Yes. When I was younger my father acquired three 9825s from his employer at a microwave manufacturer. They closed the plant and were cleaning out the lab. I remember they had those processors in that calculator just like the 3585A. I took them all apart, because that’s what I did when I was 10 but I wish I had them now. CuriousMarc has some great videos on those calculators, brought back a lot of memories seeing the insides again. Thanks for the comment.
I noticed the banding while looking at the diagrams, you might want to try changing your camera frame rate to match your mains line frequency to avoid that, so if you are on 60Hz try using 30fps
Yeah sorry about that. For some reason my video was recording in slow motion during the first half of recording. Not really sure why but luckily I was able to revert it to normal speed without having to redo the video. I’m thinking that is probably the reason for the shifting in the first half of the video. I haven’t had that issue before. Thanks for the comment.
I originally suspected the Op amp as well. I did some off camera testing of the board and fed a small negative polarity voltage into the feedback line. I had the board connected in the SA and powered on, with the local fuse pulled to isolate drive to the FBT. I was able to get a normal response from the op amp with a simulated voltage error so I ruled that out. It’s a shame because that repair would’ve been a lot easier on the wallet.
Adding some details on this: It is the year that manufacturing for this specific hardware version started. The device itself might have been made that same year too but it could also be sometime later. Those digits are generally changed only with a new main version which might have been produced several years later, if it exists at all. 2 devices with the same number does not guarantee identical devices but these will be very close. Some service manuals provide more information about specific serial numbers. Inscriptions on the components inside can provide an indication on year of manufacturing.
Thanks for the information. I did some date coding on my original 3585 just going off some of the logic chips and it put the unit date inline with the serial number. I believe it’s the first two numbers added to 60 so 29 would date it, as you said, to 1989. I didn’t validate the date of the parts unit. Maybe I’ll have a look next time I’m in it. Thanks for the comment.
I’ve had a more in-depth look at the parts unit. The A14, which I somehow overlooked the glaring “bad” written on the chassis, has several caps missing. Not terrible to replace but I suspect other parts might be missing also. As for now it will be a parts unit. I have managed to acquire another A65 assembly though so who knows. Maybe I’ll tackle a repair on the parts 3585. Don’t know what I’d do with two of them though. Thanks for the comment.
Hey. We found your videos so rewarding, and were wondering if any prototype services may help? Such as custom PCBs, 3DP, CNC etc. If so, would love to supply freely and reach any YT collab together! (PCBWay luz)
I believe the CPU in the 3585A is the same one used in the 9825 computer. The 3585B uses a 10MHz 68000.
Yes. When I was younger my father acquired three 9825s from his employer at a microwave manufacturer. They closed the plant and were cleaning out the lab. I remember they had those processors in that calculator just like the 3585A. I took them all apart, because that’s what I did when I was 10 but I wish I had them now. CuriousMarc has some great videos on those calculators, brought back a lot of memories seeing the insides again. Thanks for the comment.
I noticed the banding while looking at the diagrams, you might want to try changing your camera frame rate to match your mains line frequency to avoid that, so if you are on 60Hz try using 30fps
Yeah sorry about that. For some reason my video was recording in slow motion during the first half of recording. Not really sure why but luckily I was able to revert it to normal speed without having to redo the video. I’m thinking that is probably the reason for the shifting in the first half of the video. I haven’t had that issue before. Thanks for the comment.
@27:00 I would be suspecting the op amp.
I originally suspected the Op amp as well. I did some off camera testing of the board and fed a small negative polarity voltage into the feedback line. I had the board connected in the SA and powered on, with the local fuse pulled to isolate drive to the FBT. I was able to get a normal response from the op amp with a simulated voltage error so I ruled that out. It’s a shame because that repair would’ve been a lot easier on the wallet.
The serial number starting in 29 means it was made in 1989, in case you didn’t know that.
Adding some details on this: It is the year that manufacturing for this specific hardware version started. The device itself might have been made that same year too but it could also be sometime later. Those digits are generally changed only with a new main version which might have been produced several years later, if it exists at all. 2 devices with the same number does not guarantee identical devices but these will be very close. Some service manuals provide more information about specific serial numbers. Inscriptions on the components inside can provide an indication on year of manufacturing.
Thanks for the information. I did some date coding on my original 3585 just going off some of the logic chips and it put the unit date inline with the serial number. I believe it’s the first two numbers added to 60 so 29 would date it, as you said, to 1989. I didn’t validate the date of the parts unit. Maybe I’ll have a look next time I’m in it. Thanks for the comment.
2nd Anode on CRT
Great to it back to life...as for the new unit, will you repair it or as a donor unit?
I’ve had a more in-depth look at the parts unit. The A14, which I somehow overlooked the glaring “bad” written on the chassis, has several caps missing. Not terrible to replace but I suspect other parts might be missing also. As for now it will be a parts unit. I have managed to acquire another A65 assembly though so who knows. Maybe I’ll tackle a repair on the parts 3585. Don’t know what I’d do with two of them though. Thanks for the comment.
Hey. We found your videos so rewarding, and were wondering if any prototype services may help? Such as custom PCBs, 3DP, CNC etc. If so, would love to supply freely and reach any YT collab together! (PCBWay luz)
Thank you for the kind offer. I will certainly keep you in mind as I plan future projects.
Salve. Non ne vende uno?😂