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| Just got a Tek 2465A, couple questions (how I screwed the calibration data)!! |
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| usuthu65:
Hello, I happen to have a still functioning 2465A. A safety-copy video with the Exerciser 02 data is here: https://photos.app.goo.gl/g5OUIetQAZVJYZfs2 Sorry that I don't have time to transcribe it but you can pick it off the video. By the way, I don't have any illusions this scope is still even close to being in calibration so I'm planning in the future to get one done. I suggest you budget for one as well. Chuck Harris would be a go-to person for the task and he has all the right gear. Good luck! |
| alpher:
Thanks Phil, much appreciated. I will transcribe your data and post it later. For most of the evening I've been fighting my programmer (wellon vp480) trying to program the SRAM in the scope, so far no-go. :( It errors out after only a dozen bytes or so, I suspect that the loading on CE2 and/or OE maybe even vcc is too high, may have to cut some traces to isolate the chip. Have to dig into uPD4464 datasheet. :( Anybody has a good suggestion as to what chip to use as a template during write? I've trried dallas ds1225Y, no go even if I slow down the cycle to 1mS, in desperation I even tried to program it as a 28C64 EEPROM :) . Somehoe the geniuses at wellon didn't think that writing and reading SRAM can be useful. The chip is listed as supported but the read button is grayed out and the write button doesn't actually write the buffer data but performs a test of some sort, damn. >:( |
| alpher:
--- Quote from: usuthu65 on March 29, 2018, 02:05:01 am ---Hello, I happen to have a still functioning 2465A. A safety-copy video with the Exerciser 02 data is here: https://photos.app.goo.gl/g5OUIetQAZVJYZfs2 Sorry that I don't have time to transcribe it but you can pick it off the video. By the way, I don't have any illusions this scope is still even close to being in calibration so I'm planning in the future to get one done. I suggest you budget for one as well. Chuck Harris would be a go-to person for the task and he has all the right gear. Good luck! --- End quote --- Thanks again usuthu65, here's your data copied to hex. Hope there are no errors there, it took me a couple of hours. --- Code: ---Offset(h) 00 02 04 06 08 0A 0C 0E 00000000 00CD 06DC 26DB 06C1 268B 265A 06FD 270E 00000010 2702 06F8 06E3 21BA 01C5 21C4 21C1 01DB 00000020 01F3 0203 2204 2202 221A 2081 001C 001A 00000030 001F 201E 1BE3 3D44 1CAC 1D25 1FAC 1FC6 00000040 3FAD 3FA7 1FBD 0247 0247 2237 0242 3CB0 00000050 1E0D 1CF6 1000 3FAD 1FA6 3FB0 1F9F 3FB5 00000060 22E3 22E3 22E0 02DE 071B 084E 283B 282C 00000070 281F 083A 0828 205F 2849 2832 282A 281C 00000080 082E 281C 2060 2344 0331 2330 266C 0654 00000090 266A 0679 229E 22D0 1815 2ED0 0E9C 2726 000000A0 2725 020F 222F 214C 2132 0444 2633 03B3 000000B0 0331 049A 246E 236C 2514 27FE 27FE 27FE 000000C0 039E 059D 03A2 22F1 248A 06F8 0568 2770 000000D0 079F 26EE 27FE 02DD 00BC 00C1 20A5 005F 000000E0 5301 8CFA DC07 A720 5BE5 6556 FA65 188A 000000F0 FA00 40FF FF20 00DE FBC0 009E E620 18AF 00000100 EFC7 23CF B40E EDEA 7130 889E DC52 47DD 00000110 FF31 30FF DB00 86DE F7B2 5CF9 DF24 40F6 00000120 B24B 8E8C FAFC ED7B D91D 83E7 6D81 E1A0 00000130 EF10 6031 FC04 687A FF08 007E DB0A 04DD 00000140 BB24 82D7 EC33 0AD7 2E95 23EC 5F3F 44F1 00000150 B300 01FF 2501 A4F7 3D03 027F FD15 00DF 00000160 22C9 AB16 D60C 0A2B E525 84D5 D241 9E9D 00000170 FF04 00D9 6F1A D5FD 6302 70FD DB80 027D 00000180 86DA 4A9D F656 EED9 A40D 0EC9 BBE2 9CDF 00000190 7218 13FF 7D08 18BB E708 10FE 6D85 20F7 000001A0 EC2A 9C60 F443 0EDC BC6E C59A 873F A2A6 000001B0 FD80 6493 7F01 6963 FB86 0C3F E718 80DF 000001C0 C1A0 C4CF 2588 0553 7351 03FB DF23 A734 000001D0 FF42 44FF DF08 41FF DD80 9186 9F91 04B7 000001E0 E349 A5C4 C1AB 7D0B 3746 429D 7019 E5D3 000001F0 FF84 4EBF FF10 25FF FD04 81BF 1AFE 0000 --- End code --- And here's a full image with your constants inserted. |
| alpher:
OK, I read the 4464 datasheet again, didn't discover anything unusual. Except maybe a small detail, under "Low Vcc Data Retention " heading noticed that they somehow insist that "CE2 must be equal to or higher that Vcc-0.2V, or less that 0.2V " while the "normal" Vih calls for just over half of Vcc. I also noticed that there are 2 resistors 680omhs each in series pulling CE2 to the ground, since I'm feeding it to the Vcc through 1K no wonder that CE2 stays just below 4 Volts. Wonder, should I just short the CE2 to Vcc or cut the trace? |
| MarkL:
--- Quote from: alpher on March 29, 2018, 02:09:05 pm ---... Wonder, should I just short the CE2 to Vcc or cut the trace? --- End quote --- It looks like shorting CE2 to Vcc should be ok. I don't see anything pulling it down except R2470 and R2471. Maybe go to 100 ohms or whatever value gets you above Vcc-0.2V. I'm not a fan of shorting stuff. |
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