugee.

Lawrence.

[Refugee]

The digital readouts are quite tricky to work on. The input signal is constant currant in and resistors are switched to produce a voltage that is measured by a DAC to translate them into digital codes that are used to select what is to be displayed from some kind of memory.
It then displays them on the CRT all using late 1970s TTL.
I had a quick look at the manual tonight and had my first poke with another scope. So far I have eliminated some chips and got no conclusive result from others.
More manual reading to do now.

[AlanBeckett]

I'm praying mine keeps working. TTL Logic and A-to-Ds were my 'Stock-in-trade' back then but there's been 40 years water under the bridge since

Alan