Hi eslapion,
Thank you for the videos on selecting an oscilloscope. I think I will buy one of these newer style units. They have more capabilities than the older ones.
I went down to the electronics store and saw the oscilloscope.
It truly was a beautifully made machine. I managed to get it for $150 AUD. Cosmetically, it is in mint condition, nothing broken scratched or missing. It has a small vinyl storage pouch on the top. There doesn't appear to be any phosphor burn in on the tube.
It has a very detailed user manual in great condition and it has detailed service records where it was serviced at the Australian Tektronics service center. A real find!
It comes up with errors. I did some online research and it seems to point to the fact that the battery backup is flat.
A new battery should help keep the calibration data going when the machine is off. A self calibration run should clear up some of the errors. I think an external one is required with a bench power supply.
I opened it up and I clipped the battery off the PCB. Fairly easy, there was a later model that used RAM chips with the battery potted on to it (Dallas DS1235 32Kx8 NVRAM module).
I ordered a newer contemporary part a 1/2AA size lithium thionyl chloride cylindrical 14250 battery, 3.6V high energy battery with soldering pins. Saft brand. Capacity: 1200mAh slightly lower than the original. It should be here in a few weeks.
I will let you know how it goes.....
Yesterday I got a delivery from China of 8 pairs of various 27C512 E/E/PROMS.
I haven't had the time to check all the chips.
This chip passes eslapion's PLA test circuit. It is a knockoff (fake),
Interestingly , I took some comparison photos of these chips with the genuine ST 27C512-90F1 from the electronics store.
Notice that the knockoff (fake) chips have a different manufacturing process to the genuine one. The genuine die is maybe 2-3 times smaller that the knockoff (fake) ones.
ST 27C512-90F1 B88AY 9605C SINGAPORE knockoff UV EPROM.
Genuine ST 27C512-90F1 vs ST 27C512-90F1 B88AY 9605C SINGAPORE knockoff
Genuine ST 27C512-90F1 vs ST 27C512-90F1 B88AY 9605C SINGAPORE knockoff
ST 27C512-90F6 5880X 9806E SINGAPORE knockoff vs Genuine ST 27C512-90F1