Have you ever considered this?

[BrownOut]

I was reading a thread about repairing a Tek scope recently, and a number of members were warning about tek's use of proprietary ( now obsolete ) IC's in their products. I recently repaired of of these scopes, and was fortunate enough to not need one of these devices. Anyway, I was wondering about the possibility of using a PIC or CPLD in place of some of these IC's. One might even be able to ascertain the chip's function by analyzing the circuitry around it, or by probing a working unit. Has anyone ever tried this? What were the results?

 

[Pommie]

Unless you are going to repair thousands of them it will not be worth your time reverse engineering and coding a chip to replace the broken one.

Mike.

 

[BrownOut]

How can you be sure it won't be worth the time? Personally, I often make repairs for the shear satisfaction of keeping a good instrument alive (also because it's more fun to work on instrumets which can be repaired, rather than just swapping chassis ). Besides, I'll bet many of these IC's are very simple, as yesterday's technology was must less complicated.

 

[Pommie]

Besides, I'll bet many of these IC's are very simple, as yesterday's technology was must less complicated.

I assumed they were modern devices. If they are 20ish years old and digital then they are probably PLAs and having worked with 20V10s (or something like that) some 25 years ago I still don't fancy your chances.

But, I like your sentiment and I too would spend many hours (days) fixing an old instrument. Because, you just have to.

Mike.

 

[BrownOut]

I fail to see what the problem might be??? Modern CLPD's are easy to program, and have enough gates to reproduce most any function that would be performed by old IC's. The whole process of trouble shooting and repairing might be considered reverse engineering, and I've found these circuits very easy to analyze and repair. The only roadblock would seem to be working voltages. That might be solved by using miniture surface mount components.

And yes, I was talking about older instruments. My last repair was a tek 465 with a triggering problem. The signal path included an IC which appeared to be little more than a multiplexer. It would be interesting, and a good exercise, to try to replace it, had there been a problem with it. My lab might rightly be considered an electronic instrument museum. Although I have more modern instruments, the ancient ones are right along side them.

 

[Hero999]

I was reading a thread about repairing a Tek scope recently, and a number of members were warning about tek's use of proprietary ( now obsolete ) IC's in their products. I recently repaired of of these scopes, and was fortunate enough to not need one of these devices. Anyway, I was wondering about the possibility of using a PIC or CPLD in place of some of these IC's. One might even be able to ascertain the chip's function by analyzing the circuitry around it, or by probing a working unit. Has anyone ever tried this? What were the results?

Please post a link to the thread?

Was it the one with the matched jugfet pair, I managed to find a substitute for?

 

[BrownOut]

Please post a link to the thread?

Was it the one with the matched jugfet pair, I managed to find a substitute for?

Um no. It was somewhere in this thread. BTW, I forgot to mention that FPGA ( and maybe CPLD's ) have I/0's that are programmable to many different interface standards, extending the technologies with with they can be interfaced. Also, my Xilinx development system arrived in the mail last week. I'll report on it after I've had a change to connect and at least look at some of the demo designs.