TL;DR: Is it okay to socket an IC which amplifies signals up in the 20-30 MHz range?
I'm working on the repair of a 3325A function generator, which I obtained as "does not power on".
Imagine my surprise when I was probing around, and all of a sudden the thing comes to life. It turns out that several mounting screws were missing on the PSU assembly. One of the screws is needed to complete the ground path through the chassis. Another issue with the power supply was the leads on one of the pass transistors had broken off. That's fixed now.
After that was said and done, I noticed the unit did not produce and output signal. Not only that, it would happily display the following errors:
- FAIL 1
- FAIL 2
- FAIL 3
- ACAL FAIL
At this point, I'm freaking out. There's got to be a lot of stuff broken, and I'll probably never be able to get this fixed. So I follow through the service manual, get to the function circuits (section J) troubleshooting, and there's no input signal into the circuit. At that point I'm stuck, and I start following any troubleshooting procedure that didn't look like a complete wild goose chase. Every procedure says the respective circuit is good.
I finally get to the frequency mixer, and after a week of probing around there, I track the problem to the output amplifier IC: signal goes in, signal doesn't come out. It's one of those dreaded CA3000 transistor arrays, doped with Unobtainium. I pull the IC off the board, and much to my chagrin, the BC junction of one of the transistors is open.
TL:DR: When I do these sort of repairs, I like to put a socket instead of soldering the new IC directly. It saves the PCB from more thermal shocks if the component ever needs to be replaced again. In this case though, the signal has harmonics in the 30MHz range, and I'm not sure how much those signals like IC sockets. I'd really like to put in a socket, but I'm afraid that it might affect the performance of the instrument. Do you think it would be safe to use a socket in this case?
Schematic of the section attached below. Failing IC is U15. It's a CA3127E.