tektronix 468 service rom u456 and test counter ic part number 067-989-00

[xantia_99]

Hi

Do anyone knows anything of above items.  It's useful in repair of digital part of Tektronix  468 even without signature analyzer. However, a signature analyzer would certainly help.
I do not have a real problem, but just interested.

Best Regards
Stephan

[PaulAm]

There is a long running thread on 468 repair going on in the Tekscopes  io group and the service rom image was recently posted the in the files section

[xantia_99]

Hi

I could explain a bit

I got this tek  468 and look for A/D simulator test rom. 
It's an special item and it was sold separate from Tektronix for repair/test A/D with a Signature Analyzer as HP 5005B
 
Service rom and test counter IC  part number 067-0989-00.
You remove the A/D in U456 and put in the test counter chip instead. Next step is remove U565 and put in the service Rom instead

The other two original rom could be bought on ebay but that is not the same case.


Best Regards
Stephan

[xantia_99]

Hi

Since yesterday I found out it will soon be possible to buy part number 067-989-00 on Ebay and that will solve my problem. However I also need a Signature Analyzer for that.

Best Regards
Stephan
 

[jrseattle]

Hi, Stephan.

I wrote a note about this test counter IC and problems with the TRW A/D converter used in the Tektronix 468. It's attached.

Re. the Service Rom, you can program one yourself in a 28-pin 8KB Eprom chip but you'll also have to make a 24-28 pin socket adapter since the 468 used 24-pin ROMs, now obsolete.

[xantia_99]

Hi
Thank you for your reply.
I will look into it. My Tek468 project have been very passive for a while, until now,  I just got a CT-3 for calibrate the vertical input as well as A and B sweep. 

Best Regards
Stephan

[edavid]

I wrote a note about this test counter IC and problems with the TRW A/D converter used in the Tektronix 468. It's attached.

Note, the J in TDC1007J is just a package suffix, not a speed grade.

Re. the Service Rom, you can program one yourself in a 28-pin 8KB Eprom chip but you'll also have to make a 24-28 pin socket adapter since the 468 used 24-pin ROMs, now obsolete.

You could use a 24 pin MCM68766 or CY7C264 EPROM if you have a suitable vintage PROM programmer.